Johnson & Johnson will spend as much as $1 billion to buy Aragon Pharmaceuticals, primarily to acquire its prostate cancer drug, ARN-509, which inhibits both androgen receptor nuclear translocation and DNA binding.

Pharmaceutical giant Johnson & Johnson (J&J) will spend as much as $1 billion to buy Aragon Pharmaceuticals of San Diego, CA, primarily to acquire its prostate cancer drug, ARN-509.

ARN-509, which inhibits androgen receptor (AR) signaling, shows promise in phase I and II studies and aligns well with the larger company's cancer portfolio, says Kellie McLaughlin, a spokesperson for Janssen Pharmaceuticals of Titusville, NJ, a member of the J&J family of companies.

ARN-509 inhibits both AR nuclear translocation and binding to AR response elements in DNA. The drug will complement J&J's Zytiga (abiraterone acetate) “and will address unmet needs across a broader range of prostate cancer patients,” McLaughlin says. “We think there's potential for the two drugs to be used sequentially or in combination.” However, the company has not disclosed its plans for a phase III trial.

To date, ARN-509 has been tested in about 100 patients, with encouraging early results. In phase I/II results released in February, 91% of 47 patients with nonmetastatic cancer showed a measured prostate-specific antigen response to the drug.

In the deal, J&J has agreed to pay $650 million up front, plus additional contingent payments of up to $350 million based on reaching predetermined milestones, for the 4-year-old Aragon.

Before the sale, Aragon, which focuses on drugs to treat hormone-driven cancers, will spin off all its non–prostate cancer work, including a treatment for estrogen-receptor–positive breast cancer, ARN-810, which began its first phase I trial earlier this year. The spin-off, to be known as Seragon Pharmaceuticals, will not be connected to J&J.

When and if ARN-509 wins approval from the U.S. Food and Drug Administration, possibly in connection with Zytiga, J&J expects its main competitors to be the AR inhibitor Xtandi (enzalutamide) from Medivation and Astellas Pharma, Dendreon's immunotherapy Provenge (sipuleucel-T), and Bayer's radiopharmaceutical Xofigo (radium-223 dichloride).