Traditional Chinese medicine (TCM) has been practiced in humans for thousands of years, and is growing in popularity in the US. Herbal remedies, in particular, are attractive for their low cost and favorable side effect profiles. Recently, animal research on an herbal preparation, derived from a TCM formula called Wu Mei Wan, demonstrated 100% protection from peanut allergy anaphylaxis that persisted for 6 months. In the mouse-model peanut allergy study, mast cell and basophil activation and numbers were significantly decreased as well.
In this issue, Patil et al. (J Allergy Clin Immunol 2011;128:1259-1265.e2) report promising results from an extended safety study in peanut allergic subjects of Food Allergy Herbal Formula 2 (FAHF 2), an FDA-approved botanical drug, in which they also evaluated the immunomodulatory effects of FAHF 2 on basophils. After 6 months of treatment with FAHF 2, significant reductions in basophil activation markers and circulating basophil titers were demonstrated in peripheral blood allergen stimulation tests. Patil et al. also report a concomitant decrease in eosinophils, though no change in specific IgE from baseline values. They speculate that the effect on basophils is independent of IgE-mediated basophil activation and related to FAHF 2.
They report that FAHF 2 is safe based on the absence of change from baseline of laboratory values, pulmonary function testing, and electrocardiographic results. Among 14 subjects that completed the trial, the authors report one adverse event: exacerbation of eosinophilic esophagitis. The subject stopped FAHF 2 and was able to return to the study after gastroenterologic consultation.
In conclusion, FAHF 2 therapy results in reductions in basophil activation, hyperreleasibility, and circulating titers. Patil et al. note that a double-blind, placebo-controlled efficacy study is in planning stages.
We asked senior authors Xiu-Min Li and Hugh Sampson, from Mount Sinai School of Medicine, New York, to tell us about the implications of this study and future research directions:
Li and Sampson: FAHF-2 appeared safe and well-tolerated in this long-term clinical trial of food allergic patients. Although patients were not challenged in this phase I trial, basophil activation was inhibited following therapy as anticipated, suggesting that this formulation may provide a safe immunotherapeutic option for food allergic patients. A phase II trial of FAHF-2 is now underway and if it demonstrates protection against food allergic reactions, the goal is to conduct further studies to obtain FDA approval for FAHF-2 as a prescription botanical drug.