Supplementary Material for: Necitumumab plus Gemcitabine and Cisplatin as First-Line Therapy in Patients with Stage IV EGFR- Expressing Squamous Non-Small-Cell Lung Cancer: German Subgroup Data from an Open-Label, Randomized Controlled Phase 3 Study (SQUIRE)

Background: In the SQUIRE study, adding the antiepidermal growth factor receptor (EGFR) IgG1 antibody necitumumab to first-line gemcitabine and cisplatin (GC + N) in advanced squamous non-small-cell lung cancer (sqNSCLC) significantly improved overall survival (OS); the safety profile was acceptable. We explored data for the German subpopulation (N = 96) of SQUIRE patients with EGFR-expressing tumors. Patient and Methods: Patients with stage IV sqNSCLC were randomized 1:1 to up to 6 cycles of open-label GC + N or GC alone. GC + N patients with no progression continued on necitumumab monotherapy until disease progression or intolerable toxicity. The primary endpoint was OS; the secondary endpoints included progression-free survival (PFS), safety and health-related quality of life (EQ-5D, Lung Cancer Symptom Scale (LCSS)). Results: The 96 German SQUIRE patients with EGFR-expressing tumors (GC + N 42, GC 54) received a median of 4 GC cycles; the GC + N patients received 5 cycles of necitumumab. Adding necitumumab was associated with 41% risk reduction of death (hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.37–0.94, p = 0.026) and 44% risk reduction of progression (HR 0.56, 95% CI 0.33–0.95, p = 0.029). Adverse events typically associated with EGFR antibody treatment (including rash, hypomagnesemia) were more common with GC + N. The time to deterioration of the EQ-5D and LCSS scores showed no notable differences between the treatment arms, except for appetite loss (delayed for GC + N). Conclusion: The survival benefit from adding necitumumab to first-line GC was more pronounced in the German SQUIRE subpopulation with EGFR-expressing tumors than in the overall (intentionto-treat) population; toxicity was manageable and consistent with the overall population.