Title: Cilomilast
CAS Registry Number: 153259-65-5
CAS Name: cis-4-Cyano-4-[3-(cyclopentyloxy)-4-methoxyphenyl]cyclohexanecarboxylic acid
Manufacturers' Codes: SB-207499
Trademarks: Ariflo (GSK)
Molecular Formula: C20H25NO4
Molecular Weight: 343.42
Percent Composition: C 69.95%, H 7.34%, N 4.08%, O 18.64%
Literature References: Selective phosphodiesterase 4 (PDE4) inhibitor. Prepn: S. B. Christensen, WO 9319749; idem, US 5552438 (1993, 1996 both to SmithKline Beecham); idem et al., J. Med. Chem. 41, 821 (1998). Anti-inflammatory activity: M. S. Barnette et al., J. Pharmacol. Exp. Ther. 284, 420 (1998); D. E. Griswold et al., ibid. 705. Pharmacology and therapeutic potential in asthma and chronic obstructive pulmonary disease (COPD): T. J. Torphy et al., Pulm. Pharmacol. Ther. 12, 131-135 (1999). Clinical pharmacokinetics and bioavailability: B. D. Zussman et al., Pharmacotherapy 21, 653 (2001). Clinical trial in COPD: C. H. Compton et al., Lancet 358, 265 (2001). Review of pharmacology and clinical experience: M. A. Giembycz, Expert Opin. Invest. Drugs 10, 1361-1379 (2001).
Properties: White solid, mp 157°.
Melting point: mp 157°
Therap-Cat: Antiasthmatic; in treatment of chronic obstructive pulmonary disease.
Keywords: Antiasthmatic (Nonbronchodilator); Phosphodiesterase Inhibitor.
Cimaterol Cimetropium Bromide Cimigenol Cinacalcet Cinametic Acid

Systematic (IUPAC) name
4-cyano-4-(3-cyclopentyloxy-4-methoxyphenyl)cyclohexane-1-carboxylic acid
Clinical data
Legal status  ?
CAS number 153259-65-5 N
ATC code None
PubChem CID 151170
ChemSpider 18826005 N
Chemical data
Formula C20H25NO4 
Mol. mass 343.417 g/mol
 N (what is this?)  (verify)

Cilomilast (Ariflo, SB-207,499) is a drug which was developed for the treatment of respiratory disorders such as asthma and Chronic Obstructive Pulmonary Disease (COPD). It is orally active and acts as a selective Phosphodiesterase-4 inhibitor.[1]

Phosphodiesterase (PDE) inhibitors, such as theophylline, have been used to treat Chronic Obstructive Pulmonary Disease (COPD) for centuries; however, the clinical benefits of these agents have never been shown to out-weigh the risks of their numerous adverse effects. Four clinical trials were identified evaluating the efficacy of cilomilast, the usual randomized, double-blind, and placebo-controlled protocols were used. It showed reasonable efficacy for treating COPD, but side effects were problematic and it is unclear whether cilomalast will be marketed, or merely used in the development of newer drugs.[2][3]

Cilomilast is a second-generation PDE4 inhibitor with antiinflammatory effects that target bronchoconstriction, mucus hypersecretion, and airway remodeling associated with COPD.