91942-114

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Background: Afatinib (A) is a selective, orally bioavailable, irreversible ErbB family blocker of EGFR (ErbB1), HER2 (ErbB2), and ErbB4. This global study investigated the efficacy and safety of A compared with pemetrexed/cisplatin (PC) in pts with EGFR mutation positive advanced lung adenocarcinoma. Methods: Following central testing for EGFR mutations (companion diagnostic TheraScreen EGFR RGQ PCR kit), 345 pts (stage IIIB/IV, PS 0–1, chemo-naive) were randomized 2:1 (A: 230; PC: 115) to daily A 40 mg or iv PC (500 mg/m² + 75 mg/m² q21 days up to 6 cycles). Primary endpoint was progression-free survival (PFS) by central independent review. Results: Baseline characteristics were balanced in both arms: median age, 61 y; female, 65%; Asian, 72%; never-smoker, 68%; Del19, 49%; L858R, 40%; other mutations, 11%. Treatment with A led to a significantly prolonged PFS vs PC (median 11.1 vs 6.9 mos; HR 0.58 [0.43–0.78]; p=0.0004). In 308 pts with common mutations (Del19/L858R), median PFS was 13.6 vs 6.9 mos, respectively (HR=0.47 [0.34–0.65]; p<0.0001). Objective response rate was significantly higher with A (56% vs 23%; p<0.0001). Significant delay in time to deterioration of cancer-related symptoms of cough (HR=0.60, p=0.0072) and dyspnea (HR=0.68, p=0.0145) was seen with A vs PC. Most common drug-related adverse events (AEs) were diarrhea (95%), rash (62%) and paronychia (57%) with A, and nausea (66%), decreased appetite (53%) and vomiting (42%) with PC. Drug-related AEs led to discontinuation in 8% (A; 1% due to diarrhea) and 12% of pts (PC). Conclusions: LUX-Lung 3 is the largest prospective trial in EGFR mutation positive lung cancer and the first study using pemetrexed/cisplatin as a comparator. Treatment with afatinib significantly prolonged PFS compared to PC, with significant improvements in secondary endpoints. AEs with afatinib were manageable, with a low discontinuation rate. With 4.2 mos PFS improvement in the overall population and 6.7 mos in pts with common mutations, afatinib is a clinically relevant first-line treatment option.