A Double-Blind Randomized Crossover Study of Oral Thalidomide Versus Placebo for Androgen Dependent Prostate Cancer Treated With Intermittent Androgen Ablation

Purpose

We determined whether thalidomide can prolong progression-free survival in men with biochemically recurrent prostate cancer treated with limited androgen deprivation therapy.

Materials and Methods

A total of 159 patients were enrolled in a double-blind randomized trial to determine if thalidomide can improve the efficacy of a gonadotropin-releasing hormone agonist in hormone responsive patients with an increasing prostate specific antigen after primary definitive therapy for prostate cancer. Patients were randomized to 6 months of gonadotropin-releasing hormone agonist followed by 200 mg per day oral thalidomide or placebo (oral phase A). At the time of prostate specific antigen progression gonadotropin-releasing hormone agonist was restarted for 6 additional months. Patients were then crossed over to the opposite drug and were treated until prostate specific antigen progression (oral phase B). Testosterone and dihydroxytestosterone were likewise monitored throughout the study.

Results

During oral phase A the median time to prostate specific antigen progression was 15 months for the thalidomide group compared to 9.6 months on placebo (p = 0.21). The median time to prostate specific antigen progression during oral phase B for the thalidomide group was 17.1 vs 6.6 months on placebo (p = 0.0002). No differences in time to serum testosterone normalization between the thalidomide and placebo arms were documented during oral phase A and oral phase B. Thalidomide was tolerable although dose reductions occurred in 47% (58 of 124) of patients.

Conclusions

Despite thalidomide having no effect on testosterone normalization, there was a clear effect on prostate specific antigen progression during oral phase B. This is the first study to our knowledge to demonstrate the effects of thalidomide using intermittent hormonal therapy.

Key Words: prostatic neoplasms, hormones, thalidomide, disease-free survival, angiogenesis inhibitors

Abbreviations and Acronyms: ADT, androgen deprivation therapy, CONSORT, Consolidated Standards of Reporting Trials, CRPC, castration resistant prostate cancer, CTEP, Cancer Therapy Evaluation Program, DHT, dihydroxytestosterone, ECOG, Eastern Cooperative Oncology Group, GnRH-A, gonadotropin-releasing hormone agonist, NCI, National Cancer Institute, OPA, oral phase A, OPB, oral phase B, PFS, progression-free survival, PSA, prostate specific antigen, T, testosterone