In those patients who are initiated on omalizumab for multiple food allergies, once baked egg and baked milk are introduced into the diet, do you rely upon skin prick testing and/or ImmunoCAP testing in order to make the decision to introduce prepared egg or whole milk into the diet?

When the patient is on omalizumab, neither skin prick testing or serum IgE testing would be reliable biomarkers to follow.

Omalizumab is known to reduce (not necessarily eliminate) skin prick responses.

Ledford, PMID 30819523

In the short term, serum-specific IgE may even increase prior to a possible decrease in the IgE from omalizumab.

Mizuma et al., PMID 26790100

Decision-making thus would not be recommended on the basis of following either skin prick or serum IgE tests. Discussion with the patient based on time and clinical history, similar patients (physician experience) would come into play. Additionally, since up to 40% of patient in OUTMATCH were able to pass significant challenges discussion would have to include whether omalizumab shou...

While the precise answer is unknown, there is considerable data that is relevant.

In the prior studies, Xolair (omalizumab) was administered anywhere from 12 to 20 weeks before food challenges were performed.

For example, and the most recent studies that led to FDA approval of using Xolair to treat patients with food allergies, Xolair (omalizumab) was administered for anywhere from 16 to 20 weeks prior to the food challenges.

These challenges were with the food as it would be normally consumed. Since the question has to do with baked food challenges, I would think the 12 to 16-week pretreatment should be adequate.