OncoMed Pharmaceuticals Inc. said Celgene Corp. would develop and market six of its anti-cancer stem cell experimental drugs for an upfront payment of $155 million.

OncoMed's stock rose 68 percent to $23.50 in premarket trading on Tuesday.

OncoMed is eligible to receive up to $3 billion in option and milestone payments if Celgene's option to license worldwide rights is exercised and approved, the companies said in a statement.

Celgene will also buy about $22.25 million of OncoMed's common stock for $15.13 per share, an 8 percent premium to OncoMed's closing on Monday.