Pemetrexed and Erlotinib for Metastatic Colorectal Cancer

Pemetrexed is a multitargeted antifolate, which primarily inhibits thymidylate synthase, dihydrofolate reductase, and glycinamide ribonucleotide formyltransferase in the folate-dependent metabolic process. Nowadays, pemetrexed is used to treat malignant pleural mesothelioma and non-squamous non-small cell lung cancer. Preclinical and clinical studies showed that pemetrexed had cytotoxic activity in many kinds of cancers including colorectal cancer. Erlotinib is a tyrosine-kinase inhibitor of EGFR, which was approved for the treatment of non-small cell lung cancer. Erlotinib also showed activity to colorectal cancer cells. Recently, Zhang et al. demonstrated synergistic cytotoxicity of pemetrexed and gefitinib in preclinical study.
In this multicenter, non randomized, open label phase II study, investigators aimed to evaluate the efficacy and safety of Pemetrexed and Erlotinib combination.