Afeyan Noubar

Row 1 · 2022-10-13 · Purchase · Acquired 2,743,902 · Balance 11,344,305

F1: On October 13, 2022, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I") and FPA, L.P. ("FPA Fund") purchased 2,743,902 shares, 914,634 shares and 3,048,780 shares, respectively, of the Issuer's Common Stock in a registered direct offering (the "October 2022 Offering") at a price of $1.64 per share pursuant to a Securities Purchase Agreement dated October 13, 2022.

F2: Shares held by Flagship Fund IV. Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 2 · 2022-10-13 · Purchase · Acquired 2,757,333 · Balance 14,101,638

F3: Represents shares of Common Stock issued upon conversion of unsecured convertible promissory notes (the "Notes") previously held by Flagship Fund IV and Flagship Opportunities I that were issued pursuant to the terms of the Securities Purchase Agreement dated September 20, 2022. In connection with the October 2022 Offering, the conversion price of the Notes became fixed at $1.64 and the outstanding principal plus accrued interest of the Notes held by Flagship Fund IV and Flagship Opportunities I automatically converted into 2,757,333 shares and 919,111 shares, respectively, of the Issuer's Common Stock.

F2: Shares held by Flagship Fund IV. Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 3 · 2022-10-13 · Purchase · Acquired 914,634 · Balance 5,380,500

F1: On October 13, 2022, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I") and FPA, L.P. ("FPA Fund") purchased 2,743,902 shares, 914,634 shares and 3,048,780 shares, respectively, of the Issuer's Common Stock in a registered direct offering (the "October 2022 Offering") at a price of $1.64 per share pursuant to a Securities Purchase Agreement dated October 13, 2022.

F4: Shares held by Flagship Opportunities I. Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP. Each of the reporting persons except for Flagship Opportunities I disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

Row 4 · 2022-10-13 · Purchase · Acquired 919,111 · Balance 6,299,611

F3: Represents shares of Common Stock issued upon conversion of unsecured convertible promissory notes (the "Notes") previously held by Flagship Fund IV and Flagship Opportunities I that were issued pursuant to the terms of the Securities Purchase Agreement dated September 20, 2022. In connection with the October 2022 Offering, the conversion price of the Notes became fixed at $1.64 and the outstanding principal plus accrued interest of the Notes held by Flagship Fund IV and Flagship Opportunities I automatically converted into 2,757,333 shares and 919,111 shares, respectively, of the Issuer's Common Stock.

F4: Shares held by Flagship Opportunities I. Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP. Each of the reporting persons except for Flagship Opportunities I disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

Row 5 · 2022-10-13 · Purchase · Acquired 3,048,780 · Balance 3,048,780

F1: On October 13, 2022, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I") and FPA, L.P. ("FPA Fund") purchased 2,743,902 shares, 914,634 shares and 3,048,780 shares, respectively, of the Issuer's Common Stock in a registered direct offering (the "October 2022 Offering") at a price of $1.64 per share pursuant to a Securities Purchase Agreement dated October 13, 2022.

F5: Shares held by FPA Fund. FPA General Partner LLC ("FPA Fund GP") is the general partner of FPA Fund. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of FPA Fund GP. Noubar B. Afeyan, Ph.D. is the CEO and sole stockholder of Flagship Pioneering. Each of the reporting persons except for FPA Fund disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 6 · Balance 2,004,657

F6: Shares held by Flagship Ventures Fund IV-Rx, L.P., ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 7 · Balance 2,035,830

F7: Shares held by Flagship VentureLabs IV, LLC ("VentureLabs IV"). Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for VentureLabs IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 8 · Balance 1,761,029

F8: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures Fund 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Noubar B. Afeyan, Ph.D. is the sole manager of Fund 2007 GP. Each of the reporting persons except for Flagship Fund 2007 disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 1 · 2022-09-15 · Purchase · Acquired 722,590 · Balance 1,865,767

F1: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F2: Shares held by Flagship Fund V. Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 2 · 2022-09-15 · Purchase · Acquired 210,743 · Balance 1,188,920

F1: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F3: Shares held by Flagship Fund V Rx. Flagship V GP is the general partner of Flagship Fund V Rx. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 4 · 2022-09-15 · Purchase · Acquired 722,590 · Balance 722,590

F1: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F2: Shares held by Flagship Fund V. Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 5 · 2022-09-15 · Purchase · Acquired 210,743 · Balance 210,743

F1: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F3: Shares held by Flagship Fund V Rx. Flagship V GP is the general partner of Flagship Fund V Rx. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 3 · Balance 485,949

F4: Shares held by Flagship VentureLabs V LLC ("VentureLabs V"). Flagship VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. Noubar B. Afeyan, Ph.D. is the CEO and sole stockholder of Flagship Pioneering. Each of the reporting persons except for VentureLabs V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 1 · 2023-07-11 · Purchase · Acquired 1,082,251 · Balance 1,461,795

F1: On July 11, 2023, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Nutritional Health LTP Fund, L.P. ("Nutritional LTP") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired 1,082,251 shares, 1,082,251 shares and 3,246,753 shares, respectively, of the Issuer's Common Stock in a private placement at a price of $2.31 per share.

F2: Shares held by Flagship Fund IV. Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 2 · 2023-07-11 · Purchase · Acquired 1,082,251 · Balance 1,493,241

F1: On July 11, 2023, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Nutritional Health LTP Fund, L.P. ("Nutritional LTP") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired 1,082,251 shares, 1,082,251 shares and 3,246,753 shares, respectively, of the Issuer's Common Stock in a private placement at a price of $2.31 per share.

F3: Shares held by Nutritional LTP. Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Nutritional LTP GP. Dr. Afeyan is the Chief Executive Officer, director and sole stockholder of Flagship Pioneering. Each of the reporting persons except for Nutritional LTP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 3 · 2023-07-11 · Purchase · Acquired 3,246,753 · Balance 3,931,685

F1: On July 11, 2023, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"), Nutritional Health LTP Fund, L.P. ("Nutritional LTP") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired 1,082,251 shares, 1,082,251 shares and 3,246,753 shares, respectively, of the Issuer's Common Stock in a private placement at a price of $2.31 per share.

F4: Shares held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the reporting persons except for Flagship Fund VII disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 4 · Balance 94,371

F5: Shares held by Flagship Ventures Fund IV-Rx, L.P ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 5 · Balance 274,766

F6: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Dr. Afeyan is the sole manager of Flagship Opportunities GP. Each of the reporting persons except for Flagship Opportunities I disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 6 · Balance 34,219

F7: Shares held by Flagship VentureLabs IV, LLC ("VentureLabs IV"). Flagship Fund IV is the manager of VentureLabs IV. Each of the reporting persons except for VentureLabs IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 7 · Balance 132,282

F8: Shares held by Flagship VentureLabs V LLC ("VentureLabs V"). Flagship VentureLabs V Manager LLC ("VentureLabs V Manager") serves as manager of VentureLabs V. Flagship Pioneering is the manager of VentureLabs V Manager. Each of the reporting persons except for VentureLabs V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 8 · Balance 210,064

F9: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Dr. Afeyan serves as sole manager of Flagship Fund V. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 9 · Balance 80,494

F10: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Each of the reporting persons except for VentureLabs Rx V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 10 · Balance 39,798

F11: Shares held by Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund"). Flagship Fund V GP is the general partner of Nutritional Health Side Fund. Each of the reporting persons except for Nutritional Health Side Fund disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 11 · Balance 179,909

F12: Shares held by Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund"). Flagship Fund V GP is the general partner of Nutritional Innovation Fund. Each of the reporting persons except for Nutritional Innovation Fund disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 1 · 2026-01-13 · Grant · Acquired 2,235,468 · Balance 2,235,468

F1: On January 13, 2026, pursuant to a registered direct offering by the Issuer, Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired warrants to purchase an aggregate of 4,470,936 shares of Common Stock, consisting of (i) Pre-Funded Warrants to purchase 2,235,468 shares of Common Stock, (ii) Series 1 Warrants to purchase 1,117,734 shares of Common Stock and (iii) Series 2 Warrants to purchase 1,117,734 shares of Common Stock (together with the Series 1 Warrants, the "Series Warrants"). The securities were acquired for a purchase price of $6.7099 per Pre-Funded Warrant and accompanying Series Warrants.

F2: Securities held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering, LLC (f/k/a Flagship Pioneering, Inc., "Flagship Pioneering") is the manager of Flagship Fund VII GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 2 · 2026-01-13 · Grant · Acquired 1,117,734 · Balance 1,117,734

F3: The Series Warrants are exercisable at an initial price of $13.42 per Series 1 Warrant and $20.13 per Series 2 Warrant. Subject to certain exclusions, if prior to June 30, 2027, the Company issues capital stock or securities convertible into or exercisable for capital stock in one or more related transactions primarily for capital raising at a weighted-average common stock equivalent price (the "Weighted-Average Price") below $13.42 per share, the exercise price of a Series Warrant shall reset upon exercise to the midpoint between the initial price and the lowest such Weighted-Average Price, but not below $6.71 per share. The exercise price may be adjusted only once pursuant to this mechanism.

F1: On January 13, 2026, pursuant to a registered direct offering by the Issuer, Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired warrants to purchase an aggregate of 4,470,936 shares of Common Stock, consisting of (i) Pre-Funded Warrants to purchase 2,235,468 shares of Common Stock, (ii) Series 1 Warrants to purchase 1,117,734 shares of Common Stock and (iii) Series 2 Warrants to purchase 1,117,734 shares of Common Stock (together with the Series 1 Warrants, the "Series Warrants"). The securities were acquired for a purchase price of $6.7099 per Pre-Funded Warrant and accompanying Series Warrants.

F2: Securities held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering, LLC (f/k/a Flagship Pioneering, Inc., "Flagship Pioneering") is the manager of Flagship Fund VII GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 3 · 2026-01-13 · Grant · Acquired 1,117,734 · Balance 1,117,734

F3: The Series Warrants are exercisable at an initial price of $13.42 per Series 1 Warrant and $20.13 per Series 2 Warrant. Subject to certain exclusions, if prior to June 30, 2027, the Company issues capital stock or securities convertible into or exercisable for capital stock in one or more related transactions primarily for capital raising at a weighted-average common stock equivalent price (the "Weighted-Average Price") below $13.42 per share, the exercise price of a Series Warrant shall reset upon exercise to the midpoint between the initial price and the lowest such Weighted-Average Price, but not below $6.71 per share. The exercise price may be adjusted only once pursuant to this mechanism.

F1: On January 13, 2026, pursuant to a registered direct offering by the Issuer, Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired warrants to purchase an aggregate of 4,470,936 shares of Common Stock, consisting of (i) Pre-Funded Warrants to purchase 2,235,468 shares of Common Stock, (ii) Series 1 Warrants to purchase 1,117,734 shares of Common Stock and (iii) Series 2 Warrants to purchase 1,117,734 shares of Common Stock (together with the Series 1 Warrants, the "Series Warrants"). The securities were acquired for a purchase price of $6.7099 per Pre-Funded Warrant and accompanying Series Warrants.

F2: Securities held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering, LLC (f/k/a Flagship Pioneering, Inc., "Flagship Pioneering") is the manager of Flagship Fund VII GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 1 · 2026-03-02 · Conversion · Acquired 12,723,940 · Balance 12,723,940

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F2: Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") automatically converted into shares of the Issuer's Common Stock on a one-for-1.5190 basis upon the closing of the Issuer's initial public offering on March 2, 2026. The Preferred Stock had no expiration date.

Row 2 · 2026-03-02 · Conversion · Acquired 13,702,224 · Balance 13,702,224

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F3: Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 6 · 2026-03-02 · Purchase · Acquired 1,562,500 · Balance 15,264,724

F3: Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 3 · 2026-03-02 · Conversion · Acquired 987,491 · Balance 987,491

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F4: Securities held by Nutritional Health LTP Fund, L.P. ("Nutritional LTP"). Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering is the manager of Nutritional LTP GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 4 · 2026-03-02 · Conversion · Acquired 2,777,752 · Balance 2,777,752

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F5: Securities held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering is the manager of Flagship Opportunities Fund II GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 5 · 2026-03-02 · Conversion · Acquired 2,777,752 · Balance 2,777,752

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F6: Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 7 · 2026-03-02 · Purchase · Acquired 1,562,500 · Balance 4,340,252

F6: Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 8 · 2026-03-02 · Purchase · Acquired 1,562,500 · Balance 1,562,500

F7: Securities held by Pioneering Medicine 02, LLC ("PM02"). Charles R. Carelli, Jr., Chief Financial Officer of Flagship Pioneering, is the sole manager of PM02, and Flagship Fund VII is its majority equity holder. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 10 · 2026-02-26 · Grant · Acquired 29,561 · Balance 29,561

F9: The shares underlying this option shall vest in full on February 19, 2027, subject to the Reporting Person's continued service on such vesting date.

Row 11 · 2026-03-02 · Conversion · Disposed 18,483,785 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F2: Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") automatically converted into shares of the Issuer's Common Stock on a one-for-1.5190 basis upon the closing of the Issuer's initial public offering on March 2, 2026. The Preferred Stock had no expiration date.

Row 12 · 2026-03-02 · Conversion · Disposed 17,016,215 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F3: Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 13 · 2026-03-02 · Conversion · Disposed 1,500,000 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F4: Securities held by Nutritional Health LTP Fund, L.P. ("Nutritional LTP"). Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Flagship Pioneering is the manager of Nutritional LTP GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 14 · 2026-03-02 · Conversion · Disposed 843,881 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F2: Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") automatically converted into shares of the Issuer's Common Stock on a one-for-1.5190 basis upon the closing of the Issuer's initial public offering on March 2, 2026. The Preferred Stock had no expiration date.

Row 15 · 2026-03-02 · Conversion · Disposed 1,265,822 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F3: Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 16 · 2026-03-02 · Conversion · Disposed 2,953,586 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F5: Securities held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering is the manager of Flagship Opportunities Fund II GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 17 · 2026-03-02 · Conversion · Disposed 2,109,704 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F6: Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 18 · 2026-03-02 · Conversion · Disposed 2,531,644 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F3: Securities held by Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII"). Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering is the manager of Flagship Fund VII GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 19 · 2026-03-02 · Conversion · Disposed 1,265,822 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F5: Securities held by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II"). Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP") is the general partner of Flagship Opportunities Fund II. Flagship Pioneering is the manager of Flagship Opportunities Fund II GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 20 · 2026-03-02 · Conversion · Disposed 2,109,704 · Balance 0

F1: Securities held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering, LLC ("Flagship Pioneering") is the manager of Flagship Fund VI GP. Noubar B. Afeyan, Ph.D. is the ultimate control person of Flagship Pioneering. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F6: Securities held by FPN II, L.P. ("FPN II Fund"). FPN General Partner LLC ("FPN GP") is the general partner of FPN II Fund. Flagship Pioneering is the manager of FPN GP. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 9 · Balance 25,016,458

F8: Securities held by Flagship VentureLabs VI LLC ("VentureLabs VI"). Flagship VentureLabs VI Manager LLC ("VentureLabs VI Manager") is the manager of VentureLabs VI. Flagship Pioneering is the manager of VentureLabs VI Manager. Each of the Reporting Persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 1 · 2021-02-08 · Purchase · Acquired 71,666 · Balance 1,685,444

F1: On February 8, 2021, Flagship Ventures Fund IV, L.P. ("Flagship Fund IV") acquired 71,666 shares pursuant to an underwritten public offering of common stock by the Issuer (the "Offering").

F2: Shares held by Flagship Fund IV. Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 2 · 2021-02-08 · Purchase · Acquired 71,667 · Balance 2,982,639

F3: On February 8, 2021, Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I") acquired 71,667 shares pursuant to the Offering.

F4: Shares held by Flagship Opportunities I. Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Dr. Afeyan serves as sole manager of Flagship Opportunities GP. Each of the reporting persons except for Flagship Opportunities I disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 3 · 2021-02-08 · Purchase · Acquired 71,667 · Balance 738,333

F5: On February 8, 2021, Nutritional Health LTP Fund, L.P. ("Nutritional LTP") acquired 71,667 shares pursuant to the Offering.

F6: Shares held by Nutritional LTP. Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Dr. Afeyan is the sole member and manager of Nutritional LTP GP. Each of the reporting persons except for Nutritional LTP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 4 · Balance 42,865

F7: Shares held by Flagship VentureLabs IV, LLC ("VentureLabs IV"). Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund IV GP is the general partner of Flagship Fund IV. Dr. Afeyan is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for VentureLabs IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 5 · Balance 2,500,000

F8: Shares held by Flagship VentureLabs V LLC ("VentureLabs V"). Flagship Ventures Fund V, L.P. ("Flagship Fund V") is a member of VentureLabs V. Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Flagship VentureLabs V Manager LLC ("VentureLabs V Manager") serves as manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. Dr. Afeyan serves as sole manager of Flagship Fund V GP and as sole director of Flagship Pioneering. Each of the reporting persons except for VentureLabs V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 6 · Balance 2,560,096

F9: Shares held by Flagship Fund V. Flagship Fund V GP is the general partner of Flagship Fund V. Dr. Afeyan serves as sole manager of Flagship Fund V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 7 · Balance 639,360

F10: Shares held by Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund"). Flagship Fund V GP is the general partner of Nutritional Health Side Fund. Dr. Afeyan serves as sole manager of Flagship Fund V GP. Each of the reporting persons except for Nutritional Health Side Fund disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 8 · Balance 6,560,523

F11: Shares held by Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund"). Flagship Fund V GP is the general partner of Nutritional Innovation Fund. Dr. Afeyan serves as sole manager of Flagship Fund V GP. Each of the reporting persons except for Nutritional Innovation Fund disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 9 · Balance 216,451

F12: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is the sole manager of Fund 2007 GP. Each of the reporting persons except for Flagship Fund 2007 disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 10 · Balance 1,649,999

F13: Shares held by Cadena LLC ("Cadena"). Dr. Afeyan is the sole manager of Cadena. Each of the reporting persons except for Cadena disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 1 · 2026-05-21 · Exercise / conversion · Acquired 9,263 · Balance 13,187

F1: On May 21, 2026, Flagship Pioneering, LLC ("Flagship Pioneering") exercised options to purchase 9,263 shares of the Issuer's Common Stock at $19.15 per share, which options were set to expire on August 10, 2026.

F2: The securities are held directly by Flagship Pioneering. Flagship Pioneering is contractually obligated to transfer and/or remit the proceeds of any sale of shares to Flagship Fund IV, L.P. ("Flagship Fund IV"). The reporting person is the ultimate control person of Flagship Pioneering and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

Row 2 · 2026-05-21 · Sale · Disposed 9,263 · Balance 3,924

F2: The securities are held directly by Flagship Pioneering. Flagship Pioneering is contractually obligated to transfer and/or remit the proceeds of any sale of shares to Flagship Fund IV, L.P. ("Flagship Fund IV"). The reporting person is the ultimate control person of Flagship Pioneering and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

Row 6 · 2026-05-21 · Exercise / conversion · Disposed 9,263 · Balance 0

F1: On May 21, 2026, Flagship Pioneering, LLC ("Flagship Pioneering") exercised options to purchase 9,263 shares of the Issuer's Common Stock at $19.15 per share, which options were set to expire on August 10, 2026.

F5: The options were fully vested and exercisable.

F2: The securities are held directly by Flagship Pioneering. Flagship Pioneering is contractually obligated to transfer and/or remit the proceeds of any sale of shares to Flagship Fund IV, L.P. ("Flagship Fund IV"). The reporting person is the ultimate control person of Flagship Pioneering and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

Row 3 · Balance 3,880,328

F3: The securities are held directly by Flagship Fund IV. Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. The reporting person is the sole manager of Flagship Fund IV GP and disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

Row 4 · Balance 747,897

F4: The securities are held directly by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. The reporting person disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.

Row 5 · Balance 2,224,015

Row 1 · 2023-06-07 · Grant · Acquired 18,118 · Balance 18,118

F1: The options vest and become exercisable on the earlier of (i) the date of the Issuer's next annual meeting of stockholders and (ii) the first anniversary of the date of grant, subject to the Reporting Person's continued service on the Issuer's Board of Directors through such vesting date.

Row 1 · 2022-05-12 · Grant · Acquired 25,000 · Balance 25,000

F1: This option shall vest in full on the earlier of (i) the one year anniversary of the grant date or (ii) the date of the next annual meeting of stockholders following the grant date, subject to the recipient's continued service.

Row 1 · 2024-02-12 · Purchase · Acquired 2,727,272 · Balance 2,727,272

F1: On February 12, 2024, pursuant to an underwritten public offering by the Issuer, Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired pre-funded warrants to purchase 2,727,272 shares of Common Stock (the "Pre-Funded Warrants") at a purchase price of $5.4999 per Pre-Funded Warrant. The Pre-Funded Warrants do not have an expiration date.

F2: Shares held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Flagship Fund VII GP. Noubar B. Afeyan, Ph.D. is the Chief Executive Officer, sole shareholder and director of Flagship Pioneering. Each of the reporting persons except Flagship Fund VII disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

Row 1 · 2022-07-05 · Purchase · Acquired 2,912,748 · Balance 5,875,711

F1: On July 5, 2022, Nutritional Health LTP Fund, L.P. ("Nutritional LTP") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired 2,912,748 shares and 5,825,495 shares, respectively, of the Issuer's Common Stock in a registered direct offering at a price of $3.15 per share.

F2: Shares held by Nutritional LTP. Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP") is the general partner of Nutritional LTP. Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole member and manager of Nutritional LTP GP. Each of the reporting persons except for Nutritional LTP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 2 · 2022-07-05 · Purchase · Acquired 5,825,495 · Balance 5,825,495

F1: On July 5, 2022, Nutritional Health LTP Fund, L.P. ("Nutritional LTP") and Flagship Pioneering Fund VII, L.P. ("Flagship Fund VII") acquired 2,912,748 shares and 5,825,495 shares, respectively, of the Issuer's Common Stock in a registered direct offering at a price of $3.15 per share.

F3: Shares held by Flagship Fund VII. Flagship Pioneering Fund VII General Partner LLC ("Flagship Fund VII GP") is the general partner of Flagship Fund VII. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of Flagship Fund VII GP. Dr. Afeyan is the Chief Executive Officer, sole shareholder and director of Flagship Pioneering. Each of the reporting persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 3 · Balance 4,434,600

F4: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Dr. Afeyan is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 4 · Balance 1,283,282

F5: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. Dr. Afeyan is the sole manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 5 · Balance 2,962,963

F6: Shares held by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering is the manager of Flagship Fund VI GP. Dr. Afeyan is the CEO, sole shareholder and director of Flagship Pioneering. Each of the reporting persons except Flagship Fund VI disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 6 · Balance 2,734,994

F7: Shares held by Flagship VentureLabs IV LLC ("VentureLabs IV"). Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Each of the reporting persons except VentureLabs IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

Row 7 · Balance 376,018

F8: Shares held by Dr. Afeyan. Each of the reporting persons except for Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein. Includes 12,853 shares held through a trust for the benefit of Dr. Afeyan's children. Dr. Afeyan disclaims Section 16 beneficial ownership of these shares except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that the reporting person is the beneficial owner of such shares for Section 16 or any other purpose.

Row 1 · 2017-09-08 · Gift · Disposed 24,527 · Balance 0