SC TO-T/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO

TENDER OFFER STATEMENT UNDER SECTION 14(D)(1)

OR 13(E)(1) OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

TETRAPHASE PHARMACEUTICALS, INC.

(Name of Subject Company (Issuer))

TTP MERGER SUB, INC.

(Offeror)

LA JOLLA PHARMACEUTICAL COMPANY

(Parent of Offeror)

Common Stock, Par Value $0.001 Per Share

(Title of Class of Securities)

88165N204

(CUSIP Number of Class of Securities)

Michael Hearne

La Jolla Pharmaceutical Company

4550 Towne Centre Court, San Diego, California 92121

Tel. (858) 333-5769

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications on Behalf of Filing Persons)

Copies to:

Ryan A. Murr

James J. Moloney

Gibson, Dunn & Crutcher LLP

555 Mission Street, 30th Floor

San Francisco, California 94105

CALCULATION OF FILING FEE

Transaction Valuation*	Amount of Filing Fee**
$16,560,178	$2,150

* Estimated for purposes of calculating the amount of the filing fee only. Calculated by multiplying the 7,263,236 issued and outstanding shares of common stock, par value of $0.001 (“Shares”), of Tetraphase, Inc., a Delaware corporation (“Tetraphase”), by $2.28, the average of the high and low sales price per share of the common stock on July 27, 2020, as reported by Nasdaq.

** The filing fee was calculated in accordance with Rule 0-11 under the Securities Exchange Act of 1934, as amended, and Fee Rate Advisory No. 1 for Fiscal Year 2020, issued August 23, 2019, by multiplying the transaction value by 0.0001298.

☒ Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid: $2,531.33	Filing Party: La Jolla Pharmaceutical Company and TTP Merger Sub, Inc.
Form or Registration No.: Schedule TO	Date Filed: June 29, 2020

☐ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

☒	third-party tender offer subject to Rule 14d-1.
☐	issuer tender offer subject to Rule 13e-4.
☐	going-private transaction subject to Rule 13e-3.
☐	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer. ☒

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

☐	Rule 13e-4(i) (Cross-Border Issuer Tender Offer)
☐	Rule 14d-1(d) (Cross-Border Third-Party Tender Offer

This Amendment No. 1 (this “Amendment”) amends and supplements the Tender Offer Statement on Schedule TO (together with any amendments and supplements thereto, the “Schedule TO”) filed with the U.S. Securities and Exchange Commission (the “SEC”) on June 29, 2020 by: (i) TTP Merger Sub Inc., a Delaware corporation (“Purchaser”) and a wholly owned subsidiary of La Jolla Pharmaceutical Company, a California corporation (“LJPC”); and (ii) LJPC. The Schedule TO relates to the offer by Purchaser to purchase all of the outstanding shares of common stock, $0.001 par value per share (the “Shares”), of Tetraphase Pharmaceuticals, Inc., a Delaware corporation (the “Company”), at a price of $2.00 per Share, to the holder in cash, without interest, plus one non-transferable contractual contingent value right (“CVR”) per Share, which represents the right to receive one or more payments in cash, currently estimated to be up to approximately $1.48 per CVR, assuming the anticipated maximum number of CVRs are issued and contingent upon the achievement of certain specified milestones, calculated as described in the Offer to Purchase dated June 29, 2020 (together with any amendments or supplements thereto, the “Offer to Purchase”) and in the accompanying Letter of Transmittal (together with any amendments or supplements thereto and with the Offer to Purchase, the “Offer”), which are annexed to and filed with the Schedule TO as Exhibits (a)(1)(A) and (a)(1)(B), respectively. Except as otherwise set forth in this Amendment, the information set forth in the Schedule TO remains unchanged and is expressly incorporated herein by reference in answer to Items 1 through 9 and Item 11 of this Amendment. This Amendment should be read together with the Schedule TO. Capitalized terms used but not defined herein have the meanings assigned to such terms in the Offer to Purchase.

Amendments to Schedule TO and the Offer to Purchase

Items 1 through 9 and Item 11.

The Offer to Purchase and Items 1 through 9 and 11 of the Schedule TO, to the extent such Items incorporate by reference the information contained in the Offer to Purchase, are hereby amended and supplemented to include the following:

“The Offer and withdrawal rights expired as scheduled at one minute following 11:59 p.m., Eastern Time on Monday, July 27, 2020 (such date and time, the “Expiration Date”). The Depositary and Paying Agent has advised LJPC and Purchaser that, as of the Expiration Date, a total of 3,737,360 Shares (excluding Shares with respect to which Notices of Guaranteed Delivery were delivered but were not yet “received” (as such term is defined in Section 251(h)(6)(f) of the DGCL)) were validly tendered pursuant to the Offer and not properly withdrawn, representing approximately 51.5% of the Shares outstanding as of the Expiration Date. In addition, the Depositary and Paying Agent has advised LJPC and Purchaser that, as of the Expiration Date, Notices of Guaranteed Delivery had been delivered with respect to 311,329 additional Shares, representing approximately 4.3% of the outstanding Shares as of the Expiration Date.

As of the Expiration Date, the number of Shares validly tendered pursuant to the Offer and not properly withdrawn satisfied the Minimum Condition, and all other Offer Conditions were satisfied or waived. Promptly following the Expiration Date, Purchaser irrevocably accepted for payment all Shares validly tendered pursuant to the Offer and not properly withdrawn. As a result of its acceptance for payment of the Shares tendered pursuant to the Offer and in accordance with Section 251(h) of the DGCL, Purchaser acquired ownership of at least the percentage of Shares that would be required to adopt the Merger Agreement by a vote of the stockholders of the Company. LJPC and Purchaser completed the acquisition of the Company on July 28, 2020 by consummating the Merger pursuant to the Merger Agreement without a vote of the stockholders of the Company in accordance with Section 251(h) of the DGCL, with the Company surviving the Merger as a wholly owned subsidiary of LJPC. At the Effective Time, all then outstanding Shares (other than: (i) Shares held by Tetraphase (or held in the treasury of Tetraphase); (ii) Shares held by La Jolla, Purchaser or any other direct or indirect wholly owned subsidiary of La Jolla; and (iii) Shares held by stockholders who have properly exercised and perfected their demands for appraisal of such Shares in accordance with the DGCL and have neither withdrawn nor lost such rights prior to the Effective Time) were converted into the right to receive consideration equal to the Offer Price, without interest, and subject to applicable withholding of taxes.

In connection with the consummation of the Merger, the Shares will be delisted and will cease to trade on the Nasdaq Global Select Market. LJPC and Purchaser intend to take steps to cause the termination of the registration of the Shares under the Exchange Act and the suspension of all of the Company’s reporting obligations under the Exchange Act as promptly as practicable.”

ITEM 12.  EXHIBITS.

Item 12 of the Schedule TO is hereby amended and supplemented by adding the following exhibit:

Index No.
(a)(5)(B)	Press Release dated July 28, 2020, announcing the expiration and results of the Offer.

EXHIBIT INDEX

Index No.
(a)(1)(A)	Offer to Purchase, dated June 29, 2020.
(a)(1)(B)	Form of Letter of Transmittal.
(a)(1)(C)	Form of Notice of Guaranteed Delivery.
(a)(1)(D)	Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.
(a)(1)(E)	Form of Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees.
(a)(1)(F)	Form of Summary Advertisement, published June 29, 2020 in the Wall Street Journal.
(a)(5)(A)	Letter to Stockholders of Tetraphase, dated June 29, 2020, from Larry Edwards, President and Chief Executive Officer of Tetraphase (incorporated herein by reference to Exhibit (a)(1)(H) to Schedule 14D-9 filed by Tetraphase on June 29, 2020).
(a)(5)(B)*	Press release dated July 28, 2020, announcing the expiration and results of the Offer.
(b)	Not applicable.
(d)(1)	Agreement and Plan of Merger, dated June 24, 2020, by and among Tetraphase, LJPC and Purchaser (incorporated herein by reference to Exhibit 2.1 to Form 8-K filed by Tetraphase on June 24, 2020).
(d)(2)	Confidentiality Agreement, dated May 8, 2020, by and between Tetraphase and LJPC.
(d)(3)	Form of Support Agreement, dated June 24, 2020, by and among LJPC, the Purchaser and the stockholder named therein (incorporated herein by reference to Exhibit 10.2 to Form 8-K filed by Tetraphase on June 24, 2020).
(d)(4)	Form of Contingent Value Rights Agreement, by and between LJPC and the Rights Agent (incorporated herein by reference to Exhibit 10.1 to Form 8-K filed by Tetraphase on June 24, 2020).
(d)(5)	Guarantee Agreement, dated June 24, 2020, by the Tang Capital Partners, LP in favor of Tetraphase.
(g)	Not applicable.
(h)	Not applicable.

* Filed herewith.

SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: July 28, 2020

TTP MERGER SUB, INC.
By:	/s/ Michael Hearne
Name:	Michael Hearne
Title:	Chief Financial Officer
LA JOLLA PHARMACEUTICAL COMPANY
By:	/s/ Michael Hearne
Name:	Michael Hearne
Title:	Chief Financial Officer

EX-99.(A)(5)(B)

Exhibit (a)(5)(B)

La Jolla Pharmaceutical Company Announces the Closing of Acquisition of Tetraphase  Pharmaceuticals, Inc.

-Combined Company Offers Two Innovative Therapies to Treat Patients Suffering from Life-threatening  Diseases-

SAN DIEGO, California and WATERTOWN, Massachusetts, July 28, 2020 (GLOBE NEWSWIRE) -- La Jolla Pharmaceutical Company (Nasdaq: LJPC), which is dedicated to the development and commercialization of innovative therapies that improve outcomes in patients suffering from life-threatening diseases, and Tetraphase Pharmaceuticals, Inc. (Nasdaq: TTPH), a biopharmaceutical company focused on commercializing its novel tetracycline XERAVA™ (eravacycline) to treat serious and life-threatening infections, today announced the closing of La Jolla's acquisition of Tetraphase. La Jolla acquired Tetraphase for $43.0 million in upfront cash plus potential future cash payments of up to $16.0 million pursuant to contingent value rights (CVRs). The holders of the CVRs are entitled to receive payments of up to an additional $16.0 million in the aggregate upon the achievement of certain net sales of XERAVA in the United States.

“With two, FDA-approved, innovative therapies for life-threatening diseases, La Jolla is well-positioned to help patients in need,” said Larry Edwards, President and Chief Executive Officer of La Jolla. “By leveraging the stronger platform that the combined company will provide, we look forward to increasing patient access to these important medicines.”

About GIAPREZA

GIAPREZA™ (angiotensin II) for injection was approved by the U.S. Food and Drug Administration (FDA) as a vasoconstrictor indicated to increase blood pressure in adults with septic or other distributive shock. GIAPREZA was approved by the European Commission (EC) for the treatment of refractory hypotension in adults with septic or other distributive shock who remain hypotensive despite adequate volume restitution and application of catecholamines and other available vasopressor therapies. GIAPREZA mimics the body’s endogenous angiotensin II peptide, which is central to the renin-angiotensin-aldosterone system, which in turn regulates blood pressure. Prescribing information for GIAPREZA is available at www.giapreza.com. The European Summary of Product Characteristics is available on the EMA website: www.ema.europa.eu/en/medicines/human/EPAR/giapreza. GIAPREZA is marketed in the U.S. by La Jolla Pharmaceutical Company on behalf of La Jolla Pharma, LLC, its wholly owned subsidiary.

GIAPREZA Important Safety Information Contraindications

None.

Warnings and Precautions

There is a potential for venous and arterial thrombotic and thromboembolic events in patients who receive GIAPREZA. Use concurrent venous thromboembolism (VTE) prophylaxis.

Adverse Reactions

The most common adverse reactions that were reported in greater than 10% of GIAPREZA-treated patients were thromboembolic events.

Drug Interactions

Angiotensin converting enzyme (ACE) inhibitors may increase response to GIAPREZA. Angiotensin II receptor blockers (ARBs) may reduce response to GIAPREZA.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800- FDA-1088.

For additional information, please see Full Prescribing Information for the United States and the Summary of Product Characteristics for the European Union.

About XERAVA

XERAVA™ (eravacycline) for injection was approved by the U.S. Food and Drug Administration (FDA) as a novel fluorocycline of the tetracycline class antibacterials indicated for the treatment of complicated intra-abdominal infections (cIAI) in patients 18 years of age and older. XERAVA was investigated for the treatment of cIAI as part of Tetraphase's IGNITE (Investigating Gram-Negative Infections Treated with Eravacycline) Phase 3 program. In the first pivotal Phase 3 trial in patients with cIAI, twice-daily intravenous (IV) XERAVA met the primary endpoint by demonstrating statistical non-inferiority of clinical response compared to ertapenem and was well tolerated. In the second Phase 3 clinical trial in patients with cIAI, twice-daily IV XERAVA met the primary endpoint by demonstrating statistical non-inferiority of clinical response compared to meropenem and was well tolerated. In both trials, XERAVA achieved high cure rates in patients with

Gram-negative pathogens, including resistant isolates. Prescribing information for XERAVA is available at www.xerava.com. XERAVA is marketed in the U.S. by Tetraphase Pharmaceuticals, Inc., a wholly owned subsidiary of La Jolla.

XERAVA Important Safety Information

XERAVA is a tetracycline class antibacterial indicated for the treatment of complicated intra-abdominal infections in patients 18 years of age and older.

XERAVA is not indicated for the treatment of complicated urinary tract infections.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of XERAVA and other antibacterial drugs, XERAVA should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.

XERAVA is contraindicated for use in patients with known hypersensitivity to eravacycline, tetracycline-class antibacterial drugs or to any of the excipients. Life-threatening hypersensitivity (anaphylactic) reactions have been reported with XERAVA.

The use of XERAVA during tooth development (last half of pregnancy, infancy and childhood to the age of eight years) may cause permanent discoloration of the teeth (yellow-gray-brown) and enamel hypoplasia.

The use of XERAVA during the second and third trimester of pregnancy, infancy and childhood up to the age of eight years may cause reversible inhibition of bone growth.

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents and may range in severity from mild diarrhea to fatal colitis.

The most common adverse reactions observed in clinical trials (incidence ≥ 3%) were infusion site reactions, nausea and vomiting.

XERAVA is structurally similar to tetracycline-class antibacterial drugs and may have similar adverse reactions. Adverse reactions including photosensitivity, pseudotumor cerebri and anti-anabolic action, which has led to increased blood urea nitrogen, azotemia, acidosis, hyperphosphatemia, pancreatitis and abnormal liver function tests, have been reported for other tetracycline-class antibacterial drugs, and may occur with XERAVA. Discontinue XERAVA if any of these adverse reactions are suspected.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800- FDA-1088.

For additional information, please see Full Prescribing Information for the United States. About La Jolla Pharmaceutical Company

La Jolla Pharmaceutical Company is dedicated to the development and commercialization of innovative therapies that improve outcomes in patients suffering from life-threatening diseases. GIAPREZA™ (angiotensin II) is approved by the U.S. FDA as a vasoconstrictor indicated to increase blood pressure in adults with septic or other distributive shock. XERAVA™ (eravacycline) is approved by the U.S. FDA for the treatment of complicated intra-abdominal infections. For more information, please visit www.ljpc.com.

Forward-looking  Statements

This press release contains “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995. We caution investors that forward-looking statements are based on management’s expectations and assumptions as of the date of this press release and involve substantial risks and uncertainties that could cause the actual outcomes to differ materially from what we currently expect.

These risks and uncertainties include, but are not limited to, those associated with: GIAPREZA™ (angiotensin II) and

XERAVA™ (eravacycline) sales; whether La Jolla will realize the benefits from the acquisition of Tetraphase Pharmaceuticals, Inc.; regulatory actions relating to La Jolla’s products by the U.S. FDA, European Commission and/or other regulatory authorities; cash used in operating activities and our capital requirements; and other risks and uncertainties identified in our filings with the U.S. Securities and Exchange Commission. Forward-looking statements in this press release apply only as of the date made, and we undertake no obligation to update or revise any forward-looking statements to reflect subsequent events or circumstances.

La Jolla Pharmaceutical Company Contact:

Michael Hearne

Chief Financial Officer

La Jolla Pharmaceutical Company (858) 333-5769

mhearne@ljpc.com