Efficacy and safety of SCT200 in patients with recurrent or metastatic head and neck squamous cell carcinoma after platinum failure: A phase 2 study

There are limited treatment options for patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) progressing after platinum-based therapy. Epidermal growth factor receptor (EGFR)-targeting monoclonal antibodies (mAbs) have demonstrated efficacy in R/M HNSCC. This phase 2 study evaluated the efficacy and safety of SCT200, a novel fully human EGFR mAb, in Chinese patients with R/M HNSCC progressing after platinum-based therapy. This was a single-arm, multi-center phase 2 study, which enrolled patients with R/M HNSCC who had progressed after ≥ 2 cycles of platinum-based therapy. All patients received SCT200 at 6.0 mg/kg weekly for the first 6 weeks, followed by 8.0 mg/kg every 2 weeks until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR). Between November 14, 2018, and April 2, 2020, 36 patients were enrolled. The ORR was 13.9% (5/36, 95% confidence interval [CI]: 4.7–29.5), the complete response rate was 2.8% (1/36), while the partial response rate was 11.1% (4/36). The disease control rate was 69.4% (25/36, 95% CI: 51.9–83.6). The median time to response was 1.38 months (95% CI: 0.99–2.60). The median duration of response was 5.95 months (95% CI: 2.60–8.71). The median progression-free survival and overall survival were 3.98 months (95% CI: 2.76–5.32) and 8.77 months (95% CI: 6.64–not reached), respectively. Grade ≥ 3 treatment-related adverse events occurred in 44.4% (16/36) of patients, with the most common being hypomagnesemia (7/36, 19.4%, 95% CI: 8.2–36.0), hypokalemia (3/36, 8.3%, 95% CI: 1.8–22.5), rash (2/36, 5.6%, 95% CI: 0.7–18.7), and anemia (2/36, 5.6%, 95% CI: 0.7–18.7). This study demonstrated promising efficacy and a manageable safety profile of SCT200 in patients with R/M HNSCC progressing after platinum-based chemotherapy. Clinical Trials.gov, NCT03713372 ; https://www.clinicaltrials.gov . • SCT200 is a novel,fully humanized anti-epidermal growth factor receptor monoclonal antibody. • The objective response rate, disease control rate, median progression-free survival, and median overall survival of SCT200 was 13.9% (5/36, 95% CI: 4.67–29.50), 69.4% (25/36, 95% CI: 51.89–83.65), 3.98 months (95% CI: 2.76–5.32), and 8.77 months (95% CI: 6.64–not reached), respectively, for patients with recurrent or metastatic head and neck squamous cell carcinoma progressing after platinum-based therapy. • SCT200 had a manageable safety profile, with primarily skin and electrolyte adverse events.