THURSDAY, Aug. 16, 2012 (HealthDay News) -- An experimental drug known as mepolizumab may reduce outbreaks by almost 50 percent in people with a type of hard-to-treat asthma, an early study finds.
About a third of people with severe asthma have what is called eosinophilic asthma, in which inflammatory cells called eosinophils cause swelling of lung airways. Standard asthma treatment with inhaled steroids isn't effective, so these patients take oral steroids, which have many side effects, the researchers explained.
Mepolizumab blocks the production of eosinophils and reduces the frequency of severe asthma outbreaks, which may reduce the need for steroids, the researchers said.
The new drug is a monoclonal antibody, a class of drugs involving naturally occurring human antibodies that are genetically altered in a laboratory, cloned in large numbers and introduced into the patient to target disease sites.
"This is a promising new drug treatment," said lead researcher Dr. Ian Pavord, a consultant physician at the University Hospitals of Leicester NHS Trust, in England. "I think it's going to become a viable treatment and it offers hope to a group of people that are having really big problems with their asthma."
The purpose of this trial was to find out the best dose of the drug and to identify the type of patients most likely to benefit from it, Pavord said.
"It's been a successful study, because we have established the drug is effective even in low doses and patients can be identified through a blood test," Pavord said.
Some patients taking mepolizumab may be able to reduce the amount of steroids they take, Pavord said.
"If that were the case it would be very attractive to the patient," he said.
GlaxoSmithKline, the maker of mepolizumab, funded the trial. The findings were published Aug. 16 in the online edition of the journal The Lancet.
For the study, Pavord's team randomly assigned more than 600 patients with severe asthma to receive one of three doses of mepolizumab or a placebo. The drug is given intravenously once a month. Participants included asthma patients from 81 medical centers in 13 countries, and their ages ranged from 12 to 74 years old.
After a year, the researchers found that patients taking mepolizumab had about half the number of severe outbreaks requiring ER visits or hospitalizations as patients taking a placebo. Patients taking mepolizumab also had half as many outbreaks that required oral steroids.
Although mepolizumab effectively reduced outbreaks, it didn't produce consistent improvements in symptoms or lung function, the study found. "It's not a cure," Pavord said. "It's likely to be a long-term treatment."
Headaches and swelling of the nasal passages were seen among patients taking the drug and those on placebo, the researchers noted. Side effects from oral steroids include mood changes, increased appetite, weight gain and acne.
Although three patients died during the study, their deaths were deemed to be unrelated to the treatment.
Since the drug is still experimental and phase 3 trials are just getting under way, the potential cost of the drug, if approved, isn't known. Approval of mepolizumab for asthma isn't expected for at least three to four years, Pavord said.
"The results of this study are very impressive," said Dr. Rubin Cohen, director of the Asthma Center at North Shore-LIJ Health System in New Hyde Park, N.Y.
He said the drug could be very helpful for patients with the most severe type of asthma that can't be controlled with inhaled steroids.
"If this pans out, these asthmatics would have a different treatment option and be able to control their asthma without the side effects of steroids," he said. "They may actually be able to get off steroids completely or reduce the amount of steroids they take substantially."
To learn more about asthma, visit the U.S. National Library of Medicine.