New research into the genetics behind asthma risk suggests a potential new treatment for the debilitating disorder could be a drug also used for rheumatoid arthritis.
Scientists led by Manuel Ferreira of the Queensland Institute of Medical Research, in Brisbane, Australia, compared the genomes of thousands of individuals with asthma to those of non-asthmatics and identified two new genetic variants that increase people's susceptibility to asthma. Both variants affect the way the body releases chemical signals involved in immunity and inflammation. It's the interaction between genes and the environment that leads to asthma.
"There have been many genetic variants that have been shown to be asthma risks, and these are two more," said Dr. Harold Nelson, allergist and professor of medicine at National Jewish Health in Denver. "They're all important because they give you clues to the mechanisms that lie behind asthma." (Nelson was not involved in this study.)
Nelson and other specialists say this type of research can possibly lead to more treatments for asthma in people with these genetic variants, including the use of drugs that are already used for other conditions.
"There's a theoretical possibility that if you could modify genetic signals using a medication, you might be able to alter the risk for asthma and allergic sensitization," said Dr. Stanley Fineman, president-elect of the American College of Allergy, Asthma and Immunology. (Fineman also had no involement in the Australian research.)
The authors say tocilizumab, a drug used to treat rheumatoid arthritis, could be a good option for treating asthma in people with one of the variants they identified and suggest that clinical trials could be beneficial.
Using a drug that already exists to treat another condition could be the most promising way to address the many genetic factors associated with asthma risk. While there are potentially thousands of variants, each one likely affects only a small amount of asthmatics.
"If there are many of these factors, it would be extremely difficult to get medications approved that act on each one," said Nelson. "It would be difficult for pharmaceutical companies to justify the investment in research and development for new drugs." Part of the potentially enormous cost would be performing genetic screening on asthmatics.
Specialists who treat asthma would certainly welcome new treatments. While allergy shots are very effective against allergic asthma, non-allergic asthma sufferers don't have as many options.
"Right now, we are just treating inflammation and symptoms," said Fineman.