The Food and Drug Administration has granted accelerated approval to pembrolizumab for the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy.
Approval was based on an objective response rate of 16% for 174 patients with recurrent or metastatic HNSCC who had disease progression on or after platinum-containing chemotherapy. These patients, a subgroup of patients in an international, multicenter, nonrandomized, open-label, multicohort study, received intravenous pembrolizumab (Keytruda) 10 mg/kg every 2 weeks or 200 mg every 3 weeks, the FDA said in a written statement .
The median response duration for patients receiving pembrolizumab, a checkpoint inhibitor targeting the PD-1/PD-L1 pathway, had not been reached at the time of analysis. The range for duration of response was 2.4 months to 27.7 months (response ongoing). Among the 28 responding patients, 23 (82%) had responses of 6 months or longer, the FDA said.
The most common adverse reactions observed in 192 patients with HNSCC who received at least one dose of pembrolizumab were fatigue, decreased appetite, and dyspnea. Adverse reactions occurring in patients with HNSCC were similar to those occurring in patients with melanoma or NSCLC, with the exception of an increased incidence of facial edema (10% all grades, 2.1% grades 3-4) and new or worsening hypothyroidism (14.6% all grades). The most frequent serious adverse reactions were 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, the FDA noted.
Merck Sharp & Dohme Corp., maker of pembrolizumab, is required to conduct a multicenter, randomized trial establishing the superiority of pembrolizumab over standard therapy as a condition for accelerated approval and is doing so with the ongoing KEYNOTE 040 study, with a primary endpoint of overall survival.
The FDA-recommended dose and schedule of pembrolizumab for patients with HNSCC and disease progression on or after platinum-containing chemotherapy is 200 mg administered as an intravenous infusion over 30 minutes every 3 weeks.
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