Abstract of presentation about the PREVAIL trial of enzalutamide in mCRPC


The American Society of Clinical Oncology (ASCO) has released the abstract of the paper by Beer et al. to be presented in full at the upcoming Genitourinary Cancers Symposium in San Francisco late next week … but it doesn’t really tell us anything new. (To find the actual abstract, click here.)

According to the abstract, and as previously announced, the PREVAIL trial, which was originally designed to enroll 1,680 patients with asymptomatic or mildly symptomatic, chemotherapy-naïve, metastatic, castration-resistant prostate cancer (mCRPC), has shown positive results favoring men treated with enzalutamide, in terms of both overall survival (OS) and radiographic progression-free survival (rPFS).

Patients were randomized to treatment with either enzalutamide (at a dose of 160 mg/day) or a placebo.

Here are the data provided in the abstract:

  • 1,717 men were actually enrolled and randomized between September 2010 and September 2012.
  • 1,715 men went on to receive treatment.
  • At the time of the latest interim analysis, 539/1,717 patients (31.4 percent) had died.
    • 28 percent of men randomized to treatment with enzalutamide had died.
    • 35 percent of men randomized to treatment with a placebo had died.
  • Compared to the results for men randomized to treatment with a placebo
    • There was a 30 percent reduction in risk of death (hazard ratio [HR] = 0.70) for patients randomized to treatment with enzalutamide.
    • There was an 81 percent reduction in risk of rPFS (HR = 0.19) for patients randomized to treatment with enzalutamide.
  • Estimated median OS was
    • 30.2 months for patients randomized to treatment with a placebo.
    • 32.4 months for patients randomized to treatment with enzalutamide.
  • Average (median) rPFS was
    • 3.9 months for patients randomized to treatment with a placebo, but
    • This time period could not yet be assessed for patients randomized to treatment with enzalutamide.
  • 2/1,715 patients are reported to have experienced seizures.

The abstract goes on to state that “Secondary endpoints and safety analysis will be presented” at the time of the actual meeting.

Alas, this abstract doesn’t seem to offer us any important new information beyond that available in the media release issued by Astellas and Medivation back on October last year. Of course it is perfectly possible that that was deliberate on the part of all concerned, and was why ASCO and the companies felt they were able to release this abstract early. (Other abstracts of paper to be presented at the meeting will not be available on line until January 28.)

One Response

  1. I had hoped to read something more promising.

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