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. Pulmonary sarcomatoid carcinoma (SC) is an aggressive subtype of lung cancer that exhibits resistance to cytotoxic chemotherapy and the efficacy of combined therapy with PD‐1 inhibitor plus cytotoxic chemotherapy as first‐line treatment has not previously been clarified. Here we 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. Our findings suggest that treatment might enhance the immunogenic response, even in immunologically ignored SCs.