Noninferiority of cetuximab every-2-weeks versus standard once-weekly administration schedule for the first-line treatment of RAS wild-type metastatic colorectal cancer.

Aim: This study assessed whether cetuximab 500 mg/m administered every 2 weeks (Q2W), when combined with chemotherapy as a first-line (1L) treatment, was noninferior to the approved dose (400 mg/m followed by 250 mg/m once weekly [Q1W]) for overall survival (OS) in adults with RAS wild-type metastatic colorectal cancer (mCRC).

Methods: This pooled analysis included patients receiving 1L treatment with cetuximab Q1W or Q2W in combination with chemotherapy from post-authorisation studies with patient-level data available to the sponsor. Baseline characteristics were adjusted with a propensity score using inverse probability of treatment weighting (IPTW). Noninferiority in terms of OS was tested with a noninferiority margin for the hazard ratio (HR) of 1.25 using a Cox proportional hazards regression model. Secondary outcomes were progression-free survival (PFS), overall response rate (ORR) and rates of lung/liver metastases resection and serious adverse events.

Results: OS time was noninferior in the Q2W cohort (n = 554) compared to the Q1W cohort (n = 763), with a HR after IPTW (95% confidence interval) of 0.827 (0.715-0.956) and median OS times of 24.7 (Q1W) and 27.9 (Q2W) months. There were no major differences in PFS (HR: 0.915 [0.804-1.042]). The odds ratios (ORs) after IPTW for ORR (1.292 [1.031-1.617]) and the rates of lung/liver metastases resection (1.419 [1.043-1.932]) favoured the Q2W regimen. No differences were noted in the occurrence rate of any SAE between groups; the OR after IPTW was 1.089 (0.858-1.382).

Conclusions: The cetuximab Q2W regimen was noninferior to the Q1W regimen for OS in the 1L treatment of mCRC.