A large epigenetics deal announced last week between Epizyme Inc. and Celgene Corp. has many similarities with January's deal between Constellation Pharmaceuticals Inc. and Genentech Inc. But the pacts are structured differently because the smaller biotechs have different goals.

Epizyme is set up to remain independent and commercialize its own products in the U.S., although the deal has elements that could ease an acquisition by partner Celgene. In contrast, Constellation's deal has set the company up to be acquired, with elements to ensure some upside if Genentech does not exercise its call option (see BioCentury, Jan. 23).