[SCHEDULE 13D/A] Mirum Pharmaceuticals, Inc. SEC Filing

Rhea-AI Filing Summary

Frazier-affiliated investment vehicles amended a Schedule 13D for Mirum Pharmaceuticals (MIRM) to correct prior attributions and restate holdings. The filing shows Frazier Life Sciences IX, L.P. directly holds 3,566,912 shares (about 7.1% of 50,237,647 outstanding shares as of August 1, 2025). Related Frazier funds and vehicles report additional direct holdings: Frazier Life Sciences X (168,308 shares), Frazier Life Sciences XI (544,954 shares), Frazier Life Sciences Public Fund (1,574,374 shares) and Frazier Life Sciences Public Overage Fund (940,573 shares). Reporting clarifies that certain investment committee members are not attributed beneficial ownership and corrects prior overstatements. Individual reporting persons James N. Topper and Patrick J. Heron are shown with aggregate beneficial ownership positions reflecting the fund holdings and, for Heron, options that affect percentage calculations.

Positive

• Clarifies beneficial ownership across multiple Frazier funds, reducing prior overstatements and improving disclosure accuracy
• Provides specific share counts and percentages for key Frazier vehicles (e.g., 3,566,912 shares for Frazier Life Sciences IX, ~7.1%)
• Explains governance attribution by noting committee-managed entities where members are not attributed ownership

Negative

• None.

Insights

Securities Analyst

TL;DR: Amendment restates and corrects beneficial ownership disclosures for Frazier funds in MIRM, clarifying prior over-attributions.

The amendment provides precise holdings by multiple Frazier entities and clarifies governance attribution: several funds directly hold material stakes (largest: Frazier Life Sciences IX with 3,566,912 shares, ~7.1%). The filing corrects past attributions to investment committee members where committees act by majority vote and thus committee members are not deemed beneficial owners. For investors, this improves the accuracy of ownership profiles and group attribution in the issuer's cap table.

Corporate Governance Expert

TL;DR: Governance detail: committee-managed LLCs clarified to avoid attributing ownership to individual committee members.

The filing emphasizes legal attribution principles: where an LLC is managed by a committee that acts by majority vote, committee members are not automatically attributed beneficial ownership of the LLC's holdings. The amendment corrects prior statements and reduces apparent individual ownership figures. This is a corrective governance disclosure rather than a change in underlying economic positions.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)

MIRUM PHARMACEUTICALS, INC.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

604749101

(CUSIP Number)

Steve R. Bailey
601 Union Street, Suite 3200,
Seattle, WA, 98101
(206) 621-7200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

08/18/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Frazier Life Sciences IX, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 3,566,912.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 3,566,912.00

11

Aggregate amount beneficially owned by each reporting person

3,566,912.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS IX, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 3,566,912.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 3,566,912.00

11

Aggregate amount beneficially owned by each reporting person

3,566,912.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS IX, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 3,566,912.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 3,566,912.00

11

Aggregate amount beneficially owned by each reporting person

3,566,912.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.1 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Frazier Life Sciences X, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 168,308.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 168,308.00

11

Aggregate amount beneficially owned by each reporting person

168,308.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.3 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS X, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 168,308.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 168,308.00

11

Aggregate amount beneficially owned by each reporting person

168,308.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.3 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS X, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 168,308.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 168,308.00

11

Aggregate amount beneficially owned by each reporting person

168,308.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.3 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Frazier Life Sciences Public Fund, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,574,374.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,574,374.00

11

Aggregate amount beneficially owned by each reporting person

1,574,374.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

3.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLSP, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,574,374.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,574,374.00

11

Aggregate amount beneficially owned by each reporting person

1,574,374.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

3.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLSP, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,574,374.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,574,374.00

11

Aggregate amount beneficially owned by each reporting person

1,574,374.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

3.1 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Frazier Life Sciences Public Overage Fund, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 940,573.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 940,573.00

11

Aggregate amount beneficially owned by each reporting person

940,573.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.9 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLSP Overage, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 940,573.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 940,573.00

11

Aggregate amount beneficially owned by each reporting person

940,573.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.9 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLSP Overage, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 940,573.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 940,573.00

11

Aggregate amount beneficially owned by each reporting person

940,573.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.9 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Frazier Life Sciences XI, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 544,954.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 544,954.00

11

Aggregate amount beneficially owned by each reporting person

544,954.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS XI, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 544,954.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 544,954.00

11

Aggregate amount beneficially owned by each reporting person

544,954.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.1 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

FHMLS XI, L.L.C.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 544,954.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 544,954.00

11

Aggregate amount beneficially owned by each reporting person

544,954.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.1 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

James N. Topper

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 3,735,220.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 3,735,220.00

11

Aggregate amount beneficially owned by each reporting person

3,735,220.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.4 %

14

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person:

The Aggregate Amount represents (i) 3,566,912 shares of Common Stock held directly by Frazier Life Sciences IX, L.P., and (ii) 163,643 shares of Common Stock held directly by Frazier Life Sciences X, L.P. The Percent of Class is calculated based on 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Patrick J. Heron

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 82,482.00
8	Shared Voting Power 3,735,220.00
9	Sole Dispositive Power 82,482.00
10	Shared Dispositive Power 3,735,220.00

11

Aggregate amount beneficially owned by each reporting person

3,735,220.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

7.6 %

14

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person:

The Aggregate Amount represents (i) 5,703 shares of Common Stock held directly by the Reporting Person, (ii) 76,779 shares of Common Stock that are issuable upon the exercise of options held directly by the Reporting Person, (iii) 3,566,912 shares of Common Stock held directly by Frazier Life Sciences IX, L.P., and (iv) 163,643 shares of Common Stock held directly by Frazier Life Sciences X, L.P. The Percent of Class is calculated based on (i) 50,237,647 shares of Common Stock outstanding on August 1, 2025 as set forth in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025 and (ii) 76,779 shares of Common Stock that are issuable upon the exercise of options held directly by the Reporting Person.

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Albert Cha

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

James Brush

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP No. 604749101

1

Name of reporting person

Daniel Estes

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: MIRUM PHARMACEUTICALS, INC.
(c)	Address of Issuer's Principal Executive Offices: 989 E Hillsdale Blvd., Suite 300, FOSTER CITY, CALIFORNIA , 94404.
Item 1 Comment: This Amendment No. 6 ("Amendment No. 6") to Schedule 13D amends the statement on Schedule 13D filed on July 26 2019 (the "Original Schedule 13D") as amended on April 29, 2020, December 18, 2020, August 16, 2022, April 14, 2023 and September 5, 2023 (the "Prior Amendments", and together with the Original Schedule 13D and this Amendment No. 6, the "Schedule 13D"). Except as otherwise specified in this Amendment No. 6, all items in the Original Schedule 13D, as amended by the Prior Amendments, are unchanged. All capitalized terms used in this Amendment No. 6 and not otherwise defined herein have the meanings ascribed to such terms in the Original Schedule 13D, as amended by the Prior Amendments.
Item 5.	Interest in Securities of the Issuer
(a)	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 1,574,374 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, and this Schedule 13D corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. FLSPOF directly holds 940,573 shares of Common Stock of the Issuer (the "FLSPOF Shares"). FHMLSP Overage, L.P. is the general partner of FLSPOF and the general partner of FHMLSP Overage, L.P. is FHMLSP Overage, 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 FLSPOF, and this Schedule 13D corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. 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, and this Schedule 13D corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. 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.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit A to Schedule 13D/A filed on September 5, 2023)

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Frazier Life Sciences IX, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS IX, L.L.C., GP of FHMLS IX, L.P., GP of Frazier Life Sciences IX, L.P.
Date:	08/20/2025

FHMLS IX, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS IX, L.L.C., GP of FHMLS IX, L.P.
Date:	08/20/2025

FHMLS IX, L.L.C.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS IX, L.L.C.
Date:	08/20/2025

Frazier Life Sciences X, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS X, L.L.C., GP of FHMLS X, L.P., GP of Frazier Life Sciences X, L.P.
Date:	08/20/2025

FHMLS X, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS X, L.L.C., GP of FHMLS X, L.P.
Date:	08/20/2025

FHMLS X, L.L.C.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS X, L.L.C.
Date:	08/20/2025

Frazier Life Sciences Public Fund, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	Steve R. Bailey, CFO of FHMLSP, L.L.C., GP of FHMLSP, L.P., GP of Frazier Life Sciences Public Fund, L.P.
Date:	08/20/2025

FHMLSP, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	Steve R. Bailey, CFO of FHMLSP, L.L.C., GP of FHMLSP, L.P.
Date:	08/20/2025

FHMLSP, L.L.C.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLSP, L.L.C.
Date:	08/20/2025

Frazier Life Sciences Public Overage Fund, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLSP Overage, L.L.C., GP of FHMLSP Overage, L.P., GP of Frazier Life Sciences Public Overage Fund, L.P.
Date:	08/20/2025

FHMLSP Overage, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLSP Overage, L.L.C., GP of FHMLSP Overage, L.P.
Date:	08/20/2025

FHMLSP Overage, L.L.C.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLSP Overage, L.L.C.
Date:	08/20/2025

Frazier Life Sciences XI, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS XI, L.L.C., GP of FHMLS XI, L.P., GP of Frazier Life Sciences XI, L.P.
Date:	08/20/2025

FHMLS XI, L.P.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS XI, L.L.C., GP of FHMLS XI, L.P.
Date:	08/20/2025

FHMLS XI, L.L.C.

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, CFO of FHMLS XI, L.L.C.
Date:	08/20/2025

James N. Topper

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, Attorney-in-Fact for James N. Topper, pursuant to a Power of Attorney, a copy of which was filed with the SEC on July 31, 2017
Date:	08/20/2025

Patrick J. Heron

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, Attorney-in-Fact for Patrick J. Heron, pursuant to a Power of Attorney, a copy of which was filed with the SEC on July 31, 2017
Date:	03/06/2025

Albert Cha

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, Attorney-in-Fact for Albert Cha, pursuant to a Power of Attorney, a copy of which was filed with the SEC on August 16, 2021
Date:	08/20/2025

James Brush

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, Attorney-in-Fact for James Brush, pursuant to a Power of Attorney, a copy of which was filed with the SEC on August 16, 2021
Date:	08/20/2025

Daniel Estes

Signature:	/s/ Steve R. Bailey
Name/Title:	By Steve R. Bailey, Attorney-in-Fact for Daniel Estes, pursuant to a Power of Attorney, a copy of which was filed with the SEC on April 18, 2022
Date:	08/20/2025

FAQ

What stake does Frazier Life Sciences IX hold in Mirum Pharmaceuticals (MIRM)?

Frazier Life Sciences IX, L.P. directly holds 3,566,912 shares, representing approximately 7.1% of 50,237,647 outstanding shares as of August 1, 2025.

How much aggregate beneficial ownership is reported for James N. Topper in the filing?

James N. Topper is reported with an aggregate beneficial ownership of 3,735,220 shares, representing about 7.4% of the class based on the stated share count.

Why does the amendment state some committee members are not attributed ownership?

The amendment explains certain general partners are managed by investment committees that act by majority vote; therefore, individual committee members are not attributed beneficial ownership of the entities' securities.

Which Frazier funds hold shares in MIRM and how many?

Reported direct holdings include: Frazier Life Sciences IX (3,566,912), Frazier Life Sciences X (168,308), Frazier Life Sciences XI (544,954), Frazier Life Sciences Public Fund (1,574,374), and Frazier Life Sciences Public Overage Fund (940,573).

Does the amendment change the total economic interests held by the Frazier entities?

The amendment corrects attributions and overstatements to individuals but does not report a change to the underlying direct shareholdings disclosed for the funds.