Peanut allergy affects approximately 1 million U.S. children, of whom only 20% will outgrow the allergy. Allergic responses can be triggered without directly eating peanuts (for example, when a child touches a surface or ingests food that has come into contact with peanuts); these responses can be severe and potentially life-threatening and can include anaphylaxis. The Food and Drug Administration (FDA) has approved peanut (Arachis hypogaea) allergen powder-dnfp (Palforzia), the first oral immunotherapy to minimize allergic reactions to peanuts.
Palforzia is a powder made from defatted peanut flour and is taken daily mixed in food such as applesauce, yogurt, or pudding. It is approved for use in children ages four to 17 years with a confirmed peanut allergy. Patients receiving Palforzia still need to avoid eating peanuts. The drug does not cure the allergy, but instead decreases the severity of the allergic response. It works similarly to "allergy shots," gradually introducing increasing doses of the allergen to decrease sensitivity to it. Although the immune system is stimulated, it's not typically enough to cause allergic reactions (yet allergy shots and Palforzia can sometimes induce allergic reactions).
Palforzia carries a boxed warning that it may produce anaphylaxis and should be avoided in patients with uncontrolled asthma, which increases the risk of death from anaphylaxis. Palforzia should not be used during acute allergic responses, including anaphylaxis. It should also not be given to those with a history of eosinophilic esophagitis (inflammation and injury to esophageal tissue from eosinophils) or other eosinophilic gastrointestinal disease, as Palforzia increased the risk of this disorder in clinical trials, although its occurrence was not common.
As with the administration of other allergens, Palforzia requires a slow dose escalation prior to maintenance dosing. Palforzia has three phases of treatment: initial dose escalation (one day), updosing (11 dose levels over several months), and maintenance (expected to be lifelong).
The effectiveness of Palforzia was determined in a randomized, double-blind, placebo-controlled trial of about 500 patients with peanut allergies. The drug was considered effective if, after six months of maintenance treatment, an oral dose of peanut powder twice the daily dose of Palforzia caused no more than mild allergy symptoms. Most of those who received Palforzia (67.2%) had a mild allergic response. In separate double-blind, placebo-controlled studies assessing safety, the most common adverse effects of Palforzia were abdominal pain, vomiting, nausea, tingling in the mouth, itching (mouth and ears), cough, runny nose, throat irritation and tightness, hives, wheezing and shortness of breath, and anaphylaxis.
The FDA is requiring a Risk Evaluation and Mitigation Strategy (REMS) with Palforzia's approval, which means the drug will only be available from certified providers, health care settings, and pharmacies enrolled in the REMS program. Health care providers will need to be educated on the risk of anaphylaxis. Nurses and NPs should tell patients and their families to carry an EpiPen and teach them how to use it.
During the initial dose escalation and first updosing day-dosing periods during which patients have the highest risk of an allergic response-patients must be monitored for at least one hour during and after receiving Palforzia. For that reason, they should receive these first doses in a treatment environment able to manage potentially severe adverse effects, including anaphylaxis. Nurses and NPs should tell patients and their families to report severe, persistent symptoms of esophagitis or gastrointestinal intolerance to the prescriber, as Palforzia may need to be discontinued if eosinophilic esophagitis occurs.
To read the complete prescribing information for Palforzia, go to http://www.fda.gov/media/134838/download.