SYBX / Synlogic, Inc. - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

As filed with the Securities and Exchange Commission on August 15, 2025

S-3/A As filed with the Securities and Exchange Commission on August 15, 2025 Registration No.

Synlogic, Inc. [ ] Trustee Dated as of [ ] Subordinated Debt Securities

EX-4.10 Exhibit 4.10 Synlogic, Inc. Issuer AND [ ] Trustee INDENTURE Dated as of [ ] Subordinated Debt Securities CROSS-REFERENCE TABLE (1) Section of Trust Indenture Act of 1939, as Amended Section of Indenture 310(a). 7.09 310(b). 7.08 7.10 310(c). Inapplicable 311(a). 7.13(a) 311(b). 7.13(b) 311(c). Inapplicable 312(a). 5.02(a) 312(b). 5.02(b) 312(c). 5.02(c) 313(a). 5.04(a) 313(b). 5.04(a) 313

Synlogic, Inc. [ ] Dated as of [ ] Senior Debt Securities

EX-4.9 Exhibit 4.9 Synlogic, Inc. Issuer AND [ ] Trustee INDENTURE Dated as of [ ] Senior Debt Securities CROSS-REFERENCE TABLE (1) Section of Trust Indenture Act of 1939, as Amended Section of Indenture 310(a). 7.09 310(b). 7.08 7.10 310(c). Inapplicable 311(a). 7.13(a) 311(b). 7.13(b) 311(c). Inapplicable 312(a) 5.02(a) 312(b). 5.02(b) 312(c). 5.02(c) 313(a). 5.04(a) 313(b). 5.04(a) 313(c). 5.04

As filed with the Securities and Exchange Commission on August 8, 2025

S-3 As filed with the Securities and Exchange Commission on August 8, 2025 Registration No.

Security Type

Calculation of Filing Fee Tables S-3 SYNLOGIC, INC. Table 1: Newly Registered and Carry Forward Securities ☐Not Applicable Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forward Form Type Carry Forward File Number Carry Forward Initial Effe

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC

Non‑Employee Director Compensation Program.

Exhibit 10.8 SYNLOGIC, INC. AMENDED & RESTATED NON-EMPLOYEE DIRECTOR COMPENSATION PROGRAM Non-employee members of the board of directors (the “Board”) of Synlogic, Inc. (the “Company”) shall be eligible to receive equity compensation as set forth in this Amended & Restated Non-Employee Director Compensation Program (this “Program”), which is being adopted pursuant to the Board’s resolutions on Apr

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1)

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 0

Subsidiaries of the registrant

Exhibit 21.1 SUBSIDIARIES OF SYNLOGIC, INC. Subsidiary Jurisdiction Synlogic Operating Company, Inc. Delaware Synlogic Securities Corporation Massachusetts

Amended Employment Letter Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of December 19, 2024

Exhibit 10.12 Synlogic, Inc. PO Box 30 Winchester, MA 01890 Mary Beth Dooley Re: Amended Employment Letter Agreement Dear Mary Beth, I am pleased to provide you with the amended terms and conditions of your continued employment by Synlogic, Inc. a Delaware corporation (hereinafter referred to collectively with its subsidiaries as the “Company”). This Amended Employment Letter Agreement (this “Agre

Synlogic's Incentive Compensation Recovery Policy

Exhibit 97.1 Incentive Compensation Recovery Policy I. Introduction The Board of Directors (the “Board”) of Synlogic, Inc. (the “Company”) believes that it is in the best interests of the Company and its shareholders to create and maintain a culture that emphasizes integrity and accountability and that reinforces the Company’s pay-for-performance compensation philosophy. The Board has therefore ad

Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of December 17, 2024

Exhibit 10.10 Synlogic Operating Company, Inc. PO Box 30 Winchester, MA 01890 December 17, 2024 Antoine Awad Dear Tony, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Company”).1 The Severance Pay and Benefits described below are contingent on your agreement to and compliance with the provisions of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, I

Synlogic's Insider Trading Policy

Exhibit 19.1 INSIDER TRADING POLICY Updated June 2023 1. BACKGROUND AND PURPOSE 1.1 Why Have We Adopted This Policy? The federal securities laws prohibit any member of the Board of Directors (a “Director”) or employee of the Company (including its subsidiaries) from purchasing or selling Company securities on the basis of material non-public information concerning the Company, or from tipping mate

Consulting Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of December 17, 2024

Exhibit 10.11 CONSULTING AGREEMENT This Consulting Agreement (“Agreement”) is entered into as of January 1, 2025 between Synlogic Operating Company, Inc., having offices at PO Box 30, Winchester, MA 01890 (“Synlogic” or the “Company”), and Tony Awad (the “Consultant”). The Company desires to retain the Consultant as an independent contractor to perform consulting and other project-based services f

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

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): February 20, 2025 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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): January 10, 2025 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

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

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): December 17, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Submission of Matters to a Vote of Security Holders

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): December 4, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

SYBX / Synlogic, Inc. / ARMISTICE CAPITAL, LLC Passive Investment

SC 13G/A 1 armistice-sybx093024a1.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* SYNLOGIC, INC. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L209 (CUSIP Number) September 30, 2024 (Date of Event Which Requires Filing of this Statement) Check the ap

Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of March 7, 2024

Exhibit 10.10 Effective Date: March 1, 2024 Mary Beth Dooley Re: Amendment to the Retention Agreement Dear Mary Beth: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Conditions If you (a) remain employed by the Company and continue

Amendment to Separation Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of February 17, 2024

Exhibit 10.9 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 October 30, 2024 Re: Amendment to Separation Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of February 16, 2024 Dear Mary Beth, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Comp

As filed with the Securities and Exchange Commission on November 12, 2024

S-8 As filed with the Securities and Exchange Commission on November 12, 2024 Registration No.

Calculation of Filing Fee Table

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc.

Amendment to Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of February 17, 2024

Exhibit 10.7 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 October 29, 2024 Antoine Awad Re: Amendment to Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of February 17, 2024 Dear Tony, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the

Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of March 7, 2024

Exhibit 10.8 Effective Date: March 1, 2024 Tony Awad Re: Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of March 7, 2024 Dear Tony: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Con

Power of Attorney. Reference is made to the signature page to the Registration Statement.

As filed with the Securities and Exchange Commission on November 12, 2024 Registration No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC,

Calculation of Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common Stock, par value $0.001 per share 457(c)

Synlogic Reports Third Quarter 2024 Financial Results

Exhibit 99.1 Synlogic Reports Third Quarter 2024 Financial Results Winchester, Mass. November 12, 2024 – Synlogic, Inc. (Nasdaq: SYBX), a biopharmaceutical company advancing novel therapeutics to transform the care of serious diseases, today reported financial results for the third quarter 2024 and provided a corporate update. As previously announced, the Company retained Lucid Capital Markets, LL

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): November 12, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

DEF 14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 8, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Numb

First Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of March 7, 2024

Exhibit 10.4 Effective Date: March 1, 2024 Tony Awad Re: Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of March 7, 2024 Dear Tony: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Con

First Amendment to Separation Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of February 17, 2024

Exhibit 10.5 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 August 5, 2024 Re: Amendment to Separation Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of February 16, 2024 Dear Mary Beth, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Compan

Lease Termination Agreement by and between BMR-Rogers Street LLC and Synlogic, Inc.

Exhibit 10.2 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. LEASE TERMINATION AGREEMENT THIS LEASE TERMINATION AGREEMENT (this “Agreement”) is entered into as of this 26 day of June 2024 (“Execution Date”), by and between BMR-ROGERS S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC.

Synlogic Reports Second Quarter 2024 Financial Results

Exhibit 99.1 Synlogic Reports Second Quarter 2024 Financial Results Winchester, Mass. August 8, 2024 – Synlogic, Inc. (Nasdaq: SYBX), a biopharmaceutical company advancing novel therapeutics to transform the care of serious diseases, today reported financial results for the second quarter 2024 and provided a corporate update. In March 2024, the Company retained Lucid Capital Markets, LLC to act as

First Amendment to Retention Bonus Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of March 7, 2024

Exhibit 10.6 Effective Date: March 1, 2024 Mary Beth Dooley Re: 1st Amendment to the Retention Agreement Dear Mary Beth: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Conditions If you (a) remain employed by the Company and contin

First Amendment to Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of February 17, 2024

Exhibit 10.3 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 August 5, 2024 Antoine Awad Re: Amendment to Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of February 17, 2024 Dear Tony, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Co

SYBX / Synlogic, Inc. / New Enterprise Associates 14, L.P. - NEW ENTERPRISE ASSOCIATES 14, L.P. -- SYNLOGIC, INC. 13D/A(#5) Activist Investment

Schedule 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* Synlogic, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 87166L209 (CUSIP Number) Stephanie Brecher New Enterprise Associates 1954 Greenspring Drive, Suite 600 Timonium, MD 21093 (410) 842-4000 (Name, Add

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

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): May 14, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Number

Statement of Work dated May 3, 2024 pursuant to Master Contract Services Agreement between Synlogic, Inc. and Azzur Group (d/b/a Azzur of New England LLC), SOW P-Cleanroom Offboarding CR3

Exhibit 10.1 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. Scope of Work P- Cleanroom Offboarding CR3 Synlogic COD Waltham Page 1 of 3 Azzur Cleanrooms on Demand Waltham – Synlogic CONFIDENTIAL 1. Synlogic Clinical Offboarding Facili

Synlogic Reports First Quarter 2024 Financial Results

Exhibit 99.1 Synlogic Reports First Quarter 2024 Financial Results Cambridge, Mass. May 14, 2024 – Synlogic, Inc. (Nasdaq: SYBX), a biopharmaceutical company advancing novel therapeutics to transform the care of serious diseases, today reported financial results for the first quarter 2024 and provided a corporate update. In March 2024, the Company retained Lucid Capital Markets, LLC to act as its

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1)

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 0

SYBX / Synlogic, Inc. / Radoff Bradley Louis - THE SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. )1 Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L209 (CUSIP Number) April 10,

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

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 19, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Numb

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 19, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Numb

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, I

Form of Stock Option Grant Notice and Stock Option Agreement under 2023 Inducement Equity Incentive Award Plan

Exhibit 10.7 SYNLOGIC, INC. 2023 INDUCEMENT EQUITY INCENTIVE AWARD PLAN STOCK OPTION GRANT NOTICE Synlogic, Inc., a Delaware corporation, (the “Company”), pursuant to its 2023 Inducement Equity Incentive Award Plan, as may be amended from time to time (the “Plan”), hereby grants to the holder listed below (“Participant”), an option to purchase the number of shares of the Company’s common stock (“S

Synlogic Reports Fourth Quarter and Full Year 2023 Financial Results

Exhibit 99.1 Synlogic Reports Fourth Quarter and Full Year 2023 Financial Results Cambridge, Mass. March 19, 2024 – Synlogic, Inc. (Nasdaq: SYBX), a biopharmaceutical company advancing novel therapeutics to transform the care of serious diseases, today reported financial results for the fourth quarter and full year ending December 31, 2023. The Company recently announced the decision to discontinu

Employment Letter Agreement dated April 11, 2018 by and between Synlogic, Inc. and Mary Beth Dooley

Exhibit 10.24 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 REVISED April 5, 2018 Mary Beth Dooley Re: Employment Letter Agreement Dear Mary Beth, I am delighted to provide you with the terms and conditions of your employment by Synlogic, Inc., a Delaware corporation (the “Company”). We were all very impressed with your candidacy and think you would make an excellent addition to

Retention Bonus Agreement by and between Synlogic, Inc. and Mary Beth Dooley, dated as of March 7, 2024

Exhibit 10.25 Effective Date: March 1, 2024 Mary Beth Dooley Re: Retention Agreement Dear Mary Beth: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Conditions If you (a) remain employed by the Company and continue to provide servic

2023 Inducement Equity Incentive Award Plan

Exhibit 10.6 SYNLOGIC, INC. 2023 INDUCEMENT EQUITY INCENTIVE AWARD PLAN ARTICLE 1. PURPOSE The purpose of the Synlogic, Inc. 2015 Inducement Equity Incentive Award Plan (as it may be amended from time to time, the “Plan”) is to promote the success and enhance the value of Synlogic, Inc. (the “Company”) by enhancing the Company’s ability to attract new Employees who are expected to make important c

Separation Agreement by and between Synlogic, Inc. and Aoife M. Brennan, MB, BCh, BAO, MMSc, dated as of February 17, 2024

Exhibit 10.16 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 Provided by February 9, 2024 Dr. Aoife M. Brennan Dear Aoife, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Company”).1 The Severance Pay and Benefits described below are contingent on your agreement to

Separation Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of February 17, 2024

Exhibit 10.22 Synlogic Operating Company, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 Provided by February 16, 2024 Tony Awad Dear Tony, The purpose of this letter agreement (“Agreement”) is to confirm the terms of this separation of employment from Synlogic, Inc. (“Synlogic” or “the Company”).1 The Severance Pay and Benefits described below are contingent on your agreement to and compli

Retention Bonus Agreement by and between Synlogic, Inc. and Antoine Awad, dated as of March 7, 2024

Exhibit 10.23 Effective Date: March 1, 2024 Tony Awad Re: Retention Agreement Dear Tony: In recognition of your value and expected contributions to Synlogic, Inc. (“the Company”) we are pleased to offer you the following Retention Bonus Agreement (the “Agreement”). Retention Bonus Amount and Eligibility Conditions If you (a) remain employed by the Company and continue to provide services at a sati

Subsidiaries of the registrant

Exhibit 21.1 SUBSIDIARIES OF SYNLOGIC, INC. Subsidiary Jurisdiction Synlogic Operating Company, Inc. Delaware Synlogic Securities Corporation Massachusetts

Separation Agreement by and between Synlogic, Inc. and Michael Jensen, dated as of November 13, 2023

Exhibit 10.18 Provided on November 9, 2023 Michael Jensen Dear Michael, The purpose of this letter agreement (“Agreement”) is to confirm the terms of your voluntary separation of employment from Synlogic, Inc. (“Synlogic” or “the Company”).1The Bonus Pay and Benefits described below are contingent on your agreement to and compliance with the provisions of this Agreement, as set forth below. In ord

Addendum to Statement of Work dated December 8, 2023 pursuant to Master Contract Services Agreement between Synlogic, Inc. and Azzur Group (d/b/a Azzur of New England LLC), SOW P-10558-01 Addendum

Exhibit 10.40 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. To: Synlogic OperatingCompany, Inc. CR3 License Fee, SOW P-10558-01 From: Azzur Cleanrooms on Demand, Waltham Re: Addendum to Scope of Work for Cleanroom 3 Use, SOW P-10558-

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): February 17, 2024 Synlogic, Inc.

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): February 17, 2024 Synlogic, Inc. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Synlogic Adopts Limited Duration Stockholders Rights Plan Engages Ladenburg Thalmann as financial advisor to assist with previously announced strategic review process

Exhibit 99.1 Synlogic Adopts Limited Duration Stockholders Rights Plan Engages Ladenburg Thalmann as financial advisor to assist with previously announced strategic review process Cambridge, Mass. February 20, 2024 – Synlogic, Inc. (Nasdaq: SYBX), a biopharmaceutical company advancing novel therapeutics to transform the care of serious diseases, today announced that its Board of Directors (the “Bo

Certificate of Designation of Series A Junior Participating Preferred Stock of Synlogic, Inc., as filed with the Secretary of State of the State of Delaware on February 20, 2024.

Exhibit 3.1 CERTIFICATE OF DESIGNATION of SERIES A JUNIOR PARTICIPATING PREFERRED STOCK of SYNLOGIC, INC. (Pursuant to Section 151 of the Delaware General Corporation Law) Synlogic, Inc., a corporation organized and existing under the General Corporation Law of the State of Delaware (the “Corporation”), hereby certifies that the following resolution was adopted by the Board of Directors of the Cor

Current Report

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): February 20, 2024 Synlogic, Inc. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Rights Agreement, dated as of February 20, 2024, between Synlogic, Inc. and Equiniti Trust Company LLC, as rights agent.

Exhibit 4.1 RIGHTS AGREEMENT Dated as of February 20, 2024 between SYNLOGIC, INC. and EQUINITI TRUST COMPANY LLC as Rights Agent TABLE OF CONTENTS Page 1. Definitions 1 2. Appointment of Rights Agent 7 3. Issue of Right Certificates 7 4. Form of Right Certificates 9 5. Countersignature and Registration 9 6. Transfer, Split-up, Combination and Exchange of Right Certificates; Mutilated, Destroyed, L

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 SYNLOGIC, INC. (Exact name of registrant as s

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 26-1824804 (State of incorporation or organization) (I.R.S. Employer Identification No.) 301 Binney St. Suite 402 Ca

SYBX / Synlogic, Inc. / Kryzanowski John A Passive Investment

SC 13G/A 1 synlogic13gamd2.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2) Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 (Title of Class of Securities) 87166L100 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to de

US87166L2097 / Synlogic, Inc. / ARMISTICE CAPITAL, LLC Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities, Results of Operations and Financial Condition, Other Events

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): February 12, 2024 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Synlogic Announces Decision to Discontinue Synpheny-3 Study and Provides Corporate Update Decision to end trial follows internal review of initial data indicating study unlikely to meet primary endpoint Data review found treatment to be safe and well

Exhibit 99.1 Synlogic Announces Decision to Discontinue Synpheny-3 Study and Provides Corporate Update Decision to end trial follows internal review of initial data indicating study unlikely to meet primary endpoint Data review found treatment to be safe and well-tolerated Board of Directors plans to perform assessment of strategic options Cambridge, Mass. February 8, 2024 – Synlogic, Inc. (Nasdaq

Amendment to Employment Agreement dated December 26, 2023, by and between the Company, and Aoife Brennan

Exhibit 10.1 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 December 26, 2023 Dr. Aoife M. Brennan Re: Amendment to Employment Agreement (the “Amendment”) Dear Aoife, I am pleased to provide you with the updated terms and conditions of your employment by Synlogic, Inc. a Delaware corporation, Inc. (hereinafter referred to collectively with its subsidiaries as the “Company”), and t

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

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): December 29, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Amendment to Employment Agreement dated December 16, 2023, by and between the Company and Antoine Awad

Exhibit 10.2 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 December 26, 2023 Antoine Awad Re: Amendment to Employment Agreement (the “Amendment”) Dear Tony, I am pleased to provide you with the updated terms and conditions of your employment by Synlogic, Inc. a Delaware corporation, Inc. (hereinafter referred to collectively with its subsidiaries as the “Company”), and together w

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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): November 17, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

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

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): November 10, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC,

Synlogic Reports Third Quarter 2023 Financial Results and Provides Corporate Update - Underwritten public offering of $21.0 million and earned $2.5 million milestone payment from Roche collaboration extended cash runway into the first half of 2025 -

Exhibit 99.1 Synlogic Reports Third Quarter 2023 Financial Results and Provides Corporate Update - Underwritten public offering of $21.0 million and earned $2.5 million milestone payment from Roche collaboration extended cash runway into the first half of 2025 - - Progress of the Synpheny-3 pivotal trial in phenylketonuria (PKU) supports enrollment completion in 2024, with top-line data in the fir

Amendment to Pilot Collaboration and Option Agreement, dated as of August 16, 2023, among Synlogic Operating Company, Inc. and Hoffman-La Roche Inc.

Exhibit 10.1 Amendment No. 1 to Pilot Collaboration and Option Agreement This amendment no. 1 to the Pilot Collaboration and Option Agreement effective as of 16 June 2021 (the "Amendment No. 1") is entered into effective as of 15 August, 2023 (the "Amendment No. 1 Effective Date") by and between Hoffmann-La Roche Inc., with an office and place of business at 150 Clove Road, Suite 8, Little Falls,

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

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): November 9, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

Synlogic Achieves Research Milestone and Earns $2.5 Million Milestone Payment from Roche Collaboration

Exhibit 99.1 Synlogic Achieves Research Milestone and Earns $2.5 Million Milestone Payment from Roche Collaboration Cambridge, Mass. November 7, 2023 – Synlogic, Inc. (Nasdaq: SYBX), a clinical-stage biotechnology company advancing novel, oral, non-systemically absorbed biotherapeutics to transform the care of serious diseases, announced today that it has achieved its third pre-specified research

Financial Statements and Exhibits, Other Events

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): November 7, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

SYBX / Synlogic Inc / New Enterprise Associates 14, L.P. - NEW ENTERPRISE ASSOCIATES 14, L.P. -- SYNLOGIC, INC. 13D/A(#4) Activist Investment

SC 13D/A 1 nea14-synlogic18766.htm NEW ENTERPRISE ASSOCIATES 14, L.P. - SYNLOGIC, INC. 13D/A(#4) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* Synlogic, Inc. (f/k/a Mirna Therapeutics, Inc.) (Name of Issuer) Common Stock, $.001 par value (Title of Class of Securities) 87166L209 (CUSIP Number) Louis

SYBX / Synlogic Inc / ORBIMED ADVISORS LLC - AMENDMENT NO. 7 Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 7)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L209 (CUSIP Number) OrbiMed Advisors LLC OrbiMed Capital GP VI LLC OrbiMed Genesis GP LLC 601 Lexington Avenue, 54th Floor New York, NY 10022 Tel

JOINT FILING AGREEMENT

EX-99.1 2 ss2562435ex9901.htm JOINT FILING AGREEMENT Exhibit 1 JOINT FILING AGREEMENT The undersigned hereby agree that the Amendment No. 7 to Schedule 13D, dated October 3, 2023, with respect to the common stock of Synlogic, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the un

SYNLOGIC, INC. 3,921,928 Shares of Common Stock Pre-Funded Warrants to Purchase up to 3,472,435 Shares of Common Stock Common Warrants to Purchase up to 7,394,363 Shares of Common Stock

Table of Contents Filed Pursuant to Rule 424(b)(4) Registration No. 333-274421 PROSPECTUS SYNLOGIC, INC. 3,921,928 Shares of Common Stock Pre-Funded Warrants to Purchase up to 3,472,435 Shares of Common Stock Common Warrants to Purchase up to 7,394,363 Shares of Common Stock We are offering 7,394,363 shares of our common stock and warrants to purchase up to an aggregate of up to 7,394,363 shares o

Form of Pre-Funded Warrant

Exhibit 4.1 FORM OF PRE-FUNDED WARRANT SYNLOGIC, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ] (“Issuance Date”) Synlogic, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ], the registered holder he

Form of Purchase Warrant

Exhibit 4.2 FORM OF COMMON WARRANT SYNLOGIC, INC. WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ], 2023 (“Issuance Date”) Synlogic, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ], the registered holder hereof or i

Other Events

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): September 28, 2023 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File

Form of Underwriting Agreement dated September 28, 2023

Exhibit 1.1 [•] Shares of Common Stock (or Pre-Funded Warrants to Purchase Shares of Common Stock in Lieu Thereof) Warrants to Purchase [•] Shares of Common Stock SYNLOGIC, INC. UNDERWRITING AGREEMENT [•], 2023 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2130 New York, NY 10004 Ladies and Gentlemen: Synlogic, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and

Synlogic Announces Pricing of $21.0 Million Underwritten Public Offering

Exhibit 99.1 Synlogic Announces Pricing of $21.0 Million Underwritten Public Offering Cambridge, Mass. September 29, 2023 – Synlogic, Inc. (Nasdaq: SYBX), a clinical-stage biotechnology company advancing novel, oral, non-systemically absorbed biotherapeutics to transform the care of serious diseases, today announced the pricing of an underwritten public offering of (i) 7,394,363 shares of common s

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): September 27, 2023 SYNLOGIC, INC.

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): September 27, 2023 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File

Certificate of Amendment (Reverse Stock Split) to the Amended and Restated Certificate of Incorporation of Synlogic, Inc., dated September 27, 2023

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF SYNLOGIC, INC. Synlogic, Inc. (the “Corporation”), a corporation organized and existing under the laws of the State of Delaware, does hereby certify as follows: FIRST: That the name of the Corporation is Synlogic, Inc. SECOND: That the Board of Directors of the Corporation duly adopted resolutions appr

Filing Fee Table

Calculation of Filing Fee Tables Form S-1 (Form Type) Synlogic, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount  Registered  Proposed  Maximum  Offering Price Per Unit Maximum Aggregate Offering Price(1)(2) Fee Rate Amount of Registration Fee  Equity  Common Stock, par value $0.001 per s

As filed with the Securities and Exchange Commission on September 28, 2023.

Table of Contents As filed with the Securities and Exchange Commission on September 28, 2023.

Synlogic Announces Reverse Stock Split

Exhibit 99.1 Synlogic Announces Reverse Stock Split Cambridge, Mass. September 27, 2023 – Synlogic, Inc. (Nasdaq: SYBX), a clinical-stage biotechnology company advancing novel, oral, non-systemically absorbed biotherapeutics to transform the care of serious diseases, today announced that it will implement a 1-for-15 Reverse Stock Split of its common stock (Reverse Stock Split), effective at 5:00 p

Certificate of Amendment to Amended and Restated Certificate of Incorporation of Synlogic, Inc., dated September 27, 2023

Exhibit 3.5 CERTIFICATE OF AMENDMENT TO THE AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF SYNLOGIC, INC. Synlogic, Inc. (the “Corporation”), a corporation organized and existing under the laws of the State of Delaware, does hereby certify as follows: FIRST: That the name of the Corporation is Synlogic, Inc. SECOND: That the Board of Directors of the Corporation duly adopted resolutions appr

As filed with the Securities and Exchange Commission on September 28, 2023

S-1MEF As filed with the Securities and Exchange Commission on September 28, 2023 Registration No.

Form of Underwriting Agreement, by and between the Registrant and Chardan Capital Markets LLC

Exhibit 1.1 [•] Shares of Common Stock (or Pre-Funded Warrants to Purchase Shares of Common Stock in Lieu Thereof) Warrants to Purchase [•] Shares of Common Stock SYNLOGIC, INC. UNDERWRITING AGREEMENT [•], 2023 CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2130 New York, NY 10004 Ladies and Gentlemen: Synlogic, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and

Form of Common Warrant

Exhibit 4.5 FORM OF COMMON WARRANT SYNLOGIC, INC. WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ], 2023 (“Issuance Date”) Synlogic, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ], the registered holder hereof or i

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Synlogic, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price(1)(2) Fee Rate Amount of Registration Fee Equity Common Stock, par value $0.001

As filed with the Securities and Exchange Commission on September 26, 2023.

Table of Contents As filed with the Securities and Exchange Commission on September 26, 2023.

Form of Pre-Funded Warrant

Exhibit 4.4 FORM OF PRE-FUNDED WARRANT SYNLOGIC, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Warrant No.: [ ] Number of Shares of Common Stock: [ ] Date of Issuance: [ ] (“Issuance Date”) Synlogic, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ], the registered holder he

Synlogic, Inc. 301 Binney St., Suite 402 Cambridge, Massachusetts 02142

Synlogic, Inc. 301 Binney St., Suite 402 Cambridge, Massachusetts 02142 September 26, 2023 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attention: Cindy Polynice Re: Synlogic, Inc. Registration Statement on Form S-1 File No. 333-274421 Request for Acceleration Dear Ms. Polynice: Pursuant to Rule 461 of Regulation C prom

CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2130 New York, NY 10004

CHARDAN CAPITAL MARKETS, LLC 17 State Street, Suite 2130 New York, NY 10004 September 26, 2023 VIA EDGAR Securities and Exchange Commission Division of Corporation Finance Office of Life Sciences 100 F Street, N.

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): September 21, 2023 SYNLOGIC, INC.

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): September 21, 2023 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File

September 20, 2023

September 20, 2023 CONFIDENTIAL – VIA EDGAR United States Securities and Exchange Commission Division of Corporate Finance Office of Life Sciences 100 F Street, N.

Filing Fee Table

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) Synlogic, Inc.

As filed with the Securities and Exchange Commission on September 8, 2023.

S-1 Table of Contents As filed with the Securities and Exchange Commission on September 8, 2023.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

DEF 14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defin

Entry into a Material Definitive Agreement

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): August 16, 2023 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Num

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

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): August 10, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Num

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC.

Synlogic Reports Second Quarter 2023 Financial Results and Provides Business Update - Recent milestones include initiation of the pivotal Phase 3 trial, Synpheny-3, and receipt of Fast Track designation for labafenogene marselecobac as a potential tr

Exhibit 99.1 Synlogic Reports Second Quarter 2023 Financial Results and Provides Business Update - Recent milestones include initiation of the pivotal Phase 3 trial, Synpheny-3, and receipt of Fast Track designation for labafenogene marselecobac as a potential treatment for PKU - Cambridge, Mass. August 10, 2023 – Synlogic, Inc. (Nasdaq: SYBX), a clinical-stage biotechnology company advancing nove

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): June 15, 2023 SYNLOGIC, INC. (Exa

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): June 15, 2023 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

Certificate of Amendment to Amended and Restated Certificate of Incorporation of Synlogic, Inc., dated June 15, 2023

EX-3.1 Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF SYNLOGIC, INC. Synlogic, Inc. (the “Corporation”), a corporation organized and existing under the laws of the State of Delaware, does hereby certify as follows: FIRST: That the name of the Corporation is Synlogic, Inc. SECOND: That the Board of Directors of the Corporation duly adopted resolutio

Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities, Other Events

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): May 31, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Number

Synlogic Announces Initiation of Synpheny-3 Global, Pivotal Phase 3 Study Evaluating SYNB1934 for Treatment of Phenylketonuria Registrational study designed to support BLA submission of first-in-class biotherapeutic Company further streamlining organ

EX-99.1 Exhibit 99.1 Synlogic Announces Initiation of Synpheny-3 Global, Pivotal Phase 3 Study Evaluating SYNB1934 for Treatment of Phenylketonuria Registrational study designed to support BLA submission of first-in-class biotherapeutic Company further streamlining organization to focus resources on execution of late clinical-stage programs in rare metabolic diseases Cambridge, Mass. June 5, 2023

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

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): May 11, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Number

Synlogic Reports First Quarter 2023 Financial Results and Provides Business Update - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in first half of 2023 – - Recent milestones include receipt of Rare Pediatric and Orphan Drug Des

EX-99 2 sybx-ex991.htm EX-99.1 Exhibit 99.1 Synlogic Reports First Quarter 2023 Financial Results and Provides Business Update - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in first half of 2023 – - Recent milestones include receipt of Rare Pediatric and Orphan Drug Designations from the FDA, and orphan designation from the EMA for SYNB1934 as a potential treatment for PKU

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defin

$16,415,139 Synlogic, Inc. Common Stock

424B5 Filed Pursuant to Rule 424(b)(5) Registration No. 333-258151 PROSPECTUS SUPPLEMENT (To the Prospectus dated July 30, 2021) $16,415,139 Synlogic, Inc. Common Stock This prospectus supplement amends and supplements the information in our prospectus dated July 30, 2021 (File No. 333-258151). This prospectus supplement should be read in conjunction with the prospectus and is qualified in its ent

Synlogic Reports Fourth Quarter and Full Year 2022 Financial Results and Corporate Updates - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in first half of 2023 - - Rare Pediatric Disease Designation granted for SYNB1934 for PKU

Exhibit 99.1 Synlogic Reports Fourth Quarter and Full Year 2022 Financial Results and Corporate Updates - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in first half of 2023 - - Rare Pediatric Disease Designation granted for SYNB1934 for PKU and SYNB1353 for homocystinuria (HCU) - - Platform presentation and two poster presentations at SIMD Annual Meeting - - $77.6 million in

Subsidiaries of the registrant

Exhibit 21.1 SUBSIDIARIES OF SYNLOGIC, INC. Subsidiary Jurisdiction Synlogic Operating Company, Inc. Delaware Synlogic Securities Corporation Massachusetts

Calculation of Filing Fee Table

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, I

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

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 29, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Numb

Statement of Work dated November 22, 2022 pursuant to Master Contract Services Agreement between Synlogic, Inc. and Azzur Group (d/b/a Azzur of New England LLC), SOW P-10558-01 Extension A

Exhibit 10.32 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. EXHIBIT A Scope of Work (SOW) Scope of Work P-10558-01 Extension A Scope of Work for Cleanroom 3 Use 1 (April 1st, 2023 to December 31st 2023 With Options through Q4 2024) 2

Power of Attorney. Reference is made to the signature page to the Registration Statement.

S-8 As filed with the Securities and Exchange Commission on March 29, 2023 Registration No.

Calculation of Filing Fee Table

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc.

Power of Attorney. Reference is made to the signature page to the Registration Statement.

S-8 As filed with the Securities and Exchange Commission on March 29, 2023 Registration No.

SYBX / Synlogic Inc / RA CAPITAL MANAGEMENT, L.P. - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L100 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule p

SYBX / Synlogic Inc / Kryzanowski John A Passive Investment

SC 13G/A 1 synlogic13gamd1.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1) Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 (Title of Class of Securities) 87166L100 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to de

SYBX / Synlogic Inc / Kryzanowski John A Passive Investment

SC 13G 1 synlogic13g.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ) Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 (Title of Class of Securities) 87166L100 (CUSIP Number) May 15, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the

Financial Statements and Exhibits, Other Events

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): January 19, 2023 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

Synlogic Receives Rare Pediatric Disease Designation from FDA for SYNB1934 for Phenylketonuria (PKU)

EX-99.1 Exhibit 99.1 Synlogic Receives Rare Pediatric Disease Designation from FDA for SYNB1934 for Phenylketonuria (PKU) Cambridge, Mass. January 19, 2023 – Synlogic, Inc. (Nasdaq: SYBX), the leading company advancing therapeutics based on synthetic biology, today announced that SYNB1934 was granted Rare Pediatric Disease Designation (RPDD) by the U.S. Food and Drug Administration (FDA) for the p

Synlogic Announces Achievement of Proof of Concept for SYNB8802 in Enteric Hyperoxaluria Based on Urinary Oxalate Lowering in Phase 1b Study Results include -38% reduction in urinary oxalate compared to placebo in Roux-en-Y gastric bypass patients Fa

EX-99.1 Exhibit 99.1 Synlogic Announces Achievement of Proof of Concept for SYNB8802 in Enteric Hyperoxaluria Based on Urinary Oxalate Lowering in Phase 1b Study Results include -38% reduction in urinary oxalate compared to placebo in Roux-en-Y gastric bypass patients Favorable safety and tolerability, with frequency and severity of adverse events similar across placebo and active arms Synlogic to

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): December 15, 2022 SYNLOGIC, INC.

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): December 15, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Forward Looking Statements This presentation contains forward-looking statements that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, other

EX-99.2 Exhibit 99.2 Transforming Medicine Through Synthetic Biology Proof of Concept for SYNB8802 for Enteric Hyperoxaluria Top-Line Results from Phase 1b Study December 15, 2022 © © 2 20 02 22 2 SY SYN NLO LOG GIIC C.. P PR RO OO OF F O OF F C CO ON NC CE EP PT T F FO OR R SY SYN NB B8 88 80 02 2 IIN N E EH H.. A ALL R LL RIIG GH HT TS R S RE ESE SER RV VE ED D.. Forward Looking Statements This

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

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): December 6, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

Synlogic Announces SYNB1353 Achieves Proof of Mechanism for Treatment of Homocystinuria and Provides Business Update Top-line Phase 1 data in healthy volunteers show that SYNB1353 reduces plasma methionine by consuming methionine in the GI tract SYNB

Exhibit 99.1 Synlogic Announces SYNB1353 Achieves Proof of Mechanism for Treatment of Homocystinuria and Provides Business Update Top-line Phase 1 data in healthy volunteers show that SYNB1353 reduces plasma methionine by consuming methionine in the GI tract SYNB1353 has been granted Orphan Drug Designation (ODD) from the FDA for the treatment of homocystinuria (HCU) Company confirms expectations

Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities, Other Events

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): November 28, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Entry into a Material Definitive Agreement

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): November 22, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

Synlogic Reports Third Quarter 2022 Financial Results and Provides Business Update Top-line Phase 2 data for phenylketonuria (PKU) demonstrated robust plasma Phe reduction and high response rate; Phase 3 study initiation planned for H1 2023 Clinical

Exhibit 99.1 Synlogic Reports Third Quarter 2022 Financial Results and Provides Business Update Top-line Phase 2 data for phenylketonuria (PKU) demonstrated robust plasma Phe reduction and high response rate; Phase 3 study initiation planned for H1 2023 Clinical readouts for SYNB1353 for homocystinuria (HCU) and SYNB8802 for enteric hyperoxaluria (EH) expected in 2022 $91.7 million in cash, cash e

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): November 10, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC,

Synlogic Announces Positive Top-Line Phase 2 Data for Phenylketonuria (PKU); SYNB1934 Advances to Phase 3 Positive results include clinically meaningful Phe reductions, with a 60% response rate and 42% reduction in plasma Phe among responders across

EX-99.1 Exhibit 99.1 Synlogic Announces Positive Top-Line Phase 2 Data for Phenylketonuria (PKU); SYNB1934 Advances to Phase 3 Positive results include clinically meaningful Phe reductions, with a 60% response rate and 42% reduction in plasma Phe among responders across the study population Consistent, positive measures of activity across all assessed endpoints Company confirms SYNB1934 as candida

Speakers Molly Harper Chief Business Officer Aoife Brennan, MB ChB President & CEO Caroline Kurtz, PhD. Chief Development Officer

EX-99.2 Synpheny-1 Phase 2 Top-Line Results Transforming Medicine Through Synthetic Biology October 18, 2022 Exhibit 99.2 Forward Looking Statements This press release contains "forward-looking statements" that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, other than statements of histor

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): October 18, 2022 SYNLOGIC, INC. (

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): October 18, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Nu

Other Events

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): August 26, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Num

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 11, 2022 SYNLOGIC, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37566 26-1824804 (State or Other Jurisdiction of Incorporation) (Commission File Num

Synlogic Reports Second Quarter 2022 Financial Results and Provides Business Update – Three clinical data readouts across three programs expected in H2 2022 – – PKU Phase 3 readiness activities underway for planned start in H1 2023 – – $106.8 million

Exhibit 99.1 Synlogic Reports Second Quarter 2022 Financial Results and Provides Business Update ? Three clinical data readouts across three programs expected in H2 2022 ? ? PKU Phase 3 readiness activities underway for planned start in H1 2023 ? ? $106.8 million in cash, cash equivalents and short-term investments support projected runway into 2024 ? ? Conference call and webcast at 8:30 a.m. ET

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC.

Submission of Matters to a Vote of Security Holders

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): June 9, 2022 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Number

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 12, 2022 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Number

Synlogic Reports First Quarter 2022 Financial Results and Provides Business Update - Clinical readouts anticipated for phenylketonuria (PKU), homocystinuria (HCU) and enteric hyperoxaluria programs in H2 2022 – - PKU program progressing with Phase 3

Exhibit 99.1 Synlogic Reports First Quarter 2022 Financial Results and Provides Business Update - Clinical readouts anticipated for phenylketonuria (PKU), homocystinuria (HCU) and enteric hyperoxaluria programs in H2 2022 ? - PKU program progressing with Phase 3 readiness activities underway ? - $120.5 million in cash, cash equivalents and short-term investments support projected runway into 2024

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ☒Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a6(e)(2)) ☐ Definiti

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defini

© 2020 SYNLOGIC. QU©AR2T0E1R9LYSYRNELSOUGLTICS.. AALLLL RRIIGGHHTTSS RREESSEERRVVEEDD.. || 33 Opening Remarks Dr. Aoife Brennan MB CHB President & CEO

Transforming Medicine through Synthetic Biology Q4 and Full Year 2021 Financial Results & Business Update March 17, 2022 Exhibit 99.

Calculation of Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common Stock, par value $0.001 per share 457(c)

As filed with the Securities and Exchange Commission on March 17, 2022

S-8 1 d339035ds8.htm S-8 As filed with the Securities and Exchange Commission on March 17, 2022 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Synlogic, Inc. (Exact name of registrant as specified in its charter) Delaware 26-1824804 (State or other jurisdiction of incorporation or organi

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 17, 2022 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

Subsidiaries of the registrant

Exhibit 21.1 SUBSIDIARIES OF SYNLOGIC, INC. Subsidiary Jurisdiction Synlogic Operating Company, Inc. Delaware Synlogic Securities Corporation Massachusetts

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, I

Statement of Work dated January 21, 2022 pursuant to Master Contract Services Agreement between Synlogic, Inc. and Azzur Group (d/b/a Azzur of New England LLC), SOW P-10558-01

Exhibit 10.30 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. EXHIBIT A Scope of Work (SOW) Scope of Work P-10558-01 Scope of Work for Cleanroom 3 Use and Customization/Expansion of Cleanroom Space (January 1st, 2022 to March 31st 2023

Calculation of Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Synlogic, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common Stock, par value $0.001 per share 457(c)

Statement of Work dated January 21, 2022 pursuant to Master Contract Services Agreement between Synlogic, Inc. and Azzur Group (d/b/a Azzur of New England LLC), SOW P-10558-2

Exhibit 10.31 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. EXHIBIT B Scope of Work (SOW) Scope of Work P-10558-02 for Scope of Work for Cleanroom 3 Expansion Customization Project (January-March 2022) Section 1 - Background/Scope Az

Synlogic Reports Fourth Quarter and Full Year 2021 Financial Results and Provides Business Update - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in H2 2022 – - Clinical readouts anticipated for PKU program in H1 2022 and in hom

Exhibit 99.1 Synlogic Reports Fourth Quarter and Full Year 2021 Financial Results and Provides Business Update - Phenylketonuria (PKU) program on track for Phase 3 trial initiation in H2 2022 ? - Clinical readouts anticipated for PKU program in H1 2022 and in homocystinuria and enteric hyperoxaluria in H2 2022 ? - $136.6 million in cash, cash equivalents and marketable securities support projected

Power of Attorney. Reference is made to the signature page to the Registration Statement.

As filed with the Securities and Exchange Commission on March 17, 2022 Registration No.

Synlogic Announces Appointment of Michael Jensen as Chief Financial Officer

Exhibit 99.1 Synlogic Announces Appointment of Michael Jensen as Chief Financial Officer CAMBRIDGE, Mass., March 3, 2022 ? Synlogic, Inc. (Nasdaq: SYBX), a clinical-stage biotechnology company developing medicines for metabolic and immunological diseases through its proprietary approach to synthetic biology, today announced the appointment of Michael Jensen as Chief Financial Officer. Mr. Jensen b

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

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 3, 2022 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

Employment Agreement dated as of January 24, 2022, by and between Synlogic and Michael Jensen

Exhibit 10.1 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 January 24, 2022 Michael Jensen 7 Abbot St. Andover, MA 01810 Re: Employment Letter Agreement Dear Michael, I am pleased to provide you with the terms and conditions of your employment by Synlogic, Inc. a Delaware corporation, Inc. (hereinafter referred to collectively with its subsidiaries as the ?Company?). 1. Position.

Entry into a Material Definitive Agreement

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): January 21, 2022 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Nu

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC,

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

EX-99.2 3 d259422dex992.htm EX-99.2 Bringing the Transformative Power of Synthetic Biology to Medicine Q3 Financial Results & Business Update 10 November 2021 Exhibit 99.2 Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995

Synlogic Reports Third Quarter Financial Results and Provides Business Update - Interim analysis of Phase 2 SynPheny-1 study demonstrated proof of concept in phenylketonuria. Program to advance to Phase 3 development - - Research milestone in inflamm

EX-99.1 2 d259422dex991.htm EX-99.1 Exhibit 99.1 Synlogic Reports Third Quarter Financial Results and Provides Business Update - Interim analysis of Phase 2 SynPheny-1 study demonstrated proof of concept in phenylketonuria. Program to advance to Phase 3 development - - Research milestone in inflammatory bowel disease collaboration with Roche achieved - - $150.1 million in cash, cash equivalents an

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): November 10, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File N

Synlogic and Ginkgo Bioworks Announce Investigational Synthetic Biotic Medicine for the Treatment of Homocystinuria Synlogic and Ginkgo collaboration generates clinical candidate SYNB1353 using Synlogic’s proprietary Synthetic Biotic platform and Gin

Exhibit 99.1 Synlogic and Ginkgo Bioworks Announce Investigational Synthetic Biotic Medicine for the Treatment of Homocystinuria Synlogic and Ginkgo collaboration generates clinical candidate SYNB1353 using Synlogic?s proprietary Synthetic Biotic platform and Ginkgo Codebase SYNB1353 is the first investigational medicine developed from Ginkgo?s platform to advance to IND-enabling studies Synlogic

Financial Statements and Exhibits, Other Events

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): November 9, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Nu

SYBX / Synlogic Inc / RA CAPITAL MANAGEMENT, L.P. - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L100 (CUSIP Number) September 23, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pur

SYBX / Synlogic Inc / ORBIMED ADVISORS LLC - AMENDMENT NO. 6 Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 6)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L100 (CUSIP Number) OrbiMed Advisors LLC OrbiMed Capital GP VI LLC OrbiMed Genesis GP LLC 601 Lexington Avenue, 54th Floor New York, NY 10022 Tel

JOINT FILING AGREEMENT

EX-99.1 2 ss519248ex9901.htm JOINT FILING AGREEMENT Exhibit 1 JOINT FILING AGREEMENT The undersigned hereby agree that the Amendment No. 6 to Schedule 13D, dated September 29, 2021, with respect to the ordinary shares of Synlogic, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of t

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

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): September 22, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File

Synlogic Announces Proposed Public Offering of Common Stock

Exhibit 99.1 Synlogic Announces Proposed Public Offering of Common Stock CAMBRIDGE, Mass.?(BUSINESS WIRE)?September 22, 2021? Synlogic (Nasdaq: SYBX), a clinical stage company bringing the transformative potential of synthetic biology to medicine, today announced that it has commenced an underwritten public offering of its common stock. All shares of common stock to be sold in the offering will be

Synlogic Announces Pricing of Public Offering of Common Stock

Exhibit 99.2 Synlogic Announces Pricing of Public Offering of Common Stock Cambridge, Mass. (Business Wire) September 22, 2021 ? Synlogic (Nasdaq: SYBX) a clinical stage company bringing the transformative potential of synthetic biology to medicine, today announced the pricing of its underwritten public offering of 15,000,000 shares of its common stock at a public offering price of $3.00 per share

Underwriting Agreement, dated September 22, 2021, among Synlogic, Inc. and Jefferies LLC and SVB Leerink LLC, as representatives of the several underwriters named therein.

Exhibit 1.1 SYNLOGIC, INC. (a Delaware corporation) 15,000,000 Shares of Common Stock UNDERWRITING AGREEMENT September 22, 2021 Jefferies LLC SVB Leerink LLC as Representatives of the several Underwriters c/o Jefferies LLC 520 Madison Avenue New York, New York 10022 c/o SVB Leerink LLC 53 State Street, 40th Floor Boston, Massachusetts 02109 Ladies and Gentlemen: Synlogic, Inc., a Delaware corporat

15,000,000 Shares Common Stock

424B5 1 d181450d424b5.htm 424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-258151 PROSPECTUS SUPPLEMENT (To Prospectus dated July 30, 2021) 15,000,000 Shares Common Stock We are offering 15,000,000 shares of our common stock in this offering. Our common stock is listed on The Nasdaq Capital Market under the symbol “SYBX.” On September 22, 2021, the last reported sale p

SUBJECT TO COMPLETION, DATED SEPTEMBER 22, 2021

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-258151 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell these

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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): September 20, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File

Synlogic Announces Positive Phase 2 Data Demonstrating Reduction in Plasma Phenylalanine Levels in Patients with Phenylketonuria – SYNB1618 demonstrated proof of concept with meaningful reduction of plasma phenylalanine (Phe) levels in an interim ana

Exhibit 99.3 Synlogic Announces Positive Phase 2 Data Demonstrating Reduction in Plasma Phenylalanine Levels in Patients with Phenylketonuria ? SYNB1618 demonstrated proof of concept with meaningful reduction of plasma phenylalanine (Phe) levels in an interim analysis of the Phase 2 SynPheny-1 Study ? ? SYNB1934, an optimized strain of SYNB1618, demonstrated two-fold increase in biomarkers of Phe

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

Bringing the Transformative Power of Synthetic Biology to Medicine Corporate Presentation September 2021 Exhibit 99.

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

Designed for Life Phenylketonuria Clinical Program Update 20 September 2021 Exhibit 99.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC.

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

Bringing the Transformative Power of Synthetic Biology to Medicine Corporate Presentation August 2021 Exhibit 99.

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

EX-99.2 3 d340812dex992.htm EX-99.2 Bringing the Transformative Power of Synthetic Biology to Medicine Q2 Financial Results & Business Update 12 August 2021 Exhibit 99.2 Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995.

Pilot Collaboration and Option Agreement, dated June 16, 2021, among Synlogic Operating Company, Inc. and Hoffman-La Roche Inc.

EXHIBIT 10.2 Confidential Execution Copy [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. Pilot Collaboration and Option Agreement This pilot collaboration and option agreement is entered into as of the Effective Date (as defined below)

Synlogic Reports Second Quarter Financial Results and Provides Business Update - Proof of concept studies for co-lead metabolic programs SYNB1618 in PKU and SYNB8802 in Enteric Hyperoxaluria on track for 2H 2021 readouts – - Immunomodulation portfoli

Exhibit 99.1 Synlogic Reports Second Quarter Financial Results and Provides Business Update - Proof of concept studies for co-lead metabolic programs SYNB1618 in PKU and SYNB8802 in Enteric Hyperoxaluria on track for 2H 2021 readouts ? - Immunomodulation portfolio expanded via strategic research collaboration in IBD - - Synlogic ends 2Q 2021 with $115.5 million in cash, cash equivalents and invest

License and Services Agreement and Statement of Work, dated April 28, 2021, by and between Synlogic Operating Company, Inc. and Azzur Cleanrooms-On-Demand – Boston, LLC.

EXHIBIT 10.1 Confidential Execution Copy [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED. THE PARTIES HERETO ACKNOWLEDGE AND AGREE THAT THIS AGREEMENT IS NOT A LEASE AND IS A MERE LICENSE AND CREATES NO TENANCY INTEREST, LEASEHOLD ESTAT

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 12, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Num

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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): July 29, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

SYNLOGIC, INC. 301 Binney Street, Suite 402 Cambridge, Massachusetts 02142

SYNLOGIC, INC. 301 Binney Street, Suite 402 Cambridge, Massachusetts 02142 July 29, 2021 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attention: Ms. Abby Adams Re: Synlogic, Inc. Registration Statement on Form S-3 Filed July 23, 2021 File No. 333- 258151 (the ?Registration Statement?) Acceleration Request Ladies and Gen

Form of Subordinated Indenture

Exhibit 4.8 SYNLOGIC, INC. Issuer AND [ ] Trustee INDENTURE Dated as of [ ] Subordinated Debt Securities CROSS-REFERENCE TABLE(1) Section of Trust Indenture Act of 1939, as Amended Section of Indenture 310(a). 7.09 310(b). 7.08 7.10 310(c). Inapplicable 311(a). 7.13(a) 311(b). 7.13(b) 311(c). Inapplicable 312(a). 5.02(a) 312(b). 5.02(b) 312(c). 5.02(c) 313(a). 5.04(a) 313(b). 5.04(a) 313(c). 5.04(

As filed with the Securities and Exchange Commission on July 23, 2021

Table of Contents As filed with the Securities and Exchange Commission on July 23, 2021 Registration No.

Form of Senior Indenture

Exhibit 4.7 SYNLOGIC, INC. Issuer AND [ ] Trustee INDENTURE Dated as of [ ] Senior Debt Securities CROSS-REFERENCE TABLE(1) Section of Trust Indenture Act of 1939, as Amended Section of Indenture 310(a). 7.09 310(b). 7.08 7.10 310(c). Inapplicable 311(a). 7.13(a) 311(b). 7.13(b) 311(c). Inapplicable 312(a). 5.02(a) 312(b). 5.02(b) 312(c). 5.02(c) 313(a). 5.04(a) 313(b). 5.04(a) 313(c). 5.04(a) 5.0

Sales Agreement, dated as of July 23, 2021, by and between the Registrant and Jefferies LLC

Exhibit 1.2 OPEN MARKET SALE AGREEMENTSM July 23, 2021 JEFFERIES LLC 520 Madison Avenue New York, New York 10022 Ladies and Gentlemen: Synlogic, Inc., a Delaware corporation (the ?Company?), proposes, subject to the terms and conditions stated herein, to issue and sell from time to time through Jefferies LLC, as sales agent and/or principal (the ?Agent?), shares of the Company?s common stock, par

Synlogic Announces Initiation of Phase 1 Study of SYNB1934, a Next-Generation Strain for the Treatment of Phenylketonuria (PKU) – SYNB1934, an evolved strain of SYNB1618, has the potential to provide increased benefit to patients living with PKU – –

EX-99.1 2 d192734dex991.htm EX-99.1 Exhibit 99.1 Synlogic Announces Initiation of Phase 1 Study of SYNB1934, a Next-Generation Strain for the Treatment of Phenylketonuria (PKU) – SYNB1934, an evolved strain of SYNB1618, has the potential to provide increased benefit to patients living with PKU – – SYNB1934 Phase 1 Study to evaluate safety, tolerability and head-to-head comparison of biomarkers of

Financial Statements and Exhibits, Other Events

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): July 15, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

Synlogic Enters Research Collaboration with Roche for Development of Novel Therapy to Treat Inflammatory Bowel Disease

EX-99.1 2 d158742dex991.htm EX-99.1 Exhibit 99.1 Synlogic Enters Research Collaboration with Roche for Development of Novel Therapy to Treat Inflammatory Bowel Disease Cambridge, Mass. (PR Newswire) June 17, 2021 – Synlogic, Inc. (Nasdaq: SYBX), a clinical stage company bringing the transformative potential of synthetic biology to medicine, announced today that it has entered into a research colla

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

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): June 16, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

Submission of Matters to a Vote of Security Holders

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): June 10, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe

Synlogic Reports First Quarter Financial Results and Provides Business Update - Proof of concept studies for co-lead metabolic programs SYNB1618 in PKU and SYNB8802 in Enteric Hyperoxaluria on track for 2H 2021 readouts - - $94.4 million in cash, cas

Exhibit 99.1 Synlogic Reports First Quarter Financial Results and Provides Business Update - Proof of concept studies for co-lead metabolic programs SYNB1618 in PKU and SYNB8802 in Enteric Hyperoxaluria on track for 2H 2021 readouts - - $94.4 million in cash, cash equivalents, and short-term investments as of March 31 plus April financing of $32.6 million (net) enables runway extension to 2H 2023

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, INC

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 13, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Number

Entry into a Material Definitive Agreement

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): April 29, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

- DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defini

- DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ?Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a?6(e)(2)) ? Definit

JOINT FILING AGREEMENT

EX-99.1 2 ss239614ex9901.htm JOINT FILING AGREEMENT Exhibit 1 JOINT FILING AGREEMENT The undersigned hereby agree that the Amendment No. 5 to Schedule 13D, dated April 22, 2021, with respect to the ordinary shares of Synlogic, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the u

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L100 (CUSIP Number) OrbiMed Advisors LLC OrbiMed Capital GP VI LLC 601 Lexington Avenue, 54th Floor New York, NY 10022 Telephone: (212) 739-6400

Form of Lock-Up Agreement April 15, 2021

EX-99.2 3 ss239614ex9902.htm FORM OF LOCK-UP AGREEMENT Form of Lock-Up Agreement April 15, 2021 SVB Leerink LLC 299 Park Avenue, 21st floor New York, NY 10171 Re: Proposed Public Offering by Synlogic, Inc. Ladies and Gentlemen: The undersigned, a stockholder, officer and/or director of Synlogic, Inc., a Delaware corporation (the “Company”), understands that SVB Leerink LLC (“Leerink”), as represen

10,000,000 Shares Common Stock

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-226730 PROSPECTUS SUPPLEMENT (To Prospectus dated August 30, 2018) 10,000,000 Shares Common Stock We are offering 10,000,000 shares of our common stock in this offering. Our common stock is listed on The Nasdaq Capital Market under the symbol “SYBX.” On April 14, 2021, the last reported sale price for our common stock on

Synlogic Announces Pricing of Public Offering of Common Stock

Exhibit 99.2 Synlogic Announces Pricing of Public Offering of Common Stock Cambridge, Mass. (Business Wire) April 16, 2021 ? Synlogic (Nasdaq: SYBX) a clinical stage company bringing the transformative potential of synthetic biology to medicine, today announced the pricing of its underwritten public offering of 10,000,000 shares of its common stock at a public offering price of $3.00 per share. Th

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

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): April 15, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

Synlogic Announces Proposed Public Offering of Common Stock

EX-99.1 Exhibit 99.1 Synlogic Announces Proposed Public Offering of Common Stock CAMBRIDGE, Mass.—(BUSINESS WIRE)—April 15, 2021— Synlogic (Nasdaq: SYBX), a clinical stage company bringing the transformative potential of synthetic biology to medicine, today announced that it has commenced an underwritten public offering of its common stock. All shares of common stock to be sold in the offering wil

Underwriting Agreement, dated April 15, 2021, among Synlogic, Inc. and SVB Leerink LLC, as representative of the several underwriters named therein.

Exhibit 1.1 SYNLOGIC, INC. (a Delaware corporation) 10,000,000 Shares of Common Stock UNDERWRITING AGREEMENT April 15, 2021 SVB Leerink LLC as Representative of the several Underwriters c/o SVB Leerink LLC One Federal Street, 37th Floor Boston, MA 02110 Ladies and Gentlemen: Synlogic, Inc., a Delaware corporation (the ?Company?), confirms its agreement with SVB Leerink LLC (?SVB Leerink?) and each

SUBJECT TO COMPLETION, DATED APRIL 15, 2021

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-226730 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell

Financial Statements and Exhibits, Other Events

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): April 10, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

Synlogic Presents Data from SYNB1891 Phase 1 Trial at American Association for Cancer Research (AACR) Annual Meeting

Exhibit 99.1 Synlogic Presents Data from SYNB1891 Phase 1 Trial at American Association for Cancer Research (AACR) Annual Meeting - Data demonstrates activation of STING pathway in patients - - Combination arm of Phase 1 study of SYNB1891 ongoing - CAMBRIDGE, Mass., April 10, 2021 /PRNewswire/ - Synlogic, Inc. (Nasdaq: SYBX), a clinical stage company bringing the transformative potential of synthe

Synlogic Presents Data Demonstrating Activity of a Solid Oral Formulation of SYNB1618 at American College of Medical Genetics (ACMG) Annual Meeting

EX-99.2 3 d156442dex992.htm EX-99.2 Exhibit 99.2 Synlogic Presents Data Demonstrating Activity of a Solid Oral Formulation of SYNB1618 at American College of Medical Genetics (ACMG) Annual Meeting - SYNB1618 demonstrates proof of mechanism and phenylalanine (Phe) consumption in GI tract of healthy volunteers - - SYNB1618 Phase 2 study in patients with PKU ongoing - CAMBRIDGE, Mass., April 13, 2021

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* Synlogic, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 87166L100 (CUSIP Number) OrbiMed Advisors LLC OrbiMed Capital GP VI LLC 601 Lexington Avenue, 54th Floor New York, NY 10022 Telephone: (212) 739-6400

JOINT FILING AGREEMENT

EX-99.1 2 ss195345ex9901.htm JOINT FILING AGREEMENT Exhibit 1 JOINT FILING AGREEMENT The undersigned hereby agree that the Amendment No. 4 to Schedule 13D, dated March 29, 2021, with respect to the ordinary shares of Synlogic, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the u

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 25, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

- S-8

As filed with the Securities and Exchange Commission on March 25, 2021 Registration No.

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

Bringing the Transformative Power of Synthetic Biology to Medicine Q4 Financial Results & Business Update 25 March 2021 Exhibit 99.

Subsidiaries of the registrant

EX-21.1 5 sybx-ex2118.htm EX-21.1 Exhibit 21.1 SUBSIDIARIES OF SYNLOGIC, INC. Subsidiary Jurisdiction Synlogic IBDCo, Inc. Delaware Synlogic Operating Company, Inc. Delaware Synlogic Securities Corporation Massachusetts

Promotion Letter, dated July 21, 2020, for Antoine Awad

Exhibit 10.14.2 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 To: Antoine Awad Date: July 21, 2020 Re: Promotion to COO Dear Tony, We are delighted to confirm your promotion to COO, effective July 1, 2020. In recognition of your promotion your compensation will be adjusted as follows: ? Base salary: $376,000 ? Target Bonus: 40% ? Promotion Equity Grant: 70,000 options The balance

Employment Letter Agreement dated November 28, 2018, by and between Synlogic and Antoine Awad

Exhibit 10.14.1 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 November 28, 2018 Antoine Awad Re: Employment Letter Agreement Dear Tony, I am pleased to provide you with the terms and conditions of your employment by Synlogic, Inc. a Delaware corporation, Inc. (hereinafter referred to collectively with its subsidiaries as the ?Company?). This offer is contingent on the receipt of

Annual Report - 10-K

t f UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-37566 SYNLOGIC, I

Forward Looking Statements This presentation contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, othe

Bringing the Transformative Power of Synthetic Biology to Medicine Corporate Presentation March 2021 Exhibit 99.

Synlogic Reports Fourth Quarter and Full Year 2020 Financial Results and Provides Business Update

Exhibit 99.1 Synlogic Reports Fourth Quarter and Full Year 2020 Financial Results and Provides Business Update - SYNB8802 advances to Phase 1B Proof of Concept After Proof of Mechanism Demonstrated in Dietary Hyperoxaluria Study - - Synlogic ended 2020 with $100.4 million in cash, cash equivalents, and short-term investments, extending projected runway into 2023 - - Management to host conference c

Employment Letter Agreement dated July 17, 2019, by and between Synlogic and Richard Riese

Exhibit 10.13 Synlogic, Inc. 301 Binney Street, Suite 402 Cambridge, MA 02142 Revised July 17, 2019 Richard Riese Re: Employment Letter Agreement Dear Richard, I am pleased to provide you with the terms and conditions of your employment by Synlogic, Inc. a Delaware corporation, Inc. (hereinafter referred to collectively with its subsidiaries as the ?Company?). This offer is contingent on the recei

- S-8

As filed with the Securities and Exchange Commission on March 25, 2021 Registration No.

Regulation FD Disclosure, Financial Statements and Exhibits

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 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numb

Synlogic Announces SYNB8802 Will Advance to Phase 1B Proof of Concept Study After Proof of Mechanism Demonstrated in Dietary Hyperoxaluria

EX-99.1 2 d144942dex991.htm EX-99.1 Exhibit 99.1 Synlogic Announces SYNB8802 Will Advance to Phase 1B Proof of Concept Study After Proof of Mechanism Demonstrated in Dietary Hyperoxaluria - 28.6% Urinary Oxalate lowering demonstrated in Dietary Hyperoxaluria in healthy volunteers - - Part B in Enteric Hyperoxaluria patients initiated - CAMBRIDGE, Mass., March 24, 2021 /PRNewswire/ - Synlogic, Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 8, 2021 SYNLOGIC, INC. (Exact name of registrant as specified in its charter) Delaware 001-37566 26-1824804 (State or other jurisdiction of incorporation) (Commission File Numbe