Company: PRME
Filing Date: 2025-11-07
Form Type: S-3ASR
Source: 0001628280-25-050428
Chunk: 59

Company: Prime Medicine, Inc.
Filing Date: 2025-11-07
Form: S-3ASR
Chunk 59
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 development to support the advancement of our current or future product candidates and the expansion of our research and development programs, and the remainder for working capital, capital expenditures and other general corporate purposes. See “Use of Proceeds” on pageS-7of this prospectus. |
| Risk Factors                                       |     | Investing in our common stock involves significant risks. You should read the “Risk Factors” section of this prospectus beginning on pageS-4and other information included in, or incorporated by reference into, this prospectus for a discussion of factors to consider before deciding to purchase shares of our common stock.                                                                                                                                                                                                                                                                           |
| Nasdaq Global Market Symbol                        |     | “PRME”                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |

All information in this prospectus related to the number of shares of our common stock to be outstanding immediately after this offering is based on 180,309,471 shares of our common stock outstanding as of September 30, 2025. The number of shares outstanding as of September 30, 2025 as used throughout this prospectus, unless otherwise indicated, excludes: • 16,393,177 shares of common stock issuable upon the exercise of stock options outstanding as of September 30, 2025, at a weighted average exercise price of $3.78 per share; • 8,655,858 shares of common stock available for future issuance under our 2022 Stock Option and Incentive Plan as of September 30, 2025, as well as any increases in the number of shares of common stock reserved for issuance thereunder; and • 1,619,579 shares of common stock available for future issuance under our 2022 Employee Stock Purchase Plan as of September 30, 2025, as well as any increases in the number of shares of common stock reserved for issuance thereunder. Unless otherwise stated, all information contained in this prospectus assumes no exercise of stock options, vesting of restricted common stock, or issuances of shares under the 2022 Employee Stock Purchase Plan after September 30, 2025, and reflects an assumed public offering price of $4.30, which was the last reported sale price of our common stock on The Nasdaq Global Market on November 4, 2025.

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### RISK FACTORS
Investing in our common stock involves a high degree of risk. Before you decide to invest in our common stock, you should carefully consider the risks and uncertainties described below