Peanut protection

The doctor fed peanuts to a patient with a serious peanut allergy …

That may sound like a teaser for a murder mystery or the opening statement in a malpractice lawsuit, but it’s actually a new treatment for food allergies. Oral immunotherapy, or OIT, works the way the ancient King Mithridates VI protected himself from poisons: The patient takes an almost undetectable amount of the harmful substance, then gradually larger doses, until the immune system becomes less sensitive to it. At least, that’s the theory.

Oral immunotherapy moved into the mainstream on Jan. 31, when the U.S. Food and Drug Administration approved Palforzia, the first standardized peanut allergy treatment for children. Palforzia is a peanut flour product designed to provide precise OIT dosings to young patients. Allergists have been preparing similar, customized treatments for individual patients for years.

Mayo Clinic estimates up to 8 percent of children under 3 are allergic to at least one food. The prevalence of food allergies and the lifestyle changes they cause have fueled public interest in potential treatments. Parents of children with food allergies often avoid playdates, camp, and restaurants. At home, cooking a family meal involves thinking about ingredients to avoid. Outside the house, the EpiPen is an ever-present reminder to its owner not to risk trying the food at the party.

The dogma has long been to keep peanut products away from children under 1 year of age, but a 2015 study changed that: The Learning Early About Peanut Allergy (LEAP) study proved infants who regularly eat peanut products are one-fifth as likely to develop a peanut allergy. A follow-up study, Enquiring About Tolerance (EAT), provided similar encouragement for other foods, such as milk, eggs, and fish.

But what of those who already have food allergies? The main advice is still to avoid allergens and carry an EpiPen. The American Academy of Allergy, Asthma, and Immunology cautions on its website that oral immunotherapy’s results are far from the guaranteed safety Mithridates had hoped for: “It is not expected that OIT will lead to ingestion of the allergen without limitation.”

“Without limitation” is an important caveat, though: Many patients with food allergies, having spent years fastidiously avoiding a particular ingredient, have no desire to sit down with a plate of it. Rather, their hope is to become “bite-proof”—that is, to avoid a serious reaction after a single accidental bite of food—and to tolerate incidental exposures such as a whiff of peanut dust.

Palforzia requires close monitoring by medical staff each time the patient’s dose goes up, which occurs several times over the course of treatment. Most patients do not have a life-threatening reaction to OIT, but it does carry risk. In three months of experimental treatment with Palforzia, almost 1 patient in 10 had a serious allergic reaction. Almost half had less serious reactions.

That’s the downside. The upside: Between one-half and two-thirds of patients in the Palforzia safety studies became able to tolerate 300 milligrams of peanut without serious consequences. In other words, they indeed became “bite-proof.”

Is the benefit worth the risks? The patient must decide that question, balancing the hope of partial immunity against the risk of reactions during treatment—and against the need to eat a small amount of the allergenic food every day, for life, lest the hard-won desensitization fade away. Even though OIT appears to be effective, the American Academy of Allergy, Asthma, and Immunology still offers patients this final piece of advice: Don’t leave the EpiPen at home—just in case.