P-MCP treatment in non-metastatic biochemically relapsed prostate cancer (BRPC-M0): Final long-term results of a prospective phase II study.

Abstract

162 Background: 30% of patients with localized PC will have a biochemical relapse post local therapy. Their optimal treatment remains elusive. While androgen deprivation therapy is effective in reducing PSA level, its long-term benefit remains undefined, and it is toxic. Thus, evaluation of new nontoxic compounds in these patients is warranted. PectaSol-C modified citrus pectin (P-MCP) is an inhibitor of galectin-3 protein, which is involved in prostate cancer pathogenesis. We herein report the final long-term results of a multi-center phase 2 study of P-MCP treatment in BRPC-M0. Methods: Patients with BRPC-M0 were enrolled and treated with P-MCP, 4.8 grams X 3/day, for 6 months (first phase of trial). Patients without PSA progression and/or with improvement of PSA doubling time (PSADT), and with negative scans, were treated for an additional 12 months (second phase of trial). Results: 59 patients were initially enrolled. After initial 6 months of therapy, 46 patients (78%) without disease progression entered the second phase of additional 12 months therapy. Among them, 7 patients withdrew consent and chose to continue therapy out of pocket. Of the remaining 39 patients, after another year of therapy (total of 18 months), 85% (n=33) had an overall long-term response, with a decreased/stable PSA (62 %, n=24), and improvement of PSADT (90 %, n=35), and with negative scans. No patient had grade 3/4 toxicity. Conclusions: P-MCP may have a durable long-term efficacy in patients with BRPC-M0. Clinical trial information: NCT01681823 .