AKTS · Aktis Oncology, Inc.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.50 to $24.66, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

These options have vested in full.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.50 to $24.66, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

These options have vested in full.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.00 to $25.4950, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

These options have vested in full.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $26.5200 to $27.5100, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

25% of the original number of shares subject to the option vested on September 19, 2023, and 1/48th of the original number of shares subject to the option vested or shall vest in monthly installments thereafter, subject to the Reporting Person's continuous service through each vesting date, inclusive.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $27.5300 to $28.5000, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $26.5200 to $27.5100, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $28.6300 to $28.7400, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $27.5200 to $28.4700, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

25% of the original number of shares subject to the option vested on July 1, 2025, and 1/48th of the original number of shares subject to the option vested or shall vest in monthly installments thereafter, subject to the Reporting Person's continuous service through each vesting date, inclusive.

The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $28.7300 to $28.7600, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

1/3 of the original number of shares subject to the option shall vest on April 15, 2027, and 1/3 of the original number of shares subject to the option shall vest in equal annual installments thereafter, subject to the Reporting Person's continuous service through each vesting date, inclusive.

The Series A Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

These shares are held by Vida Ventures II-A, LLC ("VV II-A"). VVM II is the manager of VV II-A and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II-A. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II-A and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

Represents shares of the Issuer's Common Stock received upon conversion of shares of the Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock on a 3.8044-for-1 basis without payment of additional consideration.

These shares are held by Vida Ventures II, LLC ("VV II"). VV Manager II, LLC ("VVM II") is the manager of VV II and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares of common stock were issued upon conversion as follows: 2,505,648 by BV 2018, 133,170 by BV 2018(B), 49,452 by AM BV2018, 537,654 by MPM Oncology and 2,688,273 by MPM Oncology Impact.

The Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

These shares are held by Vida Ventures II, LLC ("VV II"). VV Manager II, LLC ("VVM II") is the manager of VV II and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

These securities are held by EcoR1 Capital Fund, L.P. ("Capital Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"), 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"), 119,478 by MPM Oncology Innovations Fund, L.P. ("MPM Oncology") and 597,393 by Oncology Impact Private Investment Fund 2, L.P. ("MPM Oncology Impact"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Drs. Evnin and Gadicke are managing directors of BV 2018 LLC and managers of MPM Oncology Innovations Fund GP LLC, which is the general partner of MPM Oncology. Dr. Gadicke is the managing member of MPM Oncology Investments 2 LLC, which is the general partner of MPM Oncology Impact.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 341,709 by MPM Asset Management LLC ("MPM AM"), 556,810 by BV 2018, 29,593 by BV 2018(B), 10,988 by AM BV2018, 119,478 by MPM Oncology and 597,393 by MPM Oncology Impact. Dr. Gadicke is the manager of MPM AM.

These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B) and 13,187 by AM BV2018.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 3,730,631 by BV 2018, 198,275 by BV 2018(B) and 73,627 by AM BV2018.

The Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock.

Consists of shares held by Arvala, Inc.(f/k/a 3996953 Canada Inc.). The Reporting Person is the president and sole stockholder of Arvala, Inc. and may be deemed to share the voting and dispositive power over the shares held by Arvala, Inc.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B), 13,187 by AM BV2018, 143,374 by MPM Oncology and 716,873 by MPM Oncology Impact.

The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"), 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"), 119,478 by MPM Oncology Innovations Fund, L.P. ("MPM Oncology") and 597,393 by Oncology Impact Private Investment Fund 2, L.P. ("MPM Oncology Impact"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Drs. Evnin and Gadicke are managing directors of BV 2018 LLC and managers of MPM Oncology Innovations Fund GP LLC, which is the general partner of MPM Oncology. Dr. Gadicke is the managing member of MPM Oncology Investments 2 LLC, which is the general partner of MPM Oncology Impact.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 341,709 by MPM Asset Management LLC ("MPM AM"), 556,810 by BV 2018, 29,593 by BV 2018(B), 10,988 by AM BV2018, 119,478 by MPM Oncology and 597,393 by MPM Oncology Impact. Dr. Gadicke is the manager of MPM AM.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B), 13,187 by AM BV2018, 143,374 by MPM Oncology and 716,873 by MPM Oncology Impact.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund, L.P. ("Capital Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund, L.P. ("Capital Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

Represents shares of the Issuer's Common Stock received upon conversion of shares of the Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock on a 3.8044-for-1 basis without payment of additional consideration.

These shares are held by Vida Ventures II, LLC ("VV II"). VV Manager II, LLC ("VVM II") is the manager of VV II and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and the Reporting Person, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Venture Opportunity Fund, L.P. ("Venture Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

Each share of Class A Common Stock is convertible into one share of Common Stock at the election of the holder for no additional consideration, subject to a 4.99% beneficial ownership limitation. Each share is immediately exercisable and has no expiration date.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

These shares are held by Vida Ventures II-A, LLC ("VV II-A"). VVM II is the manager of VV II-A and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II-A. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and the Reporting Person, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II-A and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"), 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"), 119,478 by MPM Oncology Innovations Fund, L.P. ("MPM Oncology") and 597,393 by Oncology Impact Private Investment Fund 2, L.P. ("MPM Oncology Impact"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Drs. Evnin and Gadicke are managing directors of BV 2018 LLC and managers of MPM Oncology Innovations Fund GP LLC, which is the general partner of MPM Oncology. Dr. Gadicke is the managing member of MPM Oncology Investments 2 LLC, which is the general partner of MPM Oncology Impact.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

These shares are held by Vida Ventures II-A, LLC ("VV II-A"). VVM II is the manager of VV II-A and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II-A. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II-A and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

The shares were purchased as follows: 219,897 by BV 2018, 8,689 by BV 2018(B), 4,284 by AM BV2018, 46,574 by MPM Oncology and 833,333 by MPM Oncology Impact.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 341,709 by MPM AM, 3,950,528 by BV 2018, 206,964 by BV 2018(B), 77,911 by AM BV2018, 847,080 by MPM Oncology and 4,835,872 by MPM Oncology Impact.

The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)") and 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. The Reporting Person is a managing director of BV 2018 LLC.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 556,810 by BV 2018, 29,593 by BV 2018(B) and 10,988 by AM BV2018.

The shares were purchased as follows: 219,897 by BV 2018, 8,689 by BV 2018(B) and 4,284 by AM BV2018.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 3,950,528 by BV 2018, 206,964 by BV 2018(B) and 77,911 by AM BV2018.

Represents shares of the Issuer's Common Stock received upon conversion of shares of the reported series of preferred stock on a 3.8044-for-1 basis without payment of further consideration.

Consists of shares held by Arvala, Inc.(f/k/a 3996953 Canada Inc.). The Reporting Person is the president and sole stockholder of Arvala, Inc. and may be deemed to share the voting and dispositive power over the shares held by Arvala, Inc.

The shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock converted into shares of Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the initial public offering of the Issuer's Common Stock for no additional consideration. Each share was immediately exercisable and had no expiration date.

These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

The Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

These shares are held by Vida Ventures II, LLC ("VV II"). VV Manager II, LLC ("VVM II") is the manager of VV II and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and the Reporting Person, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.

The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B), 13,187 by AM BV2018, 143,374 by MPM Oncology and 716,873 by MPM Oncology Impact.

Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.

The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.

The shares are held as follows: 341,709 by MPM AM, 3,730,631 by BV 2018, 198,275 by BV 2018(B), 73,627 by AM BV2018, 800,506 by MPM Oncology and 4,002,539 by MPM Oncology Impact.