SYBX

SEC source: 0000899243-18-016589 · doc4.xml · derivative · entry 1

Shea Richard P · CIK 0001294354 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to the reporting person's continued service as a director of the Corporation.

SEC source: 0000899243-18-016592 · doc4.xml · derivative · entry 1

Barrett Peter · CIK 0001291895 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to the reporting person's continued service as a director of the Corporation.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the reporting person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-016591 · doc4.xml · derivative · entry 1

POWELL MICHAEL · CIK 0001202793 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to the reporting person's continued service as a director of the Corporation.

SEC source: 0001209191-18-037734 · doc4.xml · derivative · entry 1

Mathers Edward T · CIK 0001328625 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to each non-employee director's continued service as a director of the Corporation.

SEC source: 0000899243-18-016593 · doc4.xml · derivative · entry 1

Leschly Nick · CIK 0001578408 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to the reporting person's continued service as a director of the Corporation.

SEC source: 0000899243-18-016590 · doc4.xml · derivative · entry 1

Khuong Chau Quang · CIK 0001609405 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-06-13

F1 · derivative.exercise_date: The option vests and becomes exercisable in full on the earlier of (A) the first anniversary of the date of grant or (B) immediately prior to the next annual meeting of the Corporation's stockholders after the date of grant, subject in each case to the reporting person's continued service as a director of the Corporation.

SEC source: 0000899243-18-015255 · doc4.xml · derivative · entry 1

Brennan Aoife · CIK 0001714563 · Interim President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 54,000

Underlying: Common Stock · 54,000 shares

Expires 2028-06-05

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on July 5, 2018 and continuing until June 5, 2022, subject to the Reporting Person continuing to provide services to the Issuer as Interim President and Chief Executive Officer through each such vesting date.

SEC source: 0000899243-18-007539 · doc4.xml · derivative · entry 1

Shegog Todd · CIK 0001714564 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 48,000

Underlying: Common Stock · 48,000 shares

Expires 2028-03-14

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on April 14, 2018 and continuing until March 14, 2022, subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-007530 · doc4.xml · derivative · entry 1

Brennan Aoife · CIK 0001714563 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 56,000

Underlying: Common Stock · 56,000 shares

Expires 2028-03-14

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on April 14, 2018 and continuing until March 14, 2022, subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-007529 · doc4.xml · derivative · entry 1

Gengos Andrew · CIK 0001563623 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2028-03-14

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on April 14, 2018 and continuing until March 14, 2022, subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-007528 · doc4.xml · derivative · entry 1

Miller Paul Francis · CIK 0001714565 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,000

Underlying: Common Stock · 16,000 shares

Expires 2028-03-14

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on April 14, 2018 and continuing until March 14, 2022, subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-007675 · doc4.xml · derivative · entry 1

Gutierrez-Ramos Jose-Carlos · CIK 0001667657 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 120,540

Underlying: Common Stock · 120,540 shares

Expires 2028-03-14

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal monthly installments beginning on April 14, 2018 and continuing until March 14, 2022, subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0001209191-18-005621 · doc4.xml · nonDerivative · entry 1

BARRIS PETER J · CIK 0001005561 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005631 · doc4.xml · nonDerivative · entry 1

Viswanathan Ravi · CIK 0001479386 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005628 · doc4.xml · nonDerivative · entry 1

SANDELL SCOTT D · CIK 0001237289 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005625 · doc4.xml · nonDerivative · entry 1

KERINS PATRICK J · CIK 0001235112 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005620 · doc4.xml · nonDerivative · entry 1

BARRETT M JAMES · CIK 0001219855 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005627 · doc4.xml · nonDerivative · entry 1

MOTT DAVID M · CIK 0001219871 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005623 · doc4.xml · nonDerivative · entry 1

BASKETT FOREST · CIK 0001277631 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005630 · doc4.xml · nonDerivative · entry 1

Sonsini Peter W. · CIK 0001559807 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005624 · doc4.xml · nonDerivative · entry 1

Florence Anthony A. Jr. · CIK 0001559827 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 1

Disclosed balance after: 4,228,940

F1 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-18-005617 · doc4.xml · nonDerivative · entry 1

New Enterprise Associates 14, L.P. · CIK 0001544328 · 10% owner

NEA 14 GP, LTD · CIK 0001551532 · 10% owner

NEA Partners 14, L.P. · CIK 0001551531 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 4,228,940

F1 · ownership.direct: The securities are directly held by New Enterprise Associates 14, L.P. ("NEA 14") and are indirectly held by NEA Partners 14, L.P. ("NEA Partners 14"), the sole general partner of NEA 14, NEA 14 GP, LTD ("NEA 14 LTD"), the sole general partner of NEA Partners 14 and each of the individual directors of NEA 14 LTD (NEA Partners 14, NEA 14 LTD and the individual directors of NEA 14 LTD (collectively, the "Directors") together, the "Indirect Reporting Persons"). The Directors of NEA 14 LTD are M. James Barrett, Peter J. Barris, Forest Baskett, Anthony A. Florence, Jr., Patrick J. Kerins, David M. Mott, Scott D. Sandell, Peter W. Sonsini and Ravi Viswanathan. The Indirect Reporting Persons disclaim beneficial ownership within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 securities in which the Indirect Reporting Persons have no pecuniary interest.

SEC source: 0000899243-18-002259 · doc4.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VI LLC · CIK 0001682115 · Director

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 2,029,996

F1 · balance_after: These shares are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the sole general partner of OPI VI, and OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP VI. By virtue of such relationships, GP VI and Advisors may be deemed to have voting and investment power with respect to the securities held by OPI VI noted above and as a result may be deemed to have beneficial ownership over such securities. Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the shares held by OPI VI.

F1 · ownership.nature: These shares are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the sole general partner of OPI VI, and OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP VI. By virtue of such relationships, GP VI and Advisors may be deemed to have voting and investment power with respect to the securities held by OPI VI noted above and as a result may be deemed to have beneficial ownership over such securities. Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the shares held by OPI VI.

F2 · ownership.nature: Each of GP VI and Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Chau Khuong, an employee of Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000899243-18-002261 · doc4.xml · nonDerivative · entry 1

POWELL MICHAEL · CIK 0001202793 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 574,972

F1 · ownership.nature: The shares are held by Sofinnova Venture Partners VIII, L.P. ("SVP VIII"). Sofinnova Management VIII, L.L.C. ("SM VIII") is the general partner of SVP VIII. The individual managing members of SVP VIII are Michael Powell, James Healy and Anand Mehra. The managing members share voting and dispositive power with regard to the shares held directly by SVP VIII. Such persons and entities disclaim beneficial ownership over the shares owned by SVP VIII except to the extent of any pecuniary interest therein.

SEC source: 0000899243-18-002260 · doc4.xml · nonDerivative · entry 1

Khuong Chau Quang · CIK 0001609405 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 2,029,996

F1 · ownership.nature: These shares are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the sole general partner of OPI VI, and OrbiMed Advisors LLC ("Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP VI. By virtue of such relationships, GP VI and Advisors may be deemed to have voting and investment power with respect to the securities held by OPI VI noted above and as a result may be deemed to have beneficial ownership over such securities. Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the shares held by OPI VI. The Reporting Person is an employee of Advisors.

F2 · ownership.nature: Each of GP VI, Advisors and the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000899243-18-000274 · doc4.xml · derivative · entry 2

Barrett Peter · CIK 0001291895 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 11,570

Underlying: Common Stock · 11,570 shares

Expires 2028-01-02

F2 · derivative.exercise_date: The options were issued to the Reporting Person pursuant to the Issuer's Amended and Restated Non-Employee Director Compensation Program and 2015 Equity Incentive Award Plan in lieu of the non-employee director board and committee cash retainers of $76,250 in the aggregate. Such options vest in four quarterly installments on the last day of each calendar quarter during 2018 provided the Reporting Person continues to provide services to the Issuer.

SEC source: 0000899243-18-000273 · doc4.xml · derivative · entry 1

Shea Richard P · CIK 0001294354 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,143

Underlying: Common Stock · 17,143 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-000274 · doc4.xml · derivative · entry 1

Barrett Peter · CIK 0001291895 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,143

Underlying: Common Stock · 17,143 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-000275 · doc4.xml · derivative · entry 1

POWELL MICHAEL · CIK 0001202793 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,572

Underlying: Common Stock · 18,572 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0001209191-18-000901 · doc4.xml · derivative · entry 1

Mathers Edward T · CIK 0001328625 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,572

Underlying: Common Stock · 18,572 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-000280 · doc4.xml · derivative · entry 1

Khuong Chau Quang · CIK 0001609405 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,143

Underlying: Common Stock · 17,143 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-18-000272 · doc4.xml · derivative · entry 1

Leschly Nick · CIK 0001578408 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,143

Underlying: Common Stock · 17,143 shares

Expires 2027-12-29

F1 · derivative.exercise_date: The options vest and become exercisable in substantially equal installments on each of the first three anniversaries of August 28, 2017 subject to the Reporting Person continuing to provide services to the Issuer through each such vesting date.

SEC source: 0000899243-17-029490 · doc4.xml · derivative · entry 1

Gengos Andrew · CIK 0001563623 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 154,000

Underlying: Common Stock · 154,000 shares

Expires 2017-10-09

F1 · derivative.exercise_date: The option vests and becomes exercisable as to one-fourth (1/4th) of the shares, on October 9, 2018, and the remainder will vest at one-forty-eighth (1/48th) per month thereafter; subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

SEC source: 0000899243-18-003687 · doc5.xml · nonDerivative · entry 1

Gutierrez-Ramos Jose-Carlos · CIK 0001667657 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 352,619

F1 · shares: This Report relates to a gift of 10,000 shares of common stock made by the Reporting Person on October 2, 2017. The gifted shares were fully vested as of the date of the gift in accordance with the vesting schedule described in footnote 2.

F2 · balance_after: Pursuant to the terms of a restricted stock agreement by and between the Issuer and the Reporting Person, one-fourth of the total number of shares originally granted pursuant to the restricted stock agreement vested on May 14, 2016, with the remainder vesting in equal monthly installments until May 14, 2019, provided that at the relevant vesting dates the Reporting Person continues service to the Issuer and has not been terminated as defined in, and as determined under, the Issuer's 2017 Stock Incentive Plan.

SEC source: 0001209191-17-050731 · doc4.xml · nonDerivative · entry 1

BARRIS PETER J · CIK 0001005561 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050742 · doc4.xml · nonDerivative · entry 1

Viswanathan Ravi · CIK 0001479386 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0000899243-17-021267 · doc4.xml · derivative · entry 1

Shea Richard P · CIK 0001294354 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,857

Underlying: Common Stock · 2,857 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and becomes exercisable in substantially equal installments on each of the first three anniversaries of the Transaction Date, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

SEC source: 0000899243-17-021261 · doc4.xml · derivative · entry 1

Barrett Peter · CIK 0001291895 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,857

Underlying: Common Stock · 2,857 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and becomes exercisable in substantially equal installments on each of the first three anniversaries of the Transaction Date, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

F2 · ownership.direct: The reporting person is a member of Atlas Venture Associates IX, LLC ("AVA IX LLC") and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the equity grants to Atlas Venture Advisors, L.P. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-17-050738 · doc4.xml · nonDerivative · entry 1

SANDELL SCOTT D · CIK 0001237289 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050736 · doc4.xml · nonDerivative · entry 1

KERINS PATRICK J · CIK 0001235112 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0000899243-17-021254 · doc4.xml · derivative · entry 1

POWELL MICHAEL · CIK 0001202793 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,428

Underlying: Common Stock · 1,428 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and become exercisable in full on the earlier of (A) August 28, 2018 or (B) immediately prior to the next annual meeting of the Issuer's stockholders, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

SEC source: 0001209191-17-050730 · doc4.xml · nonDerivative · entry 1

BARRETT M JAMES · CIK 0001219855 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050737 · doc4.xml · nonDerivative · entry 1

MOTT DAVID M · CIK 0001219871 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050733 · doc4.xml · nonDerivative · entry 1

BASKETT FOREST · CIK 0001277631 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050729 · doc4.xml · derivative · entry 1

Mathers Edward T · CIK 0001328625 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,428

Underlying: Common Stock · 1,428 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and become exercisable in full on the earlier of (A) August 28, 2018 or (B) immediately prior to the next annual meeting of the Issuer's stockholders, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

SEC source: 0001209191-17-050741 · doc4.xml · nonDerivative · entry 1

Sonsini Peter W. · CIK 0001559807 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050734 · doc4.xml · nonDerivative · entry 1

Florence Anthony A. Jr. · CIK 0001559827 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Note 2

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.nature: The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. ("NEA Partners 14"). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. ("NEA 14"), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.

SEC source: 0001209191-17-050728 · doc4.xml · nonDerivative · entry 1

New Enterprise Associates 14, L.P. · CIK 0001544328 · 10% owner

NEA 14 GP, LTD · CIK 0001551532 · 10% owner

NEA Partners 14, L.P. · CIK 0001551531 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 3,818,940

F1 · price: Shares of capital stock of the corporation then known as Synlogic, Inc. ("Old Synlogic") were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the "Merger Agreement"). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.

F2 · ownership.direct: The securities are directly held by New Enterprise Associates 14, L.P. ("NEA 14") and are indirectly held by NEA Partners 14, L.P. ("NEA Partners 14"), the sole general partner of NEA 14, NEA 14 GP, LTD ("NEA 14 LTD"), the sole general partner of NEA Partners 14 and each of the individual directors of NEA 14 LTD (NEA Partners 14, NEA 14 LTD and the individual directors of NEA 14 LTD (collectively, the "Directors") together, the "Indirect Reporting Persons"). The Directors of NEA 14 LTD are M. James Barrett, Peter J. Barris, Forest Baskett, Anthony A. Florence, Jr., Patrick J. Kerins, David M. Mott, Scott D. Sandell, Peter W. Sonsini and Ravi Viswanathan. The Indirect Reporting Persons disclaim beneficial ownership within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 securities in which the Indirect Reporting Persons have no pecuniary interest.

SEC source: 0000899243-17-021269 · doc4.xml · derivative · entry 1

Leschly Nick · CIK 0001578408 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,857

Underlying: Common Stock · 2,857 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and becomes exercisable in substantially equal installments on each of the first three anniversaries of the Transaction Date, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.

SEC source: 0000899243-17-021262 · doc4.xml · derivative · entry 1

Khuong Chau Quang · CIK 0001609405 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,857

Underlying: Common Stock · 2,857 shares

Expires 2027-08-28

F1 · derivative.exercise_date: The option vests and becomes exercisable in substantially equal installments on each of the first three anniversaries of the Transaction Date, subject to the Reporting Person continuing to provide services to the Issuer through such vesting date.