Oral immunotherapy feasible for adults with food allergy
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Key takeaways:
- Oral immunotherapy was considered easy for 57 patients and difficult for 40 patients, with 11 failures.
- Specific IgE totals and the ratio between specific and total IgE were predictive of the therapy’s success.
SAN ANTONIO — Oral immunotherapy was feasible for adults with food allergy, with specific and total IgE predicting treatment success, according to data presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting.
“There is still an important gap of knowledge in clinical practice guidelines concerning oral immunotherapy in the adult food allergic population,” Nofar Kimchi, MD, resident in the allergy section of the Montreal University Hospital Center, said during her poster presentation.
“While experience has shown us that oral immunotherapy is indeed feasible in the adult age group, there remains a lack of published data describing this experience, which could be useful to inform patients and clinicians in their shared decision-making process concerning oral immunotherapy.”
During the monocentric and descriptive study, Kimchi and colleagues conducted a retrospective chart review of 97 adults (median age [interquartile range (IQR)] = 20 years [19-26]; men = 50) who had OIT between January 2017 and August 2022.
The most common allergies included peanut (73.8%), milk (19%), egg (14%), walnut (12%), cashew (11%), shellfish (7%) and pistachio (5%). Also, 41% of the patients reported multiple food allergies.
Overall, the researchers said that 57 patients had successful easy OIT, 40 patients had successful but difficult OIT and 11 patients had failed OIT.
“Treatment failure was defined as discontinuing treatment due to lack of tolerance or compliance,” Kimchi said.
Also, Kimchi noted the highly heterogenous nature of the cohort, including patients with high reactivity thresholds and low IgE as well as patients who were highly reactive.
“While no statistically significant predictors of success were identified, serum allergen specific IgE levels were associated with greater odds of difficult oral immunotherapy,”
Mean specific IgE totals included 14.3 kU/L (IQR = 2.8-48.9) for patients with easy OIT and 54.5 kU/L (IQR = 29.6 -> 100) for those with difficult OIT (P < .001).
Overall, patients with successful OIT had a mean specific IgE total of 23.9 kU/L (IQR = 4-68.4), while those who failed had a mean specific IgE total that was greater than 100 kU/L (IQR = 35.9 -> 100; P = .006).
Also, median ratios of specific and total IgE included 7.6% (IQR = 2.2% to 16%) for the easy group and 20% (IQR = 10-34) for the difficult group (P < .001), with 10% (IQR = 3.4% to 23%) for the successful population as a whole and 24% (IQR = 12% to 34%) for the population whose treatment were failures (P = .02).
Considering these findings, the researchers said that specific IgE and the ratio between specific and total IgE both helped predict treatment outcomes. These measurements also were highly correlated, the researchers said, and these associations were not independent.
“The qualitative analyses of the cases suggest that while cofactors in substance use can be a concern in this age group, they were not limiting factors for the majority of our patients,” Kimchi said.
The researchers further noted that their cohort had a higher rate of success than an adult cohort from a previous study in Israel and attributed their success to a higher rate of milk OIT in that study (55%) and greater use of omalizumab (Xolair; Genetech, Novartis), including 31% of their patients, in their study.
“Our adult oral immunotherapy cohort shows that oral immunotherapy is indeed feasible in the adult population,” Kimchi said. “Moving forward, larger studies are needed to evaluate oral immunotherapy in adults more expansively.”
Reference:
Epstein-Rigbi N, Allergy. 2021;doi:10.1111/all.15537.
Perspective
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There has been some data to suggest that OIT is less effective for adults compared with children. The authors of the study reflected in the poster point out an Israeli study suggesting this child-adult difference. The FDA approved commercial peanut OIT product was not approved for initiation in adults because the primary study did not show efficacy in adults. Ultimately, this single-center study of adults undergoing OIT adds some insights on a topic that is not well researched.
The primary take-home point may be that OIT should not be excluded as a potential therapy for adults. There can be success. An important point identified here that substantiates most studies of OIT is that people with high levels of sensitization to the food, compared to those who may be considered less allergic, have a lower chance of success.
However, there is a laundry list of caveats in this single-center study that prevent gleaning strong, specific conclusions to impart to patients for care. Among them: the adults were young, only around 20 years of age; the group size was modest; there was an unclear range of starting degree of allergy thresholds; and some had high reactivity thresholds; selection for who would be offered and accepted treatment is not stated; treatments included a biologic (omalizumab) for a subset; definitions of ease/difficulty with treatment was subjective; and OIT regimens/foods varied.
It is too early to say whether doctors can use these findings to improve their care. Ultimately, large, multicenter studies that use specific entry criteria, monitoring and treatment regimens in adults would be needed to obtain generalizable information.
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Kimchi N, et al. Abstract 102. Presented at: AAAAI Annual Meeting; Feb. 24-27, 2023; San Antonio.
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