New Glaxo drug may help tricky adult-onset asthma

By Gene Emery

BOSTON (Reuters) - GlaxoSmithKline's experimental drug mepolizumab may help a small group of asthma sufferers whose illness can be difficult to control, researchers said on Wednesday.

Two studies reported in the New England Journal of Medicine said the drug, also known as Bosatria, reduced the number of asthma attacks in patients for whom oral corticosteroid treatment was not very effective, apparently because they had high levels of immune cells known as eosinophils.

Mepolizumab reduces the number of eosinophils by inhibiting an immune system signaling chemical called interleukin-5.

The company, which is developing the drug to combat other conditions with high eosinophil counts, financed the two new studies after tests on a broader group of asthma patients failed to produce major improvement.

"Although up to 40 percent of cases of severe asthma start later in life, the eosinophilic form of asthma probably represents less than 5 percent of the total number of cases of adult-onset asthma," Dr. Sally Wenzel of the University of Pittsburgh wrote in a commentary.

"This is a very difficult-to-manage group of asthmatics," said Dr. Paul O'Byrne of Canada's McMaster University, who worked on one of the studies.

"These are people who are already on a lot of asthma medications and are also taking oral corticosteroids on a maintenance basis to try to control the symptoms they're having."

He and his colleagues found that the drug reduced the need for oral steroids.