SION

SEC source: 0001704336-26-000005 · edgardoc.xml · derivative · entry 4

Cloonan Michael · CIK 0001704336 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 436,100 shares

Expires 2036-01-01

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0001704336-26-000005 · edgardoc.xml · derivative · entry 3

Cloonan Michael · CIK 0001704336 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 436,100

Underlying: Common Stock · 436,100 shares

Expires 2036-01-01

F3 · derivative.exercise_price: The exercise price of the option is $7.18 per share, representing the fair market value per share of the Issuer's Common Stock on September 17, 2026 (the "Repricing Date"). Unless otherwise provided by the Issuer's board of directors or its compensation committee, if the option is exercised before the applicable retention period ends, the exercise price will revert to its original exercise price. The retention period begins on the Repricing Date and ends on the earliest of (i) the 18-month anniversary of the Repricing Date (March 17, 2028), (ii) a Sale Event (as defined in the Sionna Therapeutics, Inc. 2025 Stock Option and Incentive Plan (the "2025 Plan")) or (iii) certain qualifying terminations of service.

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0001704336-26-000005 · edgardoc.xml · nonDerivative · entry 2

Cloonan Michael · CIK 0001704336 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 765,393

F2 · kind: Represents a grant of RSUs. Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest upon the achievement of a designated performance milestone, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0001704336-26-000005 · edgardoc.xml · nonDerivative · entry 1

Cloonan Michael · CIK 0001704336 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 656,368

F1 · kind: Represents a grant of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest on June 17, 2027, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0002061851-26-000009 · edgardoc.xml · derivative · entry 4

Fitzpatrick Jennifer · CIK 0002061851 · CLO and Head of Program Mgmt.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 103,140 shares

Expires 2036-01-01

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0002061851-26-000009 · edgardoc.xml · derivative · entry 3

Fitzpatrick Jennifer · CIK 0002061851 · CLO and Head of Program Mgmt.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 103,140

Underlying: Common Stock · 103,140 shares

Expires 2036-01-01

F3 · derivative.exercise_price: The exercise price of the option is $7.18 per share, representing the fair market value per share of the Issuer's Common Stock on September 17, 2026 (the "Repricing Date"). Unless otherwise provided by the Issuer's board of directors or its compensation committee, if the option is exercised before the applicable retention period ends, the exercise price will revert to its original exercise price. The retention period begins on the Repricing Date and ends on the earliest of (i) the 18-month anniversary of the Repricing Date (March 17, 2028), (ii) a Sale Event (as defined in the Sionna Therapeutics, Inc. 2025 Stock Option and Incentive Plan (the "2025 Plan")) or (iii) certain qualifying terminations of service.

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0002061851-26-000009 · edgardoc.xml · nonDerivative · entry 2

Fitzpatrick Jennifer · CIK 0002061851 · CLO and Head of Program Mgmt.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,265

F2 · kind: Represents a grant of RSUs. Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest upon the achievement of a designated performance milestone, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0002061851-26-000009 · edgardoc.xml · nonDerivative · entry 1

Fitzpatrick Jennifer · CIK 0002061851 · CLO and Head of Program Mgmt.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,133

F1 · kind: Represents a grant of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest on June 17, 2027, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0002046433-26-000005 · edgardoc.xml · derivative · entry 4

McKee Charlotte · CIK 0002046433 · CMO and Head of R&D

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 155,700 shares

Expires 2036-01-01

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0002046433-26-000005 · edgardoc.xml · derivative · entry 3

McKee Charlotte · CIK 0002046433 · CMO and Head of R&D

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 155,700

Underlying: Common Stock · 155,700 shares

Expires 2036-01-01

F3 · derivative.exercise_price: The exercise price of the option is $7.18 per share, representing the fair market value per share of the Issuer's Common Stock on September 17, 2026 (the "Repricing Date"). Unless otherwise provided by the Issuer's board of directors or its compensation committee, if the option is exercised before the applicable retention period ends, the exercise price will revert to its original exercise price. The retention period begins on the Repricing Date and ends on the earliest of (i) the 18-month anniversary of the Repricing Date (March 17, 2028), (ii) a Sale Event (as defined in the Sionna Therapeutics, Inc. 2025 Stock Option and Incentive Plan (the "2025 Plan")) or (iii) certain qualifying terminations of service.

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0002046433-26-000005 · edgardoc.xml · nonDerivative · entry 2

McKee Charlotte · CIK 0002046433 · CMO and Head of R&D

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 128,415

F2 · kind: Represents a grant of RSUs. Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest upon the achievement of a designated performance milestone, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0002046433-26-000005 · edgardoc.xml · nonDerivative · entry 1

McKee Charlotte · CIK 0002046433 · CMO and Head of R&D

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 78,415

F1 · kind: Represents a grant of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest on June 17, 2027, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0001772518-26-000004 · edgardoc.xml · derivative · entry 4

Ridloff Elena · CIK 0001772518 · CFO and CBO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 165,440 shares

Expires 2036-01-01

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0001772518-26-000004 · edgardoc.xml · derivative · entry 3

Ridloff Elena · CIK 0001772518 · CFO and CBO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 165,440

Underlying: Common Stock · 165,440 shares

Expires 2036-01-01

F3 · derivative.exercise_price: The exercise price of the option is $7.18 per share, representing the fair market value per share of the Issuer's Common Stock on September 17, 2026 (the "Repricing Date"). Unless otherwise provided by the Issuer's board of directors or its compensation committee, if the option is exercised before the applicable retention period ends, the exercise price will revert to its original exercise price. The retention period begins on the Repricing Date and ends on the earliest of (i) the 18-month anniversary of the Repricing Date (March 17, 2028), (ii) a Sale Event (as defined in the Sionna Therapeutics, Inc. 2025 Stock Option and Incentive Plan (the "2025 Plan")) or (iii) certain qualifying terminations of service.

F4 · kind: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F4 · price: Effective on the Repricing Date, the Issuer's board of directors approved an option repricing. All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

F5 · derivative.exercise_date: This stock option award was issued pursuant to the 2025 Plan, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on the applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

SEC source: 0001772518-26-000004 · edgardoc.xml · nonDerivative · entry 2

Ridloff Elena · CIK 0001772518 · CFO and CBO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 133,069

F2 · kind: Represents a grant of RSUs. Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest upon the achievement of a designated performance milestone, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0001772518-26-000004 · edgardoc.xml · nonDerivative · entry 1

Ridloff Elena · CIK 0001772518 · CFO and CBO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 85,801

F1 · kind: Represents a grant of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of Common Stock of the Issuer. The RSUs will vest on June 17, 2027, subject to the Reporting Person's continued service with the Issuer as of the vesting date.

SEC source: 0001231919-26-001201 · form4-09212026_100937.xml · nonDerivative · entry 2

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · Director · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · Director

RA Capital Nexus Fund, L.P. · CIK 0001780117 · Director

RA Capital Nexus Fund III, L.P. · CIK 0001883840 · Director

Kolchinsky Peter · CIK 0001384859 · Director · 10% owner

Shah Rajeev M. · CIK 0001619841 · Director · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 3,448,812

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.30 to $7.68 inclusive. The Reporting Persons undertake 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 set forth in this footnote.

F1 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

F2 · ownership.nature: Held directly by the Fund.

SEC source: 0001231919-26-001201 · form4-09212026_100937.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · Director · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · Director

RA Capital Nexus Fund, L.P. · CIK 0001780117 · Director

RA Capital Nexus Fund III, L.P. · CIK 0001883840 · Director

Kolchinsky Peter · CIK 0001384859 · Director · 10% owner

Shah Rajeev M. · CIK 0001619841 · Director · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 3,482,612

F1 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

F2 · ownership.nature: Held directly by the Fund.

SEC source: 0000947871-26-000694 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,469,959

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000695 · ownership.xml · nonDerivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,469,959

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0002061851-26-000006 · edgardoc.xml · derivative · entry 3

Fitzpatrick Jennifer · CIK 0002061851 · Chief Legal Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 40,685

Underlying: Common Stock · 10,250 shares

Expires 2034-07-14

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: This transaction was automatically executed pursuant to a Rule 10b5-1 trading plan adopted on June 5, 2025.

F3 · derivative.exercise_date: 25% of the shares underlying this option vested on June 3, 2025, with the remainder vesting in thirty-six equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0002061851-26-000006 · edgardoc.xml · nonDerivative · entry 2

Fitzpatrick Jennifer · CIK 0002061851 · Chief Legal Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: This transaction was automatically executed pursuant to a Rule 10b5-1 trading plan adopted on June 5, 2025.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $42.89 to $44.22, inclusive. The Reporting Person undertakes to provide to the Issuer, any securityholder 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 at which the transactions were effected.

SEC source: 0002061851-26-000006 · edgardoc.xml · nonDerivative · entry 1

Fitzpatrick Jennifer · CIK 0002061851 · Chief Legal Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 10,250

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: This transaction was automatically executed pursuant to a Rule 10b5-1 trading plan adopted on June 5, 2025.

SEC source: 0000947871-26-000683 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,555,877

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000684 · ownership.xml · nonDerivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,555,877

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0001644348-26-000007 · edgardoc.xml · derivative · entry 1

Stelzer Laurie · CIK 0001644348 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001816744-26-000002 · edgardoc.xml · derivative · entry 1

Viney Joanne L. · CIK 0001816744 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001357522-26-000003 · edgardoc.xml · derivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · security: Pursuant to an agreement with OrbiMed Advisors LLC and OrbiMed Capital GP VIII LLC, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC and OrbiMed Capital GP VIII LLC, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VIII, LP.

F2 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0002023849-26-000010 · edgardoc.xml · derivative · entry 1

Ruddy Marcella K. · CIK 0002023849 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001231919-26-000674 · form4-06182026_090647.xml · derivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · Director · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · Director · 10% owner

RA Capital Nexus Fund, L.P. · CIK 0001780117 · Director

RA Capital Nexus Fund III, L.P. · CIK 0001883840 · Director

Kolchinsky Peter · CIK 0001384859 · Director · 10% owner

Shah Rajeev M. · CIK 0001619841 · Director · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · derivative.exercise_date: The shares underlying the option vest in full upon the earlier of June 17, 2027 or the date of the Issuer's next annual meeting, subject to Dr. Resnick's continued service through such date.

F2 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus Fund III, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his pecuniary interest therein.

F3 · ownership.nature: Under Dr. Resnick's arrangement with the Adviser, Dr. Resnick holds the option for the benefit of the Fund, the Nexus Fund, the Nexus Fund III, and the Account. Dr. Resnick is obligated to turn over to the Adviser any net cash or stock received upon exercise of the stock option, which will offset advisory fees owed by the Fund, the Nexus Fund, the Nexus Fund III and the Account to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the stock option and underlying Common Stock.

SEC source: 0001690959-26-000004 · edgardoc.xml · derivative · entry 1

Resnick Joshua · CIK 0001690959 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · security: Under the Reporting Person's arrangement with RA Capital Management, L.P. (the "Adviser"), the Reporting Person holds the option for the benefit of the RA Capital Healthcare Fund, L.P. (the "Fund"), the RA Capital Nexus Fund, L.P. (the "Nexus Fund"), the RA Capital Nexus Fund III, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The Reporting Person is obligated to turn over to the Adviser any net cash or stock received upon exercise of the stock option, which will offset advisory fees owed by the Fund, the Nexus Fund, the Nexus Fund III and the Account to the Adviser. The Reporting Person therefore disclaims beneficial ownership of the stock option and underlying Common Stock.

F2 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001857250-26-000002 · edgardoc.xml · derivative · entry 1

Fleming Harold Edward · CIK 0001857250 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · security: The Reporting Person has agreed to receive and hold for the benefit of Enavate Sciences, LP, any securities granted to him for his service as a director on the Issuer's board of directors. As such, the Reporting Person disclaims beneficial ownership of, and all right, title and interest in, the option and the shares issuable upon exercise thereof.

F2 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001409601-26-000010 · edgardoc.xml · derivative · entry 1

Clancy Paul J · CIK 0001409601 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0001451612-26-000008 · edgardoc.xml · derivative · entry 1

Booth Bruce · CIK 0001451612 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,340

Underlying: Common Stock · 17,340 shares

Expires 2036-06-16

F1 · security: This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

F2 · derivative.exercise_date: This option vests in full upon the earlier of June 17, 2027 or the date of the next annual meeting of Sionna Therapeutics, Inc., subject to the Reporting Person's continued service on such vesting date.

SEC source: 0000947871-26-000587 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,671,721

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000588 · ownership.xml · nonDerivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,671,721

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000517 · ownership.xml · nonDerivative · entry 3

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,671,822

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000518 · ownership.xml · nonDerivative · entry 3

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,671,822

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000517 · ownership.xml · nonDerivative · entry 2

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,856,461

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000518 · ownership.xml · nonDerivative · entry 2

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,856,461

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000517 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,916,228

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000518 · ownership.xml · nonDerivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes(

Disclosed balance after: 2,916,228

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000458 · ownership.xml · nonDerivative · entry 2

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,964,774

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000459 · ownership.xml · nonDerivative · entry 2

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,964,774

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000458 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,967,722

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000459 · ownership.xml · nonDerivative · entry 1

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 2,967,722

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000446 · ownership.xml · nonDerivative · entry 3

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 3,020,119

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000447 · ownership.xml · nonDerivative · entry 3

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 3,020,119

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000446 · ownership.xml · nonDerivative · entry 2

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

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

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 3,247,025

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII.

F3 · ownership.nature: This report on Form 4 is jointly filed by OrbiMed Advisors and GP VIII. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Peter A. Thompson, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000447 · ownership.xml · nonDerivative · entry 2

Thompson Peter A. · CIK 0001357522 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 3,247,025

F1 · shares: These securities were sold pursuant to a 10b5-1 plan.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.

F3 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.