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Peanut allergy pill gets thumbs-up from FDA advisory panel


 

FROM THE FDA ALLERGENIC PRODUCTS ADVISORY COMMITTEE MEETING

A pill designed to desensitize peanut-allergic children and teenagers may be on the way.

The Food and Drug Administration’s Allergenic Products Advisory Committee has voted to recommend approval of the AR101 peanut protein capsules (Palforzia) for use in oral immunotherapy in those aged 4-17 years old with a confirmed peanut allergy. Conditions for approval include stipulations that a black-box warning and medication use guide are included in the packaging, the panel said. The FDA usually follows the recommendations of its advisory panels.

FDA written in white letters on a wood background. bankrx/Getty Images


The committee members voted 7-2 that the drug was effective and 8-1 that it was safe.

John Kelso, MD, the sole dissenter on safety, voiced concerns about the dearth of long-term follow-up in Aimmune Therapeutic’s body of research and the finding that children who received the treatment during the dose-escalation and maintenance periods had twice the number of allergic reactions requiring epinephrine, compared with those who received placebo. There are no long-term safety data to rely on yet, he added.

“Efficacy has not been demonstrated, except on the day the peanut challenge is administered,” said Dr. Kelso, an allergist at the Scripps Clinic, San Diego, adding that only long-term follow-up data would fully convince him that the drug’s benefits outweigh the risks.

In the discussion, however, other committee members pointed out that new drugs are often approved without long-term efficacy and safety data. Those data are extrapolated from clinical trials, and only real-world experience will confirm the data, they noted.

Company representatives did not explicitly address the potential cost of the therapy, but a recent review by the Institute for Clinical and Economic Review estimated the cost to be $4,200 a year. Palforzia would have to be taken every day, for an unknown amount of time, to maintain peanut tolerance.

“Using prices from analysts for AR101 ($4,200 a year), we estimated that only 41% of eligible patients could be treated in a given year without exceeding ICER’s budget impact threshold,” the institute concluded in a publicly released analysis.

Palforzia comes in individual packs of capsules filled with peanut protein, not flour. The capsules come in doses of 0.5, 1, 10, 20, and 100, and 300 mg. A single-dose sachet contains 300 mg. Treatment begins with 0.5-6 mg over 1 day and escalates every 2 weeks until 300 mg is reached or there is a reaction requiring epinephrine. Passing at least a 300-mg dose was the requirement for exiting the escalation phase and moving on to the daily, year-long maintenance phase.

The four efficacy studies presented showed that 96% of patients tolerated 300 mg, 84% tolerated 600 mg, and 63% 1,000 mg – about 10 times the reactive dose observed in the placebo controls.

“Only 125 mg of peanut protein – the amount in about half a peanut kernel – can be enough to provoke a reaction,” said Daniel Adelman, MD, chief medical officer of Aimmune. If patients can tolerate 600 mg of protein – the equivalent of two kernels, accidental ingestion will result in a “predictable, manageable” reaction.

“This is truly a clinically significant result for patients and families who report lives dictated by the allergy,” Dr. Adelman said.

Consistent manufacturing processes and positive safety data should reassure clinicians and patients that they are receiving a safe, effective, and well-regulated treatment, he added.

The capsule, however, is not a panacea. The company advises that families continue with the peanut avoidance diet. “It’s important to remember that reactive episodes can occur with dosing, and accidental exposures can occur at unpredictable times, away from home, and despite the best efforts at avoidance,” Dr. Adelman said. “This is not a drug for everyone, but it is an effective desensitization tool and would clearly be the first therapy to treat a food allergy, providing statistically significant and clinically important improvement. Outcomes align with patients’ goals.”

Safety was assessed in 709 treated patients who received the medication and 292 who received placebo. Treatment-related adverse events were most common in initial dosing: 89% of the treatment group and 58% of the placebo group experienced at least one adverse event during that time. Adverse events were mostly mild to moderate and decreased in severity over the study period. They included abdominal pain (45% active vs. 18% placebo), throat irritation (40% vs. 17%), pruritus (33% vs. 20%), vomiting (37% vs. 16%), cough (32% vs. 24%), nausea (32% vs. 14%), urticaria (28% vs. 19%), and upper abdominal pain (30% vs. 14%).

Discontinuations caused by these adverse events were infrequent, with only 1.8% of participants who were taking the active capsule and 1% of those taking placebo discontinuing the study product during initial dose escalation. Only the severe systemic allergic reactions were considered to be anaphylaxis, and they had to affect at least two body systems.

Respiratory events were more common in those in the active group, especially in children with asthma. These events included cough, wheezing, dyspnea, dysphonia, throat irritation and tightness, and exercise-induced asthma. There was, however, no “concerning change” in asthma control.

Systemic allergic reactions and anaphylaxis were more common in the active-dose group. Systemic reactions during dose escalation occurred in 9.4% of active patients and 3.8% those taking placebo. During the maintenance phase, they occurred in 8.7% and 1.7% of patients, respectively. Three patients in the active group had a serious systemic reaction – two during up-dosing and one during maintenance.

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