Treatment of hormone-refractory prostate cancer with 90Y-CYT-356 monoclonal antibody

A Phase I dose-escalation study using 90Y-CYT-356 monoclonal antibody was performed in 12 patients with hormone-refractory prostate carcinoma. Biodistribution studies using 111In-CYT-356 were performed 1 week before 90Y-CYT-356 administration. Of the 12 patients, 58% had at least one site of disease imaged after administration of 111In-CYT-356. The dose of 90Y ranged from 1.83-12 mCi/m2. Both 111In and 90Y-CYT-356 were tolerated well, without significant nonhematological toxicity. Myelosuppression was the dose-limiting toxicity and occurred at dose levels of 4.5-12 mCi/m2. Of the patients receiving