A randomized phase II study comparing the efficacy and safety of the glyco-optimized anti-EGFR antibody tomuzotuximab against cetuximab in patients with recurrent and/or metastatic squamous cell cancer of the head and neck – the RESGEX study

The aim of the RESGEX study was to compare the efficacy and safety of the anti-epidermal growth factor receptor (anti-EGFR) antibody tomuzotuximab against cetuximab both in combination with chemotherapy in patients with recurrent and/or metastatic squamous cell cancer of the head and neck in the first-line treatment. In this phase II trial 240 patients were equally randomized for six cycles to receive either tomuzotuximab (initial dose 990 mg then 720 mg) weekly and cisplatin 100 mg/m2 and fluorouracil (5-FU; 1000 mg/m2/day, days 1-4) every 3 weeks or cetuximab (400 mg/m2 subsequent 250 mg/m2) weekly with the same chemotherapeutic backbone followed by antibody maintenance treatment. The primary endpoint was progression-free survival. Median progression-free survival was 6.5 months [95% confidence interval (CI) 5.9-7.9 months] in the tomuzotuximab group and 6.2 months (95% CI 5.8-7.3 months) in the cetuximab group (P = 0.86). The median overall survival (OS) estimate was 11.6 months (95% CI 9.5-17.2 months) in the tomuzotuximab group and 13.8 months (95% CI 12.3-16.4 months) in the cetuximab group (P = 0.96). In an exploratory analysis a small subgroup of p16-positive patients had a significantly longer OS compared with p16-negative patients (hazard ratio 1.860, 95% CI 1.09-3.16, P = 0.02). The glyco-engineered antibody tomuzotuximab failed to demonstrate improved efficacy with a chemotherapeutic backbone in the first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma. It remains a so far unanswered question whether such antibody would partner better with different drugs such as checkpoint inhibitors. •Tomuzotuximab has a potential higher antibody-dependent cell cytotoxicity than other EGFR-directed antibodies.•Comparison of two anti-EGFR antibodies combined with chemotherapy in patients with squamous cell cancer of head and neck.•Efficacy, safety, and tolerability of tomuzotuximab and cetuximab in combination with chemotherapy were similar.