The use of the basophil activation test in clinical trials
BAT has a huge potential in clinical trials, both as a biomarker of
clinical response to treatment and in the exploration of possible
underlying mechanisms at the effector cell level. However, there are
practical aspects that need to be considered in order for the results to
be informative, reproducible and comparable between sites. Table
1 presents some of the practical issues and recommendations to
circumvent them and reach an optimal use of BAT in the context of
clinical trials.
In addition to being a surrogate of clinical outcomes of therapies, a
key application of BAT in future clinical trials is to confirm
eligibility of patients for allergy treatment. This is particularly
important in the context of food allergy, for which, at the moment
eligibility for food IT requires the performance of allergen challenge
in patients that have been previously diagnosed with food allergy.
Having to undergo an oral food challenge for a patient known to be
allergic can be quite stressful and additional challenges are often
required in study protocols to assess clinical response to IT. This
approach is unlikely to be well accepted by patients and families in
clinical practice, as patients being considered for treatment have
already been diagnosed with food allergy and may be fearful of exposure
to the allergen, even in the context of an oral food challenge.
Depending on the threshold of reactivity required, challenges done as
part of study protocols can exclude allergic patients with high
threshold of reactivity that would otherwise benefit from such
treatment. Similar considerations can be made for biologicals, which are
often reserved for patients with severe allergic conditions, that may be
at additional risk of undesirable outcomes during allergen challenges.