Patrick J. Heron - 23 Jan 2026 Form 4 Insider Report for Mirum Pharmaceuticals, Inc. (MIRM)

Reporting relationship: Director
Issuer ticker: MIRM
Reported as of: 23 Jan 2026
Net transaction value: +$8,999,984
SEC form: 4
Accepted by SEC: 27 Jan 2026, 16:14:26 UTC
Prior SEC filing: 30 Sep 2025
Next SEC filing: 05 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Jennifer Martin, Attorney-in-Fact For Patrick J. Heron

Key filing fact

Patrick J. Heron filed Form 4 for Mirum Pharmaceuticals, Inc. (MIRM) on 27 Jan 2026.

Key facts

This page summarizes Patrick J. Heron's Form 4 filing for Mirum Pharmaceuticals, Inc. (MIRM).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 27 Jan 2026, 16:14.

Change

Previous filing in this sequence was filed on 30 Sep 2025.
Current net transaction value: +$8,999,984.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001365617 Primary reporting owner

Heron Patrick J

Relationship: Director
Address: C/O MIRUM PHARMACEUTICALS, INC., 989 E. HILLSDALE BLVD., SUITE 300, FOSTER CITY
Signature: /s/ Jennifer Martin, Attorney-in-Fact For Patrick J. Heron
Signature date: 27 Jan 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MIRM transaction

Common Stock

Other

Transaction value
Shares: +159,277
Change %: +95%
Price
Shares after: 327,585
Date: 23 Jan 2026
Ownership: By Frazier Life Sciences X, L.P.
Footnotes: F1, F2

MIRM transaction

Common Stock

Purchase

Transaction value: $8,999,984
Shares: +131,425
Change %: +40%
Price: $68.48
Shares after: 459,010
Date: 23 Jan 2026
Ownership: By Frazier Life Sciences X, L.P.
Footnotes: F2

MIRM holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 3,566,912
Date: 23 Jan 2026
Ownership: By Frazier Life Sciences IX, L.P.
Footnotes: F3

MIRM holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 5,703
Date: 23 Jan 2026
Ownership: Direct

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

Frazier Life Sciences X, L.P. received these shares in connection with merger of Bluejay Therapeutics, Inc. into the Issuer (the "Merger"). On the effective date of the Merger, the closing price of the Issuer's Common Stock was $94.29 per share.

Footnote F2

The shares are held directly by Frazier Life Sciences X, L.P. FHMLS X, L.P. is the general partner of Frazier Life Sciences X, L.P. and FHMLS X, L.L.C. is the general partner of FHMLS X, L.P. The Reporting Person is one of two managing members of FHMLS X, L.L.C. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.

Footnote F3

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. The Reporting Person is one of two managing members of FHMLS IX, L.L.C. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.