By Jonathan D. Rockoff 

Valeant Pharmaceuticals International Inc. said late Thursday it has reached a tentative deal to buy the prostate-cancer drug Provenge and other assets from Dendreon Corp. for $296 million in cash.

Quebec-based Valeant said it has entered into a so-called stalking-horse agreement, which means it is the preferred bidder and the company would receive an unspecified breakup fee and reimbursed expenses if its bid doesn't win the auction for Dendreon's assets. A bankruptcy court also must approve Valeant's stalking-horse bid and the sale, Valeant said.

Dendreon filed for Chapter 11 bankruptcy protection in November.

The deal would be Valeant's first big move since its failed hostile takeover of Botox maker Allergan Inc. Actavis PLC ended up buying Allergan in November for $66 billion. After losing out on Allergan, Valeant indicated it would focus on expanding its own business. But Dendreon appears to have been too tempting a target.

Dendreon filed for bankruptcy after failing to fulfill its hopes of reaping big profits from the pricey Provenge. Doctors didn't flock to Provenge, which cost $93,000 for a course of treatment but improved median survival for prostate-cancer patients by just over four months.

Provenge had about $300 million in 2014 revenue, Valeant said.

In acquiring the drug, Valeant would be making the cancer-drugs arena more of a focus. "We believe that oncology has similar characteristics to our current therapeutic portfolios, such as strong growth, high durability, strong patient and physician loyalty, and a terrific reimbursement regime," Valeant Chief Executive Michael Pearson said in a statement.

Prostate-cancer treatment is especially competitive, with Johnson & Johnson and Medivation Inc. in partnership with Astellas Pharma Inc. battling. The competition could intensify further, as J&J has high hopes for another prostate-cancer drug in development.

Write to Jonathan D. Rockoff at jonathan.rockoff@wsj.com

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