Vindesine: phase II evaluation in colon cancer and description of its platelet stimulating activity.

Fifteen previously treated patients with measurable metastatic colon carcinoma were entered into a phase II study of vindesine, 3 mg/m2/week IV. Fourteen patients were evaluable for response. No objective tumor response was observed; however, seven patients experienced stable disease lasting 9, 10, 13, 15, 16, 19, and 26 weeks. Neurologic toxicity was the most common nonhematologic side-effect noted, manifesting as abdominal pain, constipation, paralytic ileus, or paresthesias. Leukopenia was observed in 16% of the 104 weekly courses. Nine patients had a 50% increase of their platelet counts above their pretreatment platelet counts; six patients had a doubling of their pretreatment platelet counts. Mean platelet counts revealed a linear increase with successive treatments during the initial 8 weeks of therapy. Serial CEA determinations demonstrated a parallel relationship with clinical progression in six of seven patients.