I.v. melphalan in carcinoma of the lung: effect of cyclophosphamide priming on hematopoietic toxicity.

Thirty-six patients with lung cancer, 24 with prior chemotherapy and 12 without prior chemotherapy, received iv melphalan at doses ranging from 20 to 40 mg/m2 of body surface area. Patients who showed moderate myelosuppression and remained in the study were also investigated to determine if cyclophosphamide (300 mg/m2) administered 1 week before the identical dose of i.v. melphalan modified the hematopoietic toxicity of melphalan (cyclophosphamide priming). In this study, the activity of melphalan was minimal, four minor responses with no partial or complete responses. Three of these minor responses were in previously untreated patients. The major toxicity was hematopoietic and the maximum tolerated i.v. dose was 20 mg/m2 in the patients previously treated with chemotherapy and 30 mg/m2 in those without prior chemotherapy. Cyclophosphamide priming did not reduce the myeloid toxicity. Myelosuppression was more severe in the course that included cyclophosphamide. Recovery, however, appeared to be similar in both courses. I.v. melphalan at these doses has minimal activity in lung cancer. Cyclophosphamide administered 1 week before i.v. melphalan does not decrease the myelosuppression but should be investigated further for its effect on the rate of wbc and neutrophil count recovery.