Pembrolizumab for non-small cell lung cancer with central nervous system metastases: A two-case report

Non-small cell lung cancer (NSCLC) accounts for up to 85% of all lung cancers. Central nervous system metastases are a common complication of NSCLC and confer a poor prognosis and a dismal survival rate. Treatment is limited, has poor outcomes, and affects patient quality of life. Pembrolizumab is an anti-PD-1 antibody that has shown good results for the management of NSCLC. However, its penetration of the central nervous system has not been well studied, and patients with untreated brain metastases are excluded from most clinical trials. Herein, we report two cases of NSCLC with brain metastases in patients successfully treated with pembrolizumab, and discuss the efficacy and safety of pembrolizumab in these patients. Pembrolizumab has shown good control and the patients have had long progression-free survival with a high quality of life. Neither patient has experienced serious or grade 3-4 treatment-related adverse events. Pembrolizumab demonstrates activity in brain metastases in NSCLC patients with an acceptable safety profile. Thus, there may be a role for systemic immunotherapy in patients with untreated or progressive brain metastases.