CI-980 in advanced melanoma and hormone refractory prostate cancer

Introduction: CI-980 is a novel chemotherapeutic agent that inhibits polymerization of tubulin. Preclinical studies have indicated a high level activity of this agent against various tumor cell lines. Methods: 13 malignant melanoma patients who had failed prior chemotherapy and/or immunotherapy and 13 hormone refractory prostate cancer patients, including 4 who had received prior chemotherapy, were treated in 2 separate NCI-supported clinical trials. Subjects received a recommended phase II dose of CI-980 of 4.5 mg/m²/day by continuous infusion for 72 hours every 3 weeks. Results: No activity was seen in either study. Toxicity was tolerable with neutropenia being the most common, significant toxicity. Among the melanoma patients, 15% and 31% developed grade 3 and grade 4 neutropenia, while 7% and 38% of the prostate patients developed grade 3 and grade 4 neutropenia, respectively. Conclusions: CI-980 at this dose and schedule is ineffective against malignant melanoma and hormone refractory prostate cancer.