Replimune Group, Inc.

ANNUAL REPORT ON FORM 10-K

For the Year Ended March 31, 2026

Table of Contents

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Special note regarding forward-looking statements

This Annual Report on Form 10-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities and Exchange Act of 1934, as amended, including statements regarding our expectations about our cash runway, the design and advancement of our clinical trials, the timing and sufficiency of our clinical trial outcomes to support potential approval of any of our product candidates, our goals to develop and commercialize our product candidates, patient enrollments in our existing and planned clinical trials and the timing thereof, and other statements concerning our business, operations and financial performance and condition, as well as our plans, objectives and expectations for our business operations and financial performance and condition. Any statements contained herein that are not statements of historical facts may be deemed to be forward-looking statements. In some cases, you can identify these forward-looking statements by the use of words such as “outlook,” “believes,” “expects,” “potential,” “continues,” “may,” “will,” “should,” “seeks,” “approximately,” “predicts,” “intends,” “plans,” “estimates,” “anticipates” or the negative version of these words or other comparable words. Such forward-looking statements are subject to various risks and uncertainties. Accordingly, there are or will be important factors that could cause actual outcomes or results to differ materially from those indicated in these statements. We believe these factors include, among other things:

•the timing, progress, and results of preclinical studies and clinical trials for our product candidates, including the timing of initiation and completion of studies or trials and related preparatory work and the period during which the results of the trials will become available;

•our ability to obtain additional funding as necessary;

•the timing, scope or likelihood of regulatory filings and approvals, including timing of approval by the U.S. Food and Drug Administration, or the FDA, of, RP1 or any of our other product candidates;

•our ability to address comments in the second Complete Response Letter, or CRL, related to our Biologics License Application, or BLA, for RP1 in combination with nivolumab for the treatment of advanced melanoma to the satisfaction of the FDA, and the outcome of a resubmitted BLA;

•the timing, scope, or likelihood of foreign regulatory filings and approvals;

•our ability to develop our product candidates for use in combination with other checkpoint blockade therapies, including anti-PD-1;

•our ability to develop and advance any future product candidates into, and successfully complete, clinical trials;

•our expectations regarding the size of the patient populations for RP1, RP2 and/or any other product candidates from our RPx platform if approved for commercial use;

•our ability to successfully qualify, obtain approval for, and maintain successful operation, approval and qualification of our in-house manufacturing operations;

•our ability to obtain and maintain sufficient quantities of raw material supplies or access single or limited sources of goods or services needed to build or maintain our product candidate supplies or otherwise operate our in-house manufacturing facility;

•the costs of operating our in-house manufacturing facility;

•our estimates regarding expenses and capital requirements;

•the implementation of our business model and our strategic plans for our business, RP1 and our other product candidates;

•the rate and degree of market acceptance and clinical utility of RP1 and our other product candidates;

•the potential benefits of and our ability to establish or maintain future collaborations or strategic relationships;

•our ability to retain the continued service of our key professionals and to identify, hire and retain additional qualified professionals;

•our intellectual property position, including the scope of protection we are able to establish and maintain for intellectual property rights covering RP1 and our other product candidates, claims others may make regarding rights in our intellectual property, and any potential infringement, misappropriation or other violation of any third-party intellectual property rights;

•our competitive position, and developments and projections relating to our competitors and our industry;

•negative developments in the fields of immuno-oncology or oncolytic immunotherapy;

•the impact of laws and regulations; and

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•the other risks and uncertainties described under “Risk factors.”

The forward-looking statements made in this Annual Report on Form 10-K relate only to events as of the date on which the statements are made. These factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included in this Annual Report on Form 10-K. Moreover, we operate in a competitive and rapidly changing environment. New risks and uncertainties emerge from time to time, and it is not possible for us to predict all risks and uncertainties that could have an impact on the forward-looking statements contained in this Annual Report on Form 10-K. We undertake no obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments or otherwise, except to the extent required by applicable law. You should not rely on forward-looking statements as predictions of future events. We may not actually achieve the plans, intentions, or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements.

In this Report, the words “Company,” “we,” “our,” “us” and “Replimune” refer to Replimune Group, Inc. and its subsidiaries. This Report contains trademarks, service marks and trade names that are the property of, or licensed by, Replimune and its subsidiaries.

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