A new peanut allergy drug was just approved in the U.S.—and it could be a game changer

In late January, the US Food and Drug Administration (FDA) approved a pill called Palforzia, offering a dose of hope for parents of kids with food allergies.

The first treatment for food allergy to receive such recognition by a national regulatory body, Palforzia is a biologic drug manufactured from peanut, and it marks a momentous shift in the way the medical community views the potentially life-threatening condition.

“It’s a big deal to finally have something that goes beyond strict avoidance, and the use of your EpiPen if a reaction happens,” says Jennifer Gerdts, executive director of Food Allergy Canada. (An EpiPen is an auto-injector device that delivers a dose of epinephrine, which helps control symptoms either until emergency personnel arrive, or you reach the hospital.) And while the pill is not yet approved or available in Canada—at the time of this writing, Health Canada had not received a submission to review, which is the first step in obtaining approval—the FDA approval is still a big deal for all food-allergy parents.

How does the peanut allergy drug work?

Approved for children aged four to 17, Palforzia works on the same principle as allergy shots for grass or ragweed: It 'teaches' the immune system to tolerate gradually increasing amounts of an allergen, a desensitization process called immunotherapy. In this case, the treatment is delivered orally (oral immunotherapy, also known as OIT) rather than by injection.

Under expert supervision in an allergy clinic, a child with severe peanut allergy takes the contents of a pull-apart capsule containing a minuscule, standardized dose of peanut protein—the equivalent of about 1/600th of a peanut. If all goes well, that’s followed by 13 identical daily doses taken at home. (Kids have to stay quiet for a three hour window around each treatment, since, like stress and illness, exercise can lower the amount of peanut a child can tolerate.)

Every two weeks, the child returns to the clinic for an ‘updose’, repeating the cycle until reaching 300 grams—a process that typically takes six to 12 months. (If a reaction occurs, the dose may be reduced, which is why treatment duration varies.) After that milestone, the kid must continue taking a 300 mg daily dose indefinitely to maintain tolerance.

Is Palforzia a cure for peanut allergy?

The short answer is no, it's not exactly a cure.

Studies show that, “by continuing on the 300 mg, you can protect against larger amounts if you’re accidentally exposed,” explains Moshe Ben-Shoshan, a paediatric allergist and immunologist at Montreal Children’s Hospital, and one of the co-authors of a recently published clinical trial testing the treatment. In other words, Palforzia—and oral immunotherapy in general—is not a cure. “The aim is not to allow the child to eat O’Henrys and Reese’s Pieces,” Ben-Shoshan stresses.

Instead, it’s what Burlington, Ont., paediatric allergist Doug Mack, who is on the board of the Canadian Association of Clinical Allergists and Immunologists, calls a risk mitigation strategy. Increasing the amount of peanut allergen required to elicit symptoms reduces the risk of severe reactions from accidental exposure, which can happen even when parents are extremely vigilant. In clinical trials, 70 to 80 percent of kids who completed a course of treatment were able to tolerate eating 600 mg of peanut (approximately two peanuts) without ‘dose-limiting symptoms.'

How food allergy treatment eases the burden for kids

What does this mean in a practical sense? Just ask Fiona Kelder, an Oakville, Ont., mom whose 12-year-old son Andrew just graduated from oral immunotherapy for peanut. (A handful of Canadian allergists offer OIT using food, although since the labour-intensive process isn’t covered by provincial health plans, parents have to pick up the tab—in the range of $7,500.)

Until now, “every birthday party, every sleepover, had to be carefully planned,” Fiona explains. She spent days and even weeks before a hockey tournament or holiday researching restaurants to find ones with scrupulous practices for preventing possible contact with traces of peanut. Even then, the worry that her son might nonetheless be accidentally exposed to peanut never went away.

Today? While Andrew still has to avoid peanuts, and carry his EpiPen, he can now eat at places like Tim Horton’s—where he previously had to stick to orange juice—with the rest of his family. “The stress it takes away is phenomenal,” Fiona says. “It just frees us.”

Isn't the treatment risky?

Palforzia isn’t perfect, nor is it suitable for every child with severe peanut allergy. For starters, it’s contraindicated for kids with uncontrolled asthma, which amplifies the risk of a life-threatening reaction. Another limitation is that the product doesn’t contain all peanut proteins, just the most dangerous ones. “So it could be that someone who is allergic to another allergen that is present in normal peanut will not be desensitized or protected,” Ben-Shoshan notes.

Then there’s the fact that over the course of treatment, “most kids will have some type of a reaction,” says Mack. (These tend to occur less often in younger children, and decrease in frequency over time, he adds.) While the majority of reactions are mild to moderate, causing symptoms such as an itchy mouth or throat, rash, or abdominal pain, between four and 20 percent will be serious enough to require epinephrine. (To put that in perspective, in the latest trial, five percent of kids on placebo needed an epinephrine injection during the six-month study period.) And for some kids, and families, that’s simply too stressful, which is one of the reasons roughly ten percent discontinue treatment. Another small subset of children can’t stand the smell or taste of even a minute amount of peanut, which can turn the process into too much of a struggle.

There’s also a small risk, around three percent, of eventually developing chronic inflammation in the esophagus (the tube connecting the mouth and stomach) or elsewhere in the gastrointestinal tract.

The treatment requires commitment

Treatment also requires a serious commitment on the part of the whole family. It’s time consuming (bi-weekly hour-long medical appointments), and requires sticking to a rigid schedule for many months (those three-hour rest sessions mentioned above). It’s also expensive: US$10,480 ($890 per month) for the Palforzia alone.

All of the labour costs extra, since OIT treatment isn’t covered by provincial health plans. And a course of treatment requires not just close supervision by health professionals with experience treating anaphylaxis (a life-threatening allergic reaction), but education, and support as well.

And such individuals are few and far between: According to Doug Mack, only about 40 allergists in Canada are currently offering any degree of OIT. What’s more, since OIT is also time-consuming for physicians and support staff, there simply aren’t enough specialists to provide treatment for the estimated two percent of Canadian kids with peanut allergy.

Implications for the future

The excitement around the FDA approval of Palforzia goes beyond what the drug itself can do. “This opens the door for other products, and other studies, maybe even using the real food,” says Ben-Shoshan, which could potentially make treatment more affordable. “This is allergy treatment 1.0,” Mack adds.

And now that the first such product has received the stamp of approval from a major governing body, OIT is less likely to be deemed experimental, meaning private health insurers and provincial insurance plans may begin to cover it. This kind of official recognition also provides parents with ammunition to advocate for more and better treatments for allergy to peanut and other foods, and greater accessibility to those we already have. “This gets the conversation going, which will pave the way to future possibilities,” says Food Allergy Canada's Jennifer Gerdts. “It brings hope to the community.”

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