(HealthDay News) — The benefit of sublingual immunotherapy (SLIT) over placebo for seasonal grass pollen allergies is small, according to new research published online June 29 in JAMA Internal Medicine.
Gabriele Di Lorenzo, M.D., of the department of internal medicine at the University of Palermo in Italy, and colleagues looked at 25 clinical trials that evaluated the effectiveness of grass pollen sublingual tablets in reducing symptoms and the need for other allergy medications. Di Lorenzo told HealthDay that some previous trials overestimated the drugs’ benefit because of the way differences between active medicine and placebo were calculated. For the new analysis, the researchers said the real difference was estimated correctly.
In the analysis, when SLIT was compared with placebo, symptom scores differed by just 1 point. Study participants could also take allergy medicine, such as antihistamines, and this is what mainly controlled symptoms, Di Lorenzo said. Adverse effects were reported by 61.3 percent of those in the SLIT group and 20.9 percent receiving placebo. Seven patients in the SLIT group reported treatment-related adverse events that required epinephrine.
“Findings show a small benefit of the grass pollen sublingual tablets in reducing symptoms and in decreasing the use of symptomatic medication (antihistamines and corticosteroids) in patients with seasonal allergic rhinoconjunctivitis,” the authors write. “Considering the low magnitude of the benefit, the convenience and easy administration do not seem to be sufficient reasons for the choice of SLIT.”