An asthma drug has shown promise in relieving itchiness for patients with chronic hives who do not get relief from traditional antihistamine treatment.

The drug, omalizumab, known by its brand name, Xolair, is a monoclonal antibody approved to treat allergic asthma. In the Phase 3 trial, published online on Sunday in The New England Journal of Medicine, a monthly injection of the drug significantly reduced hives and itchiness.

“This is the magic bullet that patients have been waiting for for the last 40 years,” said Dr. Marcus Maurer, the lead author of the study and a professor of dermatology and allergy at Charité-Universitätsmedizin in Berlin. Dr. Maurer has received consulting fees from several pharmaceutical companies, including Genentech and Novartis, which financed the study and are developing the drug.

Dr. Jonathan Bernstein, a professor of medicine and an allergy specialist at the University of Cincinnati, who was not associated with the study, said that it was well designed and that the results were encouraging. “The drug is not a cure, but it will advance our ability to manage these patients,” he said.