Severe asthma is a growing problem, affecting a staggering 8 percent of the American population in 2009. According to a report from Medscape, however, the U.S. FDA has just approved a new treatment, Reslizumab, also known as Cinqair, which promises to provide relief for the most severe cases of the respiratory disorder.

The drug, produced by Teva Pharmaceuticals, is a monoclonal antibody and was approved for patients 18 years and older. The treatment is geared toward patients whose condition is connected to elevated eosinophilis, a type of white blood cell linked to inflammation in the respiratory tract.

Reslizumab works to reduce the eosinophils levels in the blood. According to the FDA, roughly five percent of patients with asthma suffer from severe and uncontrolled attacks related to an eosinophilic phenotype, despite the best efforts of other types of treatments.

Reslizumab is administered every four weeks by an intravenous infusion in a supervised clinical setting to keep anaphylaxis under control. The FDA voted 11 to 3 to recommend the approval of the drug for adults suffering from severe asthma based on safety and efficiency numbers from a series of clinical tests. The panel passed a unanimous vote against approving the drug for children, however, due to a lack of available data.

The FDA carried out four double-blind, randomized, placebo-controlled trials to test reslizumab. They tested the drug on patients with severe asthma who were currently receiving the next best available treatments. Participants received either reslizumab or a placebo every four weeks in addition to the treatments the were already getting for their asthma.

The trials showed that people receiving reslizumab suffered fewer asthma attacks less frequently than patients who received a placebo. The people receiving the new medication also found it easier to exhale a higher volume of air than the patients who received a placebo.

Side effects of the treatment included muscle pain, cancer, and anaphylaxis, which the FDA warned could threaten the lives of patients taking the drug. Still, the treatment could offer relief to patients with severe asthma who were previously unable to find it.

A press release from the FDA describing the treatment can be found here.