Research on a Roll
From the Spring 2010 special edition on the Future of Allergies.
What’s in the pipeline for food allergy treatments.
Idea: Peanut Allergy Vaccine
What’s Involved: The treatment is based on immunotherapy – that is, by slowly introducing the immune system to something it is allergic to, the system will eventually learn to tolerate the allergen. The problem is, with food allergy, anaphylaxis can occur.
To eliminate that risk, researchers have altered a peanut to “trick” the immune system. Dr. Scott Sicherer, an associate professor of pediatrics at the Mount Sinai School of Medicine in New York and a researcher at the school’s Jaffe Food Allergy Institute, explains the concept. He likens the changed peanut to a baby bracelet that spells the word “Peanut”.
“If you altered that bracelet a little bit, let’s say you changed the ‘A’ in peanut to a ‘D’, then it would say PEDNUT instead of PEANUT,” he says. His theory is that the allergic person’s immune system won’t recognize “pednut” and therefore will be less likely to mount an allergic reaction to it. Over time, if it sees “pednut” enough, the immune system might also learn to accept “peanut”. He does not yet know how often the treatment would need to be taken to make this happen.
Where We Stand: Researchers have developed the optimal “altered peanut” and the vaccine has, in fact, reversed peanut allergy in mice. They’ve also determined that the vaccine is best taken rectally, as a suppository. Along with the altered peanut, the vaccine contains heat-killed E. coli bacteria, to signal the immune system that it should react to a bacteria, rather than an allergen.
Now, teams at Mount Sinai and at Johns Hopkins Children’s Center in Baltimore have started a Phase 1 clinical trial with a small group of people to ensure the vaccine is safe. If all goes well, the researchers will move on to Phase 2 studies, which will determine if the vaccine actually helps to reduce peanut allergy in humans.
Idea: Herbal Formula for Food Allergy
What’s Involved: Dr. Xiu-Min Li has been toiling in her lab at the Mount Sinai School of Medicine for years, trying to zero in on the perfect concoction of Chinese herbs that can increase a person’s threshhold for allergenic foods.
She and her colleagues have tested the formula, which includes dried ginger root, processed plums, Chinese peppers and ginseng, extensively in mice. After they stopped the treatment, the mice still did not react to their former allergen six months later. Li hopes the herbal remedy will allow people to come in accidental contact with their allergens and not have a serious reaction.
Where We Stand: Li has tested the treatment in humans and concluded the formula called FAHF-2 is safe and well-tolerated. She also found that people who took FAHF-2 tablets for six months had a reduction of basophil blood cell activity, which suggests a reduction in a person’s allergic tendency.
Now, the work ahead is to prove the treatment is effective, and to determine how much and how often a person should take it. Li was set to begin a Phase 2 study in March in which patients will take FAHF-2 or a placebo for several months. At the moment, this entails taking 24 tablets a day, but Li is working on reducing that number. The theory is that the effect of the treatment will last some time after the person stops taking the tablets.
Li’s goal is to develop a drug that can be taken by prescription, but she says that once the formula is proven effective, she could begin marketing it as a dietary supplement in the U.S. and Canada, perhaps as early as next year, while she continues to get drug approval.
Idea: Oral Immunotherapy or Desensitization
What’s Involved: In this experimental food allergy treatment, doctors give allergic patients increasingly larger doses of their allergen, starting with tiny amounts, to teach their immune systems to build up tolerance to it.
Allergists Dr. Wesley Burks and Dr. Stacie Jones are running numerous trials of oral immunotherapy (OIT) in Arkansas and North Carolina. Most (but not all) children have been able to build up a tolerance to allergens like peanuts, eggs and milk.
Where We Stand: Burks and Jones continue to research the intricacies of OIT, including who should and shouldn’t try it. They’ve found the most common side effects include runny nose, itchy skin, mild wheezing, or abdominal symptoms. They also found that children react to their daily peanut dose less than 5 per cent of the time, but the reactions that do occur are unpredictable. However, it was discovered that more reactions will occur if a child has a viral infection and more if he or she eats the food on an empty stomach. Trials at other centres are also taking place.
In Canada, Dr. Susan Waserman of McMaster University and Dr. Wade Watson of Dalhousie University have secured a grant from the research network AllerGen to start up a small Canadian trial of peanut oral immunotherapy in Hamilton and Halifax. The study will enroll patients 6 years of age and older. In each city, five patients in a “low-dose” group will work their way up to a fraction of a peanut a day, and 10 higher-dose patients will aim to eat the equivalent of 10 peanuts a day. (There will also be a peanut-allergic control group.)
Investigators will draw blood and give patients an oral challenge every three months in order to pin down the stage at which desensitization truly begins. Waserman hopes to begin recruiting patients this spring. Burks suggests that having a desensitization protocol in place that can be widely used by allergists is still several years away.