Background: Responses to monotherapy corticosteroid or thalidomide have been described in prostate cancer, in chemotherapy naïve subjects.
Methods: A total of 39 men with hormone refractory, metastatic prostate cancer who had progression during or after at least 1 conventional cytotoxic drug were treated on a single-arm Phase II trial with dexamethasone, 0.75 mg twice a day plus thalidomide, 100-400 mg/day.
Results: Best-observed responses included >50% prostate-specific antigen (PSA) reduction with no radiologic progression: 10 of 39 (26%; 95% confidence interval 13% to 42%). An additional 14 of 39 had decreased PSA but then with radiologic or other progression by 12 weeks. Median progression-free survival was 84 days. Toxicity appeared treatable; there were 5 nonfatal thromboses. There was 1 subject who had complete PSA and radiologic response; 4 responders tolerated treatment without progression for more than 1 year.
Conclusions: PSA responses were frequent. Mostly, these were not durable, but some lasted more than a year. Further investigation on determinants of response durability for these or related compounds should be considered. The response rate of the present data does not support Phase III testing of this regimen for this population.