Phase II studies of mitozolomide in melanoma, lung and ovarian cancer.

Seventy-seven patients were treated with oral mitozolomide to assess the activity of this drug in melanoma, lung and ovarian cancer. Partial responses were seen in five of 18 evaluable patients with small cell lung cancer (SCLC) and three of 20 with melanoma. No activity was apparent in non small cell lung or epithelial ovarian cancer. The major toxicity was myelosuppression which necessitated reduction in the initial dosage from 115 to 90 mg/m2. However, even at this dose level, unpredictable WHO grade 4 toxicity occurred in non-pretreated patients. Thrombocytopenia was more common than leucopenia and eight patients required platelet transfusion for spontaneous or tumour-related haemorrhage. Myelotoxicity was considered responsible for two deaths and was a significant contributory factor in a further three. Non-haematological toxicity was minor. Thus, despite demonstrable activity in SCLC and melanoma, unpredictable myelosuppression is likely to preclude further assessment in combination chemotherapy regimes in these tumours.