RESUMO
OBJECTIVES: Cixutumumab (CIX) and cetuximab (CET) monoclonal antibodies block ligand-binding to insulin-like growth factor-1 receptor (IGF-1R) and epidermal growth factor receptor (EGFR) respectively. The objective of this study was to assess the efficacy of CIX alone or combined with CET in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) patients. METHODS: In this open-label phase II trial, 91 R/M HNSCC patients who progressed within 90â¯days of platinum-based chemotherapy, were randomized to CIX 10â¯mg/kg alone or with CET 500â¯mg/m2 every 2â¯weeks. Patients were stratified by prior CET use. The primary endpoint was median progression-free survival (PFS). Exploratory biomarker assessments included relevant markers on archival tumor and serial cytokine/angiogenic-factor profiles in blood. RESULTS: Forty-seven patients were treated with CIX monotherapy and 44 with combination. The median PFS was 1.9 and 2.0â¯months and clinical benefit rate (complete or partial responses and stable disease) was 5.9% and 15.3%, respectively. There was no exacerbation of CET toxicity by concurrent CIX exposure. Higher tumor expression of IGF-1 was associated with improved PFS in the CIXâ¯+â¯CET arm while increased p-EGFR expression correlated with shorter PFS in patients receiving single agent CIX. Higher serum baseline levels of IGF-1 and IGFBP-3 correlated with improved PFS and overall survival (OS) in the CIX arm. Neither regimen resulted in improved PFS or OS compared to historical data with CET alone. CONCLUSION: The results of this study do not support the use of cixutumumab alone or with cetuximab in unselected patients with R/M HNSCC.