Phase II Study of Pemetrexed as a Salvage Chemotherapy for Thymidylate Synthase–Low Squamous Cell Lung Cancer

PurposeSquamous cell carcinomas (SqCC) of the lung often express high levels of thymidylate synthase (TS), which is associated with primary resistance to pemetrexed. We explored the efficacy of pemetrexed in a selected population of patients with lung SqCC with low TS expression. Materials and MethodsIn this single-arm phase II trial, we enrolled 32 previously-treated patients with advanced lung SqCC exhibiting low immunohistochemical staining...