Shares of the Cambridge, Mass., company at last check were up nearly 4% to $174.20.
Details about the potential buyer were not known, but Bloomberg reported that several global drugmakers, including Bristol-Myers Squibb (BMY) - Get Bristol-Myers Squibb Company Report, which owns 11.5% of Acceleron's stock, are seen as potential suitors.
The acquisition would be made at about $180 a share cash, Bloomberg said, citing people familiar with the matter.
Acceleron did not immediately respond to a request for comment.
The report spurred RBC Capital analyst Kennen MacKay to raise his price target on Acceleron to $179 from $113, while keeping a sector-perform rating on the shares, according to the Fly.
M&A interest is likely given the history of consolidation in the pulmonary arterial hypertension field, MacKay said.
Acceleron's sotatercept's unique mechanism of action has the potential to complement the portfolio of current players in the space, he said.
Acceleron, which has a market value of $10.2 billion and about 370 employees, focuses on discovering, developing and commercializing therapeutics to treat serious and rare diseases.
Among other things, the company makes Reblozyl for the treatment of anemia in adults with beta-thalassemia and transfusion-dependent anemia.
In August, Acceleron reported a wider-than-expected second-quarter loss of $1.05 a share, sharper than the loss of 34 cents a year earlier and missing the Zacks consensus of a loss of 92 cents a share.
Revenue totaled $27.9 million, including $2.3 million of cost-share revenue and $25.6 million of royalty revenue from net sales of Reblozyl. All revenue was derived from the company's partnership with Bristol-Myers Squibb.