It was announced today that after observing significant benefits in overall survival (OS) and radiographic progression free survival (PFS) ,the two co-primary endpoints of the the Xtandi pre-chemotherapy trial, the Independent Data Monitoring Committee (IDMC) for The Phase 3 PREVAIL trial of enzalutamide in metastatic prostate cancer recommends that “the study be stopped and patients treated with placebo be offered enzalutamide.”
Enzalutamide (Xtanndi) reduced the risk of death by 30% (Hazard Ratio .70), and patients saw an 81% reduction in risk of radiographic progression or death (Hazard Ratio 0.19), Dr. Tomasz Beer, professor of medicine and deputy director of the Knight Cancer Institute said “To my knowledge, the benefits in overall survival and radiographic progression-free survival reported in today’s PREVAIL trial results are unprecedented in this patient population.”
This means that now we can have an almost certain expectation that Xtandi will join Provenge and Zytiga in the pre-chemotherapy treatment phase of metastatic resistant castrate resistant prostate cancer. This is great news, but it will add to the complications our doctors will now face as they decide which drug would be the more appropriate treatment at this stage.
It will also add to the problem of Step Therapy for oncology. In prostate cancer this terrible practice has already reared its head between Xtandi and Zytiga in the post chemo phase and between Zytiga and Provenge in the pre-chemo stage, now we can assume that this will appear in the prechemo stage between Provenge, Zytiga and Xtandi.
These are great problems to have (in reality, no problems are great) as this assumed approval will continue to expand our treatment vocabulary. Now, we wait for the submission of the data to the FDA and then on to its hopeful approval. Malecare will continue its Early Access Work and attempt to see Xtandi become available prior to the FDA approval as well as launching our fight against Step Therapy.
Joel T Nowak, MA, MSW