Impact of using less objective symptoms to define tolerated dose during food challenges: A data-driven approach

Standardizing outcomes in food allergy research: aligning clinical trials with patient priorities

PURPOSE OF REVIEW

This review explores the clinical outcomes used in immunoglobulin E (IgE)-mediated food allergy (FA) intervention studies, emphasizing unmet need for patient-centred outcomes. Standardizing outcome measurement is critical as research into FA treatments, particularly food immunotherapy, expands. Here we discuss how outcomes should reflect the multidimensional impact of FA on people's lives.

RECENT FINDINGS

Current evidence reveals a discrepancy between clinical trial outcomes and those most valued by patients and carers. While trials often prioritize changes in reactivity thresholds or immunological markers, patients and carers emphasize need in reducing severe reactions, improving quality of life, and enhancing confidence in disease management. This disparity highlights importance of harmonization efforts to guide FA research.The Core Outcome Measures for Food Allergy (COMFA) initiative recently identified two core outcomes - 'allergic symptoms' and 'quality of life' - through an international consensus process involving patients, caregivers, clinicians, and researchers. Outcomes like 'desensitization' and 'remission/sustained unresponsiveness' were considered important but were not seen as the most critical.

SUMMARY

Developing and implementing a COS for FA intervention studies is essential to align research with patient priorities, ensuring meaningful improvements in routine clinical care. Standardized outcome measurement will generate robust evidence, inform clinical practice, and empower patients and caregivers in decision-making about FA management.

Re-evaluating treatment success in trials of peanut oral-immunotherapy: impact of different definitions on efficacy outcomes

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is increasingly popular as a treatment strategy for food allergy. Unfortunately, there is significant heterogeneity in reported outcomes, specifically in the dose-thresholds selected for evaluation and the symptoms used to define a "tolerated dose". These considerations are often investigator-driven and do not consider patient perspectives.

RECENT FINDINGS

A systematic review by the EAACI CO-FAITH taskforce recently flagged the need to better standardize and harmonize outcomes used in clinical trials of food-AIT. Using less objective symptoms to define dose-limiting symptoms can underestimate the reaction threshold determined at baseline food challenge. As a consequence, this can overestimate the efficacy of food-AIT by 15%. In this review, we perform an individual patient data (IPD) meta-analysis using data from three randomized-controlled trials and one real-world registry, to evaluate how the definition of dose "tolerance" impacts upon reported desensitization rates.

SUMMARY

This analysis provides insight into how clinical efficacy rates for food-AIT are impacted by using different dose thresholds and definitions for when a dose might be consider tolerated. Using more patient-centric outcomes may be a more useful metric to harmonize reporting of outcomes and inform clinical practice, paving the way towards reaching a consensus on outcome reporting in trials of food-AIT.

AAAAI-EAACI PRACTALL: Standardizing oral food challenges-2024 Update

This common statement of the American Academy of Allergy, Asthma and Immunology (AAAAI) and The European Academy of Allergy and Clinical Immunology (EAACI) provides an update of the 2012 published guidelines on food challenges. The guidelines equally address food challenges in the research and the clinical settings. They first address the diagnostic tests which can guide the decision to conduct a challenge. Safety of food challenges is prime, and the various procedures and safety issues as well as medications potentially involved in challenges are extensively discussed. Challenges are suggested to be conducted with semi-logarithmic incremental doses based on the protein content, typically for IgE-mediated food allergy with intervals of 20-30 min between doses. Specific protocols for other types of reactions such atopic dermatitis or gastrointestinal food allergy are detailed separately. Proper stopping criteria are essential in order to reduce the risk of false-positive diagnoses, but also severe reactions. The guidelines recommend criteria based on "go on," "stop," or "observation." These revised guidelines will clearly provide much needed guidance for food challenges in the research and clinical settings. They will continue to evolve with new diagnostic tests or new needs in the field of food allergy.

Challenge-verified thresholds for allergens mandatory for labeling: How little is too much for the most sensitive patient?

BACKGROUND

It is mandatory to label food products with the 14 main allergens in the EU. Reasonable allergen labeling requires knowledge of population-based thresholds derived from food challenges. The aim of this study was to evaluate the threshold-distribution in clinically verified food allergic patients for allergens mandatory for labeling.

METHODS

All positive open oral food challenges and double-blind placebo-controlled food challenges (DBPCFC) performed at the Allergy Center, Odense University Hospital, Denmark (2000-2022) were included. For each included challenge, the cumulative threshold (LOAEL) was obtained and NOAEL estimated. Data were modelled as an interval censored log-normal distribution.

RESULTS

Overall, 38 of all 2612 challenges (1.5%) in 1229 patients (717 male, 986 children) reacted to <5 mg protein. The majority of the most sensitive patients reacted with a Sampson severity score of 2-3. Using interval censored log-normal models only five groups (hens´ egg, fish, peanut, milk, tree-nuts) elicited reactions after ingestion of 0.5 mg protein and in low frequencies of the population. Hen's egg was the most potent allergen, with reactivity to <0.5 mg protein in 0.24% [0.13-0.44%] of egg allergic patients while the estimated fraction of allergic patients reacting to a eliciting dose on 0.5 mg protein for most other allergens were below 0.04%.

CONCLUSION

Our data demonstrates that the majority of food allergic patients as expected tolerating traces of allergenic foods without developing severe allergic symptoms and signs. Hen's egg appears to be the food most likely to elicit reactions in the most sensitive individuals at very low doses.

Evaluation of clinical outcomes of efficacy in food allergen immunotherapy trials, COFAITH EAACI task force

Food allergy is a global public health problem that until recent years lacked any aetiological treatment supported by academy, industry and regulators. Food immunotherapy (AIT) is an evolving treatment option, supported by clinical practice and industry trial data. Recent AIT meta-analyses have highlighted the difficulty in pooling safety and efficacy data from AIT trials, due to secondary heterogeneity in the study. An EAACI task force (CO-FAITH) initiated by the Paediatric Section was created to focus on AIT efficacy outcomes for milk, egg and peanut allergy rather than in trial results. A systematic search and a narrative review of AIT controlled clinical trials and large case series was conducted. A total of 63 manuscripts met inclusion criteria, corresponding to 23, 21 and 22 studies of milk, egg and peanut AIT, respectively. The most common AIT efficacy outcome was desensitization, mostly defined as tolerating a maintenance phase dose, or reaching a particular dose upon successful exit oral food challenge (OFC). However, a large degree of heterogeneity was identified regarding the dose quantity defining this outcome. Sustained unresponsiveness and patient-reported outcomes (e.g. quality of life) were explored less frequently, and to date have been most rigorously described for peanut AIT versus other allergens. Change in allergen threshold assessed by OFC remains the most common efficacy measure, but OFC methods suffer from heterogeneity and methodological disparity. This review has identified multiple heterogeneous outcomes related to measuring the efficacy of AIT. Efforts to better standardize and harmonize which outcomes, and how to measure them must be carried out to help in the clinical development of safe and efficacious food allergy treatments.

Feast for thought: A comprehensive review of food allergy 2021-2023

A review of the latest publications in food allergy over the past couple of years confirmed that food allergy is a major public health concern, affecting about 8% of children and 10% of adults in developed countries. The prevalence of food allergy varies around the world, with the increase being driven mainly by environmental factors, possibly together with genetic susceptibility to environmental changes. A precise diagnosis of food allergy is extremely important. Both new tests (eg, the basophil activation test) and improved optimization of information provided by existing tests (eg, the skin prick test and measurement of specific IgE level) can contribute to improving the accuracy and patients' comfort of food allergy diagnosis. Understanding the underlying immune mechanisms is fundamental to designing allergen-specific treatments that can be safe and effective in the long term. New discoveries of the immune response to food allergens, including T-cell and B-cell responses, have emerged. Novel therapeutic approaches are being trialed at various stages of development as attempts to allow for more active intervention to treat food allergy. Prevention is key to reducing the increase in prevalence. Early introduction of allergenic foods seems to be the most effective intervention, but others are being studied, and will, it is hoped, lead to modification of the epidemiologic trajectory of food allergy over time.

Sesame eliciting and safe doses in a large sesame allergic population

BACKGROUND

Sesame is a significant food allergen causing severe and even fatal reactions. Given its increasing prevalence in western diet, sesame is listed as an allergenic food requiring labeling in the United States and EU. However, data on the population reaction doses to sesame are limited.

METHODS

All sesame oral food challenges (OFCs), performed either for diagnosis or for threshold identification before the beginning of sesame oral immunotherapy (OIT) between November 2011 and July 2021 in Shamir medical center were analyzed for reaction threshold distribution. Safe-dose challenges with 90-120 min intervals were also analyzed.

RESULTS

Two hundred and fifty patients underwent 338 positive OFCs, and additional 158 safe-dose OFCs were performed. The discrete and cumulative protein amounts estimated to elicit an objective reaction in 1% (ED01) of the entire cohort (n = 250) were 0.8 mg (range 0.3-6.3) and 0.7 mg (range 0.1-7.1), respectively, and those for 5% of the population (ED05) were 3.4 mg (range 1.2-20.6) and 4.5 mg (range 1.2-28.8), respectively. Safe-dose OFCs showed similar values of ED01 (0.8, 0.4-7.5 mg) and ED05 (3.4, 1.2-22.9 mg). While doses of ≤1 mg sesame protein elicited oral pruritus in 11.6% of the patients, no objective reaction was documented to this amount in any of the challenges, including safe-dose OFCs.

CONCLUSIONS

This study provides data on sesame reaction threshold distribution in the largest population of allergic patients studied, with no right or left censored data, and with validation using a safe-dose OFC. It further supports the current methods for ED determination as appropriate for establishing safety precautions for the food industry.

Promises and Remaining Challenges for Further Integration of Basophil Activation Test in Allergy-Related Research and Clinical Practice

More than 20 years after having been initially proposed, the relevance and usefulness of basophil activation test (BAT) for the field of allergy research and testing were demonstrated on many occasions. Leveraging the fully open format of a flexible, whole blood-based functional assay, BAT has been shown to be equally important for fundamental research, clinical research, and diagnosis. Regardless of whether the focus of a study is on the characterization of the allergenic moiety, on the patient side, or on the study of the fundamental processes involved in the allergic disease or its treatment, BAT enables the gathering of very important insights. In spite of this, its full capabilities have yet to be leveraged. Various bottlenecks, including but not limited to assay logistics, robustness, flow cytometry access, and/or expertise, have indeed been limiting its development beyond experts and long-term users. Now, various initiatives, aiming at resolving these bottlenecks, have been launched. If successful, a broader use of BAT could then be contemplated. In such a situation, its more thorough integration in clinical practice has the potential to significantly change the allergic patient's journey.