FDA Approval Summary: Pembrolizumab for the Treatment of Patients With Metastatic Non-Small Cell Lung Cancer Whose Tumors Express Programmed Death-Ligand 1

On October 2, 2015, the U.S. Food and Drug Administration (FDA) granted accelerated approval for pembrolizumab, a breakthrough therapy-designated drug, for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors express programmed death-ligand 1 (PD-L1), as determined by an FDA-approved test, and who have disease progression on or after platinum-containing chemotherapy or targeted therapy against anaplastic lymphoma kinase or epidermal growth factor receptor, if appropriate. This indication was approved concurrently with the PD-L1 immunohistochemistry 22C3 pharmDx, a companion diagnostic test for patient selection based on PD-L1 tumor expression. The accelerated approval was granted based on durable objective response rate (ORR) and an acceptable toxicity profile demonstrated in a multicenter, open-label trial enrolling 550 patients with metastatic NSCLC. The efficacy population comprised 61 patients with tumors identified as strongly positive for PD-L1, and the confirmed ORR as determined by blinded independent central review was 41% (95% confidence interval: 28.6%, 54.3%); all were partial responses. At the time of the analysis, responses were ongoing in 21 of 25 patients (84%), with 11 patients (44%) having response duration of ≥6 months. The most commonly occurring (≥20%) adverse reactions included fatigue, decreased appetite, dyspnea, and cough. The most frequent (≥2%) serious adverse drug reactions were pleural effusion, pneumonia, dyspnea, pulmonary embolism, and pneumonitis. Immune-mediated adverse reactions occurred in 13% of patients and included pneumonitis, colitis, hypophysitis, and thyroid disorders. The accelerated approval regulations describe approval of drugs and biologic products for serious and life-threatening illnesses based on a surrogate endpoint likely to predict clinical benefit. Under these regulations, a confirmatory trial or trials is required to verify and describe the benefit of pembrolizumab for patients with metastatic NSCLC.