Cilomilast for COPD: results of a 6-month, placebo-controlled study of a potent, selective inhibitor of phosphodiesterase 4

Chest. 2006 Jan;129(1):56-66. doi: 10.1378/chest.129.1.56.


Background: COPD is a relentless, progressive disease. This study evaluated the efficacy of cilomilast, a selective phosphodiesterase (PDE) 4 inhibitor, in the treatment of COPD.

Methods: This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter study in subjects with COPD. After a 4-week, single-blind, placebo run-in period, eligible subjects were randomized in a 2:1 ratio to receive oral cilomilast, 15 mg bid, or placebo for 24 weeks. Subjects between 40 and 80 years of age who had received a diagnosis of COPD were eligible for the study. The primary efficacy variables were changes from baseline in trough (ie, predose) FEV1 and in total score of the St. George's Respiratory Questionnaire (SGRQ). A key secondary end point was the incidence rate of COPD exacerbations.

Results: The average change from baseline in FEV1 over 24 weeks in the cilomilast group was an increase of 10 mL compared with a decrease of 30 mL in the placebo group (difference, 40 mL; p = 0.002). When averaged over 24 weeks, there was a clinically significant reduction in the mean total SGRQ score in subjects receiving cilomilast therapy, with a difference of 4.1 U compared with subjects who received placebo (p = 0.001). A greater percentage of subjects in the cilomilast group were exacerbation-free at 24 weeks (74%; p = 0.008) compared with placebo (62%). Adverse events were generally mild or moderate and were not unexpected for this class of medications. GI adverse events that interfered with daily activities (cilomilast, 17%; placebo, 8%) predominantly occurred within the first 3 weeks of initiating cilomilast therapy.

Conclusion: Cilomilast is an orally active, potent, and selective inhibitor of PDE-4. Cilomilast maintained pulmonary function and improved health status, and reduced the rate of COPD exacerbations during 24 weeks of treatment. This study supports the use of cilomilast, a novel, selective PDE-4 inhibitor, in subjects with COPD.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3',5'-Cyclic-AMP Phosphodiesterases / antagonists & inhibitors*
  • Adult
  • Aged
  • Aged, 80 and over
  • Carboxylic Acids / administration & dosage
  • Carboxylic Acids / therapeutic use
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Cyclohexanecarboxylic Acids
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume / drug effects
  • Forced Expiratory Volume / physiology
  • Humans
  • Male
  • Middle Aged
  • Nitriles / administration & dosage
  • Nitriles / therapeutic use*
  • Phosphodiesterase Inhibitors / administration & dosage
  • Phosphodiesterase Inhibitors / therapeutic use*
  • Pulmonary Disease, Chronic Obstructive / drug therapy*
  • Pulmonary Disease, Chronic Obstructive / enzymology
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Retrospective Studies
  • Treatment Outcome


  • Carboxylic Acids
  • Cyclohexanecarboxylic Acids
  • Nitriles
  • Phosphodiesterase Inhibitors
  • Cilomilast
  • 3',5'-Cyclic-AMP Phosphodiesterases
  • Cyclic Nucleotide Phosphodiesterases, Type 4