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Shortened dose of immunotherapy ineffective in allergic rhinitis

Two years of sublingual grass pollen therapy is not enough to improve nasal responses in patients with moderate to severe allergen rhinitis, according to findings recently published in JAMA.  

 “International guidelines regarding immunotherapy recommend a minimum of 3 years of treatment with both [subcutaneous or sublingual] delivery methods. If a 2-year regimen had demonstrated long-term benefits in addition to efficacy, this could have represented cost savings in terms of clinical resources and improved convenience for the patient,” Guy W. Scadding, MB, BS, PhD, Imperial College, London, and colleagues wrote. “Because this was not observed, clinicians should be advised to follow established guidelines that recommend at least 3 years’ treatment.”

Researchers randomly assigned 106 patients — 36 received 2 years of sublingual immunotherapy (daily tablets with 15 μg of major allergen Phleum p 5 and monthly placebo injections); another 36 received subcutaneous immunotherapy (monthly injections with 20 μg of Phleum p 5 and daily placebo tablets); and another 34 patients received matched double-placebo. Researchers performed a nasal allergen challenge before treatment, at 1 year, 2 years and 3 years of treatment, with the last challenge coming 1 year after treatment stopped.  Overall, 92 of patients completed the study at 3 years. The minimally clinically important difference for change in total nasal symptom score was 1.08, and a score of 12 was the worst.

Researchers found that in the intent-to-treat population, mean total nasal symptom score for the sublingual immunotherapy group was 6.36 (95% CI, 5.76-6.96) at pre-treatment and 4.73 (95% CI, 3.97-5.48) at 3 years. For the subcutaneous immunotherapy group, it was 6.1 (95% CI, 5.36-6.89) at pre-treatment and 3.89 (95% CI, 3.25-4.54) at 3 years. For the placebo group, the score was 6.06 (95% CI, 5.23-6.88) at pre-treatment and 4.81 (95% CI, 3.97-5.65) at 3 years. Investigators found that after adjusting for baseline, the between-group difference was –0.18 (95% CI, –1.25 to 0.9; [P = .75]).

In an accompanying editorial, Linda S. Cox, MD, University of Miami Miller School of Medicine at Holy Cross Hospital, Fort Lauderdale, Fla., wrote both the subcutaneous and sublingual therapies were associated with significant changes in the secondary exploratory objective assessments of allergen-specific tolerance, the early- and late-phase skin test reactivity, and allergen-specific IgG during treatment and 1 year after therapy was completed.

“Although the mechanism responsible for persistent [allergen-specific immunotherapy trial] AIT efficacy after discontinuation is unclear, the expected outcomes of effective AIT therapy include reduced allergen skin test reactivity and increased allergen-specific IgG levels. An AIT therapy failing to induce significant changes in either parameter would raise questions about its therapeutic efficacy or require an alternative mechanism to explain allergen-specific tolerance,” she wrote.

The FDA approved Grastek and Oralair, the first and second sublingual oral immunotherapies for seasonal grass allergies several years ago. Other research has explored acupuncture as an alternative therapy in treating seasonal allergic rhinitis. – by Janel Miller

Disclosures: Cox reports being on the editorial board for the Journal of Allergy and Clinical Immunology; receipt of personal fees from MedImmune and Novartis for adjudication committee participation; consultation fees from ASIT biotech sa; personal fees from Circassia and Biotech for the safety and data monitoring committee; speaker fees from Greer-Stallergenes; and personal fees from Genentech for an educational video recording. Scadding reports no relevant financial disclosures. Please see the study for a full list of the other authors’ relevant disclosures.