Other - Food Allergy
Stephen J. Galli, MD
Stanford University, Department of Medicine - Sean N Parker Center for Allergy and Asthma Research, Department of Pathology, Stanford University School of Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine
Dietary avoidance is currently recommended for peanut allergies. We evaluated sustained effects of treating peanut allergy with oral immunotherapy (OIT) in the first phase 2 randomized-controlled long-term study in adults and children.
In a double-blind, placebo-controlled, randomized study, 120 peanut-allergic participants (7-53 years) received up to 4 g of peanut protein—about one tablespoon of peanut butter—or placebo daily for 3 years. Participants received placebo (N=25) or peanut protein (N=95) over 104 weeks; 60 then discontinued (peanut-0) while 35 received 300 mg daily—about one peanut kernel—(peanut-300). Double-blind, placebo-controlled food challenges (DBPCFCs) to 4 g peanut protein were conducted at baseline, week 104, and every 13 weeks thereafter for one year.
The primary endpoint was reached at week 117 after 3 months of discontinuation to test sustained unresponsiveness: 21/60 (35%) peanut-0 participants passed the challenge with no reaction versus 1/25 (4%) placebo (primary endpoint, P=0.002). Time to failure was significantly longer in peanut-300 vs. peanut-0 vs. placebo arms (P<0.0001). The percentage of participants passing DBPCFCs in peanut-300 declined significantly (weeks 104-156; 83% vs. 37%, P<0.001). Adverse allergic reactions decreased over time in all arms. Peanut-specific IgG4/IgE levels were higher (P<0.001), and Ara h 2-specific IgE (P<0.001) and basophil activation responses (P=0.037) were lower at baseline in those achieving sustained unresponsiveness at week 117.
Peanut OIT can desensitize most peanut-allergic individuals to 4 g peanut protein but discontinuation, or even a reduction to 300 mg daily, increases the likelihood of regaining clinical reactivity to peanut.