NEW YORK (AP) — Bristol-Myers Squibb Co. said yesterday it will acquire biotechnology partner ZymoGenetics Inc. for $885 million in another move by a major drugmaker to boost its pipeline by snapping up a smaller developer.

The New York drugmaker's $9.75-per-share bid represents a 77 percent premium to Zymogenetics' closing price of $5.51. Bristol-Myers' said the deal is worth $735 million excluding ZymoGenetics' cash on hand. Both companies have approved the deal and the board of ZymoGenetics is recommending that shareholders support the bid.

ZymoGenetics stock jumped $4.50, or nearly 85 percent, to $9.76 in aftermarket trading.

Seattle-based ZymoGenetics makes Recothrom, a drug used to reduce bleeding during surgeries. Since January 2009 it has been working with Bristol-Myers to develop a potential hepatitis C treatment called pegylated interferon lambda. That drug is in midstage clinical testing, and the companies said it "could be an important contributor to Bristol-Myers Squibb's future growth" if it is approved.

ZymoGenetics is also testing experimental treatments for cancer and inflammatory disorders including atopic dermatitis.

"The acquisition of ZymoGenetics brings us full ownership of a promising investigational biologic that strengthens our very diversified Hepatitis C portfolio," said Lamberto Andreotti, CEO of Bristol-Myers Squibb.

Bristol-Myers is one of the world's largest drugmakers and sells Plavix, a blood thinner that is the world's second-best selling brand name drug. Its other products include the psychiatric disorder treatment Abilify.