Conference Coverage

Long-term peanut sublingual immunotherapy found safe

Publish date: March 5, 2017

AT THE 2017 AAAAI ANNUAL MEETING

ATLANTA – Peanut sublingual immunotherapy induces clinically significant desensitization in the majority of subjects and can induce sustained unresponsiveness in a subset of children treated for 36-60 months, results from a small study suggest.

“Sublingual immunotherapy [SLIT] is an easy-to-administer treatment that appears to be safe, and with extended treatment, may provide a clinically significant amount of protection with the potential for a lasting effect,” one of the study authors, Edwin H. Kim, MD, said in an interview in advance of the annual meeting of the American Academy of Allergy, Asthma, and Immunology.

^{Doug Brunk/Frontline Medical News}

Dr. Edwin H. Kim

To date, most phase III studies for the treatment of peanut allergy have involved oral immunotherapy and epicutaneous immunotherapy, but SLIT has been studied for the past 10 years or so, according to Dr. Kim, director of Dr. A. Wesley Burks’s Food Allergy Initiative research group at the University of North Carolina at Chapel Hill. In fact, an earlier study he and his associates published showed that SLIT can desensitize patients with peanut allergy, compared with placebo, after only 12 months of treatment (J Allergy Clin Immunol. 2011;127[3]:640-6). “However, the effect range was broad, with some tolerating the maximum tested 8-10 peanuts, some falling in the middle, and a few who were no better than placebo,” Dr. Kim said. “The current study is the long-term extension of that study, with the original 18 patients plus an additional 21 more completing 3-5 years of treatment. Our questions were 1) would a longer treatment course lead to a stronger effect, and 2) would the longer treatment course lead to a lasting effect?”

To find out, the researchers treated 37 patients with 2 mg of peanut SLIT for 36-60 months and then assessed a 5,000-mg peanut oral food challenge to further assess desensitization. Those who passed the challenge discontinued SLIT for 2-4 weeks and were then re-challenged with 5,000 mg of peanut protein to assess for sustained unresponsiveness.

“Existing data suggested that about 50% of patients on oral immunotherapy develop sustained unresponsiveness, which was defined by being able to tolerate the same full amount of peanut 1 month after stopping therapy,” Dr. Kim said. “As the assumption was that SLIT would have a more modest effect, it was unclear if any patients at all on SLIT would develop sustained unresponsiveness.”

Of the 37 subjects who completed the study, 32 (86%) safely ingested more than 300 mg of peanut and 12 (32%) passed the oral food challenge at the end of SLIT therapy. The median amount of peanut tolerated was 1,750 mg (compared with 1,710 mg in the original 12-month paper). The 12 subjects who passed the oral food challenge were re-challenged with 5,000 mg of peanut 2-4 weeks after discontinuing SLIT. Of these, 10 (27%) demonstrated sustained unresponsiveness. Dr. Kim characterized the results as “better than we would have expected.”

He acknowledged certain limitations to the study, including the lack of an entry food challenge to determine a baseline reaction threshold and the lack of a placebo arm for the study’s extended maintenance phase.

Dr. Kim reported having no financial disclosures.

dbrunk@frontlinemedcom.com