Initial Registration Statement for Employee Benefit Plan (Form S-8)

As filed with the Securities and Exchange Commission on March 3, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

Under

The Securities Act of 1933

Prime Medicine, Inc.

(Exact name of registrant as specified in its charter)

Delaware						84-3097762
(State or other jurisdiction of incorporation or organization)						(I.R.S. Employer Identification Number)

60 First Street

Cambridge, MA 02141

(617) 465-0013

(Address of Principal Executive Offices)

Prime Medicine, Inc. 2022 Stock Option and Incentive Plan

(Full Title of the Plan)

Allan Reine, M.D.

Chief Executive Officer

Prime Medicine, Inc.

60 First Street

Cambridge, MA 02141

(617) 465-0013

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

Copies to:

Kingsley L. Taft, Esq.

Adam V. Johnson, Esq.

Goodwin Procter LLP

100 Northern Avenue

Boston, Massachusetts 02210

(617) 570-1000

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a 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.

Large accelerated filer

☐

Accelerated filer

☒

Non-accelerated filer

☒

Smaller reporting company

☒

Emerging growth company

☒

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. ☐

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

This Registration Statement on Form S-8 (this "Registration Statement") is being filed for the purpose of registering an additional 9,025,700 shares of common stock, par value $0.00001 per share ("Common Stock") of Prime Medicine, Inc. (the "Registrant") available for issuance under the Registrant's 2022 Stock Option and Incentive Plan, as amended (the "2022 Plan").

These additional shares of Common Stock are of the same class as other securities relating to the 2022 Plan for which the Registrant's Registration Statements on Form S-8 (File No. 333-267953, File No. 333-270400, File No. 333-277567, and File No. 333-285396), filed with the Securities and Exchange Commission (the "SEC") on October 19, 2022, March 9, 2023, March 1, 2024, and February 28, 2025, respectively, are effective (collectively, the "Earlier Registration Statements").

Pursuant to General Instruction E to Form S-8 regarding registration of additional securities, the contents of the Earlier Registration Statements, except for "Item 8. Exhibits", are incorporated herein by reference, except to the extent supplemented, amended or superseded by the information set forth herein. Only those items of Form S-8 containing new information not contained in the Earlier Registration Statements are presented herein.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 8. Exhibits.

The exhibits to this Registration Statement are listed in the Exhibit Index attached hereto and incorporated by reference herein.

EXHIBIT INDEX

Exhibit number						Description of exhibit
4.1						Third Amended and Restated Certificate of Incorporation of Prime Medicine, Inc. (incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K, filed with the SEC on October 24, 2022)
4.2						Certificate of Amendment to Third Amended and Restated Certificate of Incorporation of Prime Medicine, Inc. (incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K, filed with the SEC on June 12, 2024)
4.3						Second Amended and Restated Bylaws of Prime Medicine, Inc. (incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K, filed with the SEC on May 21, 2024).
4.4						Specimen Common Stock Certificate (incorporated by reference to Exhibit 4.2 to the Registrant's Registration Statement on Form S-1/A (File No. 333-267579), filed with the SEC on October 17, 2022)
5.1*						Opinion of Goodwin Procter LLP
23.1*						Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm
23.2*						Consent of Goodwin Procter LLP (included in Exhibit 5.1)
24.1*						Power of Attorney (included on signature page)
99.1						2022 Stock Option and Incentive Plan and forms of award agreements thereunder (incorporated by reference to Exhibit 10.2 to the registrant's Registration Statement on Form S-1, as amended (File No. 333-267579) filed on October 17, 2022
107*						Filing Fee Table

*			Filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, 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 Cambridge, Commonwealth of Massachusetts, on the 3rd day of March 2026.

PRIME MEDICINE, INC.

By:

/s/ Allan Reine

Allan Reine

Chief Executive Officer

POWER OF ATTORNEY AND SIGNATURES

KNOW ALL BY THESE PRESENT, that each individual whose signature appears below hereby constitutes and appoints each of Allan Reine and Carman Alenson as such person's true and lawful attorney-in-fact and agent with full power of substitution and resubstitution, for such person in such person's name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement on Form S-8, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Securities and Exchange Commission granting unto each said attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that any said attorney-in-fact and agent, or any substitute or substitutes of any of them, may lawfully do or cause to be done by virtue hereof.

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

Name

Title

Date

/s/ Allan Reine

Chief Executive Officer and Director (Principal Executive Officer and Principal Financial Officer)

March 3, 2026

Allan Reine

/s/ Carman Alenson

Chief Accounting Officer (Principal Accounting Officer)

March 3, 2026

Carman Alenson

/s/ Thomas Cahill

Director

March 3, 2026

Thomas Cahill

/s/ Wendy Chung

Director

March 3, 2026

Wendy Chung

/s/ Kaye Foster

Director

March 3, 2026

Kaye Foster

/s/ Michael Kelly

Director

March 3, 2026

Michael Kelly

/s/ Jeff Marrazzo

Director

March 3, 2026

Jeff Marrazzo

/s/ Robert Nelsen

Director

March 3, 2026

Robert Nelsen

/s/ David Schenkein

Director

March 3, 2026

David Schenkein