Medivation Inc. (MDVN) signed a global partnership with Japanese pharmaceutical company Astellas Pharma Inc. (ALPMY) to develop and market the San Francisco company's experimental prostate cancer treatment.

Medivation will receive $110 million in cash immediately, and is eligible to receive up to $335 million in development and regulatory milestone payments, along with $320 million in commercial milestones.

Shares of Medivation recently rose 8.2% to $28.25 in premarket trading.

The drug, MDV3100, is being studied in a recently started Phase 3 clinical trial in men with castration-resistant prostate cancer who were previously treated with docetaxel-based chemotherapy.

The two companies plan additional studies of the drug in late- and early-stage prostate cancer. They will jointly sell and develop the drug in the U.S., while Astellas will take the lead outside the U.S., paying a double-digit royalty that increases as certain sales levels are achieved.

Last year, Medivation signed a partnership with Pfizer Inc. (PFE), including $225 million in upfront cash and up to $500 million in additional payments, to develop and co-market a potential Alzheimer's disease treatment--Dimebon.

On a conference call Tuesday, Medivation Chief Executive David Hung said that Astellas was an ideal partner for MDV3100 because of its experience with selling urinary disorder treatment Flomax.

-By Thomas Gryta, Dow Jones Newswires; 212-416-2169; thomas.gryta@dowjones.com