A phase I study of the somatostatin analogue somatuline in patients with metastatic hormone‐refractory prostate cancer

Background. Somatuline, a somatostatin analogue, as proven to be effective in several animal models of prostate cancer. Preliminary clinical studies also have suggested antitumor activity in patients with prostate cancer. The authors conducted a dose‐escalation trial of 25 patients with metastatic hormone‐refractory prostate cancer. Methods. Dosages of 4, 7, 10, 13, 18, and 24 mg/day were administered by continuous intravenous infusion for at least 28 days. Results. Plasma levels of insulin‐like growth factor‐I (IGF‐I), but not those of IGF‐II, declined modestly during therapy. Toxicities included grade I diarrhea, bloating, infection, nausea, and flatus. The gastrointestinal side effects were typically self‐limiting and occurred during the initial portion of treatment cycles. In addition, three patients experienced grade II catheter‐related infections. No clinical response was noted by either radiographic or tumor marker criteria. The maximally tolerated dose of somatuline was not determined. Conclusion. A continuous intravenous infusion of 24 mg/day of somatuline is well tolerated and could be evaluated in other types of cancer or possibly in less advanced prostate cancer, but no clinical activity was noted at this dose in patients with advanced metastatic hormone‐refractory prostate cancer.