Anti-inflammatory medications for cystic fibrosis lung disease: selecting the most appropriate agent.

Abstract

The lung disease of cystic fibrosis (CF) is characterized by a self-sustaining cycle of airway obstruction, infection, and inflammation. Therapies aimed at decreasing the inflammatory response represent a relatively new strategy for treatment. Attention has focused primarily upon the therapeutic potential of corticosteroids and NSAIDs. Although beneficial, the use of systemic corticosteroids is limited by their unacceptable adverse effects. It is unclear if inhaled corticosteroids are a viable alternative, although their use in CF has dramatically increased in recent years. High-dose ibuprofen has been shown to slow progression of CF lung disease, but its use has not been widely adopted despite a favorable risk-benefit profile. Thus, other anti-inflammatory approaches are under investigation. Since the inflammatory response can be triggered by many stimuli and since the pathways activated by these stimuli produce many mediators, there are a plethora of targets for anti-inflammatory therapeutics. Specific antibodies, receptor antagonists, and counter-regulatory cytokines, such as interleukin (IL)-10 and interferon-gamma, inhibit the pro-inflammatory mediators responsible for the damaging inflammation in the CF airway, including tumor necrosis factor-alpha, IL-1beta and IL-8. Studies of molecules that modulate intracellular signaling cascades that lead to the production of inflammatory mediators, are underway in CF. For patients with established disease, recent and projected advances in therapies that are directed at neutrophil products, such as DNase, antioxidants, and protease inhibitors, hold great promise for limiting the consequences of the inflammatory response. To optimize anti-inflammatory therapy, it is necessary to understand the mechanism of action of these agents in the CF lung to determine which agents will be most beneficial, and to determine which therapies should be initiated at what age and stage of lung disease. Hope remains that correction of the abnormal CF transmembrane conductance regulator protein or gene replacement therapy will be curative. However, correction of the basic defect must also correct the dysregulated inflammatory response in order to be effective. Until those therapies aimed at repairing the basic defect are realized, limiting the effects of the inflammatory process will be important in slowing the decline in lung function and thus prolonging survival in patients with CF.