Ragweed Allergy Relieved by Daily Oral Immunotherapy

Jennifer Garcia

May 10, 2013

Symptoms of ragweed allergy may be reduced with daily sublingual immunotherapy, according to a new, multicenter study published in the May issue of the Journal of Allergy and Clinical Immunology.

The new study, led by Peter S. Creticos, MD, from Johns Hopkins University School of Medicine in Baltimore, Maryland, evaluated the safety and efficacy of a sublingual allergy immunotherapy tablet (AIT) in 784 adults with a physician-diagnosed history of ragweed-induced allergic rhinitis with or without conjunctivitis of 2 or more years' duration. The Biologics License Application for this product was recently accepted for review by the US Food and Drug Administration.

Patients were enrolled between September 2009 and May 2010 and were required to demonstrate sensitization to ragweed via skin prick test and the presence of ragweed-specific IgE. Patients were randomly assigned to treatment groups of 1.5, 6, or 12 units daily of Ambrosia artemisiifolia major allergen 1 or placebo for a 52-week period. Symptoms were scored as follows: 0, no symptoms; 1, mild symptoms; 2, moderate symptoms; or 3, severe symptoms. Medication use was scored as follows: loratadine 10-mg tablet, 6 points per tablet, a maximum of 6 points per day; olopatadine HCl 0.1% ophthalmic solution, 1.5 points per drop, a maximum of 6 points per day; mometasone furoate nasal spray 50 mg, 2 points per spray, a maximum of 8 points per day; and prednisone 5-mg tablet, 1.6 points per tablet, a maximum of 16 points per day. Patients recorded their symptoms and medication use scores daily in an electronic diary.

The researchers found that treatment with 1.5, 6, and 12 A artemisiifolia major allergen 1 ragweed AIT during peak ragweed season reduced the daily symptoms and the need for allergy rescue medication by 9% (P = .22), 19% (P = .01), and 24% (P = .002), respectively, compared with placebo. Treatment effect was found to be similar during the entire season, with reductions of 12% (P = .09), 18% (P = .01), and 27% (P < .001), respectively, compared with placebo.

The study authors also documented an increase in ragweed-specific IgG4 levels in preseason, in-season, and postseason measures among patients in the active groups compared with those receiving placebo (P < .001 for each AIT group at each time).

"These results establish a dose-response relationship of AIT in the largest clinical trial to date of this therapeutic modality's use in subjects with ragweed-induced" allergic rhinitis with or without conjunctivitis, note Dr. Creticos and colleagues.

Adverse events (AE) included application-site reactions in the mouth, throat, and ear; most were mild to moderate in severity. There were no serious local or systemic reactions reported. The most common AE leading to discontinuation of therapy was tongue edema, which occurred in 10 patients.

The authors acknowledge study limitations such as the inherent variability in pollen exposure and the introduction of bias resulting from compromised blinding from application-site reactions among patients receiving active treatment. The researchers also note that full courses of AIT are typically administered for 3 to 5 years, so the 1-year follow-up of this study may also be a limitation.

"This study is monumental in setting the stage for safe, effective at-home therapy with a single sublingual allergen that is convenient and treats the condition rather than just symptoms," Christopher C. Randolph, MD, from the Center for Allergy, Asthma & Immunology, Waterbury, Connecticut, noted in an email interview with Medscape Medical News. Dr. Randolph was not involved with the current trial.

However, "[a]n estimated 26% of the American population is ragweed-sensitive, but a large population is multiply sensitized, and this population will need to be addressed with sublingual therapy if this therapy is to impact allergen sensitivity in the US population," he added.

Funding for the study was provided by Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc. One of the authors has received financial support from Merck, Proctor and Gamble, and sanofi-aventis. One author has received financial support from Merck and has consultancy arrangements with Stallergenes. One author has consultancy arrangements with Merck, Greer Labs, Stallergenes, and Circassia. Four of the authors are employed by Merck Sharp & Dohme Corp. Dr. Randolph has disclosed no relevant financial relationships.

J Allergy Clin Immunol. 2013;131:1342-1349. Abstract