title: Pemetrexed: biochemical and cellular pharmacology, mechanisms, and clinical applications.
abstract: Pemetrexed is a new-generation antifolate, approved for the treatment of mesothelioma and non-small cell lung cancer, currently being evaluated for the treatment of a variety of other solid tumors. This review traces the history of antifolates that led to the development of pemetrexed and describes the unique properties of this agent that distinguish it from other antifolates. These include (a) its very rapid conversion to active polyglutamate derivatives in cells that build to high levels and are retained for long intervals to achieve prolonged and potent inhibition of its major target enzyme thymidylate synthase, (b) its high affinity for three folate transporters, and (c) its marked sensitivity to the level of physiologic folates in cells. The latter results in the unique and paradoxical finding that when transport mediated by the major folate transporter (the reduced folate carrier) is impaired, pemetrexed activity is preserved. This is due to concurrent contraction of competing cellular physiologic folates and utilization of a novel second transport carrier for which pemetrexed has high affinity, recently identified as the proton-coupled folate transporter (PCFT). Laboratory studies are reviewed that raise the possibility of new approaches to the use of folic acid supplementation in clinical regimens with pemetrexed.
authors.affiliation: Departments of Medicine and Molecular Pharmacology, The Albert Einstein College of Medicine Cancer Center, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
authors.forename: Shrikanta
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Richard G
authors.initials: RG
authors.lastname: Moran
authors.forename: I David
authors.initials: ID
authors.lastname: Goldman
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001692:Biological Transport; D002986:Clinical Trials as Topic; D005492:Folic Acid / Q000378:metabolism; D005493:Folic Acid Antagonists / Q000494:pharmacology*; D005971:Glutamates / Q000378:metabolism / Q000494:pharmacology*; D006147:Guanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy; D000068437:Pemetrexed
chemical_list: D000964:Antimetabolites, Antineoplastic; D005493:Folic Acid Antagonists; D005971:Glutamates; D000068437:Pemetrexed; D006147:Guanine; D005492:Folic Acid