A phase II trial of 1-(2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea (PCNU, NSC 95466) in recurrent malignant brain tumors.

Twenty-nine patients with recurrent primary malignant brain tumors were treated with 1-(2-chlorethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea (PCNU) at an initial dose of 110 mg/m2 with subsequent doses determined by the degree of delayed toxicity. The interval between treatments was usually weeks. Eleven of 25 evaluable patients (44%) showed definite improvement and ten (40%) showed disease stability as determined by sequential CT scans and neurologic examination. The estimated median time to tumor progression for all 25 patients treated with PCNU was 28 weeks, 37 weeks for the responding patients but only 20 weeks for patients with stable disease. Toxicity consisted of delayed myelosuppression which was cumulative and occurred mainly with the platelets. Gastrointestinal toxicity occurred in a minority of the patients. PCNU has definite activity in primary malignant brain tumors which appears to be comparable to that reported for BCNU alone, but with less reported gastrointestinal side effects. Further clinical trials in patients with primary malignant brain tumors are indicated.