Afatinib versus erlotinib as second-line treatment of patients with advanced squamous cell carcinoma of the lung: Final analysis of the randomised phase 3 LUX-Lung 8 trial.

Background: LUX-Lung 8 was a randomised, controlled, phase 3 study comparing afatinib and erlotinib as second-line treatment of patients with advanced squamous cell carcinoma (SCC) of the lung. We report the final overall survival (OS) and safety analyses of LUX-Lung 8 and investigate the characteristics of patients who achieved long-term benefit (≥12 months' treatment).

Methods: LUX-Lung 8 (NCT01523587) enroled patients between March 2012 and January 2014 in 183 cancer centres located in 23 countries worldwide and this final analysis had a data cut-off of March 2018. Eligible patients had stage IIIB or IV lung SCC and had progressed after at least four cycles of platinum-based chemotherapy. Patients were randomly assigned (1:1) to receive afatinib (40 mg per day) or erlotinib (150 mg per day) until disease progression. Endpoints included OS and safety; a post-hoc analysis of patients with long-term benefit (≥12 months on treatment) was also conducted.

Findings: 795 eligible patients were randomly assigned (398 to afatinib, 397 to erlotinib). OS was significantly prolonged with afatinib compared with erlotinib (median 7·8 months vs 6·8 months; hazard ratio 0·84; 95% CI 0·73-0·97;  = 0·0193). These findings were consistent with those of the primary analysis and were consistent across subgroups. Adverse events (AEs) were manageable with dose interruption and reduction, with similar AEs being experienced between both groups. Twenty-one (5·3%) patients receiving afatinib and 13 (3·3%) patients receiving erlotinib achieved long-term benefit; median OS was 34·6 months and 20·1 months, respectively. Amongst 132 afatinib-treated patients who underwent tumour genetic analysis, family mutations were more common in patients with long-term benefit than in the overall population (50% vs 21%).

Interpretation: Afatinib is a treatment option for patients with SCC of the lung progressing on chemotherapy who are ineligible for immunotherapy, particularly those with family genetic aberrations. Afatinib has a predictable and manageable tolerability profile, and long-term treatment may be well tolerated.