Avoro Capital Releases Presentation Detailing Why Acceleron Shareholders Should Not Tender Into Merck’s Inadequate Offer

Believes Now Is the Wrong Time to Cash out of Acceleron, Given Company’s Strong Momentum and Near-Term Inflection Point Coming from Phase 3 Data

Sees Continuing as Standalone Entity as Clearly Superior Path for Acceleron

Highlights What It Believes Was a Flawed and Inadequate Sale Process, Including Not Pursuing Other Strategic Alternatives

Avoro Stands Ready to Support an Independent Acceleron

NEW YORK–(BUSINESS WIRE)–Avoro Capital Advisors (“Avoro”), a long-term and collaborative investor in life sciences and biotechnology companies, together with certain of its affiliates and managed funds (“Avoro,” “we” or “us”) beneficially owns approximately 7% of Acceleron Pharma Inc. (Nasdaq: XLRN) (“Acceleron”, “XLRN” or the “Company”), making Avoro one of the Company’s most significant shareholders. Avoro today released a detailed presentation outlining why shareholders should not tender their Acceleron shares to the Merck & Co. Inc. (NYSE: MRK) (“Merck”) tender offer for $180 per share (the “Tender Offer”).

The presentation is available at: https://www.businesswire.com/news/home/52526996/en.

As highlighted in the presentation, Avoro believes that:

• Now is the wrong time to cash out of Acceleron: Significant value will be created in one year or less after the STELLAR phase 3 trial data is available. Other major shareholders agree.
• Merck’s offer does not represent fair value for Acceleron: The implied valuation based on precedent transactions is much higher than the $180 per share Tender Offer price. Sell side analysts and several other investors agree that the price is too low.
• Acceleron’s Board used a flawed process in reaching the deal: The Board only approached three potential buyers and seemingly did not pursue any other strategic alternatives. In fact, the Board appeared more focused on serving management’s interests by providing last-minute tax gross-ups and increased severance payments to Acceleron executives.
• Avoro stands ready to support an independent Acceleron: Avoro would stand ready to take the steps necessary to help modify the Board’s composition and add directors with relevant experience and expertise to create improved shareholder.

Avoro reiterates that it will not tender its shares into the Merck Tender Offer.

About Avoro Capital L.P.

Avoro Capital L.P., is the parent of Avoro Capital Advisors LLC (“Avoro Capital Advisors”) and Avoro Ventures LLC (“Avoro Ventures”). Avoro Capital Advisors is an SEC-registered investment manager located in New York City, investing in public and private equity companies focused primarily on life sciences and biotechnology. Managing Partner, Behzad Aghazadeh PhD, has over 25 years of experience spent in scientific research, healthcare consulting, institutional investment and executive leadership within the healthcare sector, and is supported by a team of seasoned professionals with advanced medical and scientific backgrounds, and extensive investment experience in the biopharmaceutical industry.

Forward-Looking Statements and Additional Information

This communication contains forward-looking statements. Forward-looking statements are statements that are not historical facts and may include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words “expects”, “anticipates”, “believes”, “intends”, “estimates”, “plans”, “will be” and similar expressions. These forward-looking statements include, without limitation, statements regarding the planned completion of the transactions contemplated by the Tender Offer. Although Avoro believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Avoro, Merck or Acceleron, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties are enumerated in Acceleron’s public filings and recent public communications regarding the Tender Offer by Acceleron and Merck. In addition, the foregoing considerations and any other publicly stated risks and uncertainties should be read in conjunction with the risks and cautionary statements discussed or identified in the public filings with the U.S. Securities and Exchange Commission (the “SEC”) made by Merck and Acceleron, including those listed under “Risk Factors” in Merck’s annual reports on Form 10-K and quarterly reports on Form 10-Q and Acceleron’s annual reports on Form 10-K and quarterly reports on Form 10-Q and current reports on Form 8-K filed with the SEC. The forward-looking statements speak only as of the date hereof and, other than as required by applicable law, Avoro does not undertake any obligation to update or revise any forward-looking information or statements. Unless otherwise noted, Avoro has neither sought nor obtained permission to use third party statements reproduced herein.

Contacts

Sloane & Company

Dan Zacchei / Joe Germani

[email protected] / [email protected]