MIRM · Mirum Pharmaceuticals, Inc.

The stock option is fully vested.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $99.901633, and the range of prices were between $99.90 and $99.93. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Includes 175 shares of common stock that were acquired by the Reporting Person on May 10, 2026, pursuant to the Issuer's Employee Stock Purchase Plan.

The stock option is fully vested.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $100.14, and the range of prices were between $99.995 and $100.2425. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $98.51, and the range of prices were between $97.93 and $98.92. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $99.25, and the range of prices were between $98.94 and $99.655. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 18, 2026.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $122.34, and the range of prices were between $122.13 and $123.1125. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $123.74, and the range of prices were between $123.24 and $124.10. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

The stock option is fully vested.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $121.65, and the range of prices were between $121.11 and $122.105. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $121.67, and the range of prices were between $121.13 and $122.13. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $123.84, and the range of prices were between $123.285 and $124.27. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $124.79, and the range of prices were between $124.27 and $124.94. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $122.43, and the range of prices were between $122.235 and $123.10. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 18, 2026.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 18, 2026.

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 Issuer's 2027 annual stockholder meeting.

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 Issuer's 2027 annual stockholder meeting.

Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

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 Issuer's 2027 annual stockholder meeting.

Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

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 Issuer's 2027 annual stockholder meeting.

Each deferred stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

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 Issuer's 2027 annual stockholder meeting.

Each deferred stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

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 Issuer's 2027 annual stockholder meeting.

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 Issuer's 2027 annual stockholder meeting.

Each deferred stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting.

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 Issuer's 2027 annual stockholder meeting.

Each deferred stock unit represents a contingent right to receive one share of the Issuer's common stock and will vest on the first anniversary of the grant date, provided that it will in any case be fully vested on the date of the Issuer's 2027 annual stockholder meeting. Each vested deferred stock unit will be paid out in the Issuer's common stock upon the earliest to occur of (i) a change in control of the Issuer and (ii) within 60 days following separation from service with the Issuer.

1/4th of the shares vested one year after January 23, 2024 (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.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $92.84, and the range of prices were between $92.485 and $93.31. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $93.95, and the range of prices were between $93.49 and $94.47. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 9, 2026.

. The weighted average sale price for the transaction reported was $95.12, and the range of prices were between $94.62 and $95.44. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

The stock option is fully vested.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $94.64, and the range of prices were between $93.90 and $94.895. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $99.66, and the range of prices were between $99.55 and $99.79. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

Reported transaction occurred pursuant to a Rule 10b5-1 Plan adopted by the reporting person on March 2, 2026.

The weighted average sale price for the transaction reported was $95.34, and the range of prices were between $94.91 and $95.91. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

The stock option is fully vested.