This filing relates solely to preliminary communications made before the commencement of a
tender offer for the outstanding common stock of Imago BioSciences, Inc. (“Imago”) by M-Inspire Merger Sub, Inc. (“Merger Sub”), a wholly owned subsidiary of Merck
Sharp & Dohme LLC (“Merck”), to be commenced pursuant to the Agreement and Plan of Merger, dated as of November 19, 2022, by and among Imago, Merger Sub and Merck.
Important Information About the Tender Offer
The tender offer described in this document has not yet commenced. This document is for informational purposes only and is neither an offer to
purchase nor a solicitation of an offer to sell any shares of the common stock of Imago or any other securities, nor is it a substitute for the tender offer materials described herein. At the time the planned tender offer is commenced, a tender
offer statement on Schedule TO, including an offer to purchase, a letter of transmittal and related documents, will be filed by Merck and Merger Sub with the Securities and Exchange Commission (the “SEC”), and a
solicitation/recommendation statement on Schedule 14D-9 will be filed by Imago with the SEC.
INVESTORS AND SECURITY HOLDERS ARE URGED TO READ CAREFULLY BOTH THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED
LETTER OF TRANSMITTAL AND CERTAIN OTHER TENDER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9 REGARDING THE OFFER, AS THEY MAY BE AMENDED FROM TIME TO TIME, WHEN THEY BECOME
AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT INVESTORS AND SECURITY HOLDERS SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SECURITIES.
Investors and security holders may obtain a free copy of the Offer to Purchase, the related Letter of Transmittal, certain other tender offer
documents and the Solicitation/Recommendation Statement (when available) and other documents filed with the SEC at the website maintained by the SEC at www.sec.gov or by directing such requests to the Information Agent for the tender offer, which
will be named in the tender offer statement. In addition, Merck’s parent company, Merck & Co., Inc. and Imago file annual, quarterly and current reports and other information with the SEC, which are available to the public from
commercial document-retrieval services and at the SEC’s website at www.sec.gov. Copies of the documents filed with the SEC by Merck & Co., Inc. may be obtained at no charge on Merck’s internet website at www.merck.com or by
contacting Merck at 2000 Galloping Hill Road, Kenilworth, N.J. 07033 or (908) 423-1000. Copies of the documents filed with the SEC by Imago may be obtained at no charge on Imago’s internet website at
https://ir.imagobio.com or by contacting Imago at 303 Twin Dolphin Drive 6th Floor, Redwood City, CA 94065 or (415) 529-5055.
Forward-Looking Statement of Merck
This document includes statements that are not statements of historical fact, or “forward-looking statements,” including with respect
to Merck’s proposed acquisition of Imago. Such forward-looking statements include, but are not limited to, the ability of Merck and Imago to complete the transactions contemplated by the merger agreement, including the parties’ ability to
satisfy the conditions to the consummation of the offer contemplated thereby and the other conditions set forth in the merger agreement, statements about the expected timetable for completing the transaction, Merck’s and Imago’s beliefs
and expectations and statements about the benefits sought to be achieved in Merck’s proposed acquisition of Imago, the potential effects of the acquisition on both Merck and Imago, the possibility of any termination of the merger agreement, as
well as the expected benefits and success of Imago’s product candidates. These statements are based upon the current beliefs and expectations of Merck’s management and are subject to significant risks and uncertainties. There can be no
guarantees that the conditions to the closing of the proposed transaction will be satisfied on the expected timetable or at all, with respect to pipeline products that the products will receive the necessary regulatory approvals or that they will
prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.
Risks and uncertainties include but are not limited to, uncertainties as to the timing of the offer and the subsequent merger; uncertainties
as to how many of Imago’s stockholders will tender their shares in the offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the merger and the offer
contemplated thereby may not be satisfied or waived; the effects of disruption from the transactions contemplated by the merger agreement and the impact of the announcement and pendency of the transactions on Imago’s business; the risk that
stockholder litigation in connection with the offer or the merger may result in significant costs of defense, indemnification and liability; general industry conditions and competition; general economic factors, including interest rate and currency
exchange rate fluctuations; the impact of the global outbreak of novel coronavirus disease (COVID-19); the impact of pharmaceutical industry regulation and health care legislation in the United States and
internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Merck’s
ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of Merck’s patents and other protections for
innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.