Carboplatin and recurrent childhood brain tumors

Abstract

Carboplatin, a cisplatin analogue, was administered as an intravenous (IV) one-hour infusion in a 4-consecutive weekly dose schedule to 44 patients with recurrent childhood brain tumors. Twenty-four patients were registered on our phase I, and 20 on our phase II studies. The maximum tolerable dose derived from our phase I study was 210 mg/m2/wk in patients with solid tumors, and the recommended dose for subsequent pediatric phase II studies was 175 mg/m2/wk. This dose was administered to 14 patients in the phase I and all 20 patients in the phase II study. Nine of 36 (25%) evaluable patients in the combined studies experienced objective responses for a median duration of 10+ months. Seven of nine responders had received prior cisplatin. Disease-specific response rates were as follows: medulloblastoma, six of 14 (43%) with three complete (CR) and three partial responses (PR); pineoblastoma, one of one (PR); germinoma, one of two (CR); and brainstem glioma, one of eight (13%) (PR). Carboplatin had mild emetic effects but no significant auditory or renal toxicity. Thrombocytopenia (less than 49,000) was encountered in nine of 28 (32%) evaluable trials at a dose of 175 mg/m2/wk. Because of its low potential for auditory, renal, and emetic toxicity, ease of administration, and high disease-specific activity, carboplatin deserves further study in multiagent phase II and III trials, especially in chemotherapy-sensitive diseases such as medulloblastoma.