In a food allergy field where avoidance is king, Aimmune is looking to flip the script with Palforzia, a therapy that slowly desensitizes patients. It's not an uncontroversial approach—or one guaranteed to gin up big sales. But now Aimmune can work to prove the doubters wrong.
The FDA on Friday approved Aimmune's Palforzia (AR101) as a treatment for peanut allergy reactions, including anaphylaxis, making it the first drug approved in that indication.
And according to Evaluate Pharma, it's a blockbuster approval. Palforzia could hit an estimated $1.28 billion in sales by 2024, the firm said, as an immunotherapy that uses gradual doses of peanut protein to fend off serious reactions.
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Despite the novel nature of Palforzia's approval, though, the drug hasn't come without controversy. In a note to investors in March 2019, Credit Suisse analyst Vamil Divan said physicians were largely positive on the clinical need for Palforzia but raised concerns about the drug's commercial chances.
"We believe there are more investor questions on the commercial opportunity for the product given the need for frequent office visits and GI side effects during the up-dosing period," Divan wrote.
"However, we see significant interest in the product from physicians and patients/parents," Divan added, saying Palforzia's side effects seem "manageable" and a targeted sales force could handle the commercial challenge.
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The FDA approval comes with a Risk Evaluation and Mitigation Strategy for Palforzia in children aged 4 to 17. Any patient prescribed Palforzia must have a valid prescription for injectable epinephrine—such as an Epi-Pen—and caregivers or patients must agree to carry the rescue remedy while taking Palforzia. Initial dosing—and the first dose of each up-dosing level—must be given at a certified site.
The agency based its nod on Palforzia's year-long Palisade trial, which tested the treatment against placebo in 555 patients aged 4 to 55. The vast majority of them were children and adolescents.
At the start of the trial, patients could not tolerate 100 mg or less of peanut protein. That's a fraction of a single peanut, which weighs in at about 300 mg.
Patients were given a higher Palfozia dose every two weeks until they reached a maintenance dose of 300 mg. After one year of treatment, 67% of Palforzia patients could tolerate 600 mg of peanut protein—about two peanuts or a small bite of a peanut butter sandwich—compared with 4% of patients who received placebo.
In early 2019, a government shutdown delayed the FDA's review of Palforzia as a direct consequence of a “lapse in appropriations." In other words, the gap hampered the agency’s ability to raise further funding through user fees, the drugmaker said.