MIRM

SEC source: 0001209191-23-037333 · doc4.xml · nonDerivative · entry 1

New Enterprise Associates 16, L.P. · CIK 0001694560 · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,186,243

F1 · kind: New Enterprise Associates 16, L.P. ("NEA 16") made a pro rata distribution of 2,000,000 shares of Common Stock of the Issuer to its general partner and limited partners for no consideration on June 13, 2023.

F2 · ownership.direct: The securities are directly held by NEA 16 and are indirectly held by NEA Partners 16, L.P. ("NEA Partners 16"), the sole general partner of NEA 16, NEA 16 GP, LLC ("NEA 16 GP"), the sole general partner of NEA Partners 16, and the individual managers of NEA 16 GP (NEA Partners 16, NEA 16 GP and the individual managers of NEA 16 GP (collectively, the "NEA 16 Managers"), together, the "NEA 16 Indirect Reporting Persons"). The NEA 16 Managers are Forest Baskett, Ali Behbahani, Carmen Chang, Anthony A. Florence, Jr., Mohamad Makhzoumi, Scott D. Sandell and Paul Walker. The NEA 16 Indirect Reporting Persons disclaim beneficial ownership within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the securities held by NEA 16 in which the NEA 16 Indirect Reporting Persons have no pecuniary interest.

SEC source: 0001209191-23-037133 · doc4.xml · derivative · entry 1

Cardon Lon · CIK 0001854337 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 7,083

Underlying: Common Stock · 7,083 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037135 · doc4.xml · derivative · entry 1

Walbert Timothy P · CIK 0001349376 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,417

Underlying: Common Stock · 1,417 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037131 · doc4.xml · derivative · entry 1

Ramasastry Saira · CIK 0001547959 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037129 · doc4.xml · derivative · entry 1

Fairey William · CIK 0001727275 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037127 · doc4.xml · derivative · entry 1

Brege Laura · CIK 0001365619 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037124 · doc4.xml · derivative · entry 1

Fischer Laurent · CIK 0001379344 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037123 · doc4.xml · derivative · entry 1

Heron Patrick J · CIK 0001365617 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-037122 · doc4.xml · derivative · entry 1

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2024 annual stockholder meeting.

SEC source: 0001209191-23-035831 · doc4.xml · derivative · entry 5

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 345,784

Underlying: Common Stock · 14,608 shares

Expires 2029-03-11

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.

F2 · derivative.exercise_date: 1/4th of the shares vest one year after November 5, 2018, and the balance of the shares vest in a series of 36 successive equal monthly installments at the end of each month thereafter. The shares subject to this option are early exercisable, subject to the Issuer's right of repurchase.

SEC source: 0001209191-23-035831 · doc4.xml · nonDerivative · entry 2

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted August 30, 2022.

SEC source: 0001209191-23-035831 · doc4.xml · nonDerivative · entry 1

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 14,608

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.

SEC source: 0001209191-23-030962 · doc4.xml · nonDerivative · entry 1

Vig Pamela · CIK 0001780069 · Head of Research & Development

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 32,211

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 684 shares by the Reporting Person on May 10, 2023 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-23-030964 · doc4.xml · nonDerivative · entry 1

Radovich Peter · CIK 0001650131 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 39,100

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 968 shares by the Reporting Person on May 10, 2023 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-23-030966 · doc4.xml · nonDerivative · entry 1

Longpre Lara · CIK 0001780347 · Chief Development Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 106,843

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 684 shares by the Reporting Person on May 10, 2023 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-23-030951 · doc4.xml · nonDerivative · entry 1

Peetz Christopher · CIK 0001614740 · Director · President and CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 120,832

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 1,256 shares by the Reporting Person on May 10, 2023 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-23-027549 · doc4.xml · derivative · entry 5

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 360,392

Underlying: Common Stock · 14,608 shares

Expires 2029-03-11

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.

F2 · derivative.exercise_date: 1/4th of the shares vest one year after November 5, 2018, and the balance of the shares vest in a series of 36 successive equal monthly installments at the end of each month thereafter. The shares subject to this option are early exercisable, subject to the Issuer's right of repurchase.

SEC source: 0001209191-23-027549 · doc4.xml · nonDerivative · entry 2

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted August 30, 2022.

SEC source: 0001209191-23-027549 · doc4.xml · nonDerivative · entry 1

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 14,608

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.

SEC source: 0001209191-23-023648 · doc4.xml · derivative · entry 1

Walbert Timothy P · CIK 0001349376 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 34,000

Underlying: Common Stock · 34,000 shares

Expires 2033-04-04

F1 · derivative.exercise_date: The shares vest in equal annual installments over a three year period such that the option is fully vested on the third anniversary of the date of grant (April 5, 2023).

SEC source: 0001209191-23-006305 · doc4.xml · derivative · entry 3

Vig Pamela · CIK 0001780069 · Head of Research & Development

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 38,500

Underlying: Common Stock · 38,500 shares

Expires 2033-01-30

F2 · derivative.exercise_date: 1/4th of the shares vest one year after January 31, 2023 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date.

SEC source: 0001209191-23-006305 · doc4.xml · nonDerivative · entry 1

Vig Pamela · CIK 0001780069 · Head of Research & Development

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 31,527

F1 · shares: Represents restricted stock unit award granted under the Issuer's 2019 Equity Incentive Plan.

SEC source: 0001209191-23-006312 · doc4.xml · derivative · entry 2

Longpre Lara · CIK 0001780347 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 38,500

Underlying: Common Stock · 38,500 shares

Expires 2033-01-30

F2 · derivative.exercise_date: 1/4th of the shares vest one year after January 31, 2023 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date.

SEC source: 0001209191-23-006312 · doc4.xml · nonDerivative · entry 1

Longpre Lara · CIK 0001780347 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 106,159

F1 · shares: Represents restricted stock unit award granted under the Issuer's 2019 Equity Incentive Plan.

SEC source: 0001209191-23-006302 · doc4.xml · derivative · entry 2

Radovich Peter · CIK 0001650131 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 57,750

Underlying: Common Stock · 57,750 shares

Expires 2033-01-30

F2 · derivative.exercise_date: 1/4th of the shares vest one year after January 31, 2023 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date.

SEC source: 0001209191-23-006302 · doc4.xml · nonDerivative · entry 1

Radovich Peter · CIK 0001650131 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 38,132

F1 · shares: Represents restricted stock unit award granted under the Issuer's 2019 Equity Incentive Plan.

SEC source: 0001209191-23-006297 · doc4.xml · derivative · entry 3

Peetz Christopher · CIK 0001614740 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 200,000

Underlying: Common Stock · 200,000 shares

Expires 2033-01-30

F2 · derivative.exercise_date: 1/4th of the shares vest one year after January 31, 2023 (the "Vesting Commencement Date") and the balance of the shares vest in a series of 36 successive equal monthly installments measured from the first anniversary of the Vesting Commencement Date.

SEC source: 0001209191-23-006297 · doc4.xml · nonDerivative · entry 1

Peetz Christopher · CIK 0001614740 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 119,576

F1 · shares: Represents restricted stock unit award granted under the Issuer's 2019 Equity Incentive Plan.

SEC source: 0001415889-24-008320 · form4-03182024_090327.xml · nonDerivative · entry 1

Vig Pamela · CIK 0001780069 · CHIEF SCIENTIFIC OFFICER

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,312

F1 · kind: Shares sold to cover tax witholding obligations associated with the vesting of restricted stock units.

SEC source: 0001415889-24-008322 · form4-03182024_090306.xml · nonDerivative · entry 1

Radovich Peter · CIK 0001650131 · PRESIDENT AND COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 33,316

F1 · kind: Shares sold to cover tax witholding obligations associated with the vesting of restricted stock units.

SEC source: 0001415889-24-008316 · form4-03182024_090300.xml · nonDerivative · entry 2

Longpre Lara · CIK 0001780347 · CHIEF DEVELOPMENT OFFICER

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 104,369

F2 · kind: Shares sold to cover tax witholding obligations associated with the vesting of restricted stock units.

SEC source: 0001415889-24-008313 · form4-03182024_090320.xml · nonDerivative · entry 1

Peetz Christopher · CIK 0001614740 · Director · CHIEF EXECUTIVE OFFICER

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 91,953

F1 · kind: Shares sold to cover tax witholding obligations associated with the vesting of restricted stock units.

F2 · balance_after: 7,000 shares held indirectly by the reporting person were inadvertently reported on prior Form 4 filings as direct holdings. The reporting person's holdings on this Form 4 have been adjusted accordingly.

SEC source: 0001209191-22-062073 · doc4.xml · derivative · entry 1

Cardon Lon · CIK 0001854337 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 34,000

Underlying: Common Stock · 34,000 shares

Expires 2032-12-18

F1 · derivative.exercise_date: The shares vest in equal annual installments over a three year period such that the option is fully vested on the third anniversary of the date of grant (December 19, 2022).

SEC source: 0000899243-22-035944 · doc4.xml · nonDerivative · entry 3

O'Donnell Niall · CIK 0001780235 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By RiverVest Venture Fund IV, L.P.

Disclosed balance after: 1,621,118

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.00 to $20.32, inclusive.

F2 · ownership.nature: RiverVest Venture Partners IV, L.P. is the general partner of RiverVest Venture Fund IV, L.P. The Reporting Person is a manager of RiverVest Venture Partners IV, LLC, the sole general partner of RiverVest Venture Partners IV, L.P., and as a result may be deemed to share dispositive voting and investment power with respect to the shares held by RiverVest Venture Partners IV, L.P. The Reporting Person disclaims beneficial ownership of all shares held by RiverVest Venture Partners IV, L.P. except to the extent of his pecuniary interests therein.

SEC source: 0000899243-22-035944 · doc4.xml · nonDerivative · entry 2

O'Donnell Niall · CIK 0001780235 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By RiverVest Venture Fund IV, L.P.

Disclosed balance after: 1,714,888

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.105 to $20.43, inclusive.

F2 · ownership.nature: RiverVest Venture Partners IV, L.P. is the general partner of RiverVest Venture Fund IV, L.P. The Reporting Person is a manager of RiverVest Venture Partners IV, LLC, the sole general partner of RiverVest Venture Partners IV, L.P., and as a result may be deemed to share dispositive voting and investment power with respect to the shares held by RiverVest Venture Partners IV, L.P. The Reporting Person disclaims beneficial ownership of all shares held by RiverVest Venture Partners IV, L.P. except to the extent of his pecuniary interests therein.

SEC source: 0000899243-22-035944 · doc4.xml · nonDerivative · entry 1

O'Donnell Niall · CIK 0001780235 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · By RiverVest Venture Fund IV, L.P.

Disclosed balance after: 1,746,997

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $19.95 to $20.28, inclusive. The reporting persons undertake to provide Mirum Pharmaceuticals, Inc., any security holder of Mirum Pharmaceuticals, Inc., 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 ranges set forth in footnotes (1), (3) and (4) to this Form 4.

F2 · ownership.nature: RiverVest Venture Partners IV, L.P. is the general partner of RiverVest Venture Fund IV, L.P. The Reporting Person is a manager of RiverVest Venture Partners IV, LLC, the sole general partner of RiverVest Venture Partners IV, L.P., and as a result may be deemed to share dispositive voting and investment power with respect to the shares held by RiverVest Venture Partners IV, L.P. The Reporting Person disclaims beneficial ownership of all shares held by RiverVest Venture Partners IV, L.P. except to the extent of his pecuniary interests therein.

SEC source: 0001209191-22-056889 · doc4.xml · nonDerivative · entry 1

Vig Pamela · CIK 0001780069 · Head of Research & Development

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 21,902

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 660 shares by the Reporting Person on November 10, 2022 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-22-056891 · doc4.xml · nonDerivative · entry 1

Clements Ian · CIK 0001780080 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 30,011

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 325 shares by the Reporting Person on November 10, 2022 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-22-056890 · doc4.xml · nonDerivative · entry 1

Peetz Christopher · CIK 0001614740 · Director · President and CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 69,576

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 49 shares by the Reporting Person on November 10, 2022 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-22-056888 · doc4.xml · nonDerivative · entry 1

Radovich Peter · CIK 0001650131 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 23,692

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 292 shares by the Reporting Person on November 10, 2022 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001209191-22-056887 · doc4.xml · nonDerivative · entry 1

Longpre Lara · CIK 0001780347 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 96,534

F1 · kind: This Form 4 is being filed voluntarily to report the acquisition of 82 shares by the Reporting Person on November 10, 2022 pursuant to the Issuer's Employee Stock Purchase Plan.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 6

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Healthcare Innovations Fund, L.P.

Disclosed balance after: 1,540,190

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 5

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Private Design Fund IV, L.P.

Disclosed balance after: 1,704,244

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 4

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Healthcare Innovations Fund, L.P.

Disclosed balance after: 1,546,433

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 3

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Private Design Fund IV, L.P.

Disclosed balance after: 1,711,153

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 2

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Healthcare Innovations Fund, L.P.

Disclosed balance after: 1,546,588

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001193805-22-000932 · e621737_4-mirum.xml · nonDerivative · entry 1

Flynn James E · CIK 0001352546 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt HIF, L.P. · CIK 0001665736 · 10% owner · * Possible Member of 10% Group

Deerfield Mgmt IV, L.P. · CIK 0001713467 · 10% owner · * Possible Member of 10% Group

DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) · CIK 0001009258 · 10% owner · * Possible Member of 10% Group

Deerfield Private Design Fund IV, L.P. · CIK 0001680307 · 10% owner · * Possible Member of 10% Group

Deerfield Healthcare Innovations Fund, L.P. · CIK 0001646981 · 10% owner · * Possible Member of 10% Group

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

10b5-1 filing: Not disclosed

Ownership: Indirect · Through Deerfield Private Design Fund IV, L.P.

Disclosed balance after: 1,711,324

F1 · ownership.nature: This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt IV, L.P. is the general partner of Deerfield Private Design Fund IV, L.P. ("Fund IV"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund IV, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt IV, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P.

F2 · ownership.nature: In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

SEC source: 0001209191-22-034741 · doc4.xml · derivative · entry 1

Ramasastry Saira · CIK 0001547959 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 34,000

Underlying: Common Stock · 34,000 shares

Expires 2032-06-01

F1 · derivative.exercise_date: The shares vest in equal annual installments over a three year period such that the option is fully vested on the third anniversary of the date of grant (June 2, 2022).

SEC source: 0001209191-22-034671 · doc4.xml · derivative · entry 1

Mathers Edward T · CIK 0001328625 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2032-06-01

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2023 annual stockholder meeting.

SEC source: 0001209191-22-034651 · doc4.xml · derivative · entry 1

GREY MICHAEL G · CIK 0001240122 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,000

Underlying: Common Stock · 17,000 shares

Expires 2032-06-01

F1 · derivative.exercise_date: The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2023 annual stockholder meeting.