Company: PRME
Filing Date: 2025-11-07
Form Type: S-3ASR
Source: 0001628280-25-050428
Chunk: 0

Company: Prime Medicine, Inc.
Filing Date: 2025-11-07
Form: S-3ASR
Chunk 0
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<div align='center'>As filed with the Securities and Exchange Commission on November 7, 2025</div>

#### Registration No. 333-

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### FORM S-3

### REGISTRATION STATEMENT

#### UNDER

#### THE SECURITIES ACT OF 1933

#### Prime Medicine, Inc.
<div align='center'>(Exact name of registrant as specified in its charter)</div>

| Delaware                                                       |     | 84-3097762                          |
| (State or other jurisdiction of incorporation or organization) |     | -I.R.S. Employer Identification No. |

#### 60 First Street

#### Cambridge, MA 02141
<div align='center'>(617) 465-0013

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)</div>

#### Allan Reine, M.D.

#### Chief Executive Officer

#### Prime Medicine, Inc.

#### 60 First Street

#### Cambridge, MA 02141
<div align='center'>(617) 465-0013

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

<div align='center'>Copy to:</div>

#### Kingsley L. Taft

#### Adam V. Johnson

#### Goodwin Procter LLP

#### 100 Northern Avenue

#### Boston, MA 02210
<div align='center'>(617) 570-1000</div>

Approximate date of commencement of proposed sale to the public: From time to time after this registration statement becomes effective.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following