An important update from the phase III PREVAIL study (Xtandi in the pre-chemotherapy stage) was released thsi evening (actually yesterday evening) in advance of a formal presentation this Thursday at ASCO GU. The news is good, no the news is great.

Last November the trial of Xtandi in men with metastatic castrate resistant prostate cancer who were still chemotherapy naive was ended early because of the very significant and positive results.

In the trial the survival benefit favoring Xtandi over placebo started very early in the study, at about four months and continues until the end when the curves finally cross with only four patients remaining alive.

The overall survival hazard ratio is 0.706, translating into a 29% reduction in the risk of death favoring Xtandi over placebo. This was highly statistically significant. At the median, the overall survival benefit favoring Xtandi is 2.2 months over placebo.

So, which drug is superior, Xtandi or Zytiga in the pre-chemo prostate cancer treatment space? Today, we don’t know this answer as the two d