Combination Chemoradiotherapy with Temozolomide, Vincristine, and Interferon-β Might Improve Outcomes Regardless of O6-Methyl-Guanine-DNA-Methyltransferase (MGMT) Promoter Methylation Status in Newly Glioblastoma

Abstract

Background: This investigator-initiated, open-label, single-arm, single-institute study was conducted to investigate the effectiveness of induction combination chemoradiotherapy for newly glioblastoma and also the effectiveness of long-term maintenance therapy with temozolomide (TMZ) plus interferon (IFN)-b. Methods: The initial induction combination chemoradiotherapy comprised radiotherapy plus TMZ plus vincristine plus IFN-b. Maintenance chemotherapy comprised monthly TMZ, continued for 24–50 cycles, plus weekly IFN-b continued for as long as possible. The primary endpoint was 2-year overall survival (2y-OS). A 2y-OS exceeding 38%, with upper limit of the 95% confidence interval (CI) exceeding 31.7%, and lower limit of the 95%CI exceeding 21.2% as compared to historical controls, was considered as the criterion for treatment effectiveness. Secondary endpoints were median progression-free survival (mPFS), median OS (mOS), 5-year OS rate (5y-OS), and mPFS and mOS classified according to MGMT promoter methylation status. Results: Forty-seven patients were analyzed. The 2y-OS was 40.7% (95%CI, 27.5–55.4%), suggesting that this protocol was effective. The mPFS and mOS were 11.0 months and 18.0 months, respectively, and 5y-OS was 20.3% (95%CI, 11.0–34.6%). The mPFS in groups with and without MGMT promoter methylation in the tumor was 10.0 months and 11.0 months (p=0.59), respectively, and mOS was 24.0 months and 18.0 months (p=0.88), respectively. The frequency of grade 3/4 neutropenia was 19.1%.Conclusions: These results suggest the efficacy of induction multicombination chemoradiotherapy, as well as of long-term maintenance therapy comprising TMZ plus IFN-b. This protocol would have the possibility to deny the MGMT promoter methylation status as prognostic factors.Trial registration: The University Hospital Medical Information Network (Number UMIN000040599)