What's Pemetrexed disodium?

Pemetrexed disodium is a potent new antifolate which inhibits many folate-dependent reactions that are essential for cell proliferation. Its primary target is thymidylate synthase but it also inhibits folate-dependent enzymes involved in purine synthesis. Cells that are resistant to antifolates are generally less resistant to pemetrexed, irrespective of the mechanism of resistance. Pemetrexed has shown good activity in preclinical models with human tumour cells and xenografts.

Pemetrexed disodium(CAS,NO:150399-23-8) is a novel, multi-targeted antifolate that has demonstrated promising clinical activity in a wide variety of solid tumors, including non-small cell lung, breast, mesothelioma, colorectal, pancreatic, gastric, bladder, cervix, and head and neck. Pemetrexed inhibits multiple folate-dependent enzymes involved in both purine and pyrimidine synthesis including thymidylate synthase, dihydrofolate reductase, glycinamide ribonucleotide formyltransferase, and aminoimidazole carboxamide ribonucleotide formyltransferase.

In the majority of clinical trials of pemetrexed, the dose-limiting toxic effect is neutropenia; other side-effects are mostly gastrointestinal. Preclinical studies indicate that the toxic effects of pemetrexed can be reduced by dietary folate, resulting in an improved therapeutic index. Low folate status is also associated with higher levels of toxicity in patients. As a single agent pemetrexed has shown good activity against non-small-cell lung cancer, squamous-cell carcinoma of head and neck, colon cancer, and breast cancer, and it appears to be particularly active in combination with cisplatin against non-small-cell lung cancer and mesothelioma.

Indications: This drug is used in combination with cisplatin in the treatment of malignant pleural mesothelioma and as a single agent in the treatment of non-small cell lung cancer.

Adverse effects: Adverse effects of this drug include creatinine elevation. Life-threatening effects include thrombosis and embolism, renal failure, neutropenia, leukopenia, thrombocytopenia, myelosuppression, anemia, and infection with or without neutropenia. Common side effects include fatigue, fever, mood alteration, neuropathy, chest pain, nausea, vomiting, anorexia, diarrhea, ulcerative stomatitis, constipation, dysphagia, dehydration, rash, desquamation, and dyspnea.

Rtionale: Drugs used in chemotherapy, such as paclitaxel and carboplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of non-small cell lung cancer by blocking blood flow to the tumor. Pemetrexed disodium may stop the growth of tumor cells by blocking some enzymes needed for cell growth. It is not yet known whether giving bevacizumab or pemetrexed disodium alone or in combination is more effective in treating non-squamous non-small cell lung cancer.