Multinational phase 3 trial of concurrent and adjuvant temozolomide for 1p/19q non-co-deleted anaplastic glioma: final analysis of CATNON

The phase 3 CATNON trial, at 137 centers across three continents, investigated the benefit of addition of concurrent or adjuvant temozolomide to radiotherapy in patients with anaplastic astrocytoma. Long-term follow-up of the study focusing on patients with IDH mutated tumors has now been published. Participants aged 18 year of older with newly diagnosed 1p/19q non-co-deleted tumors and a WHO performance status of 0-2 were randomly assigned (1:1:1:1) to radiotherapy alone (59.4 Gy in 33 fractions), radiotherapy with concurrent temozolomide, radiotherapy with adjuvant temozolomide, or radiotherapy with both concurrent and adjuvant temozolomide. The primary endpoint was overall survival. After a median follow-up of 10.9 years (IQR 9.5-12.7), adjuvant temozolomide improved overall survival compared with no adjuvant temozolomide (HR 0.65; 95% CI 0.54-0.77) but concurrent temozolomide did not compared with no concurrent temozolomide (0.91; 0.76-1.08). No benefit of temozolomide, neither concurrent nor adjuvant, was observed in patients with IDH wild-type tumors. The authors conclude that radiotherapy followed by adjuvant temozolomide without concurrent temozolomide during radiotherapy improves survival for individuals with aggressive IDH-mutant astrocytoma.