Due to a recent alarming report suggesting that the severe neurotoxicity observed following treatment with a multiagent chemotherapy regimen might be due to the interaction of vincristine and VP-16-213, the neurologic toxicity data from a randomized trial conducted by the Bowman Gray School of Medicine and the Piedmont Oncology Association in small cell carcinoma of the lung have been analyzed. Of 102 patients evaluable for toxicity, 50 were treated with a combination of cyclophosphamide, adriamycin, and vincristine (CAV) and 52 received this regimen plus VP-16-213. Vincristine dosage was the same in both arms of the study. When analyzed by severity, neurologic complications were similar in both treatment groups: Grade 1-2 neurotoxicity occurred in 55% of patients on both arms and grade 3-4 neurotoxicity was observed in six (12%) patients on the CAV arm and four (8%) on the CAV-VP-16-213 arm. Addition of VP-16-213 to vincristine did not potentiate vincristine-induced neurotoxicity when administered in this dose-schedule relationship.