On February 15, 2019, the US Food and Drug Administration (FDA) approved the immunotherapy agent pembrolizumab (Keytruda; Merck) for the adjuvant treatment of patients with resected stage III melanoma. This was the fourth approval pembrolizumab has received in the United States for the treatment of skin cancer, and the first FDA approval in the adjuvant setting.
This latest approval was based on results from the randomized, double-blind, placebo-controlled phase 3 EORTC1325/KEYNOTE 054 clinical trial, which included 1019 patients with completely resected, stage IIIA, IIIB, or IIIC melanoma who were randomized to receive pembrolizumab 200 mg every 3 weeks or placebo for up to 1 year or until disease recurrence or unacceptable toxicity. The primary efficacy outcome measure was recurrence free survival (RFS), which was defined as the time between the date of randomization and first recurrence (local, regional, or distant metastasis) or death from any cause, whichever occurred first.
Patients in the pembrolizumab arm experienced fewer recurrences/deaths―26% (n = 135), compared with 43% (n = 216) in the placebo arm. The RFS benefit with pembrolizumab was observed regardless of tumor PD-L1 expression. Median RFS was 20.4 months in the placebo arm and was not reached in the pembrolizumab arm.
Seventy-six percent of patients received pembrolizumab for ≥6 months. Pembrolizumab was discontinued because of adverse reactions in 14% of patients. The most common were diarrhea, pruritus, nausea, arthralgia, hypothyroidism, cough, rash, asthenia, influenza-like illness, weight loss, and hyperthyroidism.
The recommended dose of pembrolizumab in patients with unresectable or metastatic melanoma is 200 mg administered as an intravenous infusion over 30 minutes every 3 weeks until disease progression or unacceptable toxicity, for a maximum of 1 year.
Melanoma is the most dangerous form of skin cancer, and the incidence worldwide is increasing at a rate of approximately 5% per year. An estimated 178,560 cases of melanoma were diagnosed in the United States in 2018. The disease is more likely to invade nearby tissues and spread to other parts of the body (metastasize) than other types of skin cancer. Although it is not the most common skin cancer, it is the deadliest, killing approximately 9320 people in the United States each year.
In other news concerning pembrolizumab this past week, the drug was granted approval for priority review of 2 of its Supplemental Biologics License Applications (sBLAs). One was for the use of pembrolizumab in the treatment of patients with advanced small-cell lung cancer (SCLC) where 2 previous therapies have failed. This application marks the first use of pembrolizumab in the treatment of SCLC.
Priority review was also granted on February 15 to Merck’s sBLA for the use of pembrolizumab in combination with a tyrosine kinase inhibitor, axitinib (Inlyta; Pfizer), as first-line treatment for advanced renal-cell carcinoma (RCC). Approximately 9 of 10 kidney cancers are RCC, making it the most common type by far. In the United States alone, there will be an estimated 74,000 new cases of kidney cancer diagnosed in 2019 and approximately 15,000 people will die from the disease.
A drug manufacturer makes a supplemental license application to the FDA to obtain approval to market a drug for a purpose different from the one for which it is already being used. Previously, pembrolizumab has been approved for use in the treatment of non–small-cell lung cancer, melanoma, head and neck cancer, Hodgkin lymphoma, primary mediastinal large B-cell lymphoma, urothelial carcinoma, microsatellite instability-high cancer, gastric cancer, cervical cancer, hepatocellular carcinoma, and Merkel-cell carcinoma.