Phase II trial of granulocyte-macrophage colony-stimulating factor plus thalidomide in older patients with castration-resistant prostate cancer.

The objective of this study was to assess the efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) in combination with thalidomide for prostate-specific antigen (PSA) reduction in older patients (aged ≥70 years, life expectancy of >1 year) with castration-resistant prostate cancer (CRPC). A total of 11 CRPC patients were treated with 300 µg GM-CSF administered subcutaneously on days 1, 3 and 6 of weeks 1 and 2 of each cycle. Thalidomide was gradually increased to reach the study dose of 100 mg/day. The patients were assessed every 4 weeks with therapy continuing to 4 months. All 11 patients exhibited a decrease in PSA levels and 3 patients (27.2%) exhibited a PSA decrease of >50% in cycle 1. In cycle 2, 8 patients exhibited decreasing PSA levels. A total of 3 patients (27.2%) had a PSA rebound, with 1 patient exhibiting a PSA rebound of >50%. In cycle 3, 10 patients exhibited continuously decreasing PSA levels, with 2 patients (18.2%) exhibiting a PSA decrease of >50%; 1 patient (27.2%) had a PSA rebound of <50%. In cycle 4, 9 patients exhibited continuously decreasing PSA levels and 2 patients (18.2%) had a PSA rebound of >50%. All 11 patients in this study exhibited a decrease in PSA levels, with a median decrease of 92.2%. Therapy was well tolerated, with the majority of the patients experiencing only one adverse event. In conclusion, the combination of GM-CSF with thalidomide was found to be clinically effective and well tolerated by elderly CRPC patients. Therefore, GM-CSF plus thalidomide may be considered a viable treatment option for such patients.