Remarkable response to pembrolizumab with platinum‐doublet in PD‐L1‐low pulmonary sarcomatoid carcinoma: A case report

Pulmonary sarcomatoid carcinoma (SC) is an aggressive subtype of lung cancer that exhibits resistance to cytotoxic chemotherapy. Although programmed cell death 1 (PD‐1) inhibitors have been reported to show antitumor effects in patients with high programmed death‐ligand 1 (PD‐L1) expressing SC, the efficacy of combined therapy with PD‐1 inhibitor plus cytotoxic chemotherapy has not previously been clarified. We herein report a case of SC with low expression of PD‐L1 and few pre‐existing tumor‐infiltrating lymphocytes which showed a remarkable response to pembrolizumab plus cytotoxic chemotherapy as first‐line treatment. Our findings suggest that combined treatment might enhance the immunogenic response, even in immunologically ignored SCs.