Dose-dense regimen of temozolomide given every other week in patients with primary central nervous system tumors

Background: Temozolomide has shown activity and limited toxicity in patients with primary brain tumors at doses of 150-200 mg/m(2) /day on days 1-5 every 4 weeks. In this study, a new alternative dose-dense regimen of temozolomide was explored in patients with recurrent brain tumors. Patients and methods: In this study, we evaluated the safety, dose-limiting toxicity, maximum tolerated dose, recommended dose and activity of temozolomide given on days 1-3 and 14-16 every 28 days (one cycle). The starting daily dose was 200 mg/m(2) in a group of at least six patients, with subsequent increments of 50 mg/m(2) in groups of at least 12 patients until unacceptable toxicity was reached. Oral ondansetron (8 mg) was given I h prior to temozolomide administration. McDonald's criteria were used to evaluate antitumor activity. Results: Seventy patients with brain tumors entered this study. The median number of prior chemotherapy treatments was two (range 1-3). Patients were assigned to one of four groups to receive temozolomide at daily doses of 200 (seven patients), 250 (13 patients), 300 (38 patients) and 350 mg/m(2) /day (12 patients). The absence of dose-limiting toxicity at cycle I led us to establish dose recommendations based on toxicity after repeated cycles. A total of 23, 72, 192 and 83 cycles were given at daily doses of 200, 250, 300 and 350 mg/m(2), respectively. Grade 3-4 thrombocytopenia was observed in 0/7, 1/13, 5/38 and 4/12 patients treated at doses of 200, 250, 300 and 350 mg/m(2) /day, respectively. Grade 3-4 neutropenia was observed in 1/7, 0/13, 3/38 and 4/12 patients treated with 200, 250, 300 and 350 mg/m(2) /day temozolomide, respectively. At a dose of 350 mg/m(2), sustained grade 2-3 thrombocytopenia did not allow treatment to be resumed at day 14 in >40% of patients, and this dose was considered to be the maximum tolerated dose. Thus, a dose of 300 mg/m(2) /day that was associated with <20% treatment delay due to sustained hematological toxicity was considered as the recommended dose. Objective responses were reported in 13 patients. Conclusions: Temozolomide can be given safely using a dose-dense regimen of 300 mg/m(2) /day for 3 consecutive days every 2 weeks in patients with recurrent brain tumors.