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 Based on a review of data from 64 asthma drug trials, the new study
found that patients using inhaled corticosteroids with a long-acting
bronchodilator had about half as many symptom flare ups and asthma
attacks as those just on the steroids.
“There were some things we expected beforehand, like that oral
therapies would be inferior to inhaled steroids, but asthma is a
very individual disease and some patients will not experience any
symptoms and other patients will suffer a lot from the symptoms,”
said lead author Dr. Rik Loijmans, from the Academic Medical Center
at the University of Amsterdam.
Although the worst breathing problems associated with asthma usually
occur in episodes or “attacks,” the problem of a sensitive, swelling
airway is constant. Treating asthma means being able to take
medication that works quickly to relieve an attack as well as one
that will keep the swelling under control, he told Reuters Health.
Worldwide, approximately 300 million people have been diagnosed with
asthma, according to the Global Initiative on Asthma (GINA). That
number is expected to rise to 400 million by 2025.
Asthma rates in North America are among the highest in the world,
according to GINA, with some 36 million cases in the U.S. and
Canada, representing more than 11 percent of the total population.
While corticosteroids can keep airways from swelling and building up
with mucus, long-acting beta antagonists (LABAs) keep the muscles of
the airways relaxed, resulting in fewer asthma attacks.
Normally, when patients are diagnosed with asthma, they are first
treated with low-dose inhaled corticosteroids, and if there is
reason to step up the therapy, such as recurring attacks, then the
dose would likely be raised. Adding more drugs to the treatment
regimen would come later.
Some products combine steroids with LABAS in a single treatment,
such as GlaxoSmithKine’s Advair and AstraZeneca’s Symbicort. But in
the U.S., those products carry a “black box” warning, which
discourages their being used widely, researchers said.
To compare the effectiveness of all available asthma management
strategies, Loijmans and his colleagues sifted through data from
drug trials and selected the ones that met their criteria for making
the results comparable. For instance, trials had to last 24 weeks or
more, all patients had to have moderate to severe asthma, to have
used a “rescue drug” to stave off an attack, or to have experienced
nighttime waking because of an asthma episode.
“It scares me a bit to think that there is such an ailment that so
many people suffer from and receive years of treatment for yet there
are only 64 trials with duration of more than 24 weeks published,”
Loijmans said.
The researchers compared 15 different drug management combinations
to one another, and to treatment just with a low dose of the
anti-inflammatory corticosteroids.
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The trials included drugs that prevent swelling, as well as drugs
that block immune system chemicals that can trigger attacks and
those classified as rescue or “reliever” drugs, to be used
specifically in the case of an asthma attack. The study team gauged
the safety of medications by counting how many people dropped out of
a trial
“A side effect in the trial that results in dropping out means that
that person would have had a bad reaction to the medication if they
had tried it outside of a study and that means it wasn’t very
effective in helping that patient,” Loijmans said.
Overall, the combination of inhaled corticosteroids with LABAs –
either as two separate drugs, or in a fixed dose delivered together
- were the most effective at reducing the number of attacks patients
experienced, according to the results published in the British
medical journal BMJ.
Combinations of other drug types were not better than
corticosteroids alone, and no single drug was better than steroids
alone either.
The combination regimen also proved safe, according to the study
results, including the products that combine two drugs into one
treatment.
“Yet, these are the products with black box warnings,” noted Dr. Ken
Chapman, director of the Asthma and Airway Centre of the University
Health Network in Ontario, Canada.
The U.S. Food and Drug Administration (FDA) required the black box
label because the combination products were associated with an
increased risk of wheezing, which can lead to an asthma attack,
according to Chapman.
That makes patients leery of the products and doctors hesitant to
prescribe them, he said.
Chapman told Reuters Health that the Dutch researchers’ analysis and
conclusions are not surprising, in fact, they are very well known,
but the review is the most rigorous presentation of the data he has
ever seen.
“It’s interesting that the FDA is willing to ignore this knowledge
but there is a reason the drugs are still on the market. The world
knows that this combination is effective,” Chapman said.
SOURCE: http://bit.ly/RCjavt BMJ,
May 13, 2014.
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