Oral vinzolidine as therapy for Kaposi's sarcoma and carcinomas of lung, breast, and colon/rectum.

Vinzolidine, a semisynthetic vinca alkaloid, was studied as oral therapy in 30 patients with Kaposi's sarcoma, non-small cell lung cancer, colorectal cancer, and breast cancer. Substantial variations in morbidity were observed among the patients, some patients receiving doses up to 45 mg/m2 without toxicity while others had severe hematologic toxicity at doses as low as 25 mg/m2. Nausea/vomiting and diarrhea also occurred. Responses were seen in two of 11 patients with Kaposi's sarcoma but not in other patients. Unpredictable severe hematologic toxicity led to early closure of this study. The heterogeneity of patient tolerance may relate to variable oral drug bioavailability, and it is conceivable that vinzolidine could be administered more safely by the IV route.