311P Consolidative lazertinib following chemoradiotherapy in unresectable stage III EGFR-mutated NSCLC: Preliminary results from the phase II PLATINUM trial

PFS>median (N24) n (%) PFS<median (N30) n (%) p value Age 0.04 Median (IQR) 67 (62-70) 61 (57-67) Sex 0.4 Female 17 (71%) 18 (60%) Male 7 (29%) 12 (40%) N stage* 0.5 N1 4 (17%) 6 (20%) N2 15 (62%) 13 (43%) N3 5 (21%) 10 (33%) Unknown 0 1 (4%) Smoking status 0.2 Ever 10 (42%) 17 (57%) Never 14 (58%) 11 (37%) Unknown 0 2 (6%) EGFR mutation 0.6 Ex19del 17 (71%) 20 (67%) L858R 6 (25%) 10 (33%) Unknown 1 (4%) 0 TP53 MUT 0.03 No 11 (46%) 8 (27%) Yes 1 (4%) 10 (33%) Unknown 12 (50%) 12 (40%) ECOG PS 0.6 0-1 22 (92%) 27 (90%) >1 1 (4%) 3 (10%) Unknown 1 (4%) 0 Radiotherapy type 0.6 Concomitant 21 (88%) 28 (93%) Sequential 3 (13%) 2 (7%)*pts were staged according to the VII or VIII TNM edition; the N status is reported to ensure consistency. Conclusions:This study shows short PFS after CRT in stage III EGFR-mutant NSCLC.Osi remains effective when given at progression, but earlier systemic therapy may reduce rapid progression and brain relapse.TP53 MUT confirms its negative prognostic value.