Safety and efficacy of first-line dacomitinib in Asian patients with EGFR mutation-positive non-small cell lung cancer: Results from a randomized, open-label, phase 3 trial (ARCHER 1050)

Objectives: To compare efficacy and safety of dacomitinib versus gefitinib as first-line therapy for EGFR mutation-positive advanced NSCLC in Asian patients enrolled in the ongoing ARCHER 1050 trial.

Materials and methods: In this ongoing, randomized, open-label, phase 3 trial (NCT01774721), eligible patients with newly diagnosed advanced EGFR mutation-positive NSCLC were randomized (1:1) to receive oral dacomitinib 45 mg/day or oral gefitinib 250 mg/day. Randomization, by a central computer system, was stratified by race and EGFR mutation type (exon 19 deletion mutation/exon 21 L858R substitution mutation). The primary endpoint was PFS by blinded independent review.

Results: Of 346 Asian patients, 170 were randomized to dacomitinib and 176 to gefitinib. The hazard ratio (HR) for PFS with dacomitinib versus gefitinib was 0.509 (95 % confidence interval [CI]: 0.391-0.662; 1-sided p < 0.0001; median 16.5 months [95 % CI: 12.9-18.4] vs. 9.3 months [95 % CI: 9.2-11.0]). HR for OS with dacomitinib versus gefitinib was 0.759 (95 % CI: 0.578-0.996; median 37.7 months [95 % CI: 30.2-44.7] vs. 29.1 months [95 % CI: 25.6-36.0]). The OS benefit was still maintained in those patients who had a stepwise dose reduction of dacomitinib (to 30 and 15 mg/day). The most common adverse events (AEs) were diarrhea (154 [90.6 %] patients), paronychia (110 [64.7 %]), dermatitis acneiform (96 [56.5 %]), and stomatitis (87 [51.2 %]) with dacomitinib, and diarrhea (100 [56.8 %]), alanine aminotransferase increased (81 [46.0 %]), and aspartate aminotransferase increased (75 [42.6 %]) with gefitinib. Treatment-related serious AEs were reported in 16 (9.4 %) and 8 (4.5 %) patients treated with dacomitinib and gefitinib, respectively.

Conclusion: First-line dacomitinib was associated with significant prolongation of PFS and improved OS compared with gefitinib in Asian patients with EGFR mutation-positive advanced NSCLC. The AE profiles of dacomitinib and gefitinib in Asian patients were consistent with the overall ARCHER 1050 population.