Cytokine release syndrome and successful response to pembrolizumab therapy in a patient with EGFR-mutated non-small-cell lung cancer: A case report.

A therapeutic option for advanced non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) resistance is a clinical challenge. The clinical outcomes of pembrolizumab in those patients is inconclusive. Cytokine release syndrome (CRS) is a rarely reported immune-related adverse event in the field of immune checkpoint inhibitors therapy, raising challenges given the paucity of data with such presentations. We present the unique case of a 67-year-old female with advanced EGFR-mutated NSCLC who successfully responded to pembrolizumab after EGFR-TKI resistance. However, the patient developed CRS after pembrolizumab initiation and presented with fever, rash, hypotension, hypoxemia, tachycardia, and multiple organ dysfunction. Blood tests showed elevated levels of peripheral CD8+ T cells, C-reactive protein, and tumor necrosis factor-α. The symptoms rapidly improved after corticosteroid initiation. Based on the present case, we propose that pembrolizumab might be a potential salvage therapy for patients with advanced EGFR-mutated NSCLC after EGFR-TKI resistance; CRS would be a sign of the antitumor effect of PD-1 inhibitors in those patients. However, CRS can be a fatal adverse effect and clinicians must remain vigilant for the rare toxicities to make prompt diagnosis and treatment.