Skin patch safe, promising for treating peanut allergy
Delivery of peanut protein through the skin by means of a wearable skin patch, an approach known as epicutaneous immunotherapy, is safe and shows promise for treating peanut allergy, especially in young children, according to interim results of an ongoing study.
“Despite active avoidance, the risk of an adverse reaction from exposure is ongoing,” said researchers, who noted that peanut allergy presents the most common life-threatening food allergy. “An effective treatment for peanut allergy would be highly desirable.”
The multicentre, double-blind, phase II trial randomized 74 individuals (aged 4–20 years, median 8.2 years) with peanut allergy to placebo (n=25), 100 µg (VP100; n=24) or 250 µg (VP250; n=25) peanut immunotherapy delivered through a skin patch known as Viaskin Peanut. The participants were assessed for treatment success, which referred to success in a 5,044 mg protein oral food challenge or achievement of ≥10-fold increase in successfully consumed dose (SCD) of protein at week 52 compared with baseline. [J Allergy Clin Immunol 2016;doi:10.1016/j.jaci.2016.08.017]
Compared with placebo (12 percent), there were more participants in the VP100 group (46 percent; p=0.005) and VP250 group (48 percent; p=0.003) who had achieved treatment success at week 52. Treatment success was significantly higher among younger children (aged ≤11 years) compared with those older than 11 years (61 percent; p=0.0003 for VP250 and 59 percent; p=0.0006 for VP100 versus 6 percent for placebo).
SCD also changed significantly from 0 mg of protein in the placebo to 43 mg and 130 mg in the VP100 (p=0.014) and VP250 (p=0.003) groups, respectively.
Significant increases were observed in both peanut-specific IgG4 levels and IgG4/IgE ratios (p<0.0001 for both) between treatment and placebo groups. Additionally, there were trends toward reduced peanut specific TH2 cytokines (p=0.059 for interleukin [IL]-4 and p=0.04 for IL-13) and basophil activation.
“The trends seen in both basophil and T-cell responses suggest that exposure to peanut through intact skin might modulate TH2 responses and basophil reactivity,” researchers said.
Compliance with treatment was high (97.1 percent of doses), suggesting that the patch was convenient and well tolerated.
Although patch-site reactions occurred more frequently in the treatment groups (79.8 percent of VP100 and 79.7 percent of VP250 doses) compared with placebo (14.3 percent; p=0.003), most were mild (≤grade 2). Reactions extending past the patch area occurred in 8.9 percent of VP100 and 16.2 percent of VP250 doses compared with 1.5 percent of placebo dose, while nonpatch-site reactions were uncommon (0.2 and 0.1 percent of VP100 and VP250 doses vs 0.2 percent of placebo dose).
“Additional time on therapy is needed to determine whether the modest clinical changes noted will be enhanced after a longer duration of therapy and will provide clinically meaningful protection from anaphylaxis,” said researchers, who were awaiting further results at 130 weeks of the study.