Washington University. US: An investigational drug appears to cut the risk of severe asthma attacks
in half for patients who have difficulty controlling the disorder with
standard medications, according to results from two multicenter clinical
trials.
The findings are published Feb. 24 in the journal Lancet Respiratory Medicine.
“The drug, reslizumab, reduces asthma attacks in a particular
population of patients,” said principal investigator Mario Castro, MD,
the Alan A. and Edith L. Wolff Professor of Pulmonary and Critical Care
Medicine at Washington University School of Medicine in St. Louis. “It
helped prevent severe attacks that typically require patients to contact
their physicians and that usually result in those patients being placed
on oral steroids that come with a range of side effects.”
The Phase 3 trials involved nearly 1,000 patients at more than 200
health centers worldwide. Each of the patients had asthma that was
difficult to control with inhaled steroids, meaning they frequently
experienced attacks that doctors refer to as asthma exacerbations. Some
exacerbations are serious enough to send patients to the emergency room
or require hospitalization.
Patients in the studies also had high counts of a type of white blood
cell called an eosinophil. Eosinophils contribute to inflammation and
are believed to increase the severity of asthma in some patients.
In each study, patients were divided into two groups. All remained on
their usual asthma medications, but some also received intravenous
infusions of reslizumab every four weeks, while the others were given a
placebo. Over the course of one year, those treated with reslizumab were
at least 50 percent less likely to experience asthma exacerbations.
Data from both of the studies indicate that 50 percent of patients
who took a placebo experienced asthma exacerbations, compared with 32
percent of the patients who took the investigational drug.
Patients who received reslizumab also showed other improvements in lung function.
“Within a matter of a week or two, their eosinophil counts were
reduced,” Castro said. “Those cells go into your lungs and cause airways
to swell and inflame and turn red and produce mucus. The idea is that
by keeping those cells from doing that damage, you can improve airflow
through the windpipe. And that’s exactly what we saw. Significant
increases in lung function occurred within a few months of patients
being on this therapy, and those improvements were sustained throughout
the study.”
Reslizumab is a monoclonal antibody against an inflammatory substance
made in the body called interleukin-5. Castro said that although a
similar drug hadn’t helped patients very much in a previous study, those
patients hadn’t been screened for high eosinophil counts.
Castro estimates that 30-40 percent of asthma patients have elevated
eosinophil counts, which can be detected with a standard blood test.
The study was funded by reslizumab’s manufacturer, Teva Pharmacuetical Industries Ltd.
Castro M, Zangrilli J, Wechsler ME, Bateman ED, Brusselle GG, Bardin
P, Murphy K, Maspero JF, O’Brien C, Korn S. Reslizumab for inadequately
controlled asthma with blood eosinophil counts from two, multicentre,
parallel, double-blind, randomised, placebo-controlled, phase 3 trials.
Lancet Respiratory Medicine, Feb. 24, 2015.