KENILWORTH, NJ – (BUSINESS WIRE) – November 17, 2021–

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced that the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (“HSR”), in connection with Merck’s pending acquisition of Acceleron Pharma Inc. (Nasdaq: XLRN) expired at 11:59 pm Eastern Time on November 16, 2021.

As previously announced on October 12, 2021, Merck launched, through a subsidiary, Astros Merger Sub, Inc., a cash tender offer to purchase all of the outstanding common shares of Acceleron, for 180 $ cash, no interest and less whatever is required. tax evasion. The expiry of the HSR waiting period satisfies one of the conditions necessary for the completion of the public tender offer. Completion of the tender offer remains subject to other conditions described in the tender offer statement in Schedule TO filed with the United States Securities and Exchange Commission (the “SEC ») On October 12, 2021, including the offer of shares representing at least a majority. of the total number of Acceleron shares outstanding.

Astros Merger Sub, Inc. extends the takeover bid, which was previously scheduled to expire at 5:00 p.m. EST on November 18, 2021, until 5:00 p.m. Eastern time on November 19, 2021 in order to allow the contribution of Acceleron shares traded on November 17, 2021. The tender offer may be extended in accordance with the merger agreement and applicable SEC rules and regulations. All other terms and conditions of the tender offer will remain unchanged during the extended period. The acquisition is expected to be finalized in the fourth quarter of 2021.

The custodian of the tender offer is Computershare Trust Company, NA, c / o Voluntary Corporate Actions, PO Box 43011, Providence, RI 02940-3011. The Custodian informed Merck that at 5:00 p.m. Eastern time on November 16, 2021, the last business day before the announcement of the extension of the tender offer, approximately 11,980,722 shares of Acceleron had been validly tendered and received, and not validly withdrawn, as part of the tender offer, representing approximately 19.6% of the outstanding shares of Acceleron. Shareholders who have already tendered their shares do not need to surrender those shares or take any other action following the extension of the tender offer.

The information agent for the tender offer is Innisfree M&A Incorporated, 501 Madison Avenue, 20th floor, New York, NY 10022. The tender offer documents may be obtained free of charge by sending a request by mail to Innisfree M&A Incorporated or by calling the toll-free number at (877) 800-5195, and can also be obtained free of charge from the website maintained by the SEC at www.sec.gov.

About Merck

For more than 130 years, Merck, known as MSD outside of the United States and Canada, has been inventing for life, providing drugs and vaccines for many of the world’s toughest diseases as part of our mission to save and improve lives. We demonstrate our commitment to patients and the health of the population by increasing access to health care through broad policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten humans and animals – including cancer, infectious diseases such as HIV and Ebola, and emerging animal diseases – as we aspire to be the premier research-intensive biopharmaceutical company. in the world. For more information, visit www.merck.com and contact us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Important information about the public tender offer

This press release is for informational purposes only and is neither an offer to buy nor a solicitation of an offer to sell Acceleron Pharma Inc. (“Acceleron”) common shares or any other security, nor does not replace the tender offer documents described herein. A tender offer statement on Schedule TO, comprising an offer to purchase, transmittal letter and related documents, has been filed by Merck Sharp & Dohme Corp. (“Merck”) and Astros Merger Sub, Inc., a wholly owned subsidiary of Merck, with the Securities and Exchange Commission (the “SEC”), and a solicitation / recommendation statement on Schedule 14D-9 a has been filed by Acceleron with the SEC.

INVESTORS AND SECURITYHOLDERS ARE URGED TO CAREFULLY READ THE OFFER TO PURCHASE DOCUMENTS (INCLUDING AN OFFER TO PURCHASE, RELATED LETTER OF TRANSMITTER AND CERTAIN OTHER OFFER TO PURCHASE DOCUMENTS) AND THE DECLARATION OFFERING SOLICITATION / RECOMMENDATION 14D-9 MAY CHANGE FROM TIME TO TIME AS THEY WILL CONTAIN IMPORTANT INFORMATION THAT INVESTORS AND HOLDERS MUST CONSIDER BEFORE MAKING ANY DECISIONS CONCERNING THE OFFERING OF THEIR SECURITIES.

Investors and securityholders may obtain a free copy of the Offer to Purchase, the related Letter of Transmittal, certain other documents relating to the Takeover Offer and the Solicitation / Recommendation Statement and other documents filed with the SEC on the website maintained by the SEC at www.sec .gov or by directing such requests to Innisfree M&A Incorporated, the Offer Information Agent, by calling toll free number (877) 800-5195. In addition, Merck and Acceleron file annual, quarterly, and current reports and other information with the SEC, which are available to the public from commercial document search services and on the SEC’s website at www .sec.gov. Copies of documents filed with the SEC by Merck can be obtained free of charge from Merck’s website at www.merck.com or by contacting Merck at 2000 Galloping Hill Road, Kenilworth, NJ 07033 or (908) 740- 4000. Copies of documents filed with the SEC by Acceleron can be obtained free of charge from the Acceleron website at www.acceleronpharma.com or by contacting Acceleron at 128 Sidney Street, Cambridge, MA 02139 or (617) 649- 9200.

Forward-looking statement by Merck & Co., Inc., Kenilworth, NJ, United States

This press release from Merck & Co., Inc., Kenilworth, NJ, United States (the “Company”) includes statements that are not statements of historical fact or “forward-looking statements”, including with regard to concerns the company’s proposed acquisition of Accéléron. These forward-looking statements include, without limitation, the ability of the Company and Acceleron to complete the transactions contemplated by the merger agreement, including the ability of the parties to meet the conditions of consumption of the contemplated offering. by it and the other conditions set out in the merger agreement, the statements on the expected timetable for the completion of the transaction, the opinions and expectations of the company and Acceleron and the statements on the benefits sought in the project acquisition of Acceleron by the company, the potential effects of the acquisition on both the company and Acceleron, the possibility of a possible termination of the merger agreement, as well as the expected profits and success of the product candidates from Acceleron. These statements are based on the current beliefs and expectations of the management of the company and are subject to significant risks and uncertainties. There can be no assurance that the conditions for closing the proposed transaction will be met on schedule or at all, with respect to pipeline products, that the products will receive the necessary regulatory approvals, or that they will be met. will prove to be commercially successful. If the underlying assumptions prove to be incorrect or if risks or uncertainties materialize, actual results may differ materially from those stated in 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 the number of Acceleron shareholders will tender their shares to the offer; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions for the completion of the merger and the offer contemplated by it may not be met or removed; the effects of the transaction disruption contemplated by the merger agreement and the impact of the announcement and pending transaction on Acceleron’s business; the risk that a dispute between shareholders in connection with the offer or the merger will result in significant defense, indemnification and liability costs; general industry conditions and competition; general economic factors, including fluctuations in interest rates and exchange rates; the impact of the global epidemic of the novel coronavirus disease (COVID-19); the impact of pharmaceutical industry regulation and health care legislation in the United States and globally; global trends towards containing health care costs; technological advances, new products and patents obtained by competitors; challenges inherent in developing new products, including obtaining regulatory approval; the company’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 patents and other corporate protections for innovative products; and exposure to litigation, including patent litigation, and / or regulatory actions.

The company assumes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise, except to the extent required by law. Additional factors that could cause results to differ materially from those described in forward-looking statements can be found in the company’s 2020 Annual Report on Form 10-K and other available SEC filings. on the SEC website (www.sec .gov).

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KEYWORD: NEW YORK UNITED STATES NORTH AMERICA

INDUSTRY KEYWORD: BIOTECHNOLOGY HEALTH SCIENCE PHARMACEUTICAL RESEARCH

SOURCE: Merck & Co., Inc.

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PUB: 11/17/2021 6:45 a.m. / DISC: 11/17/2021 6:46 a.m.

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