Fidaxomicin

• CAT Number: A000989
• CAS Number: 873857-62-6
• Molecular Formula: C52H74Cl2O18
• Molecular Weight: 1058.04
• Purity: ≥95%
• Target: RNA polymerase
• Storage: -20°C
• IUPAC Name: [(2R,3S,4S,5S,6R)-6-[[(3E,5E,8S,9E,11S,12R,13E,15E,18S)-12-[(2R,3S,4R,5S)-3,4-dihydroxy-6,6-dimethyl-5-(2-methylpropanoyloxy)oxan-2-yl]oxy-11-ethyl-8-hydroxy-18-[(1R)-1-hydroxyethyl]-9,13,15-trimethyl-2-oxo-1-oxacyclooctadeca-3,5,9,13,15-pentaen-3-yl]methoxy]-4-hydroxy-5-methoxy-2-methyloxan-3-yl] 3,5-dichloro-2-ethyl-4,6-dihydroxybenzoate
• InChI: InChI=1S/C52H74Cl2O18/c1-13-30-22-26(6)33(56)18-16-15-17-31(23-66-51-45(65-12)42(61)44(29(9)67-51)69-49(64)35-32(14-2)36(53)39(58)37(54)38(35)57)48(63)68-34(28(8)55)20-19-25(5)21-27(7)43(30)70-50-41(60)40(59)46(52(10,11)72-50)71-47(62)24(3)4/h15-17,19,21-
• InChIKey: ZVGNESXIJDCBKN-LGPUCNCQSA-N
• SMILES: CCC1C=C(C(CC=CC=C(C(=O)OC(CC=C(C=C(C1OC2C(C(C(C(O2)(C)C)OC(=O)C(C)C)O)O)C)C)C(C)O)COC3C(C(C(C(O3)C)OC(=O)C4=C(C(=C(C(=C4O)Cl)O)Cl)CC)O)OC)O)C

Fidaxomicin(CAS 873857-62-6), a macrocyclic antibiotic, has a narrow spectrum of activity against gram-positive anaerobes and is bactericidal against C. difficile. 

Fidaxomicin inhibits bacterial transcription by binding to RNA polymerase, a large enzyme that consists of five subunits that comprise its core catalytic enzyme (α2 ββ/' ω) and a separate sigma (σ) subunit responsible for promoter recognition. Fidaxomicin has no activity against gram-negative bacteria. Fidaxomicin has minimal activity against Bacteroides species, which may be advantageous in maintaining colonization resistance and protecting the gastrointestinal tract from colonization by C. difficile. 

Overview of Clinical Research

Fidaxomicin is a protein synthesis inhibitor developed by Abott Laboratories. There is no orphan drug yet.

Reference

1: Zhanel GG, Walkty AJ, Karlowsky JA. Fidaxomicin: A novel agent for the treatment of Clostridium difficile infection. Can J Infect Dis Med Microbiol. 2015 Nov-Dec;26(6):305-12. Review. PubMed PMID: 26744587; PubMed Central PMCID: PMC4692299.
2: Cornely OA, Nathwani D, Ivanescu C, Odufowora-Sita O, Retsa P, Odeyemi IA. Clinical efficacy of fidaxomicin compared with vancomycin and metronidazole in Clostridium difficile infections: a meta-analysis and indirect treatment comparison. J Antimicrob Chemother. 2014 Nov;69(11):2892-900. doi: 10.1093/jac/dku261. Epub 2014 Jul 28. Review. PubMed PMID: 25074856.
3: Sears P, Ichikawa Y, Ruiz N, Gorbach S. Advances in the treatment of Clostridium difficile with fidaxomicin: a narrow spectrum antibiotic. Ann N Y Acad Sci. 2013 Jul;1291:33-41. doi: 10.1111/nyas.12135. Epub 2013 May 14. Review. PubMed PMID: 23672600.
4: Cornely OA. Current and emerging management options for Clostridium difficile infection: what is the role of fidaxomicin? Clin Microbiol Infect. 2012 Dec;18 Suppl 6:28-35. doi: 10.1111/1469-0691.12012. Review. PubMed PMID: 23121552.
5: Lancaster JW, Matthews SJ. Fidaxomicin: the newest addition to the armamentarium against Clostridium difficile infections. Clin Ther. 2012 Jan;34(1):1-13. doi: 10.1016/j.clinthera.2011.12.003. Review. PubMed PMID: 22284993.