Astellas/Medivation initiate Phase III trial of enzalutamide in nmCRPC

According to a media release issued by Astellas Pharma and Medivation earlier today, the companies have initiated a new Phase III clinical trial to investigate the efficacy and safety of enzalutamide in the management of non-metastatic (TxNxM0), castration-resistant prostate cancer (nmCRPC).

The so-called PROSPER trial is designed to seek approval of enzalutamide in the management of men with nmCRPC. At present there is no therapy at all specifically approved for the treatment of men with this particular subcategory of prostate cancer, i.e., men with a rising PSA after treatment with standard forms of androgen deprivation therapy (ADT) but no clear evidence of metastatic disease on bone or CT scans.

The PROSPER trial is a randomized, double-blind, placebo-controlled, multi-national trial expected to enroll ~ 1,500 patients with nmCRPC at sites in the United States, Canada, Europe, South America, and the Asia Pacific region.  Eligible patients must have progressive disease on ADT, but be asymptomatic — with no prior or present evidence of metastatic disease.  The primary endpoint of the trial is metastasis-free survival. All patients will be maintained on standard ADT and will be random,ized to treatment with either enzalutamide (at a dose of 160 mg/day) or a placebo.

Additional information about patient eligibility and enrollment can be obtained by calling the PROSPER hotline toll-free at 855-977-3825 or by looking at relevant trial information on the web site. As of 2:25 pm Eastern time today (December 3), however, there is no information about this trial posted on We assume that such information will be available shortly.

2 Responses

  1. This appears to be the same intervention strategy as Aragon and ARN-509 with the focus being men with a rising PSA while on therapy but no identified metastases. A race to the (ambiguous) finish.

  2. Except that there isn’t really any Aragon Pharmaceuticals anymore. Johnson & Johnson bought it, along with ARN-509 and related, prostate cancer-specific assets.

    However, you are correct in noting that the new enzalutamide trial is an almost precise match to the Phase III trial of ARN-509 (see this link at

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