27 October 2016. A skin patch worn by children with peanut allergies was shown in a clinical trial to increase the wearers’ tolerance for peanuts by 10 times after 1 year. Results of the study, funded by National Institute of Allergy and Infectious Diseases, part of National Institutes of Health, appear in the 26 October issue of the Journal of Allergy and Clinical Immunology (paid subscription required).
Allergies to peanuts and other foods are a result of the body’s immune system misinterpreting certain foods as pathogens, and responding by the release of histamines, chemicals in the body causing the allergy symptoms. In most cases, the symptoms are mild, such as runny nose and itching, but people with peanut allergies face a real and elevated risk of anaphylaxis, a life-threatening condition constricting airways, swelling the throat, and causing a sharp drop in blood pressure. Food Allergy Research and Education says some 15 million people in the U.S. and 17 million people in Europe have a food allergy, with growing numbers of people reporting an allergy.
The skin patch is developed by DBV Technologies, a medical device company in Montrouge, France and New York. The patch is based on the company’s Viaskin technology that sprays electrically charged proteins — in this case, small quantities of peanut protein antigens — in a liquid solution that dries and attaches to the back of the patch. The patch forms a condensation layer with the skin, hydrating and dissolving the antigens that penetrate the skin’s outer layers.
In the skin’s outer layers are immune system cells known as Langerhans cells that transport the antigens directly to lymph nodes and T-cells, where they initiate an immune response for training the immune system to tolerate peanut antigens. By transporting antigens through Langerhans cells, says DBV Technologies, the antigens bypass the blood stream, thus avoiding a system-wide immune response.
The clinical trial was led by pediatric immunologists Stacie Jones of University of Arkansas for Medical Sciences in Little Rock and Hugh Sampson of Mount Sinai medical school in New York, under the auspices of Consortium of Food Allergy Research, or CoFAR, that studies a number of food allergies. The trial recruited 74 children and young adults, age 4 to 25, at 5 sites in the U.S.
All 74 participants wore a Viaskin patch, which they changed every day for 1 year, with the individuals randomly assigned to receive a high-dose (250 microgram), low-dose (100 microgram), or empty placebo patch. Participants started by wearing the patch for 3 hours a day, gradually increasing the amount of time with the patch over 21 days, to 24 hours. After 1 year, participants were asked to eat 10 times more peanut protein than they could tolerate before the study began, up to 5,044 milligrams, and were watched for adverse reactions to the treatments. Follow-up observations continue for 30 months.
Results show that after 1 year, nearly half of both the high-dose (48%) and low-dose (46%) patch recipients were able to consume the 10-fold increase in peanut protein, compared to 12 percent of those receiving the placebo patch. The researchers say the immune responses generated by the patch were similar to responses found in studies of immunotherapies for food allergies. The treatments show more success among younger children, age 4 to 11, than adolescents and young adults age 12 and over.
In addition, adherence to the treatments was high, with nearly all participants continuing the treatments for 1 year. Some 80 percent of respondents receiving the low or high dose patch noted mild or patch-site reactions, with no adverse effects reported.
“Risks of severe reactions from accidental exposure are a constant threat for these patients, even when following a peanut-free diet,” says Jones in a DBV Technologies statement. “A novel treatment that can provide an essential balance between safety and efficacy will be of key importance in the treatment of these patients.”
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