Aims
To determine the efficacy of MGMT depletion plus BCNU (carmustine) therapy and the impact of methylation status in adults with glioblastoma (GBM) and gliosarcoma.
Methods
Methylation analysis was performed on GBM patients with adequate tissue samples. Patients with newly-diagnosed GBM or gliosarcoma were eligible for this Phase III open-label clinical trial. At registration patients were randomized to Arm 1: O6-BG + BCNU (reduced dose) plus radiation therapy (RT) or Arm 2: BCNU plus radiation therapy.
Results
One hundred eighty-three patients with newly diagnosed GBM or gliosarcoma were enrolled from 42 United States institutions; 90 eligible patients received O6-BG + BCNU plus radiation therapy (RT), and 89 received BCNU plus RT. The trial was halted at first interim analysis per stopping guidelines due to futility (less than 40% improvement on O6BG + BCNU arm). Following adjustment for stratification factors, there was no significant difference in overall (OS) or progression-free survival (PFS) between the two groups (one sided p=0.94 and p=0.88 respectively). Median OS was 11 months (95% c.i. 8 – 13 months) for patients on the O6BG+BCNU arm and 10 months (95% c.i. 8 – 12) for the BCNU arm. PFS was 4 months for patients in each arm. Adverse events were reported in both arms, with significantly more grade 4 and 5 events in the experimental arm.
Conclusions
The addition of O6-BG to the standard regimen of radiation and BCNU for treatment of newly-diagnosed glioblastoma and gliosarcoma did not offer added benefit and in fact caused additional toxicity.