Live long (without mets) and PROSPER.
The Study: The remarkably similar phase 3 PROSPER trial enrolled 1400 men with local CRPC with a prostate-specific antigen doubling time (PSADT) <10 months as determined by at least three sequential PSA rises in the face of castration-level testosterone (<0.5 ng/mL) on some form of androgen deprivation therapy (ADT). They were then randomized 2:1 to enzalutamide 160 mg daily or placebo. The primary endpoint, like in SPARTAN, was metastasis-free survival which was 37 months with enzalutamide versus 15 without, also like in SPARTAN where it was 40 months with apalutamide and 16 without. Median survival was not reached in either arm. Before you extrapolate these big benefits to all your patients with high-risk prostate cancer, take note of the number of deaths without radiographic evidence of disease—or clear etiology—in each arm: 32 versus 4, respectively. And, remember, these enrollees really had a lot to gain with a median PSA >10 ng/mL and median PSADT of <4 months. In any case, Pfizer just put another promising treatment option on the menu for non-metastatic CRPC, pending no hold ups with publication plagiarism litigation from Johnson & Johnson (aka sponsor of SPARTAN). But, hey, one word you decidedly won’t find reused in this pub is “apalutamide.”
Bottom Line: Like apalutamide, enzalutamide offers a huge almost 2 year advantage in life without metastatic disease for men with localized CRPC and a PSADT <10 months. | Hussain, N Engl J Med 2018