Severe asthma is a subtype of asthma where treatments usually do not have any effect on the individual.
Present treatments for severe asthma more than often involve increased doses of corticosteroids, such as prednisone, in order to control exacerbations. Decreasing the dependence for corticosteroids with alternative options is desirable, since these medicines are often associated with serious side effects from long-term use, such as multi-organ toxicities and immunosuppression.
Now, investigators at McMaster University and the Firestone Institute for Respiratory Health at St. Joseph's Healthcare Hamilton, in collaboration with other partnering institutions, have found a new method in treating severe asthma. Through a study of over 200 participants with severe asthma, the developed treatment was seen to improve symptoms of asthma and lung function, while decreasing the need for corticosteroids for up to 70%.
Professor of medicine and pulmonologist, Dr. Parameswaran Nair, at St. Joseph's Healthcare Hamilton in McMaster University, plus a team of investigators have isolated an antibody by the name dupilumab which holds high efficacy in the treatment of severe asthma in comparison to high doses of prednisone. More so, the researchers sought participants who were using oral corticosteroids (prednisone) for at least 6 months to treat their severe asthma. For a 24 week period, these participants used dupilumab in addition to their standard regimen of corticosteroids, however, the corticosteroid doses was gradually lowered over the 24 weeks. "The ability of dupilumab to increase lung function as markedly as it did in this study, even in the face of [corticosteroid] withdrawal, indicates that it appears to be inhibiting key drivers of lung inflammation," the researchers noted.
Dupilumab is essentially an inhibitor that works to treat asthma by blocking two specific protein known as interleukin-4 and interleukin-13 which are associated with inflammation of the airways. Studies on Dupilumab were based on previous published work by Dr. Nair. Those studies found that inhibiting the function of another protein, interleukin-5, allowed patients with high eosinophil levels in their blood and airways to lower their corticosteroid dose. Eosinophils are a subtype of white blood cells that are involved with the production of interleukins. Increased eosinophil levels are directly linked to a high risk of severe asthma.
In comparison to the previous studies, dupilumab was shown to be effective regardless of the affected individuals eosinophil levels. Even though the prednisone levels were reduced, patients in this study not only experienced a decrease in asthma exacerbations, but their lung function also improved. "Ultimately, our goal is to find new treatment pathways that allow us to circumvent the use of corticosteroids," said Dr. Nair. "Since dupilumab showed a significant improvement on asthma control regardless of eosinophil levels, we may be able to use this treatment for a wider range of patients than we previously thought possible. This might be due to the broad effects on inflammation in asthma of the two proteins that we were able to block with dupilumab. The treatment was not associated with any serious side effects."
Sources: New England Journal of Medicine