Preirradiation chemotherapy with methotrexate, rituximab, and temozolomide and post-irradiation temozolomide for primary central nervous system lymphoma: RTOG 0227 phase II study results.

Abstract

2033 Background: This prospective phase II study tested a methotrexate (MTX), temozolomide (TMZ) and rituximab (RTX) pre-irradiation regimen with hyperfractionated whole brain radiation therapy (hWBRT) followed by post-irradiation TMZ for patients with primary CNS lymphoma (PCNSL). The primary phase II endpoint was the 2-year overall survival (OS) rate compared with the 2-year OS from RTOG 93-10 (MTX, procarbazine, vincristine, whole brain radiation therapy, cytarabine). Secondary endpoints were pre-irradiation chemotherapy tumor response rates (compared to RTOG 93-10), progression free survival (PFS), acute and late neurologic toxicities, and quality of life. Methods: 53 patients (28 women, 25 men), median age 57.5 years, median Zubrod 1 were treated with RTX 375 mg/m2 3 days prior to first cycle of MTX; 5 cycles of intravenous MTX 3.5 g/m2 with leucovorin rescue on weeks 1, 3, 5, 7, 9; TMZ 100 mg/m2 daily for 5 days weeks 4 and 8; hWBRT 1.2 Gy twice daily fractions 5 days/week on weeks 11, 12, 13 for a total of 36 Gy and TMZ 200 mg/m2 daily for 5 days on weeks 14, 18, 22, 26, 30, 34, 38, 42, 46, 50. Results: Dosing of pre-irradiation temozolomide at 100 mg/m2 was determined in the phase I portion of the study. With a median follow-up of 3.6 years, 2-year OS and PFS rates were 80.8% and 63.6%, respectively. Compared with historical controls from RTOG 93-10, 2-year OS and PFS were significantly improved (p = 0.006 and 0.03). The overall response rate to the pre-irradiation chemotherapy was 37.7% (complete response 11.3%, partial response 26.4%). 38% experienced grade 3 and 25% experienced grade 4 toxicities before the start of hWBRT. 33% experienced grade 3 and 21% experienced grade 4 toxicities attributable to post-hWBRT chemotherapy. Conclusions: The combination of MTX, TMZ, RTX followed by hWBRT and TMZ for PCNSL is safe with demonstrated improved 2 year OS and PFS compared with RTOG 93-10. Further investigations regarding the role of hWBRT and post-hWBRT TMZ are indicated. This project was supported by RTOG grant U10 CA21661 and CCOP grant U10 CA37422 from the National Cancer Institute (NCI) and Schering-Plough. Clinical trial information: NCT00068250.