title: PDE inhibitors currently in early clinical trials for the treatment of asthma.
abstract: BACKGROUND
  PDE inhibitors could be useful in the treatment of asthma because of their bronchodilator and/or anti-inflammatory activities. Recently, some selective PDE3, PDE4 and PDE3/4 inhibitors have been shown to have beneficial effects in patients with asthma suggesting that such drugs may offer novel therapeutic options for the treatment of this disease.
  
  
  METHODS
  The authors describe the main PDE families that could be involved in asthma as well as the PDE inhibitors that have been evaluated for the treatment of asthma.
  
  
  CONCLUSIONS
  Although the potential therapeutic utility of PDE inhibitors has been demonstrated in various animal models of asthma, their clinical efficacy have been restricted by the dose-limiting side effects; no PDE inhibitor has yet been approved for the treatment of patients with asthma. Although new PDE inhibitors have been synthesised, most data are from cellular and tissue-level studies with human trials still on the horizon. Apparently, only CHF 6001, an inhaled PDE4 inhibitor, and RPL554, a dual PDE3/4 inhibitor, are still under clinical development. Further data from these new drugs are eagerly anticipated to better understand where these drugs might stand in the future treatment of asthma.
authors.affiliation: Second University of Naples, Department of Experimental Medicine, Unit of Pharmacology , Naples , Italy.
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Matera
authors.forename: Clive
authors.initials: C
authors.lastname: Page
authors.forename: Mario
authors.initials: M
authors.lastname: Cazzola
mesh_terms: D000818:Animals; D018927:Anti-Asthmatic Agents / Q000009:adverse effects / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D015195:Drug Design; D006801:Humans; D058987:Phosphodiesterase 3 Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D058988:Phosphodiesterase 4 Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D018927:Anti-Asthmatic Agents; D000893:Anti-Inflammatory Agents; D001993:Bronchodilator Agents; D058987:Phosphodiesterase 3 Inhibitors; D058988:Phosphodiesterase 4 Inhibitors
keywords: PDE inhibitors; PDE isoforms; RPL554; asthma