A phase II study of muscadine grape skin extract in men with biochemically recurrent prostate cancer.

248Background: Pulverized muscadine grape (Vitis rotundifolia) skin (MPX) is a potential therapeutic option for men with biochemically recurrent (BCR) prostate cancer (PCa) wishing to defer androgen deprivation therapy. MPX demonstrated antitumor effects in PCa through antioxidant activity of its principal polyphenol components, ellagic acid, quercetin, and resveratrol. A Phase I trial demonstrated safety of MPX in doses up to 4000 mg/day. Methods: This is a 12-month, multi-center, placebo-controlled, two-dose, double-blinded trial of MPX (manufactured by Muscadine Naturals Inc. in Warsaw, NC) in 125 men with BCR PCa. Participants were stratified by baseline PSADT and Gleason score, with no restrictions for PSADT and no upper limit PSA value. Patients were randomly assigned 2:2:1 to receive 4000 mg (8 capsules) of MPX, 500 mg (1 capsule) of MPX plus 7 capsules of placebo, or 8 capsules of placebo. PSA levels were obtained every 3 months The trial was powered to detect a statistically significant between-g...