Efficacy and Safety of Necitumumab Continuation Therapy in the Phase III SQUIRE Study of Patients With Stage IV Squamous Non-Small-Cell Lung Cancer.

INTRODUCTION: In a retrospective analysis of the SQUamous NSCLC treatment with the Inhibitor of EGF REceptor (SQUIRE) study, we investigated the efficacy and safety of single-agent necitumumab continuation therapy in patients with stage IV squamous non-small-cell lung cancer and in a subpopulation of patients with epidermal growth factor receptor (EGFR)-expressing tumors.

PATIENTS AND METHODS: Patients were randomized 1:1 for ≤ 6 cycles of gemcitabine and cisplatin either with or without necitumumab. Patients who received necitumumab continued receiving single-agent necitumumab until progressive disease (necitumumab continuation). Tissue collection was mandatory in SQUIRE. EGFR protein expression was assessed using immunohistochemistry in a central lab. In this subgroup analysis we compared patients treated with necitumumab monotherapy after completion of ≥ 4 cycles of chemotherapy with those in the chemotherapy arm who were progression-free and did not discontinue because of adverse events (AEs) after completion of ≥ 4 cycles of chemotherapy (gemcitabine-cisplatin nonprogressors). The same analysis was done for the subgroup of EGFR-expressing patients (EGFR > 0).

RESULTS: Baseline characteristics and chemotherapy exposure were well balanced between the necitumumab continuation (n = 261) and gemcitabine-cisplatin nonprogressor (n = 215) arms and in the EGFR-expressing population. Median overall survival (OS) from randomization in the necitumumab with gemcitabine-cisplatin versus gemcitabine-cisplatin nonprogressor arm was 15.9 versus 15.0 months (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.69-1.05) and median progression-free survival (PFS) from randomization was 7.4 versus 6.9 months (HR, 0.86; 95% CI, 0.70-1.06). OS and PFS benefits were similar when assessed from the postinduction period and in EGFR-expressing patients. No new safety findings emerged.

CONCLUSION: There was a consistent treatment effect in favor of necitumumab continuation versus that in gemcitabine-cisplatin nonprogressors, with no unexpected increases in AEs in intention-to-treat as well as EGFR-expressing populations.