BBOT · BridgeBio Oncology Therapeutics, Inc.

Cormorant Private Healthcare Fund V, LP ("Fund V"), which is an investment vehicle managed by CAM, is a member of the Sponsor and received such shares in a pro rata distribution by the Sponsor for no consideration.

CAM serves as the investment manager to Fund III, Cormorant Private Healthcare Fund IV, LP ("Fund IV"), Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of CAM. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and CAM. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Cormorant Private Healthcare Fund III, LP ("Fund III"), which is an investment vehicle managed by Cormorant Asset Management, LP ("CAM"), is a member of the Sponsor and received such shares in a pro rata distribution by the Sponsor for no consideration.

CAM serves as the investment manager to Fund III, Cormorant Private Healthcare Fund IV, LP ("Fund IV"), Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of CAM. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and CAM. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.

Cormorant Global Healthcare Master Fund, LP ("Master Fund"), which is an investment vehicle managed by CAM, is a member of the Sponsor and received such shares in a pro rata distribution by the Sponsor for no consideration.

CAM serves as the investment manager to Fund III, Cormorant Private Healthcare Fund IV, LP ("Fund IV"), Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of CAM. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and CAM. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.

Represents a pro rata distribution to the members of Helix Holdings II LLC (the "Sponsor") for no consideration.

Sponsor is the record holder of the securities reported herein. Fund III, Fund V, and Master Fund are the members of Sponsor. Bihua Chen is the manager of Sponsor and has voting and investment discretion with respect to the shares held of record by Sponsor. Each of Fund III, Fund V, Master Fund and Ms. Chen disclaims any beneficial ownership of the securities held by Sponsor other than to the extent of any pecuniary interest she or it may have therein, directly or indirectly.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

The shares underlying the stock option vest in full upon the earlier of (i) the first anniversary of the date of grant or (ii) the date of the next Annual Meeting of Stockholders of the Issuer following the date of grant, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of April 20, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of April 20, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

Represents shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

1/36th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of March 24, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

Represents a grant of restricted stock units ("RSUs"), each representing a contingent right to receive one share of the Issuer's Common Stock. The RSUs vest in 16 equal quarterly installments over a period of four years from January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date. The RSUs will be settled in shares of Common Stock upon vesting.

Represents a grant of restricted stock units ("RSUs"), each representing a contingent right to receive one share of the Issuer's Common Stock. The RSUs vest in 16 equal quarterly installments over a period of four years from January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date. The RSUs will be settled in shares of Common Stock upon vesting.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date.

Represents a grant of restricted stock units ("RSUs"), each representing a contingent right to receive one share of the Issuer's Common Stock. The RSUs vest in 16 equal quarterly installments over a period of four years from January 1, 2026, subject to the Reporting Person's continuous service to the Issuer on each such date. The RSUs will be settled in shares of Common Stock upon vesting.

69,650 of the shares underlying the option vested on January 2, 2026. Thereafter, 1/48th of the shares underlying the option will vest monthly, with full vesting scheduled for October 2, 2029, subject to the Reporting Person's continuous service with the Issuer on each such vesting date.

On December 10, 2025, the Issuer rescinded 1,114,400 stock options that were part of the Reporting Person's option grant dated October 2, 2025 (the "Rescinded Portion"). The Rescinded Portion was cancelled and the remaining 500,000 stock options from the original grant continue to remain outstanding. The rescission was an exempt disposition to the Issuer per Rule 16b-3.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of October 2, 2025, subject to the Reporting Person's continuous service to the Issuer on each such date.

1/48th of the shares subject to such option vest and become exercisable in substantially equal monthly installments on each monthly anniversary of October 2, 2025, subject to the Reporting Person's continuous service to the Issuer on each such date.

A fraction of the shares underlying such option equal to (x) the number of full months between April 25, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

25% of the shares underlying such option shall vest on July 21, 2026, with the remainder vesting in thirty-six substantially equal monthly installments thereafter, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

A fraction of the shares underlying such option equal to (x) the number of full months between August 11, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

A fraction of the shares underlying such option equal to (x) the number of full months between August 11, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

A fraction of the shares underlying such option equal to (x) the number of full months between August 11, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

A fraction of the shares underlying such option equal to (x) the number of full months between August 11, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

A fraction of the shares underlying such option equal to (x) the number of full months between August 11, 2025 ("Vesting Commencement Date") and the date on which a registration statement on Form S-8 is filed and effective with the Securities and Exchange Commission (the "S-8 Filing Date") divided by (y) 48 shall vest on the S-8 Filing Date, and 1/48th of the shares underlying such option shall vest each month thereafter on the day of the month corresponding to the Vesting Commencement Date (and if there is no suchcorresponding day for a month, then the vesting date shall be the last day of the applicable month) until 100% of the shares underlying such option is vested on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continuous service the Issuer on each such vesting date.

The Helix Class B ordinary shares have no expiration date and automatically convert into Class A ordinary shares at the time of Helix's initial business combination as described under the heading "Description of Securities" in Helix's registration statement on Form S-1 (File No. 333-276591).

In connection with and prior to the closing of the Business Combination, among other things, (i) each of Helix's Class B ordinary shares converted into one Helix Class A ordinary share, on a one-for-one basis, (ii) Helix migrated to and domesticated as a Delaware corporation in accordance with Section 388 of the Delaware General Corporation Law, as amended, and the Cayman Islands Companies Act (As Revised) (the "Domestication"), and (iii) as a result of the Domestication, each Class A ordinary share of Helix converted into one share of the Issuer's common stock, par value $0.0001 per share ("Common Stock"), on a one-for-one basis.

Sponsor is the record holder of the securities reported herein. Fund III, Fund V, and Master Fund are the members of Sponsor. Bihua Chen is the manager of Sponsor and has voting and investment discretion with respect to the shares held of record by Sponsor. Each of Fund III, Fund V, Master Fund and Ms. Chen disclaims any beneficial ownership of the securities held by Sponsor other than to the extent of any pecuniary interest she or it may have therein, directly or indirectly.

In connection with and immediately prior to the closing of the Business Combination, pursuant to the terms of the Subscription Agreement, Cormorant Global Healthcare Master Fund, LP ("Master Fund"), which is an investment vehicle managed by Cormorant Asset Management, LP, purchased from the Issuer 5,598,425 shares of Common Stock at a purchase price of $10.7173 per share.

Cormorant Asset Management, LP serves as the investment manager to Fund III, Fund IV, Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of Cormorant Asset Management, LP. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and Cormorant Asset Management, LP. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.

In connection with and prior to the closing of the business combination between the Issuer (which was formerly known as Helix Acquisition Corp. II, "Helix") and TheRas, Inc., among other things, (i) each of Helix's Class B ordinary shares converted into one Helix Class A ordinary share, on a one-for-one basis, as described under the heading "Description of Securities" in Helix's Registration Statement on Form S-1 (File No. 333-276591), (ii) Helix migrated to and domesticated as a Delaware corporation in accordance with Section 388 of the Delaware General Corporation Law, as amended, and the Cayman Islands Companies Act (As Revised) (the "Domestication"), and (iii) as a result of the Domestication, each Class A ordinary share of Helix converted into one share of the Issuer's common stock, on a one-for-one basis. Prior to such conversion, the Helix Class B ordinary shares had no expiration date.

The Helix Class B ordinary shares have no expiration date and automatically convert into Class A ordinary shares at the time of Helix's initial business combination as described under the heading "Description of Securities" in Helix's registration statement on Form S-1 (File No. 333-276591).

In connection with and prior to the closing of the business combination (the "Business Combination") between the Issuer (which was formerly known as Helix Acquisition Corp. II, "Helix") and TheRas, Inc. ("Legacy BBOT"), Helix Holdings II LLC (the "Sponsor") forfeited 307,874 Helix Class B ordinary shares for no consideration pursuant to the terms of the Sponsor Support Agreement dated February 28, 2025, between Sponsor, Helix, and Legacy BBOT (the "Sponsor Support Agreement").

Sponsor is the record holder of the securities reported herein. Fund III, Fund V, and Master Fund are the members of Sponsor. Bihua Chen is the manager of Sponsor and has voting and investment discretion with respect to the shares held of record by Sponsor. Each of Fund III, Fund V, Master Fund and Ms. Chen disclaims any beneficial ownership of the securities held by Sponsor other than to the extent of any pecuniary interest she or it may have therein, directly or indirectly.

In connection with and immediately prior to the closing of the Business Combination, the Sponsor forfeited 152,940 shares of Common Stock for no consideration, pursuant to the terms of the Sponsor Support Agreement.

Sponsor is the record holder of the securities reported herein. Fund III, Fund V, and Master Fund are the members of Sponsor. Bihua Chen is the manager of Sponsor and has voting and investment discretion with respect to the shares held of record by Sponsor. Each of Fund III, Fund V, Master Fund and Ms. Chen disclaims any beneficial ownership of the securities held by Sponsor other than to the extent of any pecuniary interest she or it may have therein, directly or indirectly.

In connection with and prior to the closing of the business combination between the Issuer (which was formerly known as Helix Acquisition Corp. II, "Helix") and TheRas, Inc., among other things, (i) each of Helix's Class B ordinary shares converted into one Helix Class A ordinary share, on a one-for-one basis, as described under the heading "Description of Securities" in Helix's Registration Statement on Form S-1 (File No. 333-276591), (ii) Helix migrated to and domesticated as a Delaware corporation in accordance with Section 388 of the Delaware General Corporation Law, as amended, and the Cayman Islands Companies Act (As Revised) (the "Domestication"), and (iii) as a result of the Domestication, each Class A ordinary share of Helix converted into one share of the Issuer's common stock, on a one-for-one basis. Prior to such conversion, the Helix Class B ordinary shares had no expiration date.

In connection with and immediately prior to the closing of the Business Combination, pursuant to the terms of a subscription agreement dated February 28, 2025 between Helix and Cormorant Asset Management, LP (the "Subscription Agreement"), Cormorant Private Healthcare Fund III, LP ("Fund III"), which is an investment vehicle managed by Cormorant Asset Management, LP, purchased from the Issuer 760,496 shares of Common Stock at a purchase price of $10.7173 per share.

Cormorant Asset Management, LP serves as the investment manager to Fund III, Fund IV, Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of Cormorant Asset Management, LP. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and Cormorant Asset Management, LP. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.

Upon the closing of the Business Combination, as contemplated by the terms of the Business Combination Agreement, dated as of February 28, 2025 (as amended, the "Business Combination Agreement"), by and among Helix, Legacy BBOT, and Helix Merger Sub, Inc., the owners of Legacy BBOT equity as of immediately prior to the closing, including Fund V, Master Fund, and Cormorant Private Healthcare Fund IV, LP ("Fund IV"), received as consideration therefor, shares of common stock of the Issuer.

Cormorant Asset Management, LP serves as the investment manager to Fund III, Fund IV, Fund V, and Master Fund (collectively, the "Cormorant Funds"). Cormorant Private Healthcare GP III, LLC ("GP III") is the general partner of Fund III; Cormorant Private Healthcare GP IV, LLC ("GP IV") is the general partner of Fund IV; Cormorant Private Healthcare GP V, LLC ("GP V") is the general partner of Fund V; and Cormorant Global Healthcare GP, LLC ("Global GP") is the general partner of the Master Fund. Bihua Chen serves as the managing member of GP III, GP IV, GP V, and Global GP, and as the general partner of Cormorant Asset Management, LP. Accordingly, Ms. Chen has voting and investment discretion with respect to the shares held by each of the Cormorant Funds and Cormorant Asset Management, LP. Ms. Chen disclaims any beneficial ownership of the securities held by each of the Cormorant Funds other than to the extent of any pecuniary interest she may have therein, directly or indirectly.