Phase II trial of acai juice product in biochemically recurrent prostate cancer.

Abstract

230 Background: There are conflicting data as to the benefit of treating patients with biochemically recurrent prostate cancer (PCa). Plant derivatives, called “nutraceuticals” such as grape seed extract or milk thistle, have been studied as therapies for PCa based on their purported anti-inflammatory and anti-oxidant properties and low toxicities. Acai is a fruit rich in bioflavinoids shown to induce apoptosis in preclinical studies of PCa, leukemia and esophageal cancer. Anecdotal experience of two patients with falling prostate specific antigen (PSA) values while consuming acai juice prompted us to evaluate its efficacy in a clinical trial. Methods: This was a phase II Simon two-stage open-label single-arm single-institution study of the efficacy of Acai Juice Product in asymptomatic PCa patients with a rising PSA. Eligibility included lack of current hormone therapy, hormone sensitivity, and a PSA doubling time of >4 weeks. Patients consumed 2 oz of Acai Juice Product twice daily for 30 weeks, with a primary endpoint of PSA response. Secondary endpoints included PSA doubling time, PSA velocity, and duration of PSA response. Progression was defined as a rise of 25% from baseline PSA with absolute rise of 2ng/dL. Results: 21 patients were enrolled in the first stage of the trial. Median baseline PSA was 2.74 (range 0.38-36.88). Eighteen patients have completed therapy with 1 PSA response. In the one responder, the patient entered with a doubling time of 4 months and a PSA of 12.57, which was 2.15 at 36 weeks suggesting a prolonged and continued response. PSA either decreased or doubling time prolonged from baseline in 18 patients. PSA velocity was a negative rate of change per month in 4 patients. Conclusions: Acai juice did not produce enough PSA responses in this patient population to proceed beyond the first stage of this trial. However, PSA doubling time did slow in 85.7% of patients, and the one observed PSA response was sustained over at least 36 weeks at the time of data cutoff. Thus, we will analyze potential cellular signals through an M30 Apotosense ELISA assay and Human Cytokine 10-plex panel on patient samples with data available for presentation at the meeting. Clinical trial information: NCT01521949.