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 “The reported benefit is very small on average,” said lead author
Dr. Danilo Di Bona of the Azienda Ospedaliera Universitaria
Policlinico di Palermo in Italy. “This means that some patients will
respond, but the majority will not, and it is not possible to
predict who will respond to the treatment.”
An injectable version of the same therapy, which is also available,
is preferable, since more patients will respond to it, he said.
The researchers considered 13 randomized controlled trials comparing
under-the-tongue “meltaway” immunotherapy tablets with placebo
pills, and measuring changes in reported allergy symptoms and the
use of other allergy medications. In total, the trials included more
than 4,000 patients with seasonal allergies.
All of the studies found some symptom alleviation with the
immunotherapy tablets, but six of the 13 did not demonstrate more
improvement than was seen in the placebo group.
In seven studies, the group taking the immunotherapy tablets
decreased their use of other medications like antihistamines and
corticosteroids, but not in the others.
About 60 percent of people taking the immunotherapy tablets suffered
a side effect due to the medication, usually a moderate one like
mouth itching or burning and gastrointestinal tract symptoms,
compared to 21 percent of those in the placebo group, as reported in
JAMA Internal Medicine.
Of the 4,659 people included in the trials, seven people - all in
the immunotherapy group - reported a serious allergic side effect
requiring epinephrine, a rescue treatment for potentially
life-threatening allergic reaction.
The benefit of the tablets originally reported from these randomized
controlled trials was overestimated, Di Bona said.
“With the metric we used, that is the one suggested by the World
Allergy Organization, the real difference between (under-the-tongue
tablets) and placebo was correctly estimated, and the benefit was
comparable to placebo,” and below the 15 percent difference required
by the U.S. Food and Drug Administration (FDA), Di Bona told Reuters
Health by email.
Last year, the FDA approved two types of immunotherapy tablets for
pollen allergies, including Merck’s product, Grastek and Oralair
from French manufacturer Stallergenes S.A.
Under-the-tongue Grastek tablets can be prescribed to anyone age
five to 65 who has grass pollen allergies and suffers from sneezing,
runny nose and itchy or watery eyes. As directed, it can be taken
daily for 12 weeks before springtime, the grass pollen season, and
throughout the season.
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In an editor’s note accompanying the new study, Dr. Patrick G.
O’Malley of the Uniformed Services University in Bethesda, Maryland,
called the immunotherapy’s benefit an “unimpressive small effect.”
Doctors should be aware of these data, in addition to the cost of
these medications, which is approximately $90 for a three-month
supply, plus the requirement to co-prescribe an epinephrine
autoinjector, writes O’Malley, who was not involved in the study.
“Sublingual immunotherapy may seem more convenient than nasal
corticosteroids or subcutaneous immunotherapy and therefore tempting
to prescribe, but the evidence shows minimal benefit and moderate
adverse effects for patients with seasonal grass pollen allergies,”
he writes.
Untreated or inadequately treated seasonal allergies can cause sleep
and mood disorders and impair school or work performance, Di Bona
said. About 20 percent of Americans suffer from these allergies,
largely due to grass pollen, he said.
Other available treatments, like antihistamines and nasal or oral
corticosteroids, are effective in controlling most symptoms, Di Bona
said.
Immunotherapy tablets, though their mechanism is poorly understood,
modify the immune system to induce a kind of tolerance for the
allergen, he said.
“The treatment would be worth the expense if the response rate was
higher,” he said.
SOURCE: http://bit.ly/1dsH7jI and http://bit.ly/1GOKU38 JAMA
Internal Medicine, online June 29, 2015.
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