X0306 4 2019-07-22 0 0001759425 Mirum Pharmaceuticals, Inc. MIRM 0001720320 Frazier Life Sciences IX, L.P. 70 WILLOW ROAD, STE. 200 MENLO PARK CA 94025 0 0 1 0 0001782789 FHMLS IX, L.P. 70 WILLOW ROAD, STE. 200 MENLO PARK CA 94025 0 0 1 0 0001782791 FHMLS IX, L.L.C. 70 WILLOW ROAD, STE. 200 MENLO PARK CA 94025 0 0 1 0 0001341382 Topper James N 70 WILLOW ROAD, STE. 200 MENLO PARK CA 94025 0 0 1 0 Common Stock 2019-07-22 4 C 0 3116912 A 3116912 D Common Stock 2019-07-22 4 P 0 450000 15.00 A 3566912 D Series A Preferred Stock 2019-07-22 4 C 0 24935300 0.00 D Common Stock 3116912 0 D In connection with the Issuer's initial public offering, each share of the Issuer's Series A Preferred Stock automatically converted into 0.125 shares of the Issuer's Common Stock. The shares have no expiration date. The shares are held directly by Frazier Life Sciences IX, L.P. FHMLS IX, L.P. is the general partner of Frazier Life Sciences IX, L.P. FHMLS IX, L.L.C. is the general partner of FHMLS IX, L.P. James N. Topper and Patrick Heron are the managing members of FHMLS IX, L.L.C. and share voting and dispositive power over the shares held by Frazier Life Sciences IX, L.P. Mr. Topper, FHMLS IX, L.P. and FHMLS IX, L.L.C. disclaim beneficial ownership of the shares held by Frazier Life Sciences IX, L.P., except to the extent of his or its pecuniary interest therein, if any. The shares were purchased in the Issuer's initial public offering. Frazier Life Sciences IX, L.P. By: FHMLS IX, L.P., its general partner, By: FHMLS IX, L.L.C., its general partner, By: /s/ Steve Bailey, Chief Financial Officer 2019-07-24 FHMLS IX, L.P. By: FHMLS IX, L.L.C., its general partner, By: /s/ Steve Bailey, Chief Financial Officer 2019-07-24 FHMLS IX, L.L.C. By: /s/ Steve Bailey, Chief Financial Officer 2019-07-24 /s/ Steve Bailey, Attorney-in-Fact for James N. Topper 2019-07-24