Filed Pursuant to Rule 424(b)(5)
Registration No.: 333-225391

PROSPECTUS SUPPLEMENT (To Prospectus dated June 19, 2018)

9,000,000 Shares

Common Stock

We are offering 9,000,000 shares of our common stock. Our common stock is listed on The Nasdaq Global Select Market under the symbol “OVID.” On October 3, 2019, the last reported sale price of our common stock was $3.27 per share.

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-10 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement and the accompanying prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement and the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Concurrently with this offering of common stock, and pursuant to a separate prospectus supplement, we are offering 4,000 shares of our Series A convertible preferred stock, or the Series A preferred stock, (and the shares of common stock issuable from time to time upon conversion of the Series A preferred stock), which we refer to herein as the Concurrent Offering.

	Per Share		Total
Public offering price	$	2.50	$	22,500,000
Underwriting discounts and commissions(1)	$	0.15	$	1,350,000
Proceeds, before expenses, to us	$	2.35	$	21,150,000

(1) See “Underwriting” for a description of compensation payable to the underwriters.

Delivery of the shares of common stock in this offering is expected to be made on or about October 8, 2019.

Entities affiliated with Takeda Pharmaceutical Company Limited, or Takeda, our collaboration partner and existing stockholder, entities affiliated with Biotechnology Value Fund, L.P., or BVF, an existing stockholder, entities affiliated with Shira Capital, LLC, or Shira, an existing stockholder, and Dr. Jeremy M. Levin, our Chief Executive Officer and Chairman, have indicated an interest to purchase up to an aggregate of $14.3 million of the shares offered hereby and in the Concurrent Offering, in the aggregate. However, because these indications of interest are not binding agreements or commitments to purchase, such stockholders or their affiliates may elect to purchase fewer shares or not purchase any shares in this offering or in the Concurrent Offering. In addition, the underwriters may determine to sell more, fewer or no shares in this offering or in the Concurrent Offering to such stockholders or their affiliates.

We have granted the underwriters an option for a period of 30 days to purchase up to 1,350,000 additional shares of our common stock from us at the public offering price, less the underwriting discounts and commissions.

Joint Book-Running Managers

Cowen William Blair

Co-Managers

JMP Securities Ladenburg Thalmann

The date of this prospectus supplement is October 4, 2019.

TABLE OF CONTENTS

Prospectus Supplement

ABOUT THIS PROSPECTUS SUPPLEMENT	S-ii
PROSPECTUS SUPPLEMENT SUMMARY	S-1
RISK FACTORS	S-10
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	S-13
USE OF PROCEEDS	S-15
DILUTION	S-16
UNDERWRITING	S-18
LEGAL MATTERS	S-23
EXPERTS	S-23
WHERE YOU CAN FIND MORE INFORMATION	S-23
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	S-24
Prospectus
ABOUT THIS PROSPECTUS	i
SUMMARY	1
RISK FACTORS	7
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	8
RATIO OF EARNINGS TO FIXED CHARGES	10
USE OF PROCEEDS	11
DESCRIPTION OF CAPITAL STOCK	12
DESCRIPTION OF DEBT SECURITIES	18
DESCRIPTION OF WARRANTS	25
LEGAL OWNERSHIP OF SECURITIES	27
PLAN OF DISTRIBUTION	31
LEGAL MATTERS	32
EXPERTS	32
WHERE YOU CAN FIND MORE INFORMATION	33
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	33

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is part of a “shelf” registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, and is in two parts. The first part is this prospectus supplement, which describes the specific terms of this common stock offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein. The second part, the accompanying prospectus, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement and the information contained in the accompanying prospectus or any document incorporated by reference therein filed prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement; provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference herein were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

Neither we nor the underwriters have authorized anyone to provide any information other than that contained or incorporated by reference in this prospectus supplement or in the accompanying prospectus. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. This prospectus supplement and the accompanying prospectus do not constitute an offer to sell, or a solicitation of an offer to purchase, the securities offered by this prospectus supplement and the accompanying prospectus in any jurisdiction to or from any person to whom or from whom it is unlawful to make such offer or solicitation of an offer in such jurisdiction. The information contained in this prospectus supplement or the accompanying prospectus, or incorporated by reference herein or therein is accurate only as of the respective dates thereof, regardless of the time of delivery of this prospectus supplement and the accompanying prospectus or of any sale of our common stock. It is important for you to read and consider all information contained in this prospectus supplement and the accompanying prospectus, including the documents incorporated by reference herein and therein, in making your investment decision. You should also read and consider the information in the documents to which we have referred you in the sections entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” in this prospectus supplement and in the accompanying prospectus.

We are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the common stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe any restrictions relating to, the offering of the common stock and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

Unless the context indicates otherwise, references in this prospectus to “Ovid,” “the Company,” “we,” “us,” “our” and similar references refer to Ovid Therapeutics Inc. and its wholly owned subsidiaries.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights selected information contained elsewhere in this prospectus supplement and the accompanying prospectus and in the documents we incorporate by reference. This summary does not contain all of the information you should consider before investing in our common stock. You should read this entire prospectus supplement and the accompanying prospectus carefully, especially the risks of investing in our common stock discussed under the section titled “Risk Factors” in this prospectus supplement and under similar headings in our Annual Report on Form 10-K for the year ended December 31, 2018 and in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2019, which are incorporated by reference in this prospectus supplement, along with our consolidated financial statements and notes to those consolidated financial statements and the other information incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment decision.

Company Overview

We are a late-stage clinical biopharmaceutical company focused exclusively on developing impactful medicines for patients and families living with rare neurological disorders. We believe these disorders represent an attractive area for drug development as the understanding of the underlying biology has grown meaningfully over the last few years and only now is being appreciated by the industry. Our experienced team began with a vision to integrate the biology and symptomology of rare neurological conditions to employ innovative research and clinical strategies for the development of our drug candidates. Based on recent scientific advances in genetics and the biological pathways of the brain, we created a proprietary map of disease-relevant pathways and used it to identify and acquire novel compounds for the treatment of rare neurological disorders. We are also building a deep knowledge of the diseases and the clinically meaningful endpoints required for development of a compound in these rare neurological disorders. We continue to execute on our strategy by in-licensing and collaborating with leading biopharmaceutical companies and academic institutions. We have developed a robust pipeline of first-in-class and only-in-class clinical assets with an initial focus on neurodevelopmental disorders and developmental and epileptic encephalopathies, or DEE.

The following table sets forth the status and mechanism of action of our product candidates and key milestones expected within the next 12 months:

Our most advanced drug candidate is OV101 (gaboxadol). Our development plan for OV101 highlights our ability to translate new scientific and clinical insights into drug candidates. We believe

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that OV101 modulates tonic inhibition, an important physiological process in the brain that has been identified as a potential central cause of the symptoms seen in a number of disorders of the brain. Disruption of tonic inhibition can lead to a multiplicity of symptoms including, but not limited to, motor deficiencies, sleep abnormalities, behavioral manifestations, delayed development, intellectual disability and severe speech impairment. We believe modulating tonic inhibition may have a meaningful clinical impact in patients with Angelman syndrome and Fragile X syndrome. We have successfully completed a Phase 2 trial of OV101 in adults and adolescents with Angelman syndrome, which we refer to as the STARS clinical trial. As previously announced, the STARS clinical trial achieved its primary endpoint of safety and tolerability and showed statistically significant improvement in the once-daily OV101 dosing group on the pre-specified physician-rated Clinical Global Impressions-Improvement, or CGI-I, exploratory endpoint as well as improvements in relevant symptoms such as sleep, motor function and behavior. Following discussion of the STARS clinical trial with the U.S. Food and Drug Administration, or FDA, and German regulatory authorities, we designed and initiated a pivotal Phase 3 clinical trial in OV101 for Angelman syndrome in June 2019, which we refer to as the NEPTUNE clinical trial. In September 2019, we announced that the first patient had been randomized in NEPTUNE, and we expect to report data from this trial by mid-2020. There are no other drug candidates in clinical development, or drugs approved, for treatment of Angelman syndrome.

We also are currently conducting a Phase 2 trial evaluating OV101 in adolescent and young male adults with Fragile X Syndrome, which we refer to as the ROCKET clinical trial. The primary endpoint of ROCKET is safety and tolerability of OV101 over 12 weeks of treatment in three different cohorts of either 5mg once daily, 5mg twice daily or 5mg three times daily. A secondary efficacy endpoint evaluates changes in behavior during 12 weeks of treatment with OV101 using the Activities-specific Balance Confidence Scale that has been used in previous trials for Fragile X syndrome. We expect to report data from ROCKET in early 2020.

In addition, we are in a joint collaboration with Takeda to develop and commercialize TAK-935, which we have licensed from Takeda and refer to as OV935 (soticlestat). We believe that OV935’s inhibition of the cholesterol metabolism pathway in the brain may modulate the excitatory signals involved in epilepsy, which may suppress seizures. In addition to these effects on seizures and excitability of the brain, we believe that OV935 may reduce inflammation in and neurotoxic damage to the brain, which may lead to long-term, disease modifying effect. As a result, we are targeting rare and difficult to treat epilepsies with the goal to develop OV935 not just as a potential medicine to treat the seizures but also one that may conceivably heal the brain. We are initially studying OV935 for those suffering from severe and often intractable forms of DEE, including Dravet syndrome, Lennox-Gastaut syndrome, or LGS, and CDKL5 Deficiency Disorder and Duplication 15q syndrome. Each of these disorders either has limited or no therapeutic options. We completed a Phase 1b/2a clinical trial of OV935 in a heterogeneous group of adults with DEE and announced the results in December 2018. The trial achieved its primary endpoint of safety and tolerability, dose proportional reduction in a potential plasma biomarker called 24HC, and a robust reduction in seizure frequency (61% at day 92) with two patients becoming seizure-free at the end of the treatment period. Following this trial and as further discussed below, we reported the initial data from the ENDYMION Phase 2 open-label extension study of OV935 in six patients who previously completed our 12-week Phase 1b/2a clinical trial of OV935 in adults with DEE. OV935 is currently in multiple Phase 2 clinical trials and we expect to report data in these trials in 2020. The FDA has granted orphan drug designation for OV935 for the treatment of Dravet syndrome and LGS.

Additionally, Takeda elected to initiate a placebo-controlled trial of TAK-935 to treat patients with chronic complex regional pain syndrome, or CRPS. This trial will look at the efficacy, safety and tolerability of TAK-935 as an adjunctive therapy in participants with CRPS. Pursuant to our agreement

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with Takeda, we have a one-time right to opt into this program but we are not responsible for funding this trial.

Recent Clinical Developments

OV935

ENDYMION

The ENDYMION clinical trial is a prospective, multi-center, open-label extension study of OV935 in patients with DEE who have participated in a previous OV935 clinical trial. The primary objective is to assess the long-term safety and tolerability of OV935 over two years of treatment in patients with rare epilepsies. A secondary endpoint will evaluate the effect of OV935 on seizure frequency over two years.

On September 23, 2019, we announced initial data from ENDYMION. This data includes six patients who previously completed our 12-week Phase 1b/2a clinical trial of OV935 in adults with DEE. As shown in Table 1, longer-term data from ENDYMION out to 48 weeks suggest increased seizure reduction with prolonged treatment of OV935 and is consistent with the believed mechanism of action of OV935. Median seizure frequency reductions were 84% following 25 to 36 weeks (n=6) and 90% following 37 to 48 weeks (n=4) of treatment.

Table 1: % Reduction from Baseline in Seizure Frequency

	Weeks 1-12	Weeks 13-24	Weeks 25-36	Weeks 37-48
Overall median % reduction in seizure frequency from baseline	48% (n=6)	65% (n=6)	84% (n=6)	90% (n=4)*
% of Patients with ³50% reduction in seizure frequency from baseline	50%	50%	67%	75%

* At the time of data analysis, two patients had not yet completed 48 weeks of dosing.

Patient baseline seizure frequency ranged from 2 to 71 (median=11.5). In general, a greater reduction in seizure frequency was observed in those with higher baseline seizure frequency. In terms of overall seizure-free interval during treatment, one patient experienced 264 consecutive days and one patient experienced 150 consecutive days without a seizure.

In addition to the six patients from the Phase 1b/2a adult DEE trial included in this data analysis, all patients who have completed the ARCADE and ELEKTRA trials to date have enrolled in ENDYMION. Data from patients who have completed ARCADE, our Phase 2, multi-center, open-label, pilot study evaluating the treatment of OV935 in patients with epileptic seizures associated with CDKL5 Deficiency Disorder or Duplication 15q syndrome, are not included the above analysis due to their limited treatment duration in ENDYMION. Data from patients previously treated in ELEKTRA are not included in the above analysis due to the ongoing trial being double-blinded and placebo-controlled.

Overall, at 48 weeks, safety observations were consistent with the completed Phase 1b/2a clinical trial in adults with DEE. OV935 continues to show a favorable safety and tolerability profile. The majority of adverse events were mild and comparable with those from the Phase 1b/2a trial. Specifically, adverse events that occurred included upper abdominal pain, pyrexia, bronchial wall thickening and rales. There was one treatment-related adverse event of nausea. No serious adverse events were observed.

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ELEKTRA

Our ELEKTRA clinical study is an international Phase 2, multi-center, randomized, double-blind, placebo-controlled study that will evaluate the treatment of OV935 in approximately 126 pediatric patients, aged two to 17 years, with epileptic seizures associated with Dravet syndrome or LGS. The trial consists of a four- to six-week screening period to establish baseline seizure frequency followed by a 20-week treatment period that includes an eight-week dose titration period and a 12-week maintenance period. The primary endpoint is the change from baseline in seizure frequency in patients treated with OV935 compared to placebo by disorder (Dravet and LGS). The secondary endpoints include safety, tolerability and pharmacokinetics assessments as well as the percentage of patients considered treatment responders, changes in Clinician’s Clinical Global Impressions of Severity and Change and correlation of OV935 concentration with plasma 24HC levels. In September 2019, we announced that enrollment in ELEKTRA has been proceeding at a more rapid rate than anticipated, and we now expect to report topline results from ELEKTRA by the second half of 2020, approximately six to eight months earlier than originally anticipated. We attribute the strong enrollment to high interest in the trial from multiple sites across the globe. Upon the completion of ELEKTRA, patients are eligible to enroll in the ENDYMION open-label extension trial.

OV101

NEPTUNE

In September 2019, we enrolled our first patient in our NEPTUNE clinical study, which is a pivotal Phase 3 clinical trial of OV101 in pediatric patients with Angelman syndrome. NEPTUNE is a single 12-week, two-arm, randomized, double-blind, placebo-controlled trial with a once-daily, weight-based dose of OV101 with expected enrollment of approximately 60 patients aged four to 12 years and a few patients aged two to three years. Similar to the initial endpoint for the STARS clinical study, the primary and sole endpoint of NEPTUNE is the change in the overall Angelman syndrome-specific CGI-I score at 12 weeks versus baseline between the OV101 and placebo groups.

We designed NEPTUNE based upon feedback from our End of Phase 2 meeting with the FDA in November 2018, a scientific advice meeting with the German regulatory authority (BfArM) in April 2019, and a second FDA Type C guidance meeting in May 2019. The design is also based on the results of the STARS clinical study that showed, among other data, a statistically significant improvement (p = 0.0006) on the CGI-I scale at 12 weeks for the once-daily dosing versus placebo.

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The NEPTUNE trial design is provided in the table below:

Objectives	Trial design
Primary endpoint: CGI-I-AS at week 12 of OV101 vs placebo. Secondary endpoint: ∎   Sleep measures ∎   Communication, motor skills, socialization, daily living skills, and maladaptive behavior domains, as assessed by the Vineland Adaptive Behavior Scale 3rd edition ∎   Change in CGI-S-AS Symptoms Overall	∎   Randomized, double-blond, Phase 3 study based on FDA feedback ∎   Up to 15 sites on United States, Israel, Australia and Europe ∎   Approximately 60 subjects (ages 4 -12 years) ∎   Approximately 5 subjects ages 2-3 years for safety only ∎   95% powered to detect a 0.8 difference in CGI-1-AS

STARS

We conducted a post hoc analysis of the data from our STARS clinical study which demonstrated that the study subjects in the once-daily dosing group of OV101 showed (i) improvements on the CGI-I scale increasing over time at 6 weeks and 12 weeks for the once-daily dosing group versus placebo, and (ii) improvements on the CGI-I scale being more robust in younger patients for the once-daily dosing group at 12 weeks. As depicted in the figures below, the data suggest that younger patients who received a once-daily dose had the greatest response to OV101 compared to older age groups.

For more information on these and our other clinical development programs, please see the business section in Item 1 of our Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on March 7, 2019 and our other SEC filings incorporated by reference into this prospectus supplement and accompanying prospectus.

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Financial Update

As of September 30, 2019, we had approximately $37.9 million of cash, cash equivalents and short-term investments. This amount is unaudited and preliminary, and does not present all information necessary for an understanding of our financial condition as of September 30, 2019. The review of our unaudited condensed consolidated financial statements for the three months ended September 30, 2019 is ongoing and could result in changes to this amount. Our unaudited condensed consolidated financial statements for the three months ended September 30, 2019 will not be available until after this offering is completed, and consequently will not be available to you prior to investing in this offering.

Corporate Information

We were incorporated in Delaware in April 2014. Our principal executive offices are located at 1460 Broadway, Suite 15044, New York, New York 10036 and our telephone number is (646) 661-7661. Our corporate website address is www.ovidrx.com. Information contained on or accessible through our website is not incorporated by reference into this prospectus supplement and the accompanying prospectus.

Our name “Ovid Therapeutics,” the Ovid logo, BoldMedicine and other trademarks, trade names or service marks of Ovid Therapeutics Inc. appearing in this prospectus supplement and the accompanying prospectus are the property of Ovid Therapeutics Inc. All other trademarks, trade names and service marks appearing in this prospectus supplement and the accompanying prospectus are the property of their respective owners. Solely for convenience, the trademarks and trade names in this prospectus supplement and the accompanying prospectus are referred to without the ^® and ^™ symbols, but such references should not be construed as any indicator that their respective owners will not assert their rights thereto.

Implications of Being an Emerging Growth Company

We qualify as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. An emerging growth company may take advantage of specified reduced disclosure and other requirements that are otherwise applicable generally to public companies. Some of these exemptions include:

∎ only two years of audited financial statements, in addition to any required unaudited interim financial statements, with correspondingly reduced “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure;

∎ not being required to comply with the auditor attestation requirements in the assessment of our internal control over financial reporting; and

∎ reduced disclosure obligations regarding executive compensation in our periodic reports, proxy statements and registration statements.

We will remain an emerging growth company until the earlier of (1) December 31, 2022, (2) the last day of the fiscal year in which we have total annual gross revenue of at least $1.07 billion, (3) the last day of the fiscal year in which the market value of our common stock that is held by non-affiliates exceeds $700 million as of the prior June 30th, and (4) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period. We have chosen to take advantage of some but not all of these available exemptions. We have irrevocably elected not to avail ourselves of delayed adoption of new or revised accounting standards and, therefore, we will be subject to the same requirements to adopt new or revised accounting standards as other public companies that are not emerging growth companies.

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Concurrent Offering of Series A Preferred Stock

Concurrently with this offering of common stock, we are offering 4,000 shares of our Series A preferred stock (and the 4,000,000 shares of common stock issuable from time to time upon conversion of the Series A preferred stock), which we refer to as the Concurrent Offering. The Concurrent Offering is being conducted as a separate public offering by means of a separate prospectus supplement. This offering is not contingent upon the completion of the Concurrent Offering and the Concurrent Offering is not contingent upon the completion of this offering. We cannot assure you that either or both of the offerings will be completed.

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THE OFFERING

Common stock to be offered by us 9,000,000 shares

Option to purchase additional shares from us We have granted the underwriters an option for a period of 30 days to purchase up to 1,350,000 additional shares of our common stock from us at the public offering price, less the underwriting discounts and commissions.

Common stock to be outstanding immediately following this offering 47,693,018 shares (or 49,043,018 shares if the underwriters’ option to purchase additional shares from us is exercised in full)

Use of proceeds We currently intend to use the net proceeds from this offering and the Concurrent Offering, together with other available funds, primarily to advance: (1) the clinical development program of OV101 for Angelman syndrome and Fragile X syndrome, and (2) the clinical development program of OV935 for DEEs. We intend to use the remainder of the net proceeds for working capital and general corporate purposes. See “Use of Proceeds.”

Risk factors An investment in our common stock involves a high degree of risk. See the section titled “Risk Factors” in this prospectus supplement and under similar headings in the other documents that are incorporated by reference herein and therein.

Concurrent offering Concurrently with this offering, we are offering 4,000 shares of our Series A preferred stock (and 4,000,000 shares of common stock issuable from time to time upon conversion of the Series A preferred stock). The Concurrent Offering is being conducted as a separate public offering by means of a separate prospectus supplement. This offering is not contingent upon the completion of the Concurrent Offering and the Concurrent Offering is not contingent upon the completion of this offering.

Nasdaq Global Select Market symbol “OVID”

Entities affiliated with Takeda, our collaboration partner and existing stockholder, entities affiliated with BVF, an existing stockholder, entities affiliated with Shira, an existing stockholder, and Dr. Jeremy M. Levin, our Chief Executive Officer and Chairman, have indicated an interest to purchase up to an aggregate of $14.3 million of the shares offered hereby and in the Concurrent Offering, in the aggregate. However, because these indications of interest are not binding agreements or commitments

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to purchase, such stockholders or their affiliates may elect to purchase fewer shares or not purchase any shares in this offering or in the Concurrent Offering. In addition, the underwriters may determine to sell more, fewer or no shares in this offering or in the Concurrent Offering to such stockholders or their affiliates.

The number of shares of our common stock to be outstanding immediately after this offering is based on 38,693,018 shares of our common stock outstanding as of June 30, 2019, and excludes:

∎ 5,916,944 shares of our common stock issuable upon the exercise of stock options outstanding as of June 30, 2019 under our 2014 Stock Plan, as amended, or 2014 Plan, and our 2017 Equity Incentive Plan, or 2017 Plan, at a weighted average exercise price of $6.36 per share;

∎ 3,688,116 shares of common stock reserved for future issuance under our 2017 Plan, plus any additional shares of our common stock that may become available under our 2017 Plan;

∎ 694,432 shares of our common stock reserved for issuance under our 2017 Employee Stock Purchase Plan, or ESPP, as well as any future increases in the number of shares of our common stock reserved for issuance under the ESPP;

∎ 2,500,000 shares of our common stock issuable upon the conversion of 2,500 shares of Series A preferred stock outstanding as of June 30, 2019; and

∎ 4,000,000 shares of our common stock issuable upon conversion of Series A preferred stock being offered by us in the Concurrent Offering.

Except as otherwise indicated, the information in this prospectus supplement assumes no exercise of the outstanding stock options, no conversion of the outstanding Series A preferred stock and no exercise by the underwriters of their option to purchase additional shares.

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RISK FACTORS

An investment in our common stock involves a high degree of risk. Before deciding whether to invest in our common stock, you should carefully consider the risks described below and those discussed under the section titled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2018 and in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2019, which are incorporated by reference in this prospectus supplement and the accompanying prospectus, together with other information in this prospectus supplement, the accompanying prospectus, the information and documents incorporated by reference herein and therein, and in any free writing prospectus that we have authorized for use in connection with this offering. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment.

Risks Related to this Offering

If you purchase our common stock in this offering, you will experience immediate and substantial dilution in investment. You will experience further dilution if we issue additional equity securities in future financing transactions.

You will suffer immediate and substantial dilution in the net tangible book value of the common stock you purchase in this offering. As a result, investors purchasing shares of common stock in this offering will incur immediate dilution of approximately $1.11 per share, representing the difference between the public offering price of $2.50 per share and our net tangible book value as of June 30, 2019 after giving effect to this offering, but excluding the effect of the conversion of the outstanding shares of Series A preferred stock and the shares of Series A preferred stock to be issued in the Concurrent Offering into shares of common stock. In addition, we have a significant number of stock options outstanding. To the extent that outstanding stock options have been or may be exercised, or, if shares of Series A preferred stock are converted into shares of our common stock, investors in this offering may experience further dilution.

We will require more capital to pursue our preclinical and clinical activities, regulatory approval and the commercialization of our current or future drug candidates. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders or result in downward pressure on the price of our common stock. See the section titled “Dilution” for a more detailed discussion of the dilution you will incur if you purchase common stock in this offering.

Our management might apply the net proceeds from this offering and the Concurrent Offering in ways with which you do not agree and in ways that may impair the value of your investment.

We currently intend to use the net proceeds from this offering and the Concurrent Offering primarily to fund the development of our drug candidates and for working capital and general corporate purposes. We may also use the net proceeds from this offering and the Concurrent Offering for certain pre-commercialization activities and to acquire or invest in businesses, products or technologies that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus supplement. Pending the use of net proceeds from this offering and the Concurrent Offering as further described in the section titled “Use of Proceeds,” we intend to invest the net proceeds in short-term, investment-grade, interest bearing obligations, certificates of deposit or direct or guaranteed obligations of the United States. Our management has broad discretion as to the use of these proceeds and you will be relying on the

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judgment of our management regarding the application of these proceeds. We might apply these proceeds in ways with which you do not agree, or in ways that do not yield a favorable return. If our management applies these proceeds in a manner that does not yield a significant return, if any, on our investment of these net proceeds, it could compromise our ability to pursue our growth strategy and adversely affect the market price of our common stock.

Concentration of ownership of our common stock among our existing executive officers, directors and principal stockholders may prevent new investors from influencing significant corporate decisions.

Based upon our shares of our common stock outstanding as of September 30, 2019, our executive officers, directors and stockholders who own more than 5% of our outstanding common stock before this offering, in the aggregate, beneficially own shares representing approximately 61% of our outstanding common stock (excluding the effect of the conversion of the shares of Series A preferred stock to be issued in the Concurrent Offering into shares of common stock).

Entities affiliated with Takeda, our collaboration partner and existing stockholder, entities affiliated with BVF, an existing stockholder, entities affiliated with Shira, an existing stockholder, and Dr. Jeremy M. Levin, our Chief Executive Officer and Chairman, have indicated an interest to purchase up to an aggregate of $14.3 million of the shares offered hereby and in the Concurrent Offering, in the aggregate. The ownership percentage upon the completion of this offering noted above does not reflect the potential purchase of any shares in this offering by such stockholders. If these entities participate in this offering or in the Concurrent Offering, the percentage noted above could potentially increase. These stockholders, acting together, will be able to significantly influence all matters requiring stockholder approval, including the election and removal of directors and any merger or other significant corporate transactions. The interests of this group of stockholders may not coincide with the interests of other stockholders.

Risks Related to the Development and Commercialization of Our Drug Candidates

Because the results of preclinical studies or earlier clinical trials are not necessarily predictive of future results, our drug candidates may not have favorable results in planned or future preclinical studies or clinical trials, or may not receive regulatory approval.

Success in preclinical testing and early clinical trials does not ensure that subsequent clinical trials will generate similar results or otherwise provide adequate data to demonstrate the efficacy and safety of a drug candidate. Frequently, drug candidates that have shown promising results in early clinical trials have subsequently suffered significant setbacks in later clinical trials. For instance, our STARS trial was the first clinical trial evaluating efficacy of OV101 in patients with Angelman syndrome and OV101 has not been evaluated in a clinical trial to treat Fragile X syndrome. We may be unable to demonstrate efficacy in any future trials, including any future clinical trials of OV101 to treat Angelman syndrome. Similarly, our Phase 1b/2a adult study in OV935 showed exploratory signals of efficacy in seizure frequency reduction, but we may be unable to demonstrate efficacy in future trials in patients with DEE, or the related indications of Dravet syndrome, Lennox-Gastaut syndrome, CDKL5 Deficiency Disorder or Duplication 15q syndrome, and the FDA has not yet made any determination regarding safety and efficacy of OV935 in any of these indications. The results from preclinical studies of OV101 and OV935 in animal models and the results from our STARS clinical trial of OV101 in patients with Angelman syndrome and clinical trials of OV101 in patients with primary insomnia may not be predictive of the effects of these compounds in later stage clinical trials. Our approach of targeting the extrasynaptic GABA_A receptor with OV101, and cholesterol 24-hydroxylase (CH24H) with OV935, are both novel and unproven, and as such, the cost and time needed to develop OV101 and OV935 is difficult to predict and our efforts may not be successful. If we do not observe favorable results in clinical trials of one of our drug candidates, we may decide to delay or abandon clinical development of

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that drug candidate. Any such delay or abandonment could harm our business, financial condition, results of operations and prospects.

In similar fashion, preliminary or interim data from clinical trials should be considered carefully and with caution since the final data may be materially different from the preliminary or interim data, particularly as more patient data become available. From time to time, we have and may in the future publish or report preliminary or interim data from our clinical trials, such as the initial data we announced from the ENDYMION open label extension trial for OV935 in September 2019, which involved data from the first six patients enrolled in that extension trial which showed promising signs of efficacy over the treatment period. Preliminary or interim data from our clinical trials and those of our partners may not be indicative of the final results of the trial and are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and/or more patient data become available. As a result, preliminary or interim data should be considered carefully and with caution until final data are available.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus, the documents incorporated by reference and any free writing prospectus that we have authorized for use in connection with this offering contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, which are subject to the “safe harbor” created by those sections. We may, in some cases, use words such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” or the negative of those terms, and similar expressions that convey uncertainty of future events or outcomes to identify these forward-looking statements. Any statements contained herein that are not statements of historical facts may be deemed to be forward-looking statements. Forward-looking statements may include, but are not limited to, statements about:

∎ the initiation, timing, progress and results of our current and future clinical trials and preclinical studies and our research and development programs;

∎ our expectations regarding the time it takes to enroll patients in our current and future clinical trials;

∎ our estimates regarding expenses, future revenue, capital requirements and needs for additional financing;

∎ our ability to identify additional novel compounds with significant commercial potential to acquire or in-license;

∎ our ability to successfully acquire or in-license additional drug candidates on reasonable terms;

∎ our ability to obtain regulatory approval of our current and future drug candidates;

∎ our expectations regarding the potential market size and the rate and degree of market acceptance of our current and future drug candidates;

∎ our ability to fund our working capital requirements;

∎ the cost and timing to prepare for commercialization of any of our products and our ability to commercialize drug candidates for which we receive marketing approval;

∎ the implementation of our business model and strategic plans for our business and drug candidates;

∎ developments or disputes concerning our intellectual property or other proprietary rights;

∎ our ability to maintain and establish collaborations or obtain additional funding;

∎ our expectations regarding government and third-party payor coverage and reimbursement;

∎ our ability to compete in the markets we serve;

∎ the impact of government laws and regulations;

∎ developments relating to our competitors and our industry;

∎ the successful completion of this offering and the Concurrent Offering; and

∎ the factors that may impact our financial results.

These forward-looking statements reflect our management’s beliefs and views with respect to future events and are based on estimates and assumptions as of the date of this prospectus supplement and are subject to risks and uncertainties. We discuss many of these risks in greater detail under the section titled “Risk Factors” in this prospectus supplement and under similar headings in the other documents that are incorporated by reference herein and therein. Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. Given these uncertainties, you should not place undue reliance on these forward-looking statements.

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You should read this prospectus supplement and the accompanying prospectus together with the documents that we have filed with the SEC that are incorporated by reference and any free writing prospectus we have authorized for use in connection with a specific offering completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements in this prospectus supplement and the accompanying prospectus, and the documents incorporated herein and therein, by these cautionary statements. Except as required by law, we undertake no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

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USE OF PROCEEDS

We expect to receive approximately $21.1 million in net proceeds from the sale of 9,000,000 shares of common stock offered by us in this offering (or approximately $24.2 million if the underwriters exercise their option to purchase additional shares in full), after deducting underwriting discounts and commissions and estimated offering expenses payable by us. In addition, we estimate that the net proceeds we will receive from the Concurrent Offering will be approximately $9.2 million, after deducting underwriting discounts and commissions and estimated offering expenses payable by us. This offering is not contingent upon the completion of the Concurrent Offering and the Concurrent Offering is not contingent upon the completion of this offering.

We expect to use the net proceeds from this offering and the Concurrent Offering, together with other available funds, primarily to advance: (1) the clinical development program of OV101 for Angelman syndrome and Fragile X syndrome and (2) the clinical development program of OV935 for DEEs. We intend to use the remainder of the net proceeds from this offering and the Concurrent Offering for working capital and general corporate purposes, which may include, but is not limited to, seeking marketing approvals for our current drug candidates that successfully complete clinical trials, pre-commercialization activities related to our drug candidates, current and future research and development efforts, establishing a sales, marketing and distribution infrastructure to commercialize any drug candidate for which we obtain marketing approval, and implementing operational, financial and management systems for such a commercial launch.

The expected use of the net proceeds from this offering and the Concurrent Offering represents our intentions based upon our current plans and business conditions, which could change in the future as our plans and business conditions evolve. The amounts and timing of our actual expenditures depend on numerous factors, including the progress of our preclinical development efforts, the ongoing status of and results from our clinical trials and other studies and any unforeseen cash needs. As a result, our management will have broad discretion in applying the net proceeds from this offering and the Concurrent Offering. Pending the use of the net proceeds from this offering and the Concurrent Offering, we intend to invest the net proceeds in short-term, investment-grade, interest bearing obligations, certificates of deposit or direct or guaranteed obligations of the United States.

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DILUTION

Our net tangible book value as of June 30, 2019 was $45.2 million, or $1.17 per share. Net tangible book value per share is determined by dividing our total tangible assets, less total liabilities, by the number of shares of our common stock outstanding as of June 30, 2019. Dilution with respect to net tangible book value per share represents the difference between the amount per share paid by investors purchasing shares of common stock in this offering and the net tangible book value per share of our common stock immediately after this offering (excluding the effect of the conversion of outstanding shares of Series A preferred stock and the shares of Series A preferred stock to be issued in the Concurrent Offering into shares of common stock).

After giving effect to the sale of 9,000,000 shares of our common stock in this offering at a public offering price of $2.50 per share, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of June 30, 2019 would have been approximately $66.2 million, or $1.39 per share. This represents an immediate increase in net tangible book value of $0.22 per share to existing stockholders and immediate dilution of $1.11 per share to investors purchasing our common stock in this offering. The following table illustrates this dilution on a per share basis:

Public offering price per share			$	2.50
Net tangible book value per share as of June 30, 2019	$	1.17
Increase in net tangible book value per share attributable to investors in this offering	$	0.22
As adjusted net tangible book value per share as of June 30, 2019, after giving effect to this offering			$	1.39
Dilution per share to investors purchasing our common stock in this offering			$	1.11

If the underwriters exercise in full their option to purchase up to 1,350,000 additional shares of common stock at the public offering price of $2.50 per share, the as adjusted net tangible book value after this offering would be approximately $69.5 million, representing an immediate increase in net tangible book value of $0.25 per share to existing stockholders and immediate dilution in net tangible book value of $1.08 per share to investors purchasing our common stock in this offering.

The above discussion and table are based on 38,693,018 shares of our common stock outstanding as of June 30, 2019, which excludes:

∎ 5,916,944 shares of our common stock issuable upon the exercise of stock options outstanding as of June 30, 2019 under our 2014 Plan and our 2017 Plan at a weighted average exercise price of $6.36 per share;

∎ 3,688,116 shares of common stock reserved for future issuance under our 2017 Plan, plus any additional shares of our common stock that may become available under our 2017 Plan;

∎ 694,432 shares of our common stock reserved for issuance under our ESPP, as well as any future increases in the number of shares of our common stock reserved for issuance under the ESPP;

∎ 2,500,000 shares of our common stock issuable upon conversion of 2,500 shares of Series A preferred stock outstanding as of June 30, 2019; and

∎ 4,000,000 shares of our common stock issuable upon conversion of shares of Series A preferred stock being offered by us in connection with the Concurrent Offering.

The above discussion and table do not take into account giving effect to the 4,000,000 shares of common stock issuable upon conversion of the 4,000 Series A preferred stock offered by us in the

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Concurrent Offering at the public offering price of $2,500 per share. Giving effect to both this offering (assuming no exercise of the underwriters’ option to purchase additional shares) and the Concurrent Offering, our as adjusted net tangible book value as of June 30, 2019, would have been approximately $75.4 million, or $1.46 per share (assuming conversion of all shares of Series A preferred stock offered in the Concurrent Offering), which represents an immediate increase in net tangible book value of $0.29 per share to existing stockholders and immediate dilution in net tangible book value of $1.04 per share to investors purchasing our common stock in this offering.

To the extent that outstanding options outstanding as of June 30, 2019 have been or may be exercised or other shares of common stock are issued, including shares of our common stock issuable upon conversion of Series A preferred stock outstanding or Series A preferred stock being offered in the Concurrent Offering, investors purchasing our common stock in this offering may experience further dilution. We will require more capital to pursue our preclinical and clinical activities, regulatory approval and the commercialization of our current or future drug candidates. In addition, we may also choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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UNDERWRITING

We and the underwriters for the offering named below have entered into an underwriting agreement with respect to the common stock being offered. Subject to the terms and conditions of the underwriting agreement, each underwriter has severally agreed to purchase from us the number of shares of our common stock set forth opposite its name below. Cowen and Company, LLC and William Blair & Company, L.L.C. are the representatives of the underwriters, or the Representatives.

Underwriters	Number of Shares
Cowen and Company, LLC		4,365,000
William Blair & Company, L.L.C.		3,240,000
JMP Securities LLC		900,000
Ladenburg Thalmann & Co. Inc.		495,000
Total		9,000,000

Entities affiliated with Takeda, our collaboration partner and existing stockholder, entities affiliated with BVF, an existing stockholder, entities affiliated with Shira, an existing stockholder, and Dr. Jeremy M. Levin, our Chief Executive Officer and Chairman, have indicated an interest to purchase up to an aggregate of $14.3 million of the shares offered hereby and in the Concurrent Offering, in the aggregate. However, because these indications of interest are not binding agreements or commitments to purchase, such stockholders or their affiliates may elect to purchase fewer shares or not purchase any shares in this offering or the Concurrent Offering. In addition, the underwriters may determine to sell more, fewer or no shares to such stockholders or their affiliates.

The underwriting agreement provides that the obligations of the underwriters are subject to certain conditions precedent and that the underwriters have agreed, severally and not jointly, to purchase all of the shares sold under the underwriting agreement if any of these shares are purchased, other than those shares covered by the option to purchase additional shares described below. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the non-defaulting underwriters may be increased or the underwriting agreement may be terminated.

We have agreed to indemnify the underwriters against specified liabilities, including liabilities under the Securities Act and to contribute to payments the underwriters may be required to make in respect thereof.

The underwriters are offering the shares, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel and other conditions specified in the underwriting agreement. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Option to Purchase Additional Shares.    We have granted to the underwriters an option to purchase up to 1,350,000 additional shares of common stock at the public offering price, less the underwriting discount. This option is exercisable for a period of 30 days. To the extent that the underwriters exercise this option, the underwriters will purchase additional shares from us in approximately the same proportion as shown in the table above.

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Discounts and Commissions.    The following table shows the public offering price, underwriting discount and proceeds, before expenses to us. These amounts are shown assuming both no exercise and full exercise of the underwriters’ option to purchase additional shares.

			Total(1)
	Per Share		Without Option		With Option
Public offering price	$	2.50	$	22,500,000	$	25,875,000
Underwriting discount	$	0.15	$	1,350,000	$	1,552,500
Proceeds, before expenses, to us	$	1.35	$	21,150,000	$	24,322,500

(1) Excludes the proceeds to be received by us pursuant to the Concurrent Offering and any discounts and commissions paid by us to the underwriters in connection with the Concurrent Offering.

The underwriters propose to offer the shares of common stock to the public at the public offering price set forth on the cover page of this prospectus. The underwriters may offer the shares of common stock to securities dealers at the public offering price less a concession not in excess of $0.09 per share. If all of the shares are not sold at the public offering price, the underwriters may change the offering price and other selling terms.

We estimate that the total expenses of this offering and the Concurrent Offering, excluding underwriting discounts and commissions, will be approximately $400,000, which includes $35,000 that we have agreed to reimburse the underwriters for the fees incurred by them in connection with this offering and the Concurrent Offering. The underwriters have also agreed to reimburse us for certain of our expenses incurred in connection with this offering and the Concurrent Offering.

Discretionary Accounts.    The underwriters do not intend to confirm sales of the shares to any accounts over which they have discretionary authority.

Stabilization.    In connection with this offering, the underwriters may engage in stabilizing transactions, overallotment transactions, syndicate covering transactions, penalty bids and purchases to cover positions created by short sales.

∎ Stabilizing transactions permit bids to purchase shares of common stock so long as the stabilizing bids do not exceed a specified maximum, and are engaged in for the purpose of preventing or retarding a decline in the market price of the common stock while the offering is in progress.

∎ Over-allotment transactions involve sales by the underwriters of shares of common stock in excess of the number of shares the underwriters are obligated to purchase. This creates a syndicate short position which may be either a covered short position or a naked short position. In a covered short position, the number of shares over-allotted by the underwriters is not greater than the number of shares that they may purchase in the over-allotment option. In a naked short position, the number of shares involved is greater than the number of shares in the over-allotment option. The underwriters may close out any short position by exercising their over-allotment option and/or purchasing shares in the open market.

∎ Syndicate covering transactions involve purchases of common stock in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares to close out the short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared with the price at which they may purchase shares through exercise of the over-allotment option. If the underwriters sell more shares than could be covered by exercise of the over-allotment option and, therefore, have a naked short position, the position can be closed out only by buying shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that after pricing there could be downward pressure on the price of the shares in the open market that could adversely affect investors who purchase in the offering.

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∎ Penalty bids permit the representative to reclaim a selling concession from a syndicate member when the common stock originally sold by that syndicate member is purchased in stabilizing or syndicate covering transactions to cover syndicate short positions.

These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result, the price of our common stock in the open market may be higher than it would otherwise be in the absence of these transactions. Neither we nor the underwriters make any representation or prediction as to the effect that the transactions described above may have on the price of our common stock. These transactions may be effected on the Nasdaq Stock Market, in the over-the-counter market or otherwise and, if commenced, may be discontinued at any time.

Passive Market Making.    In connection with this offering, underwriters and selling group members may engage in passive market making transactions in our common stock on the Nasdaq Stock Market in accordance with Rule 103 of Regulation M under the Securities Exchange Act of 1934, as amended, during a period before the commencement of offers or sales of common stock and extending through the completion of the distribution. A passive market maker must display its bid at a price not in excess of the highest independent bid of that security. However, if all independent bids are lowered below the passive market maker’s bid, that bid must then be lowered when specified purchase limits are exceeded.

Lock-Up Agreements.    Pursuant to certain ‘‘lock-up’’ agreements, we and our executive officers and directors have agreed, subject to certain exceptions, not to offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of or announce the intention to otherwise dispose of, or enter into any swap, hedge or similar agreement or arrangement that transfers, in whole or in part, the economic consequence of ownership of, directly or indirectly, or make any demand or request or exercise any right with respect to the registration of, or file with the SEC a registration statement under the Securities Act relating to, any common stock or securities convertible into or exchangeable or exercisable for any common stock without the prior written consent of the Representatives, for a period of 90 days after the date of the pricing of the offering.

The Representatives, in their sole discretion, may release our common stock and other securities subject to the lock-up agreements described above in whole or in part at any time. When determining whether or not to release our common stock and other securities from lock-up agreements, the Representatives will consider, among other factors, the holder’s reasons for requesting the release, the number of shares for which the release is being requested and market conditions at the time of the request.

Canada.    The common stock may be sold only to purchasers purchasing, or deemed to be purchasing, as principal, who are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations . Any resale of the common stock must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

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Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

United Kingdom.    Each of the underwriters has represented and agreed that:

∎ it has not made or will not make an offer of the securities to the public in the United Kingdom within the meaning of section 102B of the Financial Services and Markets Act 2000 (as amended) (FSMA) except to legal entities which are authorized or regulated to operate in the financial markets or, if not so authorized or regulated, whose corporate purpose is solely to invest in securities or otherwise in circumstances which do not require the publication by us of a prospectus pursuant to the Prospectus Rules of the Financial Services Authority (FSA);

∎ it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of section 21 of FSMA) to persons who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 or in circumstances in which section 21 of FSMA does not apply to us; and

∎ it has complied with and will comply with all applicable provisions of FSMA with respect to anything done by it in relation to the securities in, from or otherwise involving the United Kingdom.

Switzerland.    The securities will not be offered, directly or indirectly, to the public in Switzerland and this prospectus does not constitute a public offering prospectus as that term is understood pursuant to article 652a or 1156 of the Swiss Federal Code of Obligations.

European Economic Area.    In relation to each Member State of the European Economic Area (each, a “Member State”), no offer of shares may be made to the public in that Member State other than:

(a) to any legal entity which is a qualified investor as defined in the Prospectus Regulation;

(b) to fewer than 150 natural or legal persons (other than qualified investors as defined in the Prospectus Regulation), subject to obtaining the prior consent of the representatives; or

(c) in any other circumstances falling within Article 1(4) of the Prospectus Regulation, provided that no such offer of shares shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Regulation or supplement a prospectus pursuant to Article 23 of the Prospectus Regulation and each person who initially acquires any shares or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with each of the underwriters and us that it is a “qualified investor” as defined in the Prospectus Regulation.

In the case of any shares being offered to a financial intermediary as that term is used in Article 5 of the Prospectus Regulation, each such financial intermediary will be deemed to have represented, acknowledged and agreed that the shares acquired by it in the offer have not been acquired on a nondiscretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer of any shares to the public other than their offer or resale in a Member State to qualified investors as so defined or in circumstances in which the prior consent of the underwriters has been obtained to each such proposed offer or resale.

For the purposes of this provision, the expression an “offer of shares to the public” in relation to any shares in any Member State means the communication in any form and by means of sufficient information on the terms of the offer and the shares to be offered so as to enable an investor to decide to purchase shares, and the expression “Prospectus Regulation” means Regulation (EU) 2017/1129 (as amended).

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Israel.     In the State of Israel this prospectus shall not be regarded as an offer to the public to purchase shares of common stock under the Israeli Securities Law, 5728 – 1968, which requires a prospectus to be published and authorized by the Israel Securities Authority, if it complies with certain provisions of Section 15 of the Israeli Securities Law, 5728–1968, including, inter alia, if: (i) the offer is made, distributed or directed to not more than 35 investors, subject to certain conditions, or the Addressed Investors; or (ii) the offer is made, distributed or directed to certain qualified investors defined in the First Addendum of the Israeli Securities Law, 5728 – 1968, subject to certain conditions, or the Qualified Investors. The Qualified Investors shall not be taken into account in the count of the Addressed Investors and may be offered to purchase securities in addition to the 35 Addressed Investors. The company has not and will not take any action that would require it to publish a prospectus in accordance with and subject to the Israeli Securities Law, 5728 – 1968. We have not and will not distribute this prospectus or make, distribute or direct an offer to subscribe for our common stock to any person within the State of Israel, other than to Qualified Investors and up to 35 Addressed Investors.

Qualified Investors may have to submit written evidence that they meet the definitions set out in of the First Addendum to the Israeli Securities Law, 5728 – 1968. In particular, we may request, as a condition to be offered common stock, that Qualified Investors will each represent, warrant and certify to us and/or to anyone acting on our behalf: (i) that it is an investor falling within one of the categories listed in the First Addendum to the Israeli Securities Law, 5728 – 1968; (ii) which of the categories listed in the First Addendum to the Israeli Securities Law, 5728 – 1968 regarding Qualified Investors is applicable to it; (iii) that it will abide by all provisions set forth in the Israeli Securities Law, 5728 – 1968 and the regulations promulgated thereunder in connection with the offer to be issued common stock; (iv) that the shares of common stock that it will be issued are, subject to exemptions available under the Israeli Securities Law, 5728 – 1968: (a) for its own account; (b) for investment purposes only; and (c) not issued with a view to resale within the State of Israel, other than in accordance with the provisions of the Israeli Securities Law, 5728 – 1968; and (v) that it is willing to provide further evidence of its Qualified Investor status. Addressed Investors may have to submit written evidence in respect of their identity and may have to sign and submit a declaration containing, inter alia, the Addressed Investor’s name, address and passport number or Israeli identification number.

Electronic Offer, Sale and Distribution of Shares.    A prospectus in electronic format may be made available on the websites maintained by one or more of the underwriters or selling group members, if any, participating in this offering and one or more of the underwriters participating in this offering may distribute prospectuses electronically. The Representatives may agree to allocate a number of shares to underwriters and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the underwriters and selling group members that will make internet distributions on the same basis as other allocations. Other than the prospectus in electronic format, the information on these websites is not part of this prospectus or the registration statement of which this prospectus forms a part, has not been approved or endorsed by us or any underwriter in its capacity as underwriter, and should not be relied upon by investors.

Other Relationships.    Certain of the underwriters and their affiliates have provided, and may in the future provide, various investment banking, commercial banking and other financial services for us and our affiliates for which they have received, and may in the future receive, customary fees. The underwriters and certain of their affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of the common stock and may at any time hold, or recommend to clients that they acquire, long and/or short positions in the common stock.

We are party to a sales agreement with Cowen and Company, LLC, pursuant to which we may sell up to $50.0 million of our common stock, from time to time, through an “at-the-market offering” program.

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LEGAL MATTERS

Cooley LLP, Palo Alto, California, will pass upon the validity of the issuance of the shares being sold in this offering. Certain legal matters related to this offering will be passed upon for the underwriters by Goodwin Procter LLP, New York, New York.

EXPERTS

The financial statements of Ovid Therapeutics Inc. as of December 31, 2018 and 2017, and for each of the years in the two-year period ended December 31, 2018, have been incorporated by reference herein in reliance upon the report of KPMG LLP, an independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement and the accompanying prospectus are part of the registration statement on Form S-3 we filed with the SEC under the Securities Act and do not contain all of the information set forth or incorporated by reference in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus supplement, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC, including Ovid. The address of the SEC website is www.sec.gov.

We maintain a website at www.ovidrx.com. Information contained in or accessible through our website does not constitute a part of this prospectus supplement.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus supplement, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The SEC file number for the documents incorporated by reference in this prospectus supplement is 001-38085. The documents incorporated by reference into this prospectus supplement contain important information that you should read about us.

The following documents are incorporated by reference into this document:

∎ our Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 7, 2019;

∎ the information specifically incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2018 from our Definitive Proxy Statement on Schedule 14A for our 2019 Annual Meeting of Stockholders, filed with the SEC on April 24, 2019;

∎ our Quarterly Reports on Form 10-Q for the quarter ended March 31, 2019 filed with the SEC on May 7, 2019, and the quarter ended June  30, 2019 filed with the SEC on August 7, 2019;

∎ our Current Reports on Form 8-K filed with the SEC on January 4, 2019, February 21, 2019, March 1, 2019, March 21, 2019, March 28, 2019 (as amended on March  28, 2019), May  15, 2019 (as amended on June  17, 2019), June 10, 2019, June  18, 2019, June 27, 2019, July 2, 2019, September 9, 2019, September  12, 2019, September 19, 2019, September  23, 2019 and September 24, 2019, to the extent the information in such reports is filed and not furnished; and

∎ the description of our common stock contained in our Registration Statement on Form 8-A, filed with the SEC on May 4, 2017, including any amendments or reports filed for the purposes of updating this description.

We also incorporate by reference into this prospectus supplement all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus supplement but prior to the termination of the offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to Ovid Therapeutics Inc., Attn: Thomas M. Perone, Senior Vice President, General Counsel and Secretary, 1460 Broadway, 15044, New York, NY 10036; telephone: (646) 701-5169.

S-24

PROSPECTUS

$200,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

From time to time, we may offer up to $200,000,000 of any combination of the securities described in this prospectus in one or more offerings. We may also offer securities as may be issuable upon conversion, redemption, repurchase, exchange or exercise of any securities registered hereunder, including any applicable antidilution provisions.

This prospectus provides a general description of the securities we may offer. Each time we offer securities, we will provide specific terms of the securities offered in a supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.

This prospectus may not be used to consummate a sale of any securities unless accompanied by a prospectus supplement.

Our common stock is listed on The Nasdaq Global Select Market, or Nasdaq, under the symbol “OVID.” On May 30, 2018, the last reported sale price of our common stock was $7.73 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing on Nasdaq or any securities market or other exchange of the securities, if any, covered by the prospectus supplement.

We will sell these securities directly to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section titled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts or over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus as described on page 33 of this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is June 19, 2018.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS	i
SUMMARY	1
RISK FACTORS	7
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	8
RATIO OF EARNINGS TO FIXED CHARGES	10
USE OF PROCEEDS	11
DESCRIPTION OF CAPITAL STOCK	12
DESCRIPTION OF DEBT SECURITIES	18
DESCRIPTION OF WARRANTS	25
LEGAL OWNERSHIP OF SECURITIES	27
PLAN OF DISTRIBUTION	31
LEGAL MATTERS	32
EXPERTS	32
WHERE YOU CAN FIND MORE INFORMATION	33
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	33

ABOUT THIS PROSPECTUS

This prospectus is a part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total aggregate offering price of $200,000,000. This prospectus provides you with a general description of the securities we may offer.

Each time we sell securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in any documents that we have incorporated by reference into this prospectus. You should read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Incorporation of Certain Information by Reference,” before investing in any of the securities offered.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

Neither we, nor any agent, underwriter or dealer has authorized any person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus prepared by or on behalf of us or to which we have referred you. This prospectus, any applicable supplement to this prospectus or any related free writing prospectus do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus, any applicable supplement to this prospectus or any related free writing prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction.

You should not assume that the information contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.

This prospectus and the information incorporated herein by reference contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.”

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SUMMARY

The following summary highlights information contained elsewhere in this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our consolidated financial statements, and the exhibits to the registration statement of which this prospectus is a part.

Unless the context indicates otherwise, references in this prospectus to “Ovid,” “the Company,” “we,” “us,” “our” and similar references refer to Ovid Therapeutics Inc. and its wholly owned subsidiaries.

Company Overview

We are a biopharmaceutical company focused exclusively on developing impactful medicines for patients and families living with rare neurological disorders. We believe these disorders represent an attractive area for drug development as the understanding of the underlying biology has grown meaningfully over the last few years; yet has remained underappreciated by the industry. Our experienced team began with a vision to integrate the biology and symptomology of rare neurological conditions to employ innovative research and clinical strategies for the development of our drug candidates. Based on recent scientific advances in genetics and the biological pathways of the brain, we created a proprietary map of disease-relevant pathways and used it to identify and acquire novel compounds for the treatment of rare neurological disorders. We are executing on our strategy by in-licensing and collaborating with leading biopharmaceutical companies and academic institutions. We are developing a robust pipeline of clinical assets with an initial focus on neurodevelopmental disorders and developmental and rare epileptic encephalopathies, or dEE. OV101, has completed randomization of a Phase 2 trial, which is primarily a safety trial with exploratory efficacy parameters, in adults and adolescents with Angelman syndrome. We completed a Phase 1 trial in adolescents with Angelman syndrome or Fragile X syndrome in which OV101 was found to be generally well tolerated and its pharmacokinetic, or PK, profile in adolescents was similar to previous data generated in young adults. Along with our collaborator, Takeda Pharmaceutical Company Limited, or Takeda, in June 2017 we initiated patient recruitment in our Phase 1b/2a trial of OV935 in adults with dEE. We expect data from the OV101 Phase 2 clinical trial in the third quarter of 2018 and data from the Phase 1b/2a clinical trial of OV935 in the second half of 2018.

Our most advanced drug candidate is OV101, which we acquired from H. Lundbeck A/S, or Lundbeck, in 2015. For OV101, the U.S. Food and Drug Administration, or FDA, granted orphan drug designation for the treatment of Angelman syndrome and for the treatment of Fragile X syndrome in September 2016 and October 2017, respectively, and fast track designation for the treatment of Angelman Syndrome and Fragile X syndrome in December 2017 and March 2018, respectively. We believe our development plan for OV101 highlights our ability to translate new scientific insights into drug candidates that target an unexplored disease-relevant pathway. OV101 targets disorders characterized by diminished tonic inhibition, a neurological signaling abnormality that has been identified as a potential central cause of the symptoms seen in a number of disorders of the brain. This can lead to certain symptoms including, but not limited to motor deficiencies, sleep abnormalities, behavioral manifestations and seizures. We believe modulating tonic inhibition may have a meaningful clinical impact in patients with Angelman syndrome and Fragile X syndrome.

In January 2017, we entered into a collaboration with Takeda for its compound TAK-935, which we refer to as OV935. The collaboration enables us to share equally in building upon Takeda’s discoveries, bringing together

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the capabilities of both companies in development, regulatory and commercialization activities. We believe that OV935’s inhibition of the cholesterol metabolism pathway may down regulate the excitatory signals involved in epilepsy, which may suppress seizures and also lead to a long-term disease-modifying effect. We are initially targeting OV935 for illnesses with high unmet medical needs that fall under the umbrella term dEE, which includes Dravet syndrome, Lennox-Gastaut syndrome and Tuberous Sclerosis Complex. OV935 has completed four Phase 1 trials in healthy individuals, preliminarily demonstrating favorable tolerability at doses that we believe may be therapeutically relevant. The FDA granted orphan drug designation for OV935 for the treatment of Dravet syndrome and Lennox-Gastaut syndrome both in December 2017.

Our management team is a critical component to the execution of our overall strategy and our business model. We have assembled a team with significant experience in translational science, drug evaluation, clinical development, regulatory affairs and business development. We believe these capabilities will drive our ability to identify, acquire, develop and commercialize novel compounds that have the potential to modify the devastating course of rare neurological disorders. We believe our expertise will make us the partner of choice for leading biopharmaceutical companies or academic institutions that wish to maximize the value of their neurology drug candidates. The members of our team have been collectively involved in the development and approval of over 20 marketed drugs. Further, we believe that we are particularly well positioned to execute on our business development strategy given the extensive network and breadth of expertise of our Chairman and Chief Executive Officer Dr. Jeremy Levin and the other members of our management team. Our management team is supported by our board of directors, which has extensive experience in the biopharmaceutical industry.

Our Pipeline

The following table sets forth the status and mechanism of action of our drug candidates: 

Corporate Information

We were incorporated in Delaware in April 2014. Our principal executive offices are located at 1460 Broadway, Suite 15044, New York, New York 10036 and our telephone number is (646) 661-7661. Our common

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stock is listed on Nasdaq under the symbol “OVID.” Our corporate website address is www.ovidrx.com. Information contained on or accessible through our website is not incorporated by reference into this prospectus, and you should not consider any information contained on, or that can be accessed through, our website as part of this prospectus.

Our name “Ovid Therapeutics,” the Ovid logo, BoldMedicine and other trademarks, trade names or service marks of Ovid Therapeutics Inc. appearing in this prospectus are the property of Ovid Therapeutics Inc. All other trademarks, trade names and service marks appearing in this prospectus are the property of their respective owners. Solely for convenience, the trademarks and trade names in this prospectus are referred to without the ^® and ™ symbols, but such references should not be construed as any indicator that their respective owners will not assert their rights thereto.

Implications of Being an Emerging Growth Company

We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. An emerging growth company may take advantage of specified reduced reporting and other burdens that are otherwise applicable generally to public companies. These exemptions include:

• being permitted to provide only two years of audited financial statements, in addition to any required unaudited interim financial statements, with correspondingly reduced “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure;

• not being required to comply with the auditor attestation requirements in the assessment of our internal control over financial reporting;

• not being required to comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financial statements;

• reduced disclosure obligations regarding executive compensation in our periodic reports, proxy statements and registration statements; and

• not being required to hold a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved.

We may take advantage of these reporting exemptions until we are no longer an emerging growth company. We will remain an emerging growth company until the earlier of (1) December 31, 2022, (2) the last day of the fiscal year in which we have total annual gross revenue of at least $1.07 billion, (3) the last day of the fiscal year in which we are deemed to be a large accelerated filer, which means the market value of our common stock that is held by non-affiliates exceeds $700 million as of the prior June 30th, and (4) the date on which we have issued more than $1 billion in non-convertible debt during the prior three-year period. We may choose to take advantage of some or all of these available exemptions. We have taken advantage of some reduced reporting requirements in our public filings. Accordingly, the information that we provide stockholders may be different than the information you receive from other public companies in which you hold stock.

In addition, the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This provision allows an emerging growth company to delay the adoption of some accounting standards until those standards would otherwise apply to private companies. We have irrevocably elected not to avail ourselves of delayed adoption of new or revised accounting standards and, therefore, we will be subject to the same requirements to adopt new or revised accounting standards as other public companies that are not emerging growth companies.

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The Securities We May Offer

We may offer shares of our common stock and preferred stock, various series of debt securities and warrants to purchase any of such securities, up to a total aggregate offering price of $200,000,000 from time to time in one or more offerings under this prospectus, together with any applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of the relevant offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

• designation or classification;

• aggregate principal amount or aggregate offering price;

• maturity;

• original issue discount;

• rates and times of payment of interest or dividends;

• redemption, conversion, exchange or sinking fund terms;

• ranking;

• restrictive covenants;

• voting or other rights;

• conversion or exchange prices or rates and any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange; and

• important U.S. federal income tax considerations.

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

We may sell the securities directly to investors or through underwriters, dealers or agents. We, and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

• the names of those underwriters or agents;

• applicable fees, discounts and commissions to be paid to them;

• details regarding over-allotment options, if any; and

• the estimated net proceeds to us.

This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

Common Stock. We may issue shares of our common stock from time to time. Each holder of common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders and does not

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have cumulative voting rights. Subject to preferences that may apply to any outstanding preferred stock, holders of our common stock are entitled to receive ratably any dividends that our board of directors may declare out of funds legally available for that purpose. In the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preference of any outstanding preferred stock. Holders of our common stock have no preemptive, conversion, subscription or other rights, and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of our common stock are subject to and may be adversely affected by the rights of the holders of shares of any series of our preferred stock that we may designate in the future. In this prospectus, we have summarized certain general features of our common stock under the heading “Description of Capital Stock—Common Stock.” We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to any common stock being offered.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our certificate of incorporation, our board of directors has the authority, without further action by our stockholders (unless such stockholder action is required by applicable law or the rules of any stock exchange or market on which our securities are then traded), to issue up to 10,000,000 shares of preferred stock in one or more series and to fix the number, rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences and sinking fund terms, and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. Any convertible preferred stock we may issue will be convertible into our common stock or exchangeable for our other securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.

If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. In this prospectus, we have summarized certain general features of the preferred stock under the heading “Description of Capital Stock—Preferred Stock.” We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. From time to time, we may issue debt securities in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.

Any debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities under the heading “Description of Debt Securities.” We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indenture(s) and any supplemental indentures that contain the terms of the debt securities. We have filed a form of indenture as an exhibit to the registration statement of which this prospectus is

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a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will be incorporated by reference from reports that we file with the SEC, supplemental indentures and forms of debt securities containing the terms of the debt securities being offered.

Warrants. We may issue warrants for the purchase of common stock, preferred stock or debt securities, in one or more series, from time to time. We may issue warrants independently or in combination with common stock, preferred stock or debt securities. In this prospectus, we have summarized certain general features of the warrants under the heading “Description of Warrants.” We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that we may offer as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will be incorporated by reference from reports that we file with the SEC, the form of warrant or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants.

Any warrants issued under this prospectus may be evidenced by warrant certificates. Warrants may be issued under a warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

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RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in our Annual Report on Form 10-K for the year ended December 31, 2017 and in our most recent Quarterly Report on Form 10-Q, as updated by our subsequent filings, which are incorporated by reference into this prospectus, before deciding whether to purchase any of the securities being registered pursuant to the registration statement of which this prospectus is a part. Each of the risk factors could adversely affect our business, results of operations, financial condition and cash flows, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference contain forward-looking statements. These are based on our management’s current beliefs, expectations and assumptions about future events, conditions and results and on information currently available to us. Discussions containing these forward-looking statements may be found, among other places, in the sections titled “Business,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” incorporated by reference from our most recent Annual Report on Form 10-K, as well as any amendments thereto, filed with the SEC.

Any statements in this prospectus, or incorporated herein, about our expectations, beliefs, plans, objectives, assumptions or future events or performance are not historical facts and are forward-looking statements. Within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, these forward-looking statements include statements regarding:

• the initiation, timing, progress and results of our current and future preclinical studies and clinical trials and our research and development programs;

• our estimates regarding expenses, future revenue, capital requirements and needs for additional financing;

• our ability to identify additional novel compounds with significant commercial potential to acquire or in-license;

• our ability to successfully acquire or in-license additional drug candidates on reasonable terms;

• our ability to obtain regulatory approval of our current and future drug candidates;

• our expectations regarding the potential market size and the rate and degree of market acceptance

• of such drug candidates;

• our ability to fund our working capital requirements;

• the implementation of our business model and strategic plans for our business and drug candidates;

• developments or disputes concerning our intellectual property or other proprietary rights;

• our ability to maintain and establish collaborations or obtain additional funding;

• our expectations regarding government and third-party payor coverage and reimbursement;

• our ability to compete in the markets we serve;

• the impact of government laws and regulations;

• developments relating to our competitors and our industry; and

• the factors that may impact our financial results.

In some cases, you can identify forward-looking statements by terminology such as “anticipate,” “believe,” “could,” “estimate,” “expects,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” or the negative or plural of those terms, and similar expressions intended to identify statements about the future, although not all forward-looking statements contain these words. These statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements.

You should refer to the “Risk Factors” section contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus, for a discussion of important factors that may cause our actual results to differ

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materially from those expressed or implied by our forward-looking statements. Given these risks, uncertainties and other factors, many of which are beyond our control, we cannot assure you that the forward-looking statements in this prospectus will prove to be accurate, and you should not place undue reliance on these forward-looking statements. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to revise any forward-looking statements to reflect events or developments occurring after the date of this prospectus, even if new information becomes available in the future.

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RATIO OF EARNINGS TO FIXED CHARGES

Our earnings were insufficient to cover fixed charges for each of the periods in the table below and, accordingly, we have not included a ratio of earnings to fixed charges for these periods. The following table sets forth our ratio of earnings to fixed charges for each of the periods presented. We do not have any preferred stock outstanding as of the date of this prospectus and did not have any preferred stock with required dividend payments during any of the periods presented below. Therefore, there are no preferred dividends included in our calculation of these ratios. This table is qualified by the more detailed information appearing in the computation table set forth in Exhibit 12.1 to the registration statement of which this prospectus is a part.

	Three Months Ended March 31, 2018			Year Ended December 31,									Period from April 1, 2014 (date of inception) to December 31, 2014
(in thousands, except ratios)				2017			2016			2015
Deficiency of earnings available to cover fixed charges	$	(13,183	)	$	(64,806	)	$	(22,414	)	$	(13,160	)	$	(335	)

(1) “Fixed charges” are calculated as the sum of (a) interest costs (both expensed and capitalized), (b) amortization of debt expense and discount or premium relating to any indebtedness and (c) that portion of rental expense that is representative of the interest factor.

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USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. Except as described in any applicable prospectus supplement or in any free writing prospectuses that we may authorize to be provided to you in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered hereby, if any, to fund research and development, acquire or invest in businesses, products or technologies that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus, and for working capital and general corporate purposes. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus. Pending the use of net proceeds, we intend to invest the net proceeds in short-term, investment-grade, interest-bearing obligations, certificates of deposit or direct or guaranteed obligations of the United States.

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DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock and provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries. You should also refer to the amended and restated certificate of incorporation and the amended and restated bylaws, which are filed as exhibits to the registration statement of which this prospectus is part.

General

Under our amended and restated certificate of incorporation we are authorized to issue up to 125,000,000 shares of common stock, par value $0.001 per share, and 10,000,000 shares of preferred stock, par value $0.001 per share, all of which shares of preferred stock are undesignated. Our board of directors may establish the rights and preferences of the preferred stock from time to time. As of March 31, 2018, we had outstanding 24,617,979 shares of common stock.

Common Stock

Voting Rights

Each holder of common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders. The affirmative vote of holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of capital stock, voting as a single class, will be required to amend certain provisions of our amended and restated certificate of incorporation, including provisions relating to amending our amended and restated bylaws, the classified board, the size of our board, removal of directors, director liability, vacancies on our board, special meetings, stockholder notices, actions by written consent and exclusive jurisdiction.

Dividends

Subject to preferences that may apply to any outstanding preferred stock, holders of our common stock are entitled to receive ratably any dividends that our board of directors may declare out of funds legally available for that purpose on a non-cumulative basis.

Liquidation

In the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preference of any outstanding preferred stock.

Rights and Preferences

Holders of our common stock have no preemptive, conversion, subscription or other rights, and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of our common stock are subject to and may be adversely affected by the rights of the holders of shares of any series of our preferred stock that we may designate in the future.

Preferred Stock

Pursuant to our amended and restated certificate of incorporation, our board of directors has the authority, without further action by our stockholders, to issue up to 10,000,000 shares of preferred stock in one or more series and to fix the number, rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences and sinking fund terms, and the number of shares constituting any series or the designation of such

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series, any or all of which may be greater than the rights of common stock. The issuance of our preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deferring or preventing a change of control or other corporate action, or make the removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of the common stock.

Our board of directors will fix the designations, voting powers, preferences and rights of each series, as well as the qualifications, limitations or restrictions thereof, of the preferred stock of each series that we offer under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that series of preferred stock. This description will include:

• the title and stated value;

• the number of shares we are offering;

• the liquidation preference per share;

• the purchase price per share;

• the dividend rate per share, dividend period and payment dates and method of calculation for dividends;

• whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

• our right, if any, to defer payment of dividends and the maximum length of any such deferral period;

• the procedures for any auction and remarketing, if any;

• the provisions for a sinking fund, if any;

• the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

• any listing of the preferred stock on any securities exchange or market;

• whether the preferred stock will be convertible into our common stock or other securities of ours, including depositary shares and warrants, and, if applicable, the conversion period, the conversion price, or how it will be calculated, and under what circumstances it may be adjusted;

• whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange period, the exchange price, or how it will be calculated, and under what circumstances it may be adjusted;

• voting rights, if any, of the preferred stock;

• preemption rights, if any;

• restrictions on transfer, sale or other assignment, if any;

• whether interests in the preferred stock will be represented by depositary shares;

• a discussion of any material or special U.S. federal income tax considerations applicable to the preferred stock;

• the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

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• any limitations on issuances of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock being issued as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

• any other specific terms, rights, preferences, privileges, qualifications or restrictions of the preferred stock.

The Delaware General Corporation Law, or DGCL, which is the law of the state of our incorporation, provides that the holders of preferred stock will have the right to vote separately as a class (or, in some cases, as a series) on an amendment to our certificate of incorporation if the amendment would change the par value, the powers, preferences or special rights of the class or series so as to adversely affect the class or series, as the case may be, or, unless the certificate of incorporation provided otherwise, the number of authorized shares of the class. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

Registration Rights

Certain holders of shares of our common stock have the right to demand that we file a registration statement or request that we cover their shares by a registration statement that we otherwise file, as described below.

Demand Registration Rights

The holders of at least 75% of the shares having demand registration rights may, on not more than one occasion, request that we register all or a portion of their shares of common stock for sale under the Securities Act, subject to certain specified exceptions. Such request for registration must cover at least 75% of the registrable securities then outstanding for an aggregate offering price equal or greater than $25.0 million and a price per share equal to at least $26.79. In addition, holders of at least 25% of the shares having demand registration rights may, on no more than two registrations on Form S-3 within any 12-month period, request that we register all or a portion of their common stock for sale under the Securities Act on Form S-3, or any successor form, subject to specific exceptions, so long as the aggregate offering price to the public in connection with any such offering is more than $25.0 million.

Incidental Registration Rights

If we propose to register any shares of our common stock under the Securities Act either for our own account or for the account of other stockholders, the holders of all shares having piggyback registration rights are entitled to notice of the registration and to include all or a portion of their shares of common stock in the registration.

Other Provisions

In the event that any registration in which the holders of registrable shares participate pursuant to the investors’ rights agreement is an underwritten public offering, the number of registrable shares to be included may, in specified circumstances, be limited due to market conditions.

We will pay all registration expenses, other than underwriting discounts, selling commissions and stock transfer taxes, and the reasonable fees and expenses of a single special counsel for the selling stockholders, related to any demand, piggyback and Form S-3 registration. The investors’ rights agreement contains customary cross-indemnification provisions, pursuant to which we must indemnify the selling stockholders in the event of material misstatements or omissions in the registration statement attributable to us, and they must indemnify us for material misstatements or omissions in the registration statement attributable to them. The demand, piggyback and Form S-3 registration rights described above will expire, with respect to any particular stockholder, will expire no later than five years after our initial public offering, or with respect to any particular holder, at such time that such holder can sell its shares under Rule 144 of the Securities Act during any three-month period.

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Anti-Takeover Provisions

Section 203 of the Delaware General Corporation Law

We are subject to Section 203 of the DGCL, which prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:

• before such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

• upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding, but not the outstanding voting stock owned by the interested stockholder, those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

• on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock that is not owned by the interested stockholder.

In general, Section 203 defines a “business combination” to include the following:

• any merger or consolidation involving the corporation and the interested stockholder;

• any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;

• subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

• any transaction involving the corporation that has the effect of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; or

• the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits by or through the corporation.

In general, Section 203 defines an “interested stockholder” as an entity or person who, together with the entity or person’s affiliates and associates, beneficially owns, or is an affiliate or associate of the corporation and within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws

Among other things, our amended and restated certificate of incorporation and amended and restated bylaws will:

• permit our board of directors to issue up to 10,000,000 shares of preferred stock, with any rights, preferences and privileges as they may designate, including the right to approve an acquisition or other change in control;

• provide that the authorized number of directors may be changed only by resolution of our board of directors;

• provide that our board of directors will be classified into three classes of directors;

• provide that, subject to the rights of any series of preferred stock to elect directors, directors may only be removed for cause, which removal may be effected, subject to any limitation imposed by law, by the

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holders of at least a majority of the voting power of all of our then-outstanding shares of the capital stock entitled to vote generally at an election of directors;

• provide that all vacancies, including newly created directorships, may, except as otherwise required by law, be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum;

• require that any action to be taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and not be taken by written consent or electronic transmission;

• provide that stockholders seeking to present proposals before a meeting of stockholders or to nominate candidates for election as directors at a meeting of stockholders must provide advance notice in writing, and also specify requirements as to the form and content of a stockholder’s notice;

• provide that special meetings of our stockholders may be called only by the chairman of our board of directors, our chief executive officer or president or by our board of directors pursuant to a resolution adopted by a majority of the total number of authorized directors; and

• not provide for cumulative voting rights, therefore allowing the holders of a majority of the shares of common stock entitled to vote in any election of directors to elect all of the directors standing for election, if they should so choose.

• The amendment of any of these provisions would require approval by the holders of at least 66 ²/₃% of the voting power of all of our then-outstanding common stock entitled to vote generally in the election of directors, voting together as a single class.

The combination of these provisions will make it more difficult for our existing stockholders to replace our board of directors as well as for another party to obtain control of us by replacing our board of directors. Because our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change our control.

These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to reduce our vulnerability to hostile takeovers and to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and may have the effect of delaying changes in our control or management. As a consequence, these provisions may also inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts. We believe that the benefits of these provisions, including increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure our company, outweigh the disadvantages of discouraging takeover proposals, because negotiation of takeover proposals could result in an improvement of their terms.

Choice of Forum

Our amended and restated certificate of incorporation will provide that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall (or, if and only if the Court of Chancery of the State of Delaware lacks subject matter jurisdiction, any state court located within the State of Delaware or, if and only if all such state courts lack subject matter jurisdiction, the federal district court for the District of Delaware), the Court of Chancery of the State of Delaware will be the exclusive forum for (1) any derivative action or proceeding brought on our behalf, (2) any action or proceeding commenced by any of our stockholders (including any class action) asserting a breach of fiduciary duty owed, or other wrongdoing, by any director, officer, employee or agent to us or our stockholders, (3) any action or proceeding commenced by any of our stockholders (including any class action) asserting a claim against us arising pursuant to the DGCL or

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our amended and restated certificate of incorporation or our amended and restated bylaws, (4) any action or proceeding commenced by any of our stockholders (including any class action) to interpret, apply, enforce or determine the validity of our amended and restated certificate of incorporation or our amended and restated bylaws, or (5) any action or proceeding commenced by any of our stockholders (including any class action) asserting a claim against us that is governed by the internal affairs doctrine. The enforceability of similar choice of forum provisions in other companies’ certificates of incorporation has been challenged in legal proceedings, and it is possible that, in connection with one or more actions or proceedings described above, a court could find the choice of forum provisions contained in our amended and restated certificate of incorporation to be inapplicable or unenforceable.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent’s address is P.O. Box 30170, College Station, Texas 77842-3170. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the prospectus supplement for that series.

Listing on The Nasdaq Global Select Market

Our common stock is listed on Nasdaq under the symbol “OVID.”

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DESCRIPTION OF DEBT SECURITIES

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will be incorporated by reference from reports that we file with the SEC, supplemental indentures and forms of debt securities containing the terms of the debt securities being offered.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

General

The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

• the title of the series of debt securities;

• any limit upon the aggregate principal amount that may be issued;

• the maturity date or dates;

• the form of the debt securities of the series;

• the applicability of any guarantees;

• whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

• whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;

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• if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;

• the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

• our right, if any, to defer payment of interest and the maximum length of any such deferral period;

• if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

• the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

• the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

• any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

• whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

• if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

• if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;

• additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;

• additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

• additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

• additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

• additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

• the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

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• whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;

• the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;

• any restrictions on transfer, sale or assignment of the debt securities of the series; and

• any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

• if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;

• if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

• if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

• if specified events of bankruptcy, insolvency or reorganization occur.

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If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

• the direction so given by the holder is not in conflict with any law or the applicable indenture; and

• subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

• the holder has given written notice to the trustee of a continuing event of default with respect to that series;

• the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request,

• such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and

• the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

Modification of Indenture; Waiver

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

• to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

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• to comply with the provisions described above under “Description of Debt Securities—Consolidation, Merger or Sale;”

• to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

• to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;

• to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

• to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;

• to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under “Description of Debt Securities—General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

• to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

• to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

• extending the fixed maturity of any debt securities of any series;

• reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or

• reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

• provide for payment;

• register the transfer or exchange of debt securities of the series;

• replace stolen, lost or mutilated debt securities of the series;

• pay principal of and premium and interest on any debt securities of the series;

• maintain paying agencies;

• hold monies for payment in trust;

• recover excess money held by the trustee;

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• compensate and indemnify the trustee; and

• appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company, or DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

• issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

• register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

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Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.

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DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplement and in any related free writing prospectus that we may authorize to be distributed to you, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates listing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, as well as any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that list the terms of the warrants.

General

In the applicable prospectus supplement, we will describe the terms of the series of warrants being offered, including, to the extent applicable:

• the offering price and aggregate number of warrants offered;

• the currency for which the warrants may be purchased;

• the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

• in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable on exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased on such exercise;

• in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable on the exercise of one warrant and the price at which these shares may be purchased on such exercise;

• the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

• the terms of any rights to redeem or call the warrants;

• any provisions for changes to or adjustments in the exercise price or number of securities issuable on exercise of the warrants;

• the dates on which the right to exercise the warrants will commence and expire;

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• the manner in which the warrant agreements and warrants may be modified;

• a discussion of material or special U.S. federal income tax considerations of holding or exercising the warrants;

• the terms of the securities issuable on exercise of the warrants; and

• any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable on such exercise, including:

• in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or payments on our liquidation, dissolution or winding up or to exercise voting rights, if any; or

• in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable on exercise or to enforce covenants in the applicable indenture.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. The warrants may be exercised as listed in the prospectus supplement relating to the warrants offered. Unless we otherwise specify in the applicable prospectus supplement, warrants may be exercised at any time up to the specified time on the expiration date that we list in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

On receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable on such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand on us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable on exercise of, its warrants.

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LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee or depositary maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Global securities will be registered in the name of the depositary or its participants. Consequently, for global securities, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities that are not issued in global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

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For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of an indenture, or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

• how it handles securities payments and notices;

• whether it imposes fees or charges;

• how it would handle a request for the holders’ consent, if ever required;

• whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

• how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

• if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “—Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued as a global security, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

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Special Considerations for Global Securities

As an indirect holder, an investor’s rights relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only as global securities, an investor should be aware of the following:

• an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

• an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

• an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

• an investor may not be able to pledge his or her interest in the global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

• the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in the global security;

• we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in the global security, nor will we or any applicable trustee supervise the depositary in any way;

• the depositary may, and we understand that DTC will, require that those who purchase and sell interests in the global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

• financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in the global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, a global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

• if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

• if we notify any applicable trustee that we wish to terminate that global security; or

• if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

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The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the prospectus supplement. When a global security terminates, the depositary, and neither we nor any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

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PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

• at a fixed price or prices, which may be changed;

• at market prices prevailing at the time of sale;

• at prices related to such prevailing market prices; or

• at negotiated prices.

We may also sell equity securities covered by this registration statement in an “at the market offering” as defined in Rule 415 under the Securities Act. Such offering may be made into an existing trading market for such securities in transactions at other than a fixed price, either:

• on or through the facilities of Nasdaq or any other securities exchange or quotation or trading service on which such securities may be listed, quoted or traded at the time of sale; and/or

• other than on Nasdaq or such other securities exchanges or quotation or trading services.

Such at the market offerings, if any, may be conducted by underwriters acting as principal or agent.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

• the name or names of any underwriters, dealers or agents, if any;

• the purchase price of the securities and the proceeds we will receive from the sale;

• any over-allotment options under which underwriters may purchase additional securities from us;

• any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

• any public offering price;

• any discounts or concessions allowed or reallowed or paid to dealers; and

• any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities, and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

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We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. These transactions may be effected on any exchange or over-the-counter market or otherwise.

Any underwriters who are qualified market makers on Nasdaq may engage in passive market making transactions in the securities on Nasdaq in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, certain legal matters in connection with the offering and the validity of the securities offered by this prospectus, and any supplement thereto, will be passed upon by Cooley LLP. As of the date of this prospectus, a partner of Cooley LLP beneficially holds an aggregate of 7,465 shares of our common stock. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

The financial statements of Ovid Therapeutics, Inc. as of December 31, 2017 and 2016, and for each of the years in the three-year period ended December 31, 2017, have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of the registration statement on Form S-3 we filed with the SEC under the Securities Act. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. You should rely only on the information contained in this prospectus or incorporated by reference. We have not authorized anyone else to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy the registration statement, as well as any other document filed by us with the SEC, at the SEC’s Public Reference Room at 100 F Street NE, Washington, D.C. 20549. You can also request copies of these documents by writing to the SEC and paying a fee for the copying cost. You may obtain information on the operation of the Public Reference Room by calling the SEC at (800) SEC-0330. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC, including Ovid. The address of the SEC website is www.sec.gov.

We maintain a website at www.ovidrx.com. Information contained in or accessible through our website does not constitute a part of this prospectus.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The SEC file number for the documents incorporated by reference in this prospectus is 001-37708. The documents incorporated by reference into this prospectus contain important information that you should read about us.

The following documents are incorporated by reference into this document:

• our Annual Report on Form 10-K for the year ended December 31, 2017, filed with the SEC on March 29, 2018;

• the information specifically incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2017 from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 24, 2018;

• our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2018, filed with the SEC on May 8, 2018;

• our Current Reports on Form 8-K filed with the SEC on January 24, 2018, to the extent the information in such reports is filed and not furnished; and

• the description of our common stock contained in our Registration Statement on Form 8-A, filed with the SEC on May 4, 2017, including any amendments or reports filed for the purposes of updating this description.

We also incorporate by reference into this prospectus all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the initial filing of the registration statement of which this prospectus forms a part and prior to effectiveness of

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the registration statement, or (ii) after the date of this prospectus but prior to the termination of the offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to Ovid Therapeutics Inc., Attn: Ana C. Ward, Senior Vice President, General Counsel and Secretary, 1460 Broadway, 15044, New York, NY 10036; telephone: (646) 661-7661.

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9,000,000 Shares

Common Stock

PROSPECTUS SUPPLEMENT

Joint Book-Running Managers

Cowen William Blair

Co-Managers

JMP Securities Ladenburg Thalmann

October 4, 2019