Extensive use of omalizumab for asthma, FDA approved since 2003. Anaphylaxis rate is 0.1-0.2% so initial injections must be supervised (and adrenaline provided for home). Use in under 5s only approved since 2024, however.

Various small studies showed benefit in food allergy. 2024 OUtMATCH study of 180 patients (mostly children) with peanut allergy and at least 2 other food allergies found that after 16 weeks treatment, 67% of those treated with omalizumab could tolerate a 600mg single dose (1044mg cumulative) of peanut plus 1000mg challenge of the 2 other foods (cashew, egg, milk, walnut, hazelnut, wheat all included).

Dosing is as done for asthma, based on weight and total IgE.

1 study found efficacy with only 3-8 weeks of treatment. Duration of regimens varies from 16-34 weeks.

Sustained unresponsiveness (“cure”) has not yet been documented. In fact, protection seems to drop off within 8-12 weeks, so important to continue OIT.

Skin testing and sIgE levels are unreliable once omalizumab is started, so the only way to monitor response to treatment is with food challenges.

Study of omalizumab as monotherapy, but also as adjunct to multi-food oral immunotherapy. 180 children (age 1+) and 3 adults.

Lots more studies underway, now that Omalizumab approved for treatment of food allergy.

All have peanut allergy, but at least 2 other food allergies (milk, egg, wheat, cashew, hazelnut, walnut).

“Standard” dosing based on weight and total IgE levels, with omalizumab (ranging from 75 mg to 600 mg) administered every 2–4 weeks for a duration of 16–20 weeks.

After 16 weeks Omalizumab, 66.7% achieved challenge dose of 600mg peanut AND 1000mg for the other 2 foods. Success associated with higher total IgE (?), 2 week (vs 4 week) dosing (!), smaller SPT size, higher tolerated baseline threshold dose.

No change in quality of life!!! Only difference in adverse events was skin reactions to injections!

Threshold maintained or increased during open label extension (24 weeks total). Most people with milk, egg or wheat managed to continue foods in diet after negative challenge for 12 months (61-70%), only 38-56% managed to continue peanut or tree nuts… Consumption generally declined over time, apparently due to symptoms and patient preference. Higher screening challenge threshold predicted success, not surprisingly. 2 cases of EOE.

Stage 2 is 8 weeks of omalizumab for everyone, then either omalizumab for another 8 weeks PLUS OIT, or else omalizumab alone (placebo OIT) for 52 weeks total OIT.

Stage 3 (n=80) randomised to continued omalizumab or OIT. Initial Dose escalation was 3, 30, 60, 125, 250, 250, 375mg of each food, every 15 minutes.

Showed more than 60% of patients achieved endpoint after 12 months, whether doing omalizumab alone or doing OIT. Safety similar – 2 of OIT group had serious adverse events during real world transition. 1 case of EOE after omalizumab.

Thomas Casale review says don’t exclude high threshold patients, as still likely to have meaningful benefit. Dosing can include total IgE <30 or weight <10kg, just use nearest. Aim to suppress total IgE to below 10 IU/ml – calculate 0.005mg/kg per week for each 1IU/ml – see table here.

Of the 33% who did not respond, an extra 34% did seem to respond with extension – the rest did not (or actually worsened). Given this treatment is expensive, consider at least a single dose challenge at 20 weeks. Quality of life jumped significantly after challenge, once families were aware of response to therapy (since not ingesting!).

For milk/egg/wheat in young children, discontinue and do challenge at 4 months (5 half lives) after to see if resolved.

Good that no obvious safety problem with children under 6 (not previously studied). Potential concern around herpesviruses, bacterial infections, visual disorders. Congenital absence of IgE (!) possibly associated with asthma, otitis media, sinusitis, autoimmune disorders and cancer…

Similar review by Aikaterini Anagnostou from AAAI.

Multi-food OIT

Many people allergic to one nut are allergic to other nuts, and/or other foods.

Doing simultaneous OIT for multiple nuts makes sense in terms of the time/cost saving. Outcomes are pretty similar. The more foods, the more complicated – it also means a higher amount of maintenance

Obviously makes sense if younger age, lower IgE, higher reaction thresholds.

You need to think about what you are going to choose to treat, and what/if you need to challenge. Often some of the nut allergies come up on testing only and have never been eaten, so probably less important to challenge. You can always adjust the regimen to pause one food and continue another, if things are not going to plan. Most clinics just reduce both/all foods if there is a reaction, for simplicity.