New clinical standards on the treatment of patients with cystic fibrosis

Nov 16 2007

New clinical standards on the treatment of patients with cystic fibrosis (CF) have been released following an exhaustive review of all available literature.

The guidelines, a result of a two-year review of original research and systematic review literature from 1983 to 2006, were published in the second issue for November of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

CF is a complex genetic disease affecting the lungs and other organs, and is characterized by an unusually thick, sticky mucus that renders CF victims virtually incapable of fending off infections and pathogens. CF is always fatal, but thanks to advances in treatment in the last 60 years, life expectancy has increased from just a few years to 36 years. Lung disease accounts for 85 percent of the mortality among CF patients.

"Physicians treating patients with CF are faced with a growing number of treatment options" wrote lead author of the guidelines, Patrick A. Flume, M.D. "We are hopeful that clinicians will find these recommendations to be useful in their care of patients with CF."

The pulmonary guidelines committee assessed the clinical efficacy and safety of the use of aerosolized antibiotics, recombinant human DNase (dornase alfa), hypertonic saline inhalation, anti-inflammatory agents, macrolide antibiotics, the use of bronchodilators and N-acetylcysteine. They analyzed the clinical results with regard to the number of studies, strength of the study designs and the quality and consistency of results to make their final recommendations. Because of the general dearth of studies on treatments in children under the age of six, the committee restricted their recommendations to CF patients six years of age and older.

The treatments with the strongest, most consistent results yielding an "A"-grade positive recommendation were:

• Inhaled tobramycin, an antibiotic, to suppress chronic Pseudomonas aeruginosa infections in CF patients with moderate to severe disease to improve lung function and reduce exacerbations; and

• Dornase alfa, which degrades the free DNA that accumulates in CF mucus, thereby loosening the mucus, promoting airway clearance, improving lung function and reducing exacerbations.

"B" grade recommendations by the committee are for:

• Inhaled tobramycin, to suppress chronic Pseudomonas aeruginosa infections in CF patients with mild disease or who are asymptomatic, to reduce exacerbations;

• Dornase alfa, for CF patients with mild disease or who are asymptomatic, to improve lung function and reduce exacerbations;

• Hypertonic saline, which hydrates surface liquid in patients with CF, thereby improving lung function and decreasing exacerbations; and

• £]2-adrenergic receptor agonists, which relax smooth muscles and dilate bronchial passages, which improve lung-function in CF patients, and were well-tolerated.

The guidelines recommend against:

• Systemic corticosteroids in children because of "an excess number of adverse events," including abnormalities in glucose metabolism, cataracts, and percentage of patients "colonized" with Pseudomonas (this recommendation excludes patients who have concomitant asthma);

• Inhaled corticosteroids, because there was no clinical benefit (this recommendation excludes patients who have concomitant asthma); and

• Prophylactic anti-Staphylococcal antibiotics because of the lack of clinical efficacy and an apparent increase in P. aeruginosa infections with their use.

All other treatments lacked sufficient evidence to recommend for or against their use.

The article includes recommendations for physicians to help determine which therapies to use, and the order in which they should be introduced. "There is a challenge for the clinician to decide what therapy to start first, or when to add another therapy," explained Dr. Flume. "We are putting together an educational program to assist the community in implementation of the guidelines and hope to launch a web-based program in January."

Still, much work remains to be done. "We were able to support our recommendations based on the quality of the evidence," said Dr. Flume. "But also we could see clearly where we were lacking data. This will allow us to lay the foundation for how those studies should be performed."

The committee plans to update the guidelines every five years.