Acceleron Announces Clinical Trial Updates, Preclinical Presentation on Sotatercept in Pulmonary Arterial Hypertension at the 2020 American Heart Association (AHA) Scientific Sessions

The presentation of the PULSAR trial echocardiography data, which earned the AHA’s “Cardiopulmonary Best Abstract” award, will focus on sotatercept’s effects on cardiac right ventricular function in conjunction with pulmonary arterial pressure in patients with PAH. The results build upon the positive efficacy and safety results reported earlier this year during the Breaking News Session of the American Thoracic Society 2020 Virtual Conference.

The AHA Scientific Sessions will also include data from the SPECTRA Phase 2 trial as part of an invited talk by Principal Investigator Aaron Waxman, M.D., Ph.D., Director, Pulmonary Vascular Disease Program at Boston’s Brigham and Women’s Hospital. Dr. Waxman will discuss characteristics and selected outcomes from the first 10 patients with PAH participating in this ongoing trial assessing the effect of sotatercept on peak oxygen uptake, as measured by invasive cardiopulmonary exercise testing.

“We’re thrilled to be able to showcase more clinical and preclinical research on sotatercept during the AHA Scientific Sessions,” said Habib Dable, President and Chief Executive Officer of Acceleron. “The findings to be presented further solidify our belief that sotatercept acts via a unique mechanism to reverse pulmonary vascular remodeling, lending it the potential to become a backbone therapy for patients with PAH.”

Clinical Presentations

Cardiopulmonary Best Abstract Award:

Invited Talk:

Preclinical Presentation

All of the above presentations will be available to conference registrants for viewing on the AHA Scientific Session’s Virtual Platform beginning November 13, 2020 at 10:00am EST and will available on the Virtual Platform through November 17, 2020 at 9:30pm EST. The presentations will also be posted to the “Publications” page under the “Science & Pipeline” section on Acceleron’s website, www.acceleronpharma.com, beginning November 13, 2020 at 10:00 a.m. EST.

Webcast and Conference Call Information

The Company will host a webcast and conference call to review the presentations of sotatercept at AHA on November 13, 2020, at 11:00 a.m. EST.

The webcast will be accessible under “Events & Presentations” in the Investors/Media page of the company’s website at www.acceleronpharma.com. Individuals can participate in the live conference call by dialing 877-312-5848 (domestic) or 253-237-1155 (international) and referring to the “AHA Sotatercept Conference Call.”

A replay of the webcast will be available on the Acceleron website approximately two hours after the event.

About Sotatercept

Sotatercept is an investigational reverse-remodeling agent designed to be a selective ligand trap for members of the TGF-beta superfamily to rebalance BMPR-II signaling, which is a key molecular driver of PAH. The PULSAR Phase 2 trial evaluating sotatercept in combination with approved PAH-specific medicines in patients with PAH achieved its primary endpoint of improvement in pulmonary vascular resistance and its key secondary endpoint of improvement in 6-minute walk distance. Sotatercept was generally well tolerated in the trial. Adverse events observed in the study were generally consistent with previously published data on sotatercept in other diseases. Following the PULSAR results, sotatercept was granted Breakthrough Therapy designation from the FDA and Priority Medicines designation from the EMA in PAH. Sotatercept is also being evaluated in the SPECTRA Phase 2 exploratory trial.

In preclinical research published in Science Translational Medicine, sotatercept exhibited consistent effects across multiple components of disease, including suppressed proliferation of pulmonary arterial smooth muscle and microvascular endothelial cells, reduced pulmonary pressures, lessened right ventricular hypertrophy, improved right ventricular function, and attenuated vascular remodeling.

The Company recently presented details of its Phase 3 development plan, including the design for the registrational STELLAR trial, which is expected to be initiated before the end of 2020.

Sotatercept is an investigational therapy that is not approved for any use in any country. Sotatercept is part of a licensing agreement with Bristol Myers Squibb.

About PAH

PAH is a rare and chronic, rapidly progressing disorder characterized by the constriction of small pulmonary arteries and elevated blood pressure in the pulmonary circulation. PAH results in significant strain on the heart, often leading to limited physical activity, heart failure, and reduced life expectancy. The 5-year survival rate for patients with PAH is approximately 57%. Available therapies generally act by promoting the dilation of pulmonary vessels without addressing the underlying cause of the disease. As a result, PAH often progresses rapidly for many patients despite standard of care treatment. A growing body of research has implicated imbalances in BMP and TGF-beta signaling as a primary driver of PAH in familial, idiopathic, and acquired forms of the disease.

About Acceleron

Acceleron is a biopharmaceutical company dedicated to the discovery, development, and commercialization of therapeutics to treat serious and rare diseases. Acceleron’s leadership in the understanding of TGF-beta superfamily biology and protein engineering generates innovative compounds that engage the body’s ability to regulate cellular growth and repair.

Acceleron focuses its commercialization, research, and development efforts in hematologic and pulmonary diseases. In hematology, REBLOZYL® (luspatercept-aamt) is the first and only erythroid maturation agent approved in the United States, Europe, and Canada for the treatment of anemia in certain blood disorders. REBLOZYL is part of a global collaboration partnership with Bristol Myers Squibb. The Companies co-promote REBLOZYL in the United States and are also developing luspatercept for the treatment of anemia in patient populations of MDS, beta-thalassemia, and myelofibrosis. In pulmonary, Acceleron is developing sotatercept for the treatment of pulmonary arterial hypertension (PAH), having recently presented positive topline results of the Phase 2 PULSAR trial. The Company is currently planning multiple Phase 3 trials with the potential to support its long-term vision of establishing sotatercept as a backbone therapy for patients with PAH at all stages of the disease.

For more information, please visit www.acceleronpharma.com. Follow Acceleron on Social Media: @AcceleronPharma and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements about Acceleron’s strategy, future plans and prospects, including statements regarding the development of sotatercept in PAH, the timeline for clinical development and regulatory approval of sotatercept in PAH, the expected timing for reporting of data from ongoing clinical trials, and the potential of Acceleron’s compounds as therapeutic drugs. The words “anticipate,” “believe,” “could,” “estimate,” “expect,” “goal,” “intend,” “may,” “plan,” “possible,” “potential,” “project,” “should,” “target,” “will,” “would,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

Actual results could differ materially from those included in the forward-looking statements due to various factors, risks and uncertainties, including, but not limited to, that preclinical testing of Acceleron’s compounds and data from clinical trials may not be predictive of the results or success of ongoing or later clinical trials, that regulatory approval of Acceleron’s compounds in one indication or country may not be predictive of approval in another indication or country, that the development of Acceleron’s compounds will take longer and/or cost more than planned, that Acceleron will be unable to successfully complete the clinical development of Acceleron’s compounds, that Acceleron may be delayed in initiating, enrolling or completing any clinical trials, that Acceleron’s compounds will not receive regulatory approval or become commercially successful products, and that Breakthrough Therapy or PRIME designation may not expedite the development or review of sotatercept. These and other risks and uncertainties are identified under the heading “Risk Factors” included in Acceleron’s most recent Annual Report on Form 10-K, Quarterly Report on Form 10-Q, and other filings that Acceleron has made and may make with the SEC in the future.

The forward-looking statements contained in this press release are based on management’s current views, plans, estimates, assumptions, and projections with respect to future events, and Acceleron does not undertake and specifically disclaims any obligation to update any forward-looking statements.