On June 24, the U.S. Food and Drug Administration (FDA) approved pembrolizumab (Keytruda) for patients with recurrent or metastatic cutaneous squamous cell carcinoma that is not curable with surgery or radiation.
KEYNOTE-629
Efficacy was investigated in KEYNOTE-629, a multicenter, multicohort, nonrandomized, open-label trial. The trial excluded patients who had previously received therapy with an anti–PD-1, anti–PD-L1, or anti–CTLA-4 antibody and those with autoimmune disease or a medical condition that required immunosuppression.
Patients received pembrolizumab at 200 mg intravenously every 3 weeks until disease progression, unacceptable toxicity, or for a maximum of 24 months. Assessment of tumor status was performed every 6 weeks during the first year and every 9 weeks during the second year.
The major efficacy outcome measures were objective response rate and response duration as assessed by blinded independent central review according to Response Evaluation Criteria in Solid Tumors version 1.1, modified to follow a maximum of 10 target lesions and a maximum of 5 target lesions per organ.
The objective response rate was 34% (95% confidence interval = 24%–44%). The median response duration was not reached (range = 2.7–13.1+ months).
Adverse reactions occurring in patients with cutaneous squamous cell carcinoma enrolled in KEYNOTE-629 were similar to those occurring in patients who have received pembrolizumab as a single agent in other clinical trials. The most common adverse reactions to pembrolizumab are fatigue, musculoskeletal pain, decreased appetite, pruritus, diarrhea, nausea, rash, pyrexia, cough, dyspnea, constipation, pain, and abdominal pain. Pembrolizumab is associated with immune-mediated side effects including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, and skin adverse reactions.
The efficacy and safety of pembrolizumab using a dosage of 400 mg every 6 weeks for cutaneous squamous cell carcinoma was primarily based on the modeling of dose/exposure efficacy and safety relationships and observed pharmacokinetic data in patients with melanoma.
The recommended pembrolizumab dose for patients with cutaneous squamous cell carcinoma is 200 mg every 3 weeks or 400 mg every 6 weeks.
