P11.33.B Tumour Treating Fields (TTFields; 200 kHz) with chemo-radiation and maintenance TTFields/temozolomide as first-line treatment for newly-diagnosed glioblastoma: The phase 3 TRIDENT Trial (EF-32)

Abstract

Abstract Background Tumour Treating Fields therapy (TTFields; 200 kHz) is a noninvasive, loco-regional, antimitotic treatment approved for newly diagnosed glioblastoma (ndGBM) and mesothelioma. In the phase 3 EF-14 trial, TTFields/temozolomide (TMZ) significantly increased overall survival (OS) and progression-free survival (PFS) vs TMZ alone in patients with ndGBM. TTFields-related adverse events (AEs) were mainly dermatological with no increases in systemic toxicity. In preclinical models, the addition of TTFields to radiotherapy (RT) increased the therapeutic effect. In 2 clinical pilot phase 2 studies, TTFields added to RT/TMZ was reported as feasible and well-tolerated. Material and Methods TRIDENT (EF-32; NCT04471844) is an international, phase 3 randomised trial comparing TTFields (200 KHz, ≥ 18 h/day)/RT/TMZ vs RT/TMZ alone. Eligibility criteria include histologically confirmed ndGBM, ≥ 18 years of age (≥ 22 years of age; US), Karnofsky Performance Status ≥ 70, life expectancy ≥ 3 months, adequate organ function and eligible for RT/TMZ - participants will be stratified by extent-of-resection and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. During the initial 6-week investigational period, patients in the experimental arm will receive continuous TTFields and concomitant RT/TMZ whilst patients in the control arm will receive only RT/TMZ. Subsequently, all patients will receive TTFields and 6 cycles of maintenance TTFields/TMZ. TTFields will continue for 24 months or until second disease progression per Response Assessment in Neuro-Oncology (RANO), whichever occurs first. The primary endpoint is median OS. Secondary endpoints include median PFS (RANO), 1- and 2-year survival rates, overall radiological response (RANO), PFS6, PFS12, severity and frequency of AEs (Common Terminology Criteria for Adverse Events v5.0), post-treatment pathological changes in resected GBM tumours, quality-of-life per EORTC QLQ-C30, OS correlation to TTFields duration-of-usage, and neurological assessment per NANO (Neurological Assessment in Neuro-Oncology) and RANO criteria. Survival will be measured from time-of-randomisation. Sample size (N = 950; randomised 1:1) was powered for a hazard ratio < 0.8 with a 5% type I error. The hypothesis, that first-line TTFields/RT/TMZ can significantly improve OS vs RT/TMZ, will be tested using a stratified log-rank test. The study is currently open to enrollment in locations in Austria, Belgium, Czech Republic, France, Germany, Israel, Switzerland, and across the US.