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A potential breakthrough for peanut allergy treatment

  • Tripp Underwood
  • 11/4/2013 12:00:00 AM
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Peanut allergy treatmentPeanut allergies are among the most rapidly growing food allergies in the United States. Millions of children are currently living with the condition, with new cases being diagnosed daily. (A recent study shows the number of reported peanut allergies tripled in just over a decade.) And because allergic reactions to peanuts tend to be the most severe—80 to 95 percent of all food allergy deaths are peanut related—the trend is a serious cause for concern.

But a small pilot study published by the Journal of Allergy and Clinical Immunology, may offer hope for the hundred of thousands of families living with the condition. Conducted by researchers from Boston Children's Hospital's Division of Allergy and Immunology and Harvard Medical School, the new study shows that by combining a powerful anti-allergy medication and a methodical desensitization process, Boston Children's researchers may be on their way to creating the next best thing to a cure for peanut allergy.

Two-pronged attack on peanut allergy

Desensitization as a treatment for food allergies has been widely studied for the past few years. It's a process where a person is exposed to a very small amount of his or her allergy trigger—usually not enough to cause a reaction—in a controlled medical environment. The dosage is then increased by small amounts over time. When successful the participants' bodies build up a tolerance with each new dose, and eventually learn to accept the trigger food all together.

Unfortunately, food desensitization alone takes a long time and is fraught with frequent allergic reactions, which are sometimes severe. As a result as many as 30% of patients with peanut allergies are unable to successfully complete the desensitization process.

Umetsu, treatment for peanut allergyBut, based on a similar treatment he  developed for milk allergies, Dale Umetsu, MD, PhD, of Boston Children’s Division Allergy and Immunology*, began experimenting with a twofold peanut allergy treatment that combines a powerful anti-allergy medication with desensitization. Based on the success of the earlier milk study, Umetsu decided to first study his approach in patients with severe peanut allergies. He reasoned that if successful with that population it would surely work in patients with less severe peanut allergies.

Despite their great hypersensitivity to peanuts, the participants' response to Umetsu's treatment has been very promising thus far, indicating the protocol could have the potential to help thousands of children.

"These were among the most severe peanut allergic children we see in clinic, where exposure to even small amounts of peanut could lead to a serious reaction," he says. "But by the end of one day of peanut desensitization all 13 of our patients tolerated up to two and a half peanuts with no, or very mild, allergic reactions. And after just eight to ten weeks of peanut desensitization, most were tolerating 10 to 20 peanuts. The results appear to indicate that the treatment is much faster and safer than any previous desensitization method, even in high-risk peanut allergic patients."  

How does it work?

Food allergies are the result of a person's immune system mistakenly reacting to a food. When that happens the immune system produces IgE antibodies that trigger an allergic reaction when that food enters the person's system.

To address this problem, participants spent the first 12 weeks of the study receiving monthly or bi-monthly shots of omalizumab—a powerful anti-IgE medication—chosen for its effectiveness in treating allergic asthma and because it rarely presents side effects.

Schneider, treatment for peanut allergyAfter 12 weeks of pretreatment with omalizumab participants then underwent the peanut desensitization. To begin, each patient received an initial dosage of 0.1-milligram of ground up peanut—the equivalent of a very small fraction of a nut—and then had their dosage increased by small amounts every 30 minutes. By the end of the six-hour process, each child had eaten about to two and a half peanuts without developing anything more than a mild itch. (Prior to taking omalizumab, as little as a quarter of a peanut would have likely caused allergic reactions in all of the study patients.)   

"The two-peanut milestone would be enough to protect them from trace exposure, where the child eats something that doesn’t have peanuts listed as an ingredient, but has faint elements of it hidden inside," says Umetsu. "That alone is encouraging because trace exposure is a serious problem in the allergy community. It was very exciting."

For the next eight weeks the children received omalizumab and desensitization, with their peanut exposure increasing incrementally. After two months the participants were consuming about ten peanuts a day with zero to very mild reactions. The omalizumab injections were then stopped, but the patients continued to take daily peanuts.

There were a few bumps in the road, however. The researchers recorded 72 reactions during the course of the study, with 25 occurring in one patient who had an additional medical condition. Most of the reactions were mild, consisting of nausea and excessive saliva production, and were easily treated with observation or an antihistamine. There were three cases where an anaphylactic reaction required epinephrine. As with anytime epinephrine is used, these patients went to an Emergency Department for routine observation afterwards.

But by the time the year-long study had concluded, 12 of the 13 participants were tolerating up to 20 peanuts a day without receiving any additional medication, apart from the occasional anti-histamine.  (One participant left the study during the fifteenth week, because of persistent nausea and vomiting.)  

The future of food allergy treatment?

Because this protocol is a treatment and not a cure, the study participants' immune systems are still producing the antibodies that cause their allergies, but in much lower amounts. To keep those antibody amounts at safe levels, participants need to eat peanuts daily to keep their bodies "used to them", otherwise production of the allergy triggering antibodies is likely to increase.

Rachid, treatment for peanut allergyThus far daily peanut exposure has been successful in keeping the participants' antibodies low, but it has produced one unexpected negative reaction:  "I had one mother recently tell me that her daughter is getting tired of eating peanut butter cups and peanut M&M's every day. But going from a potentially deadly peanut allergy to being sick of candy is a pretty big step forward," Rima Rachid, MD,  co-author of the study, says with a smile. "However, disliking the taste of peanuts is a real issue for some of our patients, so we're working with them to provide their daily peanut intake in different ways, like baking peanut powder in cookies, or using it in pill capsules so it can be swallowed whole."

Given the success of their findings, Umetsu, Rachid and their colleague Lynda Schneider, MD, are excited to move their study into the next phase: offering the treatment to a larger population, while adding a placebo into the testing process. To do so the team is now leading a multi-centered trial where patients will be recruited at three additional hospitals in Philadelphia, Chicago and Stanford, for a larger study that aims to to reproduce and refine the initial pilot study. If successful it will lend more credence to the treatment's effectiveness and could eventually lead to it being available to more and more children. 

“This first study with children who have severe peanut allergies shows the protocol has the potential to be much faster and more effective than current treatments," Umetsu says. "Now we're excited to incorporate more patients, centers and clinicians to prove it’s as successful as we believe it can be. I'm am very hopeful for what the future of food allergy treatment may hold."

To learn more about the team's current study on peanut allergy treatment, including information on how to participate, please contact Sara Little at 617-355-6127 or sara.little@childrens.harvard.edu.

After this study, Umetsu accepted the position of Principal Medical Director at Genentech, the biotechnology company that developed Xolair, the brand of omalizumab used in this research. Boston Children's received funding from the company at the time.

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