SC 14D9/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14D-9

(Amendment No. 5)

SOLICITATION/RECOMMENDATION STATEMENT

PURSUANT TO SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934

ACCELERON PHARMA INC.

(Name of Subject Company)

ACCELERON PHARMA INC.

(Name of Person(s) Filing Statement)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

00434H108

(CUSIP Number of Common Stock)

Rita Karachun

President

Acceleron Pharma Inc.

128 Sidney Street

Cambridge, Massachusetts 02139

(617) 649-9200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications

on Behalf of the Person(s) Filing Statement)

With copies to:

Christopher D. Comeau

Marc Rubenstein

Ropes & Gray LLP

Prudential Tower

800 Boylston Street

Boston, Massachusetts 02199

(617) 951-7000

¨ Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

This Amendment No. 5 (this “Amendment”) to Schedule 14D-9 amends and supplements the Schedule 14D-9 previously filed by Acceleron Pharma Inc., a Delaware corporation (the “Company”), with the U.S. Securities and Exchange Commission (the “SEC”) on October 12, 2021 (as amended or supplemented from time to time, the “Schedule 14D-9”), with respect to the tender offer by Astros Merger Sub, Inc., a Delaware corporation (“Purchaser”) and wholly-owned subsidiary of Merck Sharp & Dohme Corp., a New Jersey corporation (“Parent”), to purchase any and all of the Company’s outstanding common stock, $0.001 par value per share (the “Shares”), in exchange for $180.00 per Share, net to the seller in cash, without interest and less applicable tax withholding (the “Offer Price”) upon the terms and subject to the conditions set forth in the Offer to Purchase, dated October 12, 2021 (together with any amendments or supplements thereto, the “Offer to Purchase”), and in the related Letter of Transmittal (together with any amendments or supplements thereto, the “Letter of Transmittal,” which, together with the Offer to Purchase, constitutes the “Offer”). The Offer is described in a Tender Offer Statement on Schedule TO (as amended or supplemented from time to time, the “Schedule TO”) filed by Parent and Purchaser with the Securities and Exchange Commission (the “SEC”) on October 12, 2021. The Offer to Purchase and the Letter of Transmittal have been filed as Exhibits (a)(1)(A) and (a)(1)(B) to the Schedule 14D-9, respectively, and are incorporated therein by reference.

Capitalized terms used in this Amendment but not defined herein shall have the respective meaning given to such terms in the Schedule 14D-9. The information set forth in the Schedule 14D-9 remains unchanged and is incorporated herein by reference, except that such information is hereby amended or supplemented to the extent specifically provided herein.

Item 8. Additional Information.

Item 8 of the Schedule 14D-9, as amended, is hereby amended and supplemented by adding the following new subsection before the subsection entitled “Cautionary Note Regarding Forward-Looking Statements” included in such Item 8:

“Final Results of the Offer and Completion of the Merger

“The Offer and related withdrawal rights expired at 5:00 p.m., Eastern Time, on November 19, 2021 (such date and time, the “Expiration Time”). The depository has advised that, as of the Expiration Time, 38,752,614 Shares had been validly tendered and “received” (as defined in Section 251(h) of the DGCL) by the depository and not properly withdrawn pursuant to the Offer, representing approximately 63.3% of the Shares outstanding as of such time. Accordingly, the Minimum Tender Condition has been satisfied. Purchaser has accepted, and has stated that it will pay for such Shares as promptly as practicable after the Expiration Time in accordance with the terms of the Offer.

Following expiration of the Offer and acceptance for payment of the Shares, Purchaser had ownership sufficient to effect the Merger under Section 251(h) of the DGCL, without a vote of stockholders of the Company. Accordingly, following completion of the Offer, Parent and Purchaser effected the Merger in accordance with Section 251(h) of the DGCL in which Purchaser merged with and into the Company, with the Company surviving the Merger and continuing as a wholly owned subsidiary of Parent. In the Merger, each Share issued and outstanding (other than (i) Shares held in the treasury of the Company or owned by the Company or any direct or indirect wholly owned subsidiary of the Company and each Share owned by Parent, Purchaser or any direct or indirect wholly owned subsidiary of Parent or Purchaser immediately prior to the Effective Time or (ii) Shares outstanding immediately prior to the Effective Time and held by stockholders who are entitled to demand, and properly demand, appraisal for such Shares in accordance with Section 262 of the DGCL) were converted into the right to receive an amount in cash equal to the Offer Price, without interest, and less any applicable tax withholding. The Shares are expected to cease to trade on the Nasdaq Global Market (“Nasdaq”) prior to the opening of business on November 22, 2021, and will be delisted from Nasdaq and deregistered under the Exchange Act.

On November 19, 2021, Merck issued a press release announcing the expiration of the Offer, and on November 22, 2021, Merck issued a press release announcing the consummation of the Merger. The full text of the press releases announcing the expiration of the Offer and the consummation of the Merger are attached as Exhibits (a)(5)(K) and (a)(5)(L) to the Schedule 14D-9, respectively, and are incorporated herein by reference.”

Item 9. Exhibits

Item 9 of the Schedule 14D-9 is hereby amended and supplemented by adding the following exhibits:

Exhibit No.	Description
(a)(5)(K)	Press release issued by Merck & Co., Inc., dated November 19, 2021.

(a)(5)(L) Press release issued by Merck & Co., Inc., dated November 22, 2021.

SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: November 22, 2021	ACCELERON PHARMA INC.
	By:	/s/ Rita Karachun
	Name:	Rita Karachun
	Title:	President

EX-99.(A)(5)(K)

Exhibit (a)(5)(k)

FOR IMMEDIATE RELEASE

Media Contacts: Patrick Ryan (973) 275-7075   Melissa Moody (215) 407-3536 Investor Contacts: Peter Dannenbaum (908) 740-1037   Steven Graziano (908) 740-6582

Merck Completes Tender Offer to Acquire Acceleron Pharma Inc.

KENILWORTH, N.J., Nov. 19, 2021—Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced the successful completion of the cash tender offer, through a subsidiary, Astros Merger Sub, Inc., for all of the outstanding shares of common stock of Acceleron Pharma Inc. (Nasdaq: XLRN), at a purchase price of $180 per share in cash, without interest and less applicable tax withholding. As of the tender offer expiration at 5:00 p.m., Eastern Time, on Nov. 19, 2021, 38,752,614 shares of common stock of Acceleron were validly tendered and not withdrawn from the tender offer, representing approximately 63.3% of the total number of Acceleron’s outstanding shares. All such shares have been accepted for payment in accordance with the terms of the tender offer, and Astros Merger Sub, Inc. expects to promptly pay for such shares.

Merck intends to complete the acquisition of Acceleron through a merger of Astros Merger Sub, Inc. with and into Acceleron, with Acceleron being the surviving corporation, in which all shares not tendered into the offer will be cancelled and converted into the right to receive cash equal to the $180 offer price per share, without interest and less any applicable tax withholding. After the completion of the merger, Acceleron will become a wholly owned subsidiary of Merck and the common stock of Acceleron will no longer be listed or traded on the Nasdaq Global Market.

About Merck

For over 130 years, Merck, known as MSD outside of the United States and Canada, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases in pursuit of our mission to save and improve lives. We demonstrate our commitment to patients and population health by increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten people 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 connect with us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Kenilworth, N.J., USA

This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the “company”) includes statements that are not statements of historical fact, or “forward-looking statements.” These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. 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, 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; 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 the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes 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 the forward-looking statements can be found in the company’s 2020 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

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EX-99.(A)(5)(L)

Exhibit (a)(5)(L)

FOR IMMEDIATE RELEASE

Media Contacts:	Jessica Fine	Investor Contacts:	Peter Dannenbaum
	(908) 608-4859		(908) 740-1037
	Melissa Moody		Steven Graziano
	(215) 407-3536		(908) 740-6582

Merck Completes Acquisition of Acceleron Pharma Inc.

KENILWORTH, N.J., Nov. 22, 2021—Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced the successful completion of the acquisition of Acceleron Pharma Inc. (Nasdaq: XLRN).

“This is an important and strategic opportunity for our company to continue growing our cardiovascular portfolio and pipeline, that builds on our long and proud legacy in cardiovascular disease and further bolsters our business development strategy,” said Rob Davis, chief executive officer and president, Merck. “Fueled by Acceleron’s groundbreaking research, we are excited to explore the opportunities and possibilities ahead to reach even more patients by addressing this critical health need.”

Acceleron is focused on harnessing the power of the transforming growth factor (TGF)-beta superfamily of proteins that is known to play a central role in the regulation of cell growth, differentiation and repair. Acceleron’s lead therapeutic candidate, sotatercept, has a novel mechanism of action with the potential to improve short-term and/or long-term clinical outcomes in patients with pulmonary arterial hypertension (PAH), a progressive and life-threatening blood vessel disorder. Sotatercept is in Phase 3 trials as add-on to current standard of care for the treatment of PAH.

About Merck

For over 130 years, Merck, known as MSD outside of the United States and Canada, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases in pursuit of our mission to save and improve lives. We demonstrate our commitment to patients and population health by increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten people 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 connect with us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Kenilworth, N.J., USA

This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates 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, 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; 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 the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes 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 the forward-looking statements can be found in the company’s 2020 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

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