For patients with recurrent or metastatic cutaneous squamous cell carcinoma (cSCC), pembrolizumab (Keytruda®, Merck & Co., Inc.) is now FDA approved.
An immunotherapy originally approved for advanced non-small cell lung cancer, melanoma, high-risk non-muscle invasive bladder cancer, and advanced cervical cancer, among others, pembrolizumab targets the programmed death (PD-1) pathway to prevent cancer cells from hiding. This allows the body's T cells to attack and kill cancer cells.
Approval was based on a multicenter, multicohort, non-randomized, open-label trial, KEYNOTE-629 (NCT03284424). Patients treated with anti-PD-1, anti-PD-L1, or anti-CTLA-4 antibody previously and/or who had an autoimmune disease or medical condition that required immunosuppression were ineligible for the study. Patients were administered 200 mg of intravenous pembrolizumab every 3 weeks for 24 months, discontinuing treatment if disease progression or unacceptable toxicity occurred.
Every 6 weeks tumor status was assessed during the first year, then every 9 weeks during the second year. The results revealed that the objective response rate (ORR), as assessed by blinded independent central review according to RECIST 1.1, was 34%; the median response duration was not reached.
The most common treatment-related adverse events in patients with cSCC taking pembrolizumab included fatigue, musculoskeletal pain, decreased appetite, pruritus, diarrhea, nausea, rash, pyrexia, cough, dyspnea, constipation, pain, and abdominal pain. In addition, pembrolizumab can cause immune-mediated side effects such as pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, and skin reactions.
The recommended dose of pembrolizumab for patients with cSCC is 200 mg every 3 weeks or 400 mg every 6 weeks.
For More Information
Clincialtrials.gov (2020). Study of pembrolizumab (MK-3475) in adults with recurrent/metastatic cutaneous squamous cell carcinoma (cSCC) or locally advanced unresectable cSCC (MK-3475-629/KEYNOTE-629). NLM Identifier: NCT03284424.
Grob JJ, Gonzalez R, Basset-Seguin N, et al (2019). KEYNOTE-629: phase 2 study of pembrolizumab for recurrent/metastatic or locally advanced unresectable cutaneous squamous cell carcinoma (cSCC). J Clin Oncol, 37(suppl_15). Abstract TPS9598. DOI:10.1200/JCO.2019.37.15_suppl.TPS9598
Keytruda® (pembrolizumab) prescribing information. Merck. Available at: https://www.keytruda.com/