8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 24, 2021

KALEIDO BIOSCIENCES, INC.

(Exact name of registrant as specified in its charter)

Delaware	001-38822	47-3048279
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

65 Hayden Avenue Lexington, MA	02421
(Address of principal executive offices)	(Zip Code)

Registrant's telephone number, including area code: (617) 674-9000

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.001 Par Value	KLDO	NASDAQ Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Item 7.01 Regulation FD Disclosure.

The Company is furnishing a presentation, attached as Exhibit 99.1 to this Current Report on Form 8-K, summarizing the results from its controlled non-IND clinical study K031 evaluating Microbiome Metabolic Therapy (MMT™) candidate KB109 when added to Supportive Self-Care for outpatients with mild-to-moderate COVID-19 disease, which the Company intends to use from time to time in meetings with investors and others. The corporate presentation also includes information on a recently completed Food & Drug Administration (FDA) clinical inspection of the K031 study, as well as K032, a second non-IND clinical study evaluating KB109 for outpatients with mild-to-moderate COVID-19 disease.  At the conclusion of the inspection, the FDA issued a Form 483 with a single observation that the Company failed to submit an IND prior to conducting a clinical investigation that the FDA concluded was of an investigational new drug.  There were no findings related to the conduct or oversight of the studies.

Item 8.01 Other Events

On March 24, 2021, the Company issued a press release announcing results from its controlled non-IND clinical study K031 evaluating Microbiome Metabolic Therapy (MMT™) candidate KB109 when added to Supportive Self-Care for outpatients with mild-to-moderate COVID-19 disease. A copy of the press release is furnished as Exhibit 99.2 to this Current Report on Form 8-K.

On March 24, 2021, the Company will host a conference call and webcast at 8:30 A.M. to discuss the K031 results. A copy of the deck attached hereto as Exhibit 99.1 will be utilized in the presentation.  An updated version of the Company’s corporate presentation will also be available in the investor relations section of the Company’s website at http://kaleido.com.

The information in this Form 8-K (including Exhibits 99.1, and 99.2) shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits:

Exhibit No.	Description
99.1	K031 Topline Final Data Analysis, dated March 24, 2021, furnished herewith
99.2	Press release issued by the Company, dated March 24, 2021, furnished herewith
104	Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	KALEIDO BIOSCIENCES, INC.
Date: March 24, 2021	By:	/s/ Daniel Menichella
		Daniel Menichella
		Chief Executive Officer, President and Director

EX-99.1

K031 Topline Final Data Analysis March 24, 2021 Exhibit 99.1

Forward-Looking Statements This presentation also contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding our strategy, business plans and focus, including the therapeutic potential of our Microbiome Metabolic Therapy (MMT) candidates, the timing of initiation, completion and reporting of results of our clinical studies and our strategy, business plans and focus. The words “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this presentation are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this presentation, including, without limitation, those related to planned clinical and preclinical studies and areas of interest, the preclinical and clinical development and safety profile of our MMT candidates and timelines associated with the programs for such MMT candidates, whether and when, if at all, the U.S. Food and Drug Administration will approve our IND application for KB109, whether and when, if at all, our MMT candidates will receive approval from the U.S. Food and Drug Administration or other applicable regulatory agencies, if any, competition from other biotechnology companies, and other risks identified in our SEC filings, including the most recently filed 10-K. We caution you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. We disclaim any obligation to update or revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

*Non-IND Clinical Study conducted under regulations supporting research with food, evaluating safety, tolerability and potential markers of human effect. KB109 in COVID-19 Final Analysis High propionate High acetate Multi-center, open label, controlled clinical study* Mild-to-moderate COVID-19 Two weeks administration Endpoints: Primary: Safety and tolerability, Healthcare Utilization, Time to resolution of symptoms, Biomarkers of the inflammatory response 350 outpatients Supportive self-care (control) N=181 Supportive self-care + KB109 N=169 1:1 randomization Up to three weeks follow up Baseline characteristics were well matched between the groups, except for a higher proportion of patients reporting comorbidities at baseline, 41% KB109 + SSC vs 36% SSC alone.

Results: Favorable Safety and Tolerability Profile Largest study of MMTs conducted so far, leading to most comprehensive safety data set to date Well tolerated with similar number of treatment emergent SAEs in both arms (2 in KB109 vs. 3 in SSC alone) Hospitalizations: 3 in KB109+SSC vs 3 in SSC alone arm More GI-related AEs reported in KB109+SSC arm (21% vs 5%) Similar to that seen in previous studies of MMTs All were mild/moderate Fewer respiratory-related AEs and infections of special interest (e.g., pneumonia/ILI) in KB109+SSC versus SSC alone arm (16 cases vs 29 cases)

COVID-19 related Hospitalization, Emergency room, or Urgent Care visits (Safety Analysis Set) KB109 – Healthcare Utilization Data Statistics SSC + KB109 (N=69) SSC alone (N=66) Overall (N=135) % change (SSC + KB109 vs SSC alone) N (%) 4 (5.8%) 10 (15.2%) 14 (10.4%) -61.8% Comorbidity Patient Subgroup Statistics SSC + KB109 (N=169) SSC alone (N=181) Overall (N=350) % change (SSC + KB109 vs SSC alone) N (%) 7 (4.1%) 15 (8.3%) 22 (6.3%) -50.6% Overall Study Population

Proportion of Patients with Resolution Natural History of COVID-19 Infection: SSC Alone Arms Comparing patients with and without comorbidities shows extended duration of symptoms, especially in patients with at least one comorbidity 13 Overall Symptoms8 Cardinal Symptoms Proportion of Patients with Resolution Median time to resolution of symptoms: SSC No comorbidity = 21 days SSC + Comorbidity = 30 days Median time to resolution of symptoms: SSC No comorbidity = 15 days SSC + Comorbidity = 21 days 13 Covid-related symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, sore throat, gastrointestinal disturbance/symptoms, diarrhea, fatigue, nasal congestion, and chest tightness; 8 cardinal symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, and sore throat

13 Symptoms Time to Resolution of Covid-19 Symptoms for Patients with Comorbidity KB109 + SSC vs. SSC alone 21 vs 30 days, HR=1.4217 (0.8982, 2.2501); p=NS 13 Covid-related symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, sore throat, gastrointestinal disturbance/symptoms, diarrhea, fatigue, nasal congestion, and chest tightness 8 cardinal symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, and sore throat 8 Symptoms 17 vs 21 days, HR=1.5743 (0.9974, 2.4848) ; p=NS

Additional studies will further elucidate the role KB109 may play in allowing patients with comorbidities to recover more quickly Potential Clinical Implications Median time to resolution of symptoms: SSC No comorbidity = 15 days SSC + Comorbidity = 21 days KB109 + SSC + Comorbidity = 17 days Median time to resolution of symptoms: SSC No comorbidity = 21 days SSC + Comorbidity = 30 days KB109 + SSC + Comorbidity = 21 days 13 Overall Symptoms8 Cardinal Symptoms Proportion of Patients with Resolution Proportion of Patients with Resolution

13 Symptoms Exploratory Analysis of Time to Resolution of Covid-19 Symptoms ≥45 years or with Comorbidity KB109 + SSC vs. SSC alone 13 Covid-related symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, sore throat, gastrointestinal disturbance/symptoms, diarrhea, fatigue, nasal congestion, and chest tightness 8 cardinal symptoms: Cough, chills/repeated shaking with chills, muscle pain, fever, headache, anosmia/ageusia, shortness of breath, and sore throat 8 Symptoms 21 vs 31 days, HR=1.597 (1.064, 2.398) ; p<0.05 16 vs 24 days, HR=1.584 (1.064, 2.347) ; p<0.05 Proportion of Patients with Resolution Proportion of Patients with Resolution

KB109: Regulatory Interactions and Next Steps Engaging with FDA and other regulatory agencies with the goal of opening an IND and CTAs in Q4 2021 Pre-IND discussions with FDA Gained alignment on nonclinical toxicology program to support IND filing Ongoing discussions to seek alignment in support of late-stage clinical development program and CMC CTA planning: Received country-level scientific advice from 4 countries in Europe related to nonclinical and clinical development Goal is to move directly into a pivotal registration program FDA recently completed a clinical inspection of K031 and K032 No findings related to the conduct or oversight of the clinical studies, supporting the high quality of the data and its inclusion in potential IND or CTA filings FDA issued one 483 observation related to not submitting an IND for the clinical studies Kaleido takes this observation seriously and is committed to working with the FDA to gain alignment Kaleido has fully responded to the observation, including an explanation of our view that safety and tolerability studies of GRAS articles are appropriate without an IND and requesting to meet with FDA to discuss our approach for conducting future clinical food studies

Population at risk for hospitalization is in great need of respiratory viral therapeutics during this current pandemic and beyond The 45% COVID-19 infected adults with comorbidities1 The 40%+ of cases that occur in adults ≥45 years old2 The 10%+ of addressable patients with “long-COVID” published long-hauler rate variable and up to 30% Exploring the potential for combination with anti-viral therapeutics (e.g., mAbs and small molecules) 1. Adams ML et al. Population-Based Estimates of Chronic Conditions Affecting Risk for Complications from Coronavirus Disease, United States. Emerg Inf Dis. 2020 2. https://covid.cdc.gov/covid-data-tracker/#demographics accessed 19 March 2021 3.monoclonal antibody 4. Bamlanivimab Fact Sheet https://www.fda.gov/media/143603/download accessed 19 March 2021. 5. Bamlanivimab and etesevimab Fact Sheet. https://www.fda.gov/media/145802/download accessed 19 March 2021. SARS-CoV-2 is still circulating globally Unknown durability and effectiveness of current vaccines to COVID-19 and variants Specific SARS-CoV-2 variants show diminished susceptibility to some mAb3,4,5 Additional respiratory viral treatment needs U.S. COVID-19 patients potentially addressable by KB109 include: The macro landscape continues to evolve:

Live Q&A Session

Back-up Slides

Symptom Duration and Risk Factors for Delayed Return to Usual Health Among Outpatients with COVID-19 in a Multistate Health Care Systems Network — United States, March–June 2020. Available at: https://www.cdc.gov/mmwr/volumes/69/wr/mm6930e1.htm Estimated Disease Burden of COVID-19. Available at: https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/burden.html Adams ML et al. Population-Based Estimates of Chronic Conditions Affecting Risk for Complications from Coronavirus Disease, United States. Emerg Inf Dis. 2020 K031 Study Population: Most Prevalent, Yet Understudied Est. 83.1M COVID-19 infections in US (2020)2 Most studies in COVID-19 to date have focused on symptoms duration and clinical outcomes in adults hospitalized with severe COVID-19. Monoclonal Antibodies are indicated for treating mild-to-moderate COVID-19 in adults and children over 12 years old who are at high risk for progressing to severe COVID-19 and/or hospitalization. Little prospective data exists in the largest segment of patients, those at low-risk for progressing to severe COVID-19 and/or hospitalization. Retrospective reports suggest it can take 3-4 weeks for resolution of symptoms and return to usual health in so-called “mild” COVID patients1 K031 assessed normal disease course and effects of KB109 in low-risk COVID-19 patients in an outpatient setting. 70.4M symptomatic2 # ~38% pts in study had at least 1 comorbidity * >60% pts in REGN and LLY mAb studies had at least 1 risk factor for hospitalization/severe COVID-19 12.7M asymptomatic2 4.1M Hosp- italizations2 K031 population# mAb population* ~ 45% with 1+ comorbidity3

K031 Study Design Enrollment Period Up to 12 Days If symptomatic: Must not report significant improvement in cardinal symptoms in 48 hrs immediately prior to randomization If pre-symptomatic: symptom development within 7 days of a positive test and randomization within 5 days of the symptoms showing Day-2 to -1 Informed consent KB109+SSC or SSC Only 14 Days Follow-up Period 21 Days Day 1-2 2 days Day 3-4 2 days Day 5-14 10 days Day 15-35 21 days Study Arm (n=350-400) KB109 + SSC (n=175-200) SSC (n=175-200) 18 g (9 g BID) 36 g (18 g BID) 72 g (36 g BID) Supportive Self-Care Supportive Self-Care Day 1* (+1 day) Day 3 (+-1 day) Day 7 (+-1 day) Day 10 (+-1 day) Day 14 (+-3 day) Day 21 (+-1 day) Day 28 (+-1 day) Day 35* (+-1 day) As needed telemedicine visit (s) = Sample collection = Telemedicine Visit (*Includes wellness assessments) = Randomization = Wellness Visit by phone

K031 Study Objectives Primary Objective: Evaluate the safety of KB109 in addition to Supportive Self Care (SSC + KB109) compared to SSC alone in outpatients with mild-to-moderate COVID‑19. Secondary Objective: Evaluate selected measures of health in outpatients with mild-to-moderate COVID-19. Exploratory Objectives: Evaluate measures of health in outpatients with mild-to-moderate COVID-19 during the follow-up period Evaluate the changes in laboratory measures, specific biomarkers, serology and viral load in outpatients with mild-to-moderate COVID-19 (to be available in Q2/Q3 2021)

Treatment Emergent AEs by SOC (≥ 2%) and Preferred Term System Organ Class Preferred Term SSC + KB109 (N=169) n (%) SSC Alone (N=181) n (%) Overall (N=350) n (%) Patients with at Least One TEAE 61 (36.1) 48 (26.5) 109 (31.1)   Gastrointestinal disorders 35 (20.7) 9 (5.0) 44 (12.6) Diarrhoea 18 (10.7) 6 (3.3) 24 (6.9) Nausea 6 (3.6) 1 (0.6) 7 (2.0) Abdominal pain 5 (3.0) 1 (0.6) 6 (1.7) Abdominal distension 4 (2.4) 0 4 (1.1) Flatulence 4 (2.4) 0 4 (1.1) Gastrointestinal disorder 3 (1.8) 0 3 (0.9) Abdominal pain upper 1 (0.6) 1 (0.6) 2 (0.6) Dyspepsia 1 (0.6) 0 1 (0.3) Gastrointestinal sounds abnormal 1 (0.6) 0 1 (0.3) Abdominal discomfort 0 1 (0.6) 1 (0.3) Gastric ulcer 0 1 (0.6) 1 (0.3) Gastritis 0 1 (0.6) 1 (0.3)   Respiratory, thoracic and mediastinal disorders 15 (8.9) 25 (13.8) 40 (11.4)   Dyspnoea 8 (4.7) 10 (5.5) 18 (5.1) Oropharyngeal pain 4 (2.4) 7 (3.9) 11 (3.1) Cough 2 (1.2) 8 (4.4) 10 (2.9) Dyspnoea exertional 2 (1.2) 1 (0.6) 3 (0.9) Nasal congestion 2 (1.2) 3 (1.7) 5 (1.4) Hypoxia 1 (0.6) 1 (0.6) 2 (0.6) Pleurisy 1 (0.6) 0 1 (0.3) Acute respiratory failure 0 1 (0.6) 1 (0.3) Lower respiratory tract congestion 0 2 (1.1) 2 (0.6)   Nervous system disorders 7 (4.1) 6 (3.3) 13 (3.7) Ageusia 4 (2.4) 1 (0.6) 5 (1.4) Anosmia 4 (2.4) 1 (0.6) 5 (1.4) Headache 3 (1.8) 5 (2.8) 8 (2.3) Hypoaesthesia 0 1 (0.6) 1 (0.3) Paraesthesia 0 1 (0.6) 1 (0.3)   System Organ Class Preferred Term SSC + KB109 (N=169) n (%) SSC Alone (N=181) n (%) Overall (N=350) n (%) Infections and infestations 6 (3.6) 7 (3.9) 13 (3.7) COVID-19 1 (0.6) 2 (1.1) 3 (0.9) Ear infection 1 (0.6) 0 1 (0.3) Pharyngitis streptococcal 1 (0.6) 0 1 (0.3) Pneumonia 1 (0.6) 4 (2.2) 5 (1.4) Tonsillitis 1 (0.6) 0 1 (0.3) Urinary tract infection 1 (0.6) 0 1 (0.3) Gastroenteritis viral 0 1 (0.6) 1 (0.3) Pneumonia viral 0 1 (0.6) 1 (0.3) Sepsis 0 1 (0.6) 1 (0.3) Sinusitis 0 1 (0.6) 1 (0.3)   General disorders and administration site conditions 3 (1.8) 6 (3.3) 9 (2.6) Chills 2 (1.2) 2 (1.1) 4 (1.1) Chest discomfort 1 (0.6) 2 (1.1) 3 (0.9) Fatigue 1 (0.6) 2 (1.1) 3 (0.9)   Influenza like illness 0 1 (0.6) 1 (0.3)   Musculoskeletal and connective tissue disorders 3 (1.8) 4 (2.2) 7 (2.0) Arthralgia 1 (0.6) 0 1 (0.3) Back pain 1 (0.6) 0 1 (0.3) Musculoskeletal pain 1 (0.6) 0 1 (0.3) Pain in extremity 1 (0.6) 0 1 (0.3) Myalgia 0 4 (2.2) 4 (1.1)  

Subgroup Analysis of Time to Resolution of Overall 13 Symptoms Intake Period and Follow-up Period                                                                     SSC + KB109 (N=169) SSC Alone (N=172) SSC + KB109 vs. SSC Alone Subgroup N1 Patients with Event n (%) Median Time (95% CI) (day)[1] N1 Patients with Event n (%) Median Time (95% CI) (day)[1] Hazard Ratio [2] 95% CI   Overall 146 113 (66.9) 19.0 (16.0, 23.0) 147 106 (61.6) 22.0 (19.0, 30.0) 1.2539 (0.9566, 1.6437)   Age Group (years) >=18 to <45 98 79 (46.7) 19.0 (14.0, 23.0) 98 75 (43.6) 20.0 (17.0, 28.0) 1.1794 (0.8539, 1.6290) >=45 to <65 41 29 (17.2) 20.0 (15.0, 31.0) 44 26 (15.1) 32.0 (21.0, NA) 1.8646 (1.0674, 3.2570) >=65 7 5 (3.0) 28.0 (13.0, NA) 5 5 (2.9) 19.0 (9.0, NA) 0.2996 (0.0104, 8.6610)   Comorbidity Status Yes 61 45 (26.6) 21.0 (16.0, 28.0) 53 35 (20.3) 30.0 (20.0, 32.0) 1.4217 (0.8982, 2.2501) No 85 68 (40.2) 18.0 (14.0, 23.0) 94 71 (41.3) 21.0 (15.0, 29.0) 1.1946 (0.8512, 1.6766)   Baseline BMI Subgroup (kg/m2) < 30 96 74 (43.8) 19.0 (15.0, 24.0) 93 67 (39.0) 22.0 (19.0, 30.0) 1.2918 (0.9174, 1.8191) >= 30 49 38 (22.5) 21.0 (16.0, 27.0) 53 38 (22.1) 24.0 (18.0, 32.0) 1.2632 (0.7911, 2.0171)   Ethnicity Hispanic or Latino 89 72 (42.6) 16.0 (14.0, 21.0) 96 70 (40.7) 20.0 (15.0, 28.0) 1.4179 (1.0112, 1.9881) Not Hispanic or Latino 56 40 (23.7) 23.0 (19.0, 30.0) 50 36 (20.9) 30.0 (21.0, 32.0) 1.2161 (0.7518, 1.9670) Table of Time to resolution - FAS

Table of Time to resolution - FAS Subgroup Analysis of Time to Resolution of 8 Cardinal Symptoms Intake Period and Follow-up Period                                                                     SSC + KB109 (N=169) SSC Alone (N=172) SSC + KB109 vs. SSC Alone Subgroup N1 Patients with Event n (%) Median Time (95% CI) (day)[1] N1 Patients with Event n (%) Median Time (95% CI) (day)[1] Hazard Ratio [2] 95% CI   Overall 130 107 (63.3) 15.0 (13.0, 19.0) 134 105 (61.0) 19.0 (14.0, 21.0) 1.1262 (0.8558, 1.4819)     Age Group (years) >=18 to <45 85 68 (40.2) 16.0 (11.0, 21.0) 89 72 (41.9) 15.0 (13.0, 19.0) 0.9764 (0.6978, 1.3662) >=45 to <65 38 32 (18.9) 15.0 (12.0, 23.0) 41 29 (16.9) 24.0 (20.0, 30.0) 1.9645 (1.1301, 3.4152) >=65 7 7 (4.1) 21.0 (7.0, NA) 4 4 (2.3) 11.0 (9.0, NA) 0.0526 (0.0031, 0.8865)   Comorbidity Status Yes 57 48 (28.4) 17.0 (12.0, 21.0) 49 36 (20.9) 21.0 (17.0, 30.0) 1.5743 (0.9974, 2.4848) No 73 59 (34.9) 14.0 (11.0, 21.0) 85 69 (40.1) 15.0 (12.0, 19.0) 0.9623 (0.6742, 1.3735)   Baseline BMI Subgroup (kg/m2) < 30 87 72 (42.6) 15.0 (12.0, 21.0) 87 69 (40.1) 17.0 (13.0, 21.0) 1.0754 (0.7634, 1.5149) >= 30 42 34 (20.1) 16.5 (11.0, 21.0) 46 35 (20.3) 20.0 (14.0, 30.0) 1.5441 (0.9293, 2.5655)   Ethnicity Hispanic or Latino 81 69 (40.8) 15.0 (10.0, 18.0) 85 68 (39.5) 15.0 (12.0, 20.0) 1.1566 (0.8181, 1.6353) Not Hispanic or Latino 48 37 (21.9) 19.0 (12.0, 25.0) 48 37 (21.5) 22.0 (17.0, 30.0) 1.1762 (0.7325, 1.8888)

Recent Antibody Data Provides Useful Context for K031 Data from broad population in the mAb studies did not show strong results for symptoms or outcomes, leading to conditions of FDA EUA requiring a population of patients with higher risk; comorbidities and advanced age: High risk is defined as patients who meet at least one of the following criteria: Have a body mass index (BMI) ≥35, chronic kidney disease, diabetes, immunosuppressive disease Currently receiving immunosuppressive treatment ≥65 years of age ≥55 years of age AND have CV disease, OR hypertension, OR COPD/chronic respiratory disease FDA Letter Issued February 25, 2021 [Lilly, Regeneron] will establish a process for monitoring genomic database(s) for the emergence of global viral variants of SARS-CoV-2. FDA may require [Lilly, Regeneron] to assess the activity of the authorized [mAb] against any global SARS-CoV-2 variant(s) of interest (e.g., variants that are prevalent or becoming prevalent that harbor substitutions in the target protein or in protein(s) that interact with the target protein). Age >45 was added as a risk factor to the analyses for K031, a precedent established in studies of mAbs to narrow population based on comorbidity and age

K031 Topline Final Data Analysis March 24, 2021

EX-99.2

Exhibit 99.2

Kaleido Biosciences Reports Positive Results from Non-IND Study Demonstrating a Reduction in COVID-19 Related Healthcare Utilization and Recovery Time in Patients with Mild-to-Moderate COVID-19 and One or More Comorbidity

KB109 demonstrated favorable safety and tolerability profile

Kaleido intends to file an Investigational New Drug (IND) application, with the goal of advancing KB109 directly into a pivotal registration program

Company to host conference call today at 8:30am ET

LEXINGTON, Mass. (March 24, 2021) – Kaleido Biosciences, Inc. (Nasdaq: KLDO) today reported positive results from a non-IND study of KB109 in patients with mild-to-moderate COVID-19. An analysis from the full dataset demonstrated a reduction in overall COVID-19 related healthcare utilization—comprised of hospitalizations, emergency room visits, and urgent care visits. The study also demonstrated a significant reduction in recovery time for patients age 45 and older or with one or more comorbidity who received KB109 plus self-supportive care as compared to patients receiving self-supportive care alone. The study was a multi-center, open label, controlled clinical study of 350 patients in which 181 received KB109 plus self-supportive care and 169 received self-supportive care alone. KB109 is a novel, orally administered product candidate based on the Company’s Microbiome Metabolic Therapy (MMT™) platform.

Summary of Results

● Primary Endpoint:  KB109 demonstrated an overall favorable safety and tolerability profile with no unexpected treatment-related adverse events.

● KB109 reduced healthcare utilization, as measured by the total number of hospitalizations, emergency room visits, and urgent care visits by approximately 62 percent among patients with one or more comorbidity and by approximately 51 percent overall.

● KB109 showed the greatest impact for patients with one or more underlying comorbidity, who have a considerably longer disease course.

● For patients with one or more comorbidity, KB109 reduced median time to resolution of the 13 overall COVID-19 symptoms from 30 to 21 days (HR=1.422 [95% CI: 0.898, 2.250]; p=NS).

● In an exploratory analysis of patients ages 45 and older or with one or more comorbidity, KB109 significantly reduced median time to resolution of the 13 overall COVID-19 symptoms from 31 to 21 days (HR=1.597 [95% CI: 1.064, 2.398]; p<0.05).

● KB109 targets the host immune system rather than the virus and is therefore likely to demonstrate similar results against emerging virus variants, though this has not yet been studied in an IND trial.

“Despite historic progress in advancing COVID-19 vaccinations, new strains of the virus continue to emerge, necessitating safe, orally available therapies for patients around the world,” said Dan Menichella, President, and Chief Executive Officer of Kaleido Biosciences. “Based on these results, we are excited to advance KB109—which can be administered at home—into an IND to assess whether it may help improve patient outcomes, particularly among more vulnerable populations.”

Continued Mr. Menichella: “Because KB109 is designed to affect the host’s immune response, rather than the virus itself, we believe it may produce a similar response to virus variants or other types of viral respiratory infections. With the goal of moving into a pivotal registration program in mild-to-moderate COVID-19 patients who are at risk for prolonged symptoms, we look forward to filing an IND application with the FDA and a Clinical Trials Application with other regulatory agencies.”

As a non-interventional extension to the completed study, Kaleido is continuing to study the impact of KB109 on the incidence of ‘Long-COVID’—an emerging concern where symptoms of the virus persist in patients for weeks and months.

“The data released today from Kaleido Biosciences are highly impressive and I believe represent an exceptional advance,” commented John P. Haran, M.D., Ph.D., Associate Professor of Emergency Medicine, Microbiology & Physiological Systems and clinical director of the UMass Center for Microbiome Research at the University of Massachusetts Medical School. “Oral therapies that reduce the duration of symptoms in patients with COVID-19 are in great need and would offer much needed therapeutics to patients suffering from the long-lasting effects after infection. If these data are replicated in a pivotal drug study, they would represent an opportunity for an oral therapeutic targeting the microbiome, the trillions of microbes living inside our bodies, to reduce healthcare utilization and accelerate patient recovery from COVID-19.”

The mechanism of KB109’s induction of short-chain fatty acid production is validated in multiple preclinical studies across both viral and bacterial respiratory pathogens, offering the potential to provide an intervention for a variety of viral respiratory infections.

Conference Call and Webcast Details

The Company will host a conference call today at 8:30am ET to discuss the data. To access the call, please dial 833-423-0448 (domestic) or 956-394-3566 (international) with conference ID

1176787. The webcast, and accompanying slide presentation, can be accessed through the “Investors” section of Kaleido’s website at www.kaleido.com.

About the Potential Role of the Microbiome in COVID-19

COVID-19 infection has been associated with activation of an inappropriate inflammatory cascade, which in some patients can cause an abnormally aggressive immune response that can lead to pneumonia and respiratory failure. Metabolites such as short chain fatty acids (SCFAs) produced by the microbiome through utilization of glycans are modulators of the immune response and therefore could play a role in limiting this inflammatory cascade.

In preclinical models, increased SFCAs and/or SFCA-producing taxa, have been shown to influence immune pathways, mitigate immune pathology, and improve survival and morbidity associated with severe respiratory viral infections.^1,2 Commensal microbiota composition critically regulates the generation of virus-specific CD4 and CD8 T cells and antibody responses following respiratory influenza virus infection.³

Human data also support the role of SCFAs in reducing the impact of viral infections. In patients undergoing hematopoietic stem cell transplants who have contracted respiratory viral infections, including coronavirus, the presence of SCFA-producing taxa has been associated with a significantly reduced risk of progression to lower respiratory tract infections, which can have substantial morbidity in this patient population.⁴ KB109 is Generally Recognized as Safe (GRAS) for its intended use and was selected for evaluation in these COVID-19 clinical studies based on its demonstrated ability to increase production of SCFAs as well as to promote commensal bacteria and reduce pathogenic bacteria ex vivo.

About Microbiome Metabolic Therapies (MMT™)

Kaleido’s Microbiome Metabolic Therapies, or MMTs, are designed to drive the function and distribution of the microbiome’s existing microbes in order to decrease or increase the production of metabolites, or to advantage or disadvantage certain bacteria in the microbiome community. The Company’s initial MMT candidates are targeted, synthetic glycans that are orally administered, have limited systemic exposure, and are selectively metabolized by enzymes in the microbiome. Kaleido utilizes its discovery and development platform to study MMTs in microbiome samples to rapidly advance MMT candidates rapidly into clinical studies in healthy subjects and patients. These human clinical studies are conducted under regulations supporting research with food, evaluating safety, tolerability and potential markers of effect. For MMT candidates that are further developed as therapeutics, the Company conducts clinical trials under an Investigational New Drug (IND) or regulatory equivalent outside the U.S., and in Phase 2 or later development.

About Kaleido Biosciences

Kaleido Biosciences is a clinical-stage healthcare company with a differentiated, chemistry-driven approach to targeting the microbiome to treat disease and improve human health. The Company has built a proprietary product platform to enable the rapid and cost-efficient discovery and development of novel Microbiome Metabolic Therapies (MMT™). MMTs are

designed to modulate the metabolic output and profile of the microbiome by driving the function and distribution of the gut’s existing microbes. Kaleido is advancing a broad pipeline of MMT candidates with the potential to address a variety of diseases and conditions with significant unmet patient needs. To learn more, visit https://kaleido.com/.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding the therapeutic potential of our MMT candidates, regulatory interactions and plans, and our strategy, business plans and focus. The words “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, those related to the breadth of our pipeline of product candidates, the strength of our proprietary product platform, the efficiency of our discovery and development approach, the clinical development and safety profile of our MMT candidates and their therapeutic potential, whether and when, if at all, regulatory agencies will approve our IND application or clinical trial applications for KB109, whether and when, if at all, our MMT candidates will receive approval from the U.S. Food and Drug Administration or other regulatory agencies and for which, if any, indications, competition from other biotechnology companies, and other risks identified in our SEC filings, including our most recent Form 10-K, and subsequent filings with the SEC. We caution you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. We disclaim any obligation to publicly update or revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

1. Antunes, K.H., et al. Microbiota-derived acetate protects against respiratory syncytial virus infection through a GPR43-type 1 interferon response. Nat Commun. 2019, 10, 3273.

2. Trompette, A., et al. Dietary Fiber Confers Protection against Flu by Shaping Ly6c- Patrolling Monocyte Hematopoiesis and CD8+ T Cell Metabolism. Immunity. 2018, May 15;48(5):992-1005.e8.

3. Ichinohe, T., et. al.  Microbiota regulates immune defense against respiratory tract influenza A virus infection. Proceedings of the National Academy of Sciences. Mar 2011, 108 (13) 5354-5359.

4. Haak, B.W., et al. Impact of gut colonization with butyrate-producing microbiota on respiratory viral infection following allo-HCT. Blood. 2018. 131, 2978-2986.

Contacts

Kaleido Biosciences

William Duke, Jr.
Chief Financial Officer

617-890-5772

william.duke@kaleido.com

Investors

Mike Biega

Solebury Trout

617-221-9660

mbiega@soleburytrout.com

Media

Amy Bonanno
Solebury Trout

914-450-0349

abonanno@soleburytrout.com

XML

Document And Entity Information	Mar. 24, 2021
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Document Period End Date	Mar. 24, 2021
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Entity Address, Address Line One	65 Hayden Avenue
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