Multicenter randomized phase II study comparing docetaxel plus curcumin versus docetaxel plus placebo in first-line treatment of metastatic castration-resistant prostate cancer.

BACKGROUND Metastatic castration-resistant prostate cancer (mCRPC) patients have a poor prognosis, and curcumin is known to have antineoplastic properties. On the basis of previous phase I and phase II studies, we investigated whether the association of curcumin with docetaxel could improve prognosis among mCRPC patients. METHODS A total of 50 mCRPC patients (included from June 2014 to July 2016) treated with docetaxel in association with oral curcumin (6 g/d for 7 days every 3 weeks) versus placebo were included in this double-blind, randomized, phase II study. The primary endpoint was to evaluate the time to progression. Among the secondary endpoints, compliance, overall survival, prostate-specific antigen (PSA) response, safety, curcumin absorption, and quality of life were investigated. An interim analysis was planned in the modified intention-to-treat population with data at 6 months (22 patients per arm). RESULTS Despite good compliance and a verified absorption of curcumin, no difference was shown for our primary endpoint: progression-free survival (PFS) between the placebo and curcumin groups was, respectively, 5.3 months versus 3.7 months, p = 0.75. Similarly, no difference was observed for the secondary objectives: PSA response rate (p = 0.88), overall survival (p = 0.50), and quality of life (p = 0.49 and p = 0.47). CONCLUSION Even though our previous studies and data in the literature seemed to support an association between curcumin and cancer therapies in order to improve patient outcome and prognosis, the results from this interim analysis clearly showed that adding curcumin to mCRPC patients' treatment strategies was not efficacious. The study was discontinued on the grounds of futility.