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

Company: Prime Medicine, Inc.
Filing Date: 2025-11-07
Form: S-3ASR
Chunk 3
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 exchange of the securities, if any, covered by the prospectus supplement.

Investing in these securities involves certain risks. See “

#### Risk Factors
” on page 1of this prospectus as well as those included in any accompanying prospectus supplement and in the documents incorporated by reference in this prospectus for a discussion of the factors you should carefully consider before deciding to purchase these securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

#### The date of this prospectus is November 7, 2025.

### TABLE OF CONTENTS
|                                                                      |     | Page |
| About This Prospectus                                                |     |   ii |
| Risk Factors                                                         |     |    1 |
| Special Note Regarding Forward-Looking Statements                    |     |    2 |
| Our Company                                                          |     |    4 |
| Use of Proceeds                                                      |     |    6 |
| Securities That May Be Offered                                       |     |    7 |
| Description of Capital Stock                                         |     |    8 |
| Description of Debt Securities                                       |     |   14 |
| Description of Warrants                                              |     |   21 |
| Description of Units                                                 |     |   23 |
| Material U.S. Federal Income Tax Considerations for Non-U.S. Holders |     |   26 |
| Plan of Distribution                                                 |     |   30 |
| Legal Matters                                                        |     |   33 |
| Experts                                                              |     |   33 |
| Where You Can Find More Information                                  |     |   33 |
| Incorporation of Certain Information by Reference                    |     |   34 |

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### ABOUT THIS PROSPECTUS
This prospectus is part of an automatic shelf registration statement on Form S-3ASR that we filed with the Securities and Exchange Commission (the “SEC”) as a “well-known seasoned issuer” as defined in Rule 405 under the Securities Act, utilizing a “shelf” registration process. Under this shelf registration process, we may from time to time sell any combination of the securities described in this prospectus in one or more offerings.

This prospectus provides you with a general description of the securities we may offer. Each time we sell securities described herein, we will provide one or more prospectus supplements that will contain specific information about