Presentation (CTI)

OBJECTIVES: Both cetuximab and panitumumab are monoclonal antibodies targeting the epidermal growth factor receptor. While cetuximab is approved for recurrent or metastatic squamous-cell carcinoma of the head and neck (SCCHN), panitumumab improved progression-free survival (PFS), but failed to demonstrate a significant benefit in overall survival (OS) in this setting. A lack of direct head-to-head randomized controlled trials presents an evidence gap for clinical guidelines and reimbursement. This study utilized an anchored Matching-Adjusted Indirect Comparison (MAIC) to compare the efficacy of panitumumab plus chemotherapy versus cetuximab plus chemotherapy for SCCHN.
METHODS: Individual patient-level data (IPD) from a phase 3 randomized trial of chemotherapy with or without panitumumab (SPECTRUM) were weighted to match the baseline treatment effect modifiers in the aggregate data of the cetuximab plus chemotherapy trial (EXTREME) population. Pseudo-IPD for OS and PFS were reconstructed from published Kaplan-Meier curves. Comparative efficacy was evaluated using weighted Cox proportional hazard models to calculate Hazard Ratios (HR) for OS and PFS and weighted logistic regression to determine Odds Ratios (OR) for best overall response (BOR). All endpoints were anchored to the common chemotherapy arm.
RESULTS: The MAIC successfully achieved balance in key baseline characteristics (effective sample size [ESS] = 208) between the weighted panitumumab cohort and the cetuximab trial population. Compared with cetuximab, panitumumab demonstrated significantly inferior PFS (HR [95% CI]: 1.55 [1.14-2.10]; p=0.005). There was also a non-statistically significant trend toward worse OS for panitumumab (HR [95% CI]: 1.27 [0.94; 1.72]; p=0.112). No significant difference was observed for BOR (OR [95% CI]: 0.74 [0.40, 1.37]; p=0.337).
CONCLUSIONS: This anchored MAIC, which addresses a critical evidence gap, supports cetuximab as a more efficacious treatment compared to panitumumab for recurrent or metastatic SCCHN, primarily based on the statistically significant improvement in PFS. These findings are important for Health Technology Assessment (HTA) decision-making processes.