In an examination of a type of treatment for allergic rhinitis and asthma that is used in Europe but not approved by the U.S. Food and Drug Administration, researchers found moderate strength in the evidence from previous studies to support the use of sublingual immunotherapy for the treatment of these conditions.
Sublingual immunotherapy involves administration of aqueous allergens under the tongue for local absorption to desensitize the allergic individual over an extended treatment period to diminish allergic symptoms, according to information in the report, which was published in the March 27 issue of the Journal of the American Medical Association.
Allergic rhinitis affects approximately 20% to 40% of the U.S. population. Considerable interest has emerged in the use of sublingual immunotherapy as a treatment, the researchers wrote. Compared with subcutaneous immunotherapy, sublingual immunotherapy is easy to administer, does not involve administration of injections and may be administered at home, thus avoiding office visits. In 1996, the World Health Organizations Task Force on Immunotherapy “cited the emerging clinical data on sublingual immunotherapy, and recognized its potential as a viable alternative to subcutaneous therapy,” the authors noted. Some physicians in the U.S. use subcutaneous aqueous allergens, off-label, for sublingual desensitization.
Sandra Y. Lin, MD, of the Johns Hopkins University School of Medicine in Baltimore, and colleagues conducted a systematic review of previous studies to examine the effectiveness and safety of aqueous sublingual immunotherapy for allergic rhinoconjunctivitis and asthma. After a review of the medical literature, the researchers identified 63 studies with 5,131 participants that met the inclusion criteria for the review. Participants ages ranged from 4 to 74. Twenty studies, consisting of 1,814 patients, enrolled only children.
The researchers found strong evidence supporting the idea that sublingual immunotherapy improves asthma symptoms, with 8 of 13 studies reporting greater than 40% improvement versus the comparator. They found moderate evidence to support the idea that sublingual immunotherapy decreases rhinitis or rhinoconjunctivitis symptoms, with 9 of 36 studies demonstrating greater than 40% improvement versus the comparator.
In addition, medication use for asthma and allergies decreased by more than 40% in 16 of 41 studies of sublingual immunotherapy with moderate-grade evidence. Moderate evidence supports the use of sublingual immunotherapy to improve conjunctivitis symptoms (13 studies), combined symptom and medication scores (20 studies) and disease-specific quality of life (eight studies), the authors wrote.
Evidence was similar in strength to support the use of sublingual immunotherapy in children for allergic rhinitis and asthma.
Local reactions were frequent, but the authors found no reported episodes of anaphylaxis, life-threatening reactions or death in any treated patients across studies.
“Our review found moderate strength in the evidence to support the use of sublingual immunotherapy for allergic rhinitis and asthma,” the authors wrote. “This indicates moderate confidence that the evidence reflects a true efficacy. However, future research could change the estimate. High-quality studies are needed to answer questions of optimal dosing strategies.”
In an accompanying editorial, Harold S. Nelson, MD, of National Jewish Health in Denver, cautioned against a rush to judgment: “Until sublingual immunotherapy gains FDA approval, physicians who choose to administer off-label sublingual immunotherapy will have limited guidance in selecting effective dosing. In addition, clinicians should be aware that the evidence for efficacy of sublingual immunotherapy is derived from studies of treatment with a single allergen extract, not with combinations of untreated allergens.”
The study abstract is available at http://jama.jamanetwork.com/article.aspx?articleid=1672214.