ACTR-13. FINAL RESULTS WITH CHEMORADIOTHERAPY FOR ANAPLASTIC OLIGODENDROGLIAL TUMORS FROM NRG ONCOLOGY/RTOG 9402

Abstract

BACKGROUND: Adding intensive‐procarbazine, lomustine, and vincristine (iPCV) to radiotherapy (RT) prolonged progression‐free (PFS) and overall survival (OS) for patients with 1p19q codeleted anaplastic oligodendroglial tumors (AOTs); some benefit was also observed for IDHmutant non‐codeleted cases (Cairncross et al 2013, 2014, 2016). Now, 25 years after study activation, we updated survival, further assessed IDH as a predictive biomarker, and are exploring the benefit from vincristine. METHODS: Eligible adults (KPS ≥ 60, adequate end‐organ function) were randomized to pre‐RT iPCV (4 cycles x 6 weeks each) vs. RT alone, stratified by age ( < 0.001) and OS (median 13.2 vs. 7.3 years, HR 0.61, 95% CI 0.40‐0.94; p=0.02). With IDH mutation but without codeletion (n=66), iPCV prolonged PFS (median 2.8 vs. 1.9 years, HR 0.58, 95% CI 0.34‐0.99, p=0.046); OS was longer with a trend for significance (median 5.5 vs. 3.3 years, HR 0.6, 95% CI 0.34‐1.03, p=0.06) on this underpowered exploratory post‐hoc analysis. CONCLUSION: For codeleted AOTs, long‐term analyses confirmed that pre‐RT iPCV produced meaningful and significant prolongations of PFS and OS. With IDH mutation but without codeletion, iPCV significantly prolonged PFS and showed a trend for prolonged OS. The value of vincristine is being assessed.