Favorable response to pembrolizumab after durvalumab failure in a stage III sarcomatoid carcinoma of the lung: a case report.

BACKGROUND: Pulmonary sarcomatoid carcinoma is a rare non-small-cell lung cancer (NSCLC) subtype with a poor prognosis. In the phase III PACIFIC study, durvalumab significantly improved progression-free survival and overall survival versus placebo, in patients with stage III NSCLC who do not have disease progression after concurrent chemoradiotherapy. However, treatments for patients who discontinue durvalumab due to disease progression, are unknown. CASE PRESENTATION: We report a case of favorable response to pembrolizumab in a patient with disease progression during durvalumab consolidation therapy after chemoradiotherapy for stage III pulmonary sarcomatoid carcinoma with high programmed cell death ligand 1 (PD-L1) and PD-L2 expression. CONCLUSION: Here, we present what, to the best of our knowledge, is the first reported case in which durvarumab resistance after definitive chemoradiotherapy in a patient with stage III pulmonary sarcomatoid carcinoma was overcome by pembrolizumab.