CTNI-74. PHASE 3 TRIDENT TRIAL: CONCOMITANT RADIATION THERAPY (RT) AND TEMOZOLOMIDE +/- TUMOR TREATING FIELDS (TTFIELDS) IN NEWLY DIAGNOSED GLIOBLASTOMA

Abstract

Abstract BACKGROUND Tumor treating fields (TTFields) is a non-invasive, regional antimitotic treatment approved as a standard-of-care for newly diagnosed glioblastoma (ndGBM). In the EF-14 Phase 3 trial, TTFields (200 kHz) plus temozolomide (TMZ) significantly increased survival of ndGBM patients without increasing systemic toxicity. TTFields-related AEs were mainly skin AEs. In preclinical models, TTFields increase the therapeutic effects of radiation therapy (RT). A pilot study showed that TTFields concomitant with RT and TMZ is well tolerated. The benefit of concomitant TTFields with RT and TMZ will be tested in the TRIDENT trial. METHODS TRIDENT is an international phase III randomized trial comparing standard RT with TMZ vs the triple combination of RT/TMZ with concomitant TTFields. RT is delivered through the TTFields arrays. Patients in both arms will receive maintenance TTFields/TMZ. TTFields (200 KHz) will be delivered >18 hours/day using Optune. Patients will continue TTFields treatment until second recurrence. Patients with pathologically confirmed ndGBM, ≥ 18 years, KPS ≥ 70, either sex, post-surgery or biopsy, and amenable for RT/TMZ therapy will be stratified by extent of resection and MGMT promoter methylation status. The primary endpoint is overall survival (OS). Secondary end points: progression free survival (PFS; RANO), 1- and 2-year survival rates, overall radiological response (ORR; RANO), progression-free survival (PFS6M, PF12M, PFS2Y); severity and frequency of AEs (CTCAE V5.0); pathological changes in resected GBM tumors post treatment; quality of life (EORTC QLQ-C30); and correlation of OS to TTFields compliance. The hypothesis is that concomitant TTFields/RT/TMZ will significantly improve OS versus RT/TMZ. Sample size (N=950; 475/arm) will detect a HR< 0.8 with 5% type I error. Survival will be measured from the time of randomization until date of death. At the time of analysis, patients lost to follow-up or still on protocol follow-up will be censored at the last date known to be alive.