Pembrolizumab (Keytruda®, Merck) is now approved by the FDA for head and neck squamous cell carcinoma as first-line treatment in combination with platinum and 5-fluorouracil.
Pembrolizumab is already FDA approved to treat advanced non-small cell lung cancer, advanced urothelial bladder cancer, classical Hodgkin lymphoma, primary mediastinal B-cell lymphoma, and many other cancers. This immunotherapy drug inhibits programmed cell death protein 1 (PD-1) in order to increase the body's ability to attack malignancies by promoting the tumor-killing effects of T cells.
The approval was based on the KEYNOTE-048 phase 3 study (NCT02358031), which enrolled 882 treatment-naive patients with locally incurable recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) whose tumor samples tested positive for programmed death-ligand 1 (PD-L1). Participants were randomized in a 1:1:1 ratio to receive either pembrolizumab monotherapy; pembrolizumab, carboplatin or cisplatin, and 5-fluorouracil; or cetuximab, carboplatin or cisplatin, and 5-fluorouracil.
The overall survival was significantly improved in patients who received pembrolizumab plus chemotherapy compared with those who received cetuximab plus chemotherapy (13.0 vs 10.7 months), even though there were no significant differences in progression-free survival between these two regimens. Pembrolizumab monotherapy did not significantly improve overall survival compared with either of the chemotherapy-containing regimens.
Side effects of pembrolizumab monotherapy reported in at least 20% of patients include fatigue, constipation, and rash. The adverse events occurring in at least 20% of patients taking pembrolizumab plus chemotherapy included nausea, fatigue, constipation, vomiting, mucosal inflammation, diarrhea, decreased appetite, stomatitis, and cough.
The study authors conclude, "These results support pembrolizumab [plus] platinum [plus] [5-fluorouracil] as new [first-line] standards of care for R/M HNSCC."
For patients with HNSCC, the recommended dose of pembrolizumab is 200 mg administered intravenously over 30 minutes every 3 weeks until disease progression or unacceptable toxicity, or up to 24 months in patients without disease progression.
For More Information
Clinicaltrials.gov (2019). A study of pembrolizumab (MK-3475) for first-line treatment of recurrent or metastatic squamous cell cancer of the head and neck (MK-3475-048/KEYNOTE-048). NLM Identifier: NCT02358031.
Keytruda® (pembrolizumab) prescribing information (2019). Merck. Available at: https://www.keytruda.com
Rischin D, Harrington KJ, Greil R, et al (2019). Protocol-specified final analysis of the phase 3 KEYNOTE-048 trial of pembrolizumab (pembro) as first-line therapy for recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). J Clin Oncol (ASCO Annual Meeting Abstracts), 37(suppl_15). Abstract 6000.
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