Giving patients with allergic rhinitis or asthma a daily dose of allergens under the tongue appears to be an effective option to help desensitize them to respiratory allergens, according to a review published in JAMA today.
Patients who experience respiratory or asthma symptoms triggered by exposure to allergens have long had the option of undergoing immunotherapy to desensitize them to the offending allergen. In the United States, this typically involves frequent visits to the allergist for injections of tiny doses of allergens over a prolonged period. But in Europe, a less invasive approach, giving tiny doses of allergens in drops or a dissolving tablet administered under the tongue, has become popular. This strategy, called sublingual therapy, accounts for 45% of the immunotherapy offered in Europe, according to the study’s authors. There are no sublingual immunotherapy products approved by the US Food and Drug Administration (FDA) for use in the United States, but some physicians do offer the therapy off label.
To assess the efficacy of sublingual immunotherapy, Sandra Y. Lin, MD, associate professor in the department of otolaryngology, head, and neck surgery at Johns Hopkins School of Medicine, and her colleagues were commissioned by the Agency for Healthcare Research and Quality (AHRQ) to conduct a review of the evidence to date.
Lin and her colleagues found a moderate amount of evidence overall supporting the efficacy of sublingual therapy. They classified the evidence for the use of sublingual therapy for asthma as strong, with 8 of 13 studies finding a 40% or greater improvement in symptoms among treated individuals compared with a control or alternate therapy group; evidence of efficacy for allergic rhinitis was moderate, with 9 of 36 studies showing a 40% or more improvement in symptoms. Overall, medication use among individuals treated with sublingual immunotherapy decreased 40% or more in 16 of 41 studies.
Lin discussed the findings on sublingual therapy with news@JAMA.
news@JAMA: What is sublingual immunotherapy and why might patients choose it over injections?
Dr Lin: You introduce small amounts of what the person is allergic to over the course of years. It just like immunotherapy injections, but for the shots you have go to the physician’s office. Injections typically start out once or twice a week and spread out over time. Subcutaneous immunotherapy is taken daily.
There are certain patients who don’t like shots, especially children. Some people may not have access to specialists to get the shots regularly.
news@JAMA: How often is sublingual immunotherapy offered in the United States?
Dr Lin: It’s kind of unknown. The last survey was about 5 years ago, and at that time it looked like it was not common. There are US physicians (including otolaryngologists, allergists, and family physicians) who use it off label. They use allergens that are FDA-approved for injection use for sublingual immunotherapy.
news@JAMA: What did you learn from your review about the effectiveness of this approach?
Dr Lin: It looks like it is effective, but for physicians in United States, we would want more studies on the allergens used here to determine the most effective doses. The majority of studies we reviewed were done outside of the United States; because of differences in the potency of allergen products from country to country, it may be difficult to translate what an effective dose in the United State would be. Only 7 of the 63 studies we reviewed were from the United States or Canada.
news@JAMA: What were you able to learn about the safety of this approach?
Dr Lin: It wasn’t a comprehensive review of safety; only randomized controlled trials were included in the review. In the studies we reviewed, there were no serious or life-threatening adverse events. But a lot of studies on the safety of therapies are not randomized controlled trials and would not have been included.
news@JAMA: This therapy is already widely used in Europe. Why isn’t it being used as much here?
Dr Lin: It would probably be more widely used if there were FDA-approved sublingual allergens. The dose translations are difficult.
news@JAMA: What should patients know about this therapy?
Dr Lin: Many patients are aware of the therapy and there is a demand. There are patients seeking this out. I think sublingual therapy would be a great way to reach younger patients and those patients in underserved areas of the United States where patients can’t easily get to a physician’s office.