Peanut desensitization therapy increases anaphylactic reactions compared with placebo or avoidance

Reference

Chu DK, Wood RA, French S, et al. Oral immunotherapy for peanut allergy (PACE): a systematic review and meta-analysis of efficacy and safety. Lancet 2019;393(10187):2222-2232.

Synopsis

These authors searched multiple registries and databases (including some I'd never encountered) to identify randomized trials of oral immunotherapy administered to children with peanut allergy. Two authors independently assessed studies for inclusion and for risk of bias. If disagreements occurred, they resolved them by consensus, and brought in a third author when consensus failed. They included 12 studies with a total of 1041 participants (range 10 - 551); all but one study had fewer than 100 patients. The median age of participants ranged from 5 years to 15 years of age. Eight studies compared oral immunotherapy with placebo, 3 with avoidance, and 1 with sublingual immunotherapy. For all the clinical outcomes (anaphylaxis, epinephrine use, allergy symptoms, vomiting, nasal congestion, hospitalization, death), the studies were at low risk of bias. Although oral immunotherapy is effective in desensitization—it takes higher doses of peanut ingestion to trigger symptoms—in all the other outcomes of interest, the rate of events was significantly higher for children who received oral immunotherapy than for control children. For example, the rate of anaphylaxis in treated patients was 22.2% compared with 7.1% in the control group (number needed to treat to harm [NNTH] = 7; 95% CI 3 - 19). The rate of epinephrine use was 8.2% for immunotherapy compared with 3.7% in the control group (NNTH = 22; 10 - 100). Angioedema was more frequent in immunotherapy-treated children than nontreated children (8.8% vs 3.9%, respectively; NNTH = 20, 7 - 200), as were rhinitis and congestion (24.1% vs 17.8%, respectively; NNTH = 16; 7 - 250). Clinical trials use in-clinic food challenges as a surrogate for treatment success, but this meta-analysis clearly demonstrates that an in-clinic food challenge has no correlation with real-world results, and oral immunotherapy leads to dramatically higher rates of anaphylaxis.