Is a Shorter Course of Sublingual Immunotherapy Effective at Alleviating Seasonal Allergy Symptoms?

According to a new study, a shorter course of sublingual immunotherapy was not more effective than placebo at improving nasal allergy symptoms in participants.

Three years of combined subcutaneous immunotherapy and sublingual immunotherapy have been shown to improve symptoms of allergic rhinitis for at least 2 years after the cessation of treatment. In their study, researchers sought to determine whether 2 years of solely sublingual immunotherapy could improve allergy symptoms in the long-term compared with placebo.
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The study included 106 participants, 92 of whom completed all 3 years of the trial. Thirty-six patients were randomly assigned to receive sublingual therapy of 15 µg of major allergen Phleum p 5 and monthly placebo injections, 36 were assigned to the subcutaneous immunotherapy positive control group and received monthly injections containing 20 µg of Phleum p 5 and daily placebo tablets, and 34 were assigned to the matched double-placebo group.

Participants received treatment for 2 years, and performed the nasal allergen challenge before treatment, at 1 and 2 years during treatment, and at year 3, (1 year after the discontinuation of treatment). Total nasal symptom scores (TNSS) were recorded between 0 and 10 hours after the nasal allergen challenge, and the minimum clinically important difference for changes in TNSS was 1.08.

In participant who received sublingual immunotherapy, the mean TNSS score was 6.36 before treatment and 4.47 at 3 years. The placebo group had a TNSS score of 6.06 before treatment and 4.81 at 3 years. The between group difference was -0.18.

The researchers noted that the study was not designed to compare the sublingual immunotherapy group with the subcutaneous immunotherapy group.

“Among patients with moderate to severe seasonal allergic rhinitis, 2 years of sublingual grass pollen immunotherapy was not significantly different from placebo in improving the nasal response to allergen challenge at 3-year follow-up,” the researchers concluded.

—Melissa Weiss

Reference:

Scadding GW, Calderon MA, Shamji MH, et al. Effect of 2 years of treatment with sublingual grass pollen immunotherapy on nasal response to allergen challenge at 3 years among patients with moderate to severe seasonl allergic rhinitis: the GRASS randomized clinical trial [published online February 14, 2017]. JAMA. doi:10.1001/jama.2016.21040.