Severe asthma remaining well‐controlled after mepolizumab discontinuation: A case report and literature review

Mepolizumab, a humanized anti‐IL‐5 monoclonal antibody used for severe asthma, results in a reduced rate of asthma exacerbation, improved lung function, reduced oral corticosteroid use, and improved quality of life. A 62‐year‐old man using high‐dose inhaled corticosteroid visited our hospital because of poorly‐controlled asthma. He had eosinophilia in peripheral blood and sputum, and high levels of fraction of exhaled nitric oxide. Therefore, he was treated with mepolizumab for severe asthma. Mepolizumab treatment resulted in significantly improved pulmonary function and reduced frequencies of asthma exacerbations. Because of his good asthma control, mepolizumab treatment was discontinued after 3 years. Since discontinuing mepolizumab, his asthma control has remained without exacerbation. Previous studies suggest that mepolizumab should be continued to sustain clinical benefits. However, cases of long‐term controlled asthma have not been reported after mepolizumab withdrawal, and our case may be instructive.