Phase 1/2 Trials of Temozolomide, Motexafin Gadolinium, and 60-Gy Fractionated Radiation for Newly Diagnosed Supratentorial Glioblastoma Multiforme: Final Results of RTOG 0513

Abstract

The purpose of phase 1 was to determine the maximum tolerated dose (MTD) of motexafin gadolinium (MGd) given concurrently with temozolomide (TMZ) and radiation therapy (RT) in patients with newly diagnosed supratentorial glioblastoma multiforme (GBM). Phase 2 determined whether this combination improved overall survival (OS) and progression-free survival (PFS) in GBM recursive partitioning analysis class III to V patients compared to therapies for recently published historical controls. Dose escalation in phase 1 progressed through 3 cohorts until 2 of 6 patients experienced dose-limiting toxicity or a dose of 5mg/kg was reached. Once MTD was established, a 1-sided 1-sample log-rank test at significance level of .1 had 85% power to detect a median survival difference (13.69 vs 18.48months) with 60 deaths over a 12-month accrual period and an additional 18months of follow-up. OS and PFS were estimated using the Kaplan-Meier method. In phase 1, 24 patients were enrolled. The MTD established was 5mg/kg, given intravenously 5days a week for the first 10 RT fractions, then 3 times a weekfor the duration of RT. The 7 patients enrolled in the third dose level and the 94 enrolled in phase 2 received this dose. Of these 101 patients, 87 were eligible and evaluable. Median survival time was 15.6months (95% confidence interval [CI]: 12.9-17.6months), not significantly different from that of the historical control (P=.36). Median PFS was 7.6months (95% CI: 5.7-9.6months). One patient (1%) experienced a grade 5 adverse event possibly related to therapy during the concurrent phase, and none experience toxicity during adjuvant TMZ therapy. Treatment was well tolerated, but median OS did not reach improvement specified by protocol compared to historical control, indicating that the combination of standard RT with TMZ and MGd did not achieve a significant survival advantage.