Aimmune aces peanut allergy phase 3, teeing up FDA filing

Aimmune has presented strong data from a phase 3 trial of its peanut allergy treatment AR101. The Brisbane, California-based biotech plans to file for FDA approval by the end of 2018 to give patients a way to protect themselves against accidental exposure to peanut protein.

Investigators enrolled almost 500 children intolerant to peanut protein doses of 100mg or less and randomized them to receive AR101 or placebo. After a 22-week dose escalation phase, participants continued to take 300mg a day of peanut flour AR101 or placebo until the end of the 12-month study. The patients were then given consecutive doses of peanut protein rising from 3mg to 1000mg to assess their ability to tolerate the allergen.

That test exposed a big difference between the treatment and placebo arms. More than two-thirds of patients on AR101 tolerated 600mg or more of peanut protein, compared to 4% of participants in the control cohort. In real-world terms, 600mg of protein is two peanuts or a small bite of a peanut butter sandwich. 

Crucially for Aimmune, the divergence from placebo was pronounced enough for the trial to easily clear the 15% threshold set by the FDA. The difference between the treatment arms was 53%. That means the Aimmune should have the efficacy data to support approval. And that it has an edge over rival DBV Technologies, which is trying to win approval despite failing to clear the 15% threshold.

AR101 performed strongly against a clutch of other efficacy endpoints, too, but the safety data are somewhat more troublesome. One-fifth of participants in the AR101 dropped out of the study. More than half of the dropouts cited adverse events as their reason for leaving the study. Gastrointestinal issues and systemic hypersensitivity reactions were the most common triggers for dropping out.

Aimmune expected to see hypersensitivity reactions and most were mild to moderate in nature—the trial saw one case of severe anaphylaxis—but DBV looks to have an edge in terms of safety. Whether that edge is enough to justify putting a child through a long course of a less efficacious treatment is questionable, though.

Investors landed on Aimmune’s side, sending its stock up more than 10% while putting an 8% dent in the value of DBV.