Report from AAAAI 2019
Report From AAAAI 2019
This weekend’s annual scientific meeting of the American Academy of Allergy, Asthma & Immunology features hundreds of research presentations, many of which provide noteworthy new findings in the field of food allergy. FARE staff are attending the San Francisco conference along with thousands of allergists, immunologists, researchers and other healthcare providers. Here are highlights from some of Sunday’s presentations in the field of food allergy.
- Reaction thresholds in peanut-allergic adults and the influence of exercise and sleep deprivation: a randomised controlled trial: Chun-Han Chan, PhD, and researchers with the United Kingdom’s Food Standards Agency sought to calculate the threshold doses of peanut that elicit reaction symptoms in a UK peanut-allergic population (n=126, mean age 25 years), and measure the effects of sleep deprivation and exercise on reaction thresholds. Following an initial blinded challenge to confirm their peanut allergy, participants underwent three, randomly ordered open peanut challenges: one followed by exercise, one preceded by sleep deprivation, and one without interventions. The eliciting dose of peanut protein was measured and differences between the non-intervention challenge and each intervention were calculated. In the absence of interventions, the mean dose that triggered symptoms was 214 mg peanut protein, but individual results varied widely. Mean eliciting doses for 1, 5 and 10 percent of the population during baseline challenge were 1.3mg, 3.8mg and 7.0mg of peanut protein, respectively. For a challenge followed by exercise or preceded by sleep deprivation, the threshold dose was reduced 45 percent, so that a much smaller dose could trigger a reaction. Patients should be informed about the increased reaction risk associated with exercise and sleep deprivation so that they can incorporate this knowledge into their food allergy management routine.
- Dosing and Safety of Peanut Food Equivalents After Immunotherapy Trials: Consuming peanut on a regular basis after immunotherapy may provide continued protection against accidental exposures, but long-term safety data for this practice is limited. In a longitudinal observational study, Edwin Kim, MD, and colleagues instructed 55 past participants of peanut oral or sublingual immunotherapy (OIT or SLIT) trials who were desensitized to at least 300mg peanut to add peanut to their diet. Ninety percent of trial graduates continued consuming peanut, with three-quarters consuming peanut daily. Reasons for discontinuing peanut included one instance of eosinophilic esophagitis, adverse reactions, and distaste for peanut. Nearly one in four subjects reported reactions, with hives, gastrointestinal symptoms, and oral itching the most common symptoms. While most reactions were treated with antihistamines, one required epinephrine and two required emergency medical care. There was no correlation between peanut dose and reactions. Most of the participants continued eating peanut foods up to eight years after study completion, and these foods may be a safe option for maintaining desensitization. The authors stressed that patients not do this without physician guidance and oversight.
- Safety and Tolerability of a Novel Peptide-Based Immunotherapy for Peanut Allergy: PVX108 is an injectable immunotherapy being developed by the clinical-stage biotechnology company Aravax to treat peanut allergy without triggering allergic reactions during treatment. Unlike peanut extract, PVX108 – a mixture of short, synthetic peptides that are based on the protein sequences of major peanut allergens – does not trigger reactivity in basophils from individuals with peanut allergy. Sixty-six peanut-allergic adults participated in a phase 1 trial to assess the safety and tolerability of PVX108 versus placebo. The first eight cohorts received a single injection, with the dose increasing for each successive cohort. The ninth cohort received six injections at the highest dose (150nmol) over 16 weeks. Most adverse events consisted of short-lived reactions at the injection site. There were no serious adverse events, and none of the adverse events was found to be clinically important by the study’s Safety Review Committee. There was no relationship between dose level and the frequency or severity of adverse events. Study authors including Robyn O’Hehir, MD, PhD, and Sara Prickett, PhD, conclude that PVX108 has a highly favorable safety profile for treatment of peanut-allergic individuals, including those with severe allergy. It remains to be determined if this approach is effective.
- Egg Oral Immunotherapy (OIT) Induces More Rapid Desensitization and Sustained Unresponsiveness (SU) in Egg-Allergic, Baked-egg Tolerant Children than the Addition of Daily Baked-egg Products: Researchers including first author Hugh Sampson, MD, compared the effectiveness of egg oral immunotherapy (OIT) and baked egg products (BEP) in establishing desensitization – the ability to tolerate roughly 7.5 grams of unbaked egg protein at the end of treatment – and sustained unresponsiveness (SU) – the ability to tolerate 7.5 grams of unbaked egg protein after treatment had been discontinued for a period of weeks. Following double-blinded placebo-controlled food challenges with baked and unbaked egg, 52 egg-allergic, baked-egg-tolerant children received either ~2g baked egg protein in BEP or 2.5g egg-white protein in egg OIT daily for up to 2-years. Forty additional children who were unable to tolerate baked-egg were assigned to egg OIT. Over the course of two years, 87 percent of OIT-treated baked-egg tolerant children became desensitized to unbaked egg, and 44 percent achieved sustained unresponsiveness. In contrast, only 22 percent of children treated with BEP became desensitized to unbaked egg, and only 11 percent developed SU. Children who tolerated baked egg and children who did not differed significantly in terms of SU, which was achieved by only 18 percent of the baked-egg-intolerant children who participated in egg OIT. However, differences in desensitization were not significant, with 69 percent of baked-egg-intolerant children able to pass a 7.5g egg protein challenge at the end of egg OIT. Adverse reactions were more common among baked-egg-intolerant participants, but most dosing symptoms were mild. Dosing compliance was about 90 percent for the BEP group and higher for both egg OIT groups. More than one in four participants treated with BEP withdrew from the study, compared to one in eight egg OIT participants who tolerated baked egg and one in six who did not. Researchers concluded that egg OIT appears superior to consumption of baked egg products in inducing both desensitization and SU in egg-allergic, baked-egg-tolerant children.