Prime Medicine, Inc.

Previous wording

Our revenues to date have been generated through research collaboration and license agreements. We recognize revenue over the expected performance period under each agreement. We expect that our revenue for the next several years will be derived primarily from our current collaboration agreements and any additional collaborations that we may enter into in the future. To date, we have not generated any revenue from product sales or royalties and do not expect to generate any revenue from the sale of products or royalties for the foreseeable future.

Current wording

To date, we have not generated any revenue from product sales and do not expect to generate any revenue from the sale of products for the foreseeable future. Our revenues to date have been generated through research collaboration and license agreements. We recognize revenue over the expected performance period under each agreement. We expect that our revenue for the next several years will be derived primarily from our current collaboration agreements and any additional collaborations that we may enter into in the future. To date, we have not received any royalties under any of our existing collaboration agreements.

Previous wording

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts, and the development of our product candidates. These expenses include:

Current wording

Research and development expenses consist primarily of costs incurred in connection with the development and research of our immediate target indications and our differentiation target indications. These expenses include:

Previous wording

•personnel-related expenses, including salaries, bonuses, benefits, and stock-based compensation for employees engaged in manufacturing, research and development functions;

Current wording

•personnel-related expenses, including salaries, bonuses, benefits and stock-based compensation for employees engaged in manufacturing, and research and development functions;

Previous wording

We expense all research and development costs in the periods in which they are incurred. Most of our research and development expenses have been related to early stage development activities. External research and development costs for any individual product candidate will be tracked upon the FDA’s clearance of the IND application for that product candidate. We do not allocate employee costs, costs associated with our discovery efforts, laboratory supplies, and facilities expenses, including depreciation or other indirect costs, to specific product development programs because these costs are deployed across multiple programs and our platform and, as such, are not separately classified.

Current wording

We expense all research and development costs in the periods in which they are incurred. Most of our research and development expenses have been related to early stage development activities. In the future, external research and development costs for any individual product candidate will be tracked commencing upon product candidate nomination. We do not allocate employee costs, costs associated with our discovery efforts, laboratory supplies, and facilities expenses, including depreciation or other indirect costs, to specific product development programs because these costs are deployed across multiple programs and our platform and, as such, are not separately classified.

Previous wording

We expect our research and development expenses to continue to increase substantially for the foreseeable future with our planned research and development activities related to developing any future product candidates, including investments in manufacturing, as we advance any product candidates we may identify and conduct clinical trials, and with our obligations under the BMS Collaboration Agreement.

Current wording

We expect our research and development expenses may continue to increase in the future with our planned research and development activities related to developing any future product candidates, including investments in manufacturing, as we advance any product candidates we may identify and begin to conduct clinical trials, and with our obligations under the BMS Collaboration Agreement.

Previous wording

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support research and development activities; increased accounting, legal, insurance, and investor and public relations costs as we continue to operate as a public company; and additional intellectual property-related expenses as we file patent applications to protect innovations arising from our research and development activities.

Current wording

We anticipate that our general and administrative expenses will increase in the future if we increase our headcount to support research and development activities; increased accounting, legal, insurance, and investor and public relations costs as we continue to operate as a public company; and additional intellectual property-related expenses as we file patent applications to protect innovations arising from our research and development activities.

Previous wording

•the change in the fair value of our short-term investment in Beam Therapeutics Inc., or Beam, a related party, in connection with the Beam Collaboration Agreement, which is discussed in greater detail in Item 1. Business, of this Annual Report on Form 10-K.

Current wording

•the change in the fair value of our short-term investment in Beam, a related party, in connection with the Beam Collaboration Agreement, which is discussed in greater detail in Item 1. Business, of this Annual Report on Form 10-K.

Previous wording

The $7.4 million increase in research and development expense for the year ended December 31, 2024 as compared to the year ended December 31, 2023 is primarily driven by:

Current wording

The $5.3 million increase in research and development expense for the year ended December 31, 2025 as compared to the year ended December 31, 2024 is primarily driven by:

Previous wording

•$11.3 million increase in facility-related expense primarily due to the expansion and build out of our laboratory space.

Current wording

•$11.0 million increase in facility-related expense primarily due to the expansion and build out of our laboratory space at 60 First Street and 500 Arsenal Street and due to a higher amount of facility costs being allocated to our research and development function;

Previous wording

The $6.8 million increase in general and administrative expense for the year ended December 31, 2024 as compared to the year ended December 31, 2023 is primarily driven by:

Current wording

The $2.2 million increase in general and administrative expense for the year ended December 31, 2025 as compared to the year ended December 31, 2024 is primarily driven by a $7.0 million increase in professional and consultant fees due to an increase in corporate legal expenses. This is offset by:

Previous wording

•$9.5 million increase in personnel expense, a majority of which was an increase in non-cash stock-based compensation expense of $7.4 million; and

Current wording

•$3.5 million decrease in personnel expense, due to a decrease in non-cash stock-based compensation expense of $3.5 million; and

Previous wording

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we commence the clinical development of our programs and continue our platform development and early-stage research activities. We have not yet commercialized any products and we do not expect to generate revenue from sales of products for several years, if at all. To date, we have funded our operations primarily with proceeds from sales of preferred stock, public offerings of our common stock, and through payments from our collaboration partners. As of December 31, 2024, we had cash and cash equivalents, short-term investments, and related party short-term investments of $190.4 million, excluding our restricted cash, or $204.5 million, including restricted cash.

Current wording

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we commence the clinical development of our programs and continue our platform development and early-stage research activities. We have not yet commercialized any products and we do not expect to generate revenue from sales of products for several years, if at all. To date, we have funded our operations primarily with proceeds from sales of preferred stock, public offerings of our common stock, and through payments from our collaboration partners. As of December 31, 2025, we had cash and cash equivalents, and short-term investments of $177.7 million, excluding our restricted cash, or $191.4 million, including restricted cash.

Previous wording

In November 2023, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies, under which we may, from time to time, issue and sell shares of our common stock having an aggregate sales proceeds of up to $300.0 million, in a series of one or more at-the-market equity offerings, or the 2023 ATM Program. Jefferies is not required to sell any specific share amounts but acts as our sales agent, using commercially reasonable efforts consistent with its normal trading and sales practices. We will pay Jefferies a commission equal to 3.0% of the aggregate gross proceeds we receive from each sale of our shares of common stock. Pursuant to the Sales Agreement, any shares will be sold pursuant to our shelf registration statement on Form S-3 (File No. 333-275321) filed with the SEC on November 3, 2023, including the base prospectus contained therein, as declared effective by the SEC on November 13, 2023. Our common stock will be sold at prevailing market prices at the time of the sale, and as a result, prices may vary. As of December 31, 2024, we have not sold any shares of common stock under the 2023 ATM Program.

Current wording

In November 2023, we entered into an Open Market Sale Agreement SM, or the Sales Agreement, with Jefferies LLC, or Jefferies, under which we may, from time to time, issue and sell shares of our common stock having an aggregate sales proceeds of up to $300.0 million, in a series of one or more at-the-market equity offerings, or the 2023 ATM Program. Any shares will be sold pursuant to the New Registration Statement and the sales agreement prospectus filed therewith, which covers the offer and sale of shares of our common stock under the 2023 ATM Program having an aggregate offering price of up to $200.0 million of the $300.0 million authorized under the Sales Agreement. If we wish to offer and sell additional shares of our common stock under the Sales Agreement in excess of the $200.0 million registered under the New Registration Statement, for up to an additional $100.0 million, we must file with the SEC one or more additional prospectus supplements to register under the Securities Act, the offer and sale of any such additional shares of our common stock we wish to offer and sell from time to time under the Sales Agreement. Jefferies is not required to sell any specific share amounts but acts as our sales agent, using commercially reasonable efforts consistent with its normal trading and sales practices. We will pay Jefferies a commission equal to 3.0% of the aggregate gross proceeds we receive from each sale of our shares of common stock. Our common stock will be sold at prevailing market prices at the time of the sale, and as a result, prices may vary. As of December 31, 2025, we have not sold any shares of common stock under the 2023 ATM Program.

Previous wording

In February 2024, we issued and sold 22,560,001 shares of our common stock, including 3,360,000 shares pursuant to the exercise of the underwriters’ option to purchase additional shares, at a price to the public of $6.25 per share. Further, in lieu of common stock to certain investors, we sold pre-funded warrants to purchase 3,200,005 shares of common stock at a public offering price of $6.24999 per pre-funded warrant, which represents the per share public offering price of each share of common stock less the $0.00001 per share exercise price for each pre-funded warrant. As a result of the offering, we received approximately $150.9 million in net proceeds, after deducting underwriting discounts, commissions and estimated offering costs of $10.1 million.

Current wording

In August 2025, we issued and sold 43,700,000 shares of our common stock, including 5,700,000 shares pursuant to the exercise of the underwriters’ option to purchase additional shares, at a price to the public of $3.30 per share. As a result of the offering, we received approximately $138.4 million in net proceeds, after deducting underwriting discounts, commissions and offering costs of approximately $5.8 million.

Previous wording

Since our inception, we have incurred substantial losses. As of December 31, 2024, we had an accumulated deficit of $687.2 million and we expect to generate operating losses and negative operating cash flows for the foreseeable future. As stated above, as of December 31, 2024, we maintained cash, cash equivalents, short-term investments, and related party short-term investments of $190.4 million.

Current wording

Since our inception, we have incurred substantial losses. As of December 31, 2025, we had an accumulated deficit of $888.4 million and we expect to generate operating losses and negative operating cash flows for the foreseeable future. As stated above, as of December 31, 2025, we maintained cash, cash equivalents, short-term investments, and related party short-term investments of $177.7 million.

Previous wording

In accordance with Accounting Standards Codification, or ASC, 205-40, Going Concern, or ASC 205-40, we evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date on which this Annual Report on Form 10-K is filed. Based on the our cash, cash equivalents, short-term investments, and related party short-term investments as of December 31, 2024, our current and forecasted level of operations and forecasted cash flows, our ability to continue as a going concern is dependent upon our ability to obtain the necessary financing to meet our obligations and repay our liabilities arising from normal business operations when they come due. Management plans to provide for capital requirements through financing or other transactions, and selling shares under our “at the market offering” program. There can be no assurance that we will be able to raise additional capital to fund operations with terms acceptable to us, or at all. Because certain elements of our plans to mitigate the conditions that raised substantial doubt about our ability to continue as a going concern are outside of our control, including the ability to raise capital through an equity or other financing, those elements cannot be considered probable according to ASC 205-40, and therefore cannot be considered in the evaluation of mitigating factors. As a result, we concluded that substantial doubt exists about our ability to continue as a going concern for 12 months from the date these consolidated financial statements are issued.

Current wording

In accordance with Accounting Standards Codification, or ASC, 205-40, Going Concern, or ASC 205-40, we evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date on which this Annual Report on Form 10-K is filed. Based on the our cash, cash equivalents, and short-term investments as of December 31, 2025, our current and forecasted level of operations and forecasted cash flows, our ability to continue as a going concern is dependent upon our ability to obtain the necessary financing to meet our obligations and repay our liabilities arising from normal business operations when they come due. Management plans to provide for capital requirements through financing or other transactions, and selling shares under our “at the market offering” program. There can be no assurance that we will be able to raise additional capital to fund operations with terms acceptable to us, or at all. Because certain elements of our plans to mitigate the conditions that raised substantial doubt about our ability to continue as a going concern are outside of our control, including the ability to raise capital through an equity or other financing, those elements cannot be considered probable according to ASC 205-40, and therefore cannot be considered in the evaluation of mitigating factors. As a result, we concluded that substantial doubt exists about our ability to continue as a going concern for 12 months from the date these consolidated financial statements are issued.

Previous wording

•$12.3 million change in lease liabilities; and

Current wording

•$5.4 million change in lease liabilities;

Previous wording

•$1.8 million change in accrued expenses and other assets.

Current wording

•$1.2 million change in accrued expenses and other assets.

Previous wording

•$30.1 million of non-cash amounts included in net loss, which primarily consisted of change in non-cash lease expense, fair value of short-term investment — related party, and stock-based compensation expense;

Current wording

•$43.9 million of non-cash amounts included in net loss, which consisted primarily of stock-based compensation expense, non-cash lease expense, and depreciation and amortization expense; and

Previous wording

•$27.6 million of maturities of short-term investments, net of purchases; and

Current wording

•$109.6 million of purchases of short-term investments, net of maturities; and

Previous wording

•$8.7 million of purchases of property and equipment.

Current wording

•$4.5 million of purchases of property and equipment.

Previous wording

•$6.0 million of proceeds received under our agreement with Cystic Fibrosis Foundation.

Current wording

•$6.0 million of proceeds received under the CFF Agreement.

Previous wording

We believe our existing cash, cash equivalents, and investments will be sufficient to fund our operating expenses and capital expenditure requirements into the first half of 2026. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. We expect that we will require additional funding to:

Current wording

We believe our existing cash, cash equivalents, and investments will be sufficient to fund our operating expenses and capital expenditure requirements into 2027. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. We expect that we will require additional funding to:

Previous wording

•develop, maintain, expand and protect our intellectual property portfolio;

Current wording

•develop, maintain, expand and protect our intellectual property portfolio and defend intellectual property-related claims;

Previous wording

Refer to Note 6, Leases, to our consolidated financial statements appearing within this Annual Report on Form 10-K for information on our lease obligations.

Current wording

Refer to Note 6, Leases, to our consolidated financial statements appearing elsewhere within this Annual Report on Form 10-K for information on our lease obligations.