A randomized, double-blind, placebo-controlled, Phase II study with and without enzastaurin in combination with docetaxel-based chemotherapy in patients with castration-resistant metastatic prostate cancer

作者：Dreicer Robert^*; Garcia Jorge; Rini Brian; Vogelzang Nicholas; Srinivas Sandy; Somer Bradley; Shi Peipei; Kania Marek; Raghavan Derek

来源：Investigational New Drugs, 2013, 31(4): 1044-1050.

DOI：10.1007/s10637-013-9940-0

• Prostate cancer
• Enzastaurin
• Prostate-specific antigen
• Docetaxel

Purpose Enzastaurin is an oral serine/threonine kinase inhibitor that inhibits the beta isoform of protein kinase C and which may have therapeutic activity in prostate cancer. We explored the efficacy of docetaxel/prednisone with or without enzastaurin in patients with castration-resistant metastatic prostate cancer. Methods A nonrandomized safety cohort consisting of 14 patients was followed by a double-blind randomized Phase II trial. Patients received standard doses of docetaxel (75 mg/m(2)) with prednisone 10 mg daily with or without 500 mg/day of enzastaurin. Results There was no difference in the objective response rate between the enzastaurin and placebo arms (placebo: 7 [15.2 %]; enzastaurin: 6 [15.0 %]; P = 1.00). The median PFS was 229 days for patients in the enzastaurin arm versus 213 days for the placebo arm (P = 0.524). The 1-year overall survival rates were almost identical, with 76.7 % and 75.1 % in the enzastaurin and placebo arms, respectively. Therapy was well tolerated although the combination of enzastaurin and docetaxel was more myelosuppressive than with docetaxel alone. Conclusions The clinical activity of docetaxel/prednisone plus enzastaurin cannot be distinguished from docetaxel/prednisone alone, given the limitations of a randomized Phase II design. Although the toxicity profile was favorable for the enzastaurin-containing regimen, there is no compelling rationale to move this combination forward for the treatment of castration-resistant metastatic prostate cancer.

• 出版日期2013-8