Roflumilast, a drug recently approved in the United States to treat severe COPD, increases the production of a protein that causes inflammation, which possibly results in patients developing a tolerance to the drug after repeated use and makes the drug less effective, according to researchers at Georgia State University, Kumamoto University and the University of Rochester Medical Center.

The findings, published on March 23 in the Proceedings of the National Academy of Sciences, may help explain the development of tolerance to roflumilast and may assist with developing new therapeutics to improve the efficacy of the drug.