9079 Background: First-line treatment of metastatic EGFR-mutated NSCLC relies on EGFR-TKIs. However, all patients (pts) eventually develop progression. Dual inhibition of EGFR with afatinib (A), an irreversible pan-erbB TKI, and cetuximab (C), an EGFR monoclonal antibody, has shown activity in EGFR-mutated pts with acquired resistance to TKIs, regardless of the T790M status. Methods: We conducted a phase II randomized trial in advanced NSCLC pts harboring an activating EGFR mutation, who had not received prior therapy. Pts were treated with A (40 mg/d) until progression alone or with C 500 mg/m² every 2 weeks during 6 months (mos) (beginning at D15 at 250 mg/m²). Primary endpoint was time-to-treatment failure (TTF) at 9 mos for pts with del19 and L858R mutations. Secondary endpoints include safety, progression-free survival (PFS), overall survival (OS). Prospective monitoring of the T790M mutation was performed on circulating tumoral DNA (ctDNA) by digital PCR. Results: Trial was stopped early due to futility analysis after 118 pts were enrolled (59 in each arm). Baseline characteristics were balanced between the 2 arms, and especially for the types of EGFR mutation (del19, 55.9 vs 50.8%; L858R, 39 vs 40.7%; others, 5.1 vs 8.5% in AC and A arms, respectively). Treatment-related AEs of any grades were similar, although there was an excess of grade 3 AEs in the AC arm (50 vs 37.3%), but no of grade 5. The excess in grade 3-5 AEs was essentially due to cutaneous (96.6 vs 81.4%), eyes (32.8 vs 27.1%), hematological (22.4 vs 15.3%) but not to digestive toxicities (89.7 vs 98.3%). Among the 117 pts included in the efficacy analysis, 9-months TTF was 63.3% (47.5-75.6) in arm A and 65.8% (50.1-77.66) in arm AC. Median TTF was 11.1 mos (8.3-not reached [NR]) and 10.8 mos (9.2-13.7) in arms A and AC, respectively. Median PFS was 11.1 mos (8.3-NR) and 12.8 mos (9.2-13.7), respectively. Median OS was 20.8 mos (17.5-NR) and NR (17-NR), respectively. Conclusions: Efficacy of AC was similar to that of A alone. These results don’t support further evaluation of this combination in this setting. Results of ctDNA monitoring will be reported during the meeting. Clinical trial information: NCT02716311.
P1.01-90 Update Phase II Results of Early Primary Tumor Stereotactic Body Radiotherapy Combined with First-Line EGFR-TKI in Advanced EGFR Mutated NSCLC