As filed with the Securities and Exchange Commission on March 9, 2021

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8 

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Mirum Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

2019 Equity Incentive Plan

2019 Employee Stock Purchase Plan

2020 Inducement Plan

(Full titles of the plans)

Christopher Peetz

President and Chief Executive Officer

Mirum Pharmaceuticals, Inc.

950 Tower Lane, Suite 1050

Foster City, California 94404

(650) 667-4085

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

CALCULATION OF REGISTRATION FEE

Explanatory Note

This Registration Statement is being filed for the purpose of registering additional securities of the same class as other securities for which Registration Statements of the Registrant on Form S-8 relating to the same employee benefit plans are effective.

The Registrant previously registered (i) shares of Common Stock for issuance under the 2019 Plan and 2019 ESPP pursuant to a Registration Statement on Form S-8 (File No. 333-233502) filed with the Securities and Exchange Commission (the “Commission”) on August 28, 2019 and (ii) additional shares of Common Stock for issuance under the 2019 Plan and 2019 ESPP and shares of Common Stock for issuance under the 2020 Inducement Plan pursuant to a Registration Statement on Form S-8 (File No. 333-238086) filed with the Commission on May 7, 2020 (collectively, the “Prior Registration Statements”). In accordance with General Instruction E to Form S-8, the contents of the Prior Registration Statements are hereby incorporated by reference.

Part II

Information Required in the Registration statement

Item 3.Incorporation of Documents by Reference.

The Registrant hereby incorporates by reference into this Registration Statement the following documents previously filed by the Registrant with the Commission:

All documents filed by the Registrant pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents; provided, however, that documents or portions thereof that are furnished and not filed in accordance with the rules of the Commission shall not be deemed incorporated by reference into this Registration Statement. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement herein or in any other subsequently filed document that also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not constitute a part of this Registration Statement, except as so modified or superseded.

Item 8.Exhibits.

The exhibits to this Registration Statement are listed below:

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Foster City, State of California, on March 9, 2021.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Christopher Peetz and Ian Clements, Ph.D., and each one of them, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in their name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement, and to sign any registration statement for the same offering covered by this registration statement that is to be effective on filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended, and all post-effective amendments thereto, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

Niall O’Donnell, Ph.D.