It has recently been announced that the US FDA have granted accelerated approval for the use of pembrolizumab in the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC). This approval is for the treatment of individuals with the disease who have progressed on or after platinum-containing chemotherapy.
This accelerated approval is the result of durable objective response rate (ORR) data that were gleaned from a subgroup of patients in an international, multicenter, nonrandomized, open-label, multicohort study.
The subgroup in question was made up of 174 individuals, all with advanced platinum-resistant HNSCC, who received intravenous pembrolizumab 10 mg / kg every 2 weeks or 200 mg every 3 weeks.
When calculated by an independent review committee, within this group of 174 individuals the ORR was determined to be 16%. The median response duration had not been reached at the time of analysis; however, the range for duration of response was 2.4 months to 27.7 months (response ongoing). Among the 28 patients who responded to pembrolizumab, 23 (82%) were determined to have had responses of 6 months or longer.
Safety analyses were carried out in a cohort of 192 HNSCC patients who received at least one dose of pembrolizumab 10 mg / kg every 2 weeks or 200 mg every 3 weeks. Common adverse events included fatigue, decreased appetite and dyspnea.
The most common serious adverse effects ( 2%) included pneumonia, dyspnea, confusional state, vomiting, pleural effusion and respiratory failure. Clinically significant immune-mediated adverse reactions included pneumonitis, colitis, hepatitis, adrenal insufficiency, diabetes mellitus, skin toxicity, myositis, and thyroid disorders.
Following this accelerated approval, Merck (NJ, USA) are required to initiate a multicenter, randomized trial establishing the superiority of pembrolizumab over standard therapy in order to verify and describe the clinical benefit of pembrolizumab.