Enzalutamide (Xtandi) monotherapy induced striking declines in prostate-specific antigen (PSA) in a majority of patients with hormone-naive prostate cancer in a phase II trial, and this oral agent appears to have little effect on bone mineral density. If these findings are confirmed in a phase III trial, then enzalutamide may be an alternative to androgen deprivation therapy in recurrent and metastatic prostate cancer with fewer side effects.

Effective Monotherapy
In a phase II trial of men who have not yet had hormone therapy (ADT), Enzalutamide (Xtandi) achieved marked PSA responses and PSA declines without some of the negative side effects associated with ADT. According to Matthew R. Smith, MD, PhD, of Massachusetts General Hospital in Boston the results of this trial compare favorably with the data for androgen deprivation therapy. In contrast with androgen deprivation therapy, men treated with Xtandi had stable bone mineral density and only modest changes in serum triglycerides, both of these being significant issues in ADT.

According to Smith, “ The beneficial effects seen in this phase II trial are consistent with those seen with potent