MIRUM PHARMACEUTICALS, INC.
7.60%
3,735,220
1759425
604749101
Oct 31, 2025
Nov 4, 2025, 05:26 PM
Reporting Persons (14)
This is a joint filing. The reported shares may overlap between reporting persons and should not be summed.
| Name | Type | % of Class | Aggregate | Sole Voting | Shared Voting |
|---|---|---|---|---|---|
| Patrick J. Heron | Individual | 7.60% | 3,735,220 | 82,482 | 3,735,220 |
| James N. Topper | Individual | 7.40% | 3,735,220 | 0 | 3,735,220 |
| FHMLS IX, L.L.C. | Other | 7.10% | 3,566,912 | 0 | 3,566,912 |
| Frazier Life Sciences IX, L.P. | Partnership | 7.10% | 3,566,912 | 0 | 3,566,912 |
| FHMLS IX, L.P. | Partnership | 7.10% | 3,566,912 | 0 | 3,566,912 |
| Frazier Life Sciences Public Fund, L.P. | Partnership | 5.00% | 2,514,947 | 0 | 2,514,947 |
| FHMLSP, L.P. | Partnership | 5.00% | 2,514,947 | 0 | 2,514,947 |
| FHMLSP, L.L.C. | Other | 5.00% | 2,514,947 | 0 | 2,514,947 |
| FHMLS XI, L.L.C. | Other | 1.10% | 544,954 | 0 | 544,954 |
| Frazier Life Sciences XI, L.P. | Partnership | 1.10% | 544,954 | 0 | 544,954 |
| FHMLS XI, L.P. | Partnership | 1.10% | 544,954 | 0 | 544,954 |
| Frazier Life Sciences X, L.P. | Partnership | 0.30% | 168,308 | 0 | 168,308 |
| FHMLS X, L.P. | Partnership | 0.30% | 168,308 | 0 | 168,308 |
| FHMLS X, L.L.C. | Other | 0.30% | 168,308 | 0 | 168,308 |
Disclosure Items (7)
Common Stock, par value $0.0001 per share
MIRUM PHARMACEUTICALS, INC.
989 E Hillsdale Blvd., Suite 300, FOSTER CITY, CA, 94404
The entities and persons filing this statement (collectively, the "Reporting Persons") are: Frazier Life Sciences IX, L.P. ("FLS IX") FHMLS IX, L.P. FHMLS IX, L.L.C. Frazier Life Sciences X, L.P. ("FLS X") FHMLS X, L.P. FHMLS X, L.L.C. Frazier Life Sciences Public Fund, L.P. ("FLSPF") FHMLSP, L.P. FHMLSP, L.L.C. Frazier Life Sciences XI, L.P. ("FLS XI") FHMLS XI, L.P. FHMLS XI, L.L.C. James N. Topper ("Topper") Patrick J. Heron ("Heron" and together with Topper, the "Members")
Item 2(c) is hereby amended and restated in its entirety to read as follows: FLS IX is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS IX, L.P. is to serve as general partner of FLS IX. The sole business of FHMLS IX, L.L.C. is to serve as general partner of FHMLS IX, L.P. FLS X is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS X, L.P. is to serve as general partner of FLS IX. The sole business of FHMLS X, L.L.C. is to serve as general partner of FHMLS X, L.P. FLSPF is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLSP, L.P. is to serve as general partner of FLSPF. The sole business of FHMLSP, L.L.C. is to serve as general partner of FHMLSP, L.P. FLS XI is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS XI, L.P. is to serve as general partner of FLS XI. The sole business of FHMLS XI, L.L.C. is to serve as general partner of FHMLS XI, L.P. The principal business of the Members is to manage FLS IX, FHMLS IX, L.P., FHMLS IX, L.L.C., FLS X, FHMLS X, L.P., FHMLS X, L.L.C., FLSPF, FHMLSP, L.P., FHMLSP, L.L.C., FLS XI, FHMLS XI, L.P., FHMLS XI, L.L.C. and a number of affiliated partnerships with similar businesses.
Item 3 of the Schedule 13D is hereby amended to incorporate Item 5(c) hereof and to replace the last paragraph with the following: The working capital of FLS IX, FLS X, FLSPF and FLS XI was the source of the funds for the purchase of the FLS IX Shares, the FLS X Shares, the FLSPF Shares, and the FLS XI Shares. No part of the purchase price of the FLS IX Shares, the FLS X Shares, the FLSPF Shares, or the FLS XI Shares was represented by funds or other consideration borrowed or otherwise obtained for the purpose of acquiring, holding, trading or voting the FLS IX Shares, the FLS X Shares, the FLSPF Shares and the FLS XI Shares.
The information contained in Rows 7, 8, 9, 10, 11, and 13 of each Reporting Person's cover page to this Schedule 13D (including the footnotes thereto) is incorporated by reference into this Item 5. FLSPF directly holds 2,514,947 shares of Common Stock of the Issuer (the "FLSPF Shares"). FHMLSP, L.P. is the general partner of FLSPF and the general partner of FHMLSP, L.P. is FHMLSP, L.L.C., which is managed by an investment committee of four that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLSPF.. FLS IX directly holds 3,566,912 shares of Common Stock of the Issuer (the "FLS IX Shares"). FHMLS IX, L.P. is the general partner of FLS IX and FHMLS IX, L.L.C. is the general partner of FHMLS IX, L.P. Heron and Topper are the members of FHMLS IX, L.L.C. and therefore share voting and investment power over the FLS IX Shares. FLS X directly holds 168,308 shares of Common Stock of the Issuer (the "FLS X Shares"). FHMLS X, L.P. is the general partner of FLS X and FHMLS X, L.L.C. is the general partner of FHMLS X, L.P. Heron and Topper are the members of FHMLS X, L.L.C. and therefore share voting and investment power over the FLS X Shares. FLS XI directly holds 544,954 shares of Common Stock of the Issuer (the "FLS XI Shares"). FHMLS XI, L.P. is the general partner of FLS XI and the general partner of FHMLS XI, L.P. is FHMLS XI, L.L.C., which is managed by an investment committee of three that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLS XI. Except as specifically stated herein, the filing of this Schedule 13D shall not be construed as an admission that any Reporting Person or any of the foregoing is, for the purposes of Section 13(d) and/or Section 13(g) of the Act or otherwise, the beneficial owner of any securities covered by this Schedule 13D or a member of a "group" with any other person.
Except as set forth in Item 6 hereof, none of the Reporting Persons has effected any transactions relating to the Common Stock of the Issuer during the past 60 days.
Item 4 is hereby amended to remove references to the "FLSPOF Shares".
On November 1, 2025, FLSPF and Frazier Life Sciences Public Overage Fund, L.P. ("FLSPOF") entered into a merger agreement, which resulted in FLSPOF merging with and into FLSPF. As a result of the merger, (i) FLSPF acquired 940,573 shares of Common Stock of the Issuer from FLSPOF and (ii) FLSPOF, FHMLSP Overage, L.P., FHMLSP Overage, L.L.C. ceased being Reporting Persons under the Schedule 13D.
Exhibit 99.1 Joint Filing Agreement