In a randomized phase II study, researchers showed that patients whose lung cancers expressed low levels of an enzyme called thymidylate synthase experienced a greater benefit from treatment with the combination of pemetrexed and cisplatin than those whose tumours expressed high levels. “Thymidylate synthase is one of the proteins that is targeted by pemetrexed which is the most widely used chemotherapeutic regimen in the treatment of non-squamous NSCLC,” explains study author Professor Myung-Ju Ahn, from the Section of Hematology-Oncology at Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. “In this study, we tried to evaluate whether expression of thymidylate synthase is a predictive factor for response to pemetrexed plus cisplatin chemotherapy compared with gemcitabine plus cisplatin in non-squamous cell lung cancer patients.” In terms of response rate and progression-free survival, the clinical benefits of the pemetrexed combination compared to other regimen were more prominent in those patients who expressed low levels of the molecule, Ahn said…