Aimmune Therapeutics, Inc. will present for the first time results from the Phase 3 POSEIDON (Peanut Oral Immunotherapy Study of Early Intervention for Desensitization) study. The trial evaluated the efficacy and safety of PALFORZIA«[Peanut (Arachis hypogaea) AllergenPowder-dnfp] in peanut-allergic children aged 1 to 3 years. These findings will be presented at the American College of Allergy, Asthma & Immunology (ACAAI) 2022 Annual Scientific Meeting in Louisville, Kentucky on November 12, 2022.

The study met the primary outcome, with the majority of patients treated with PALFORZIA tolerating at least a 600 mg single dose (1,043 mg cumulative) or 1,000 mg single dose (2,043 mg cumulative) of peanut protein (73.5% and 68.4%, respectively, compared to 6.3% and 4.2% of patients who received placebo, respectively). In addition, the majority of patients treated with PALFORZIA (61.2% compared with 2.1% of placebo-treated patients) tolerated the highest exit double-blind, placebo-controlled exit food challenge (DBPCFC) dose level of 2,000 mg (4,043 mg cumulative), and the median highest tolerated dose of peanut increased 66-fold between baseline and exit DBPCFC. PALFORZIA demonstrated a favorable safety profile.

Overall, 84.7% of patients on PALFORZIA and 93.8% of patients on placebo completed the study. There were no PALFORZIA-related serious or severe adverse events (AEs), and systemic allergic reactions due to any cause were similar between PALFORZIA and placebo-treated patients (8.1% and 8.3%, respectively). Treatment-related systemic allergic reactions occurred in 2% of PALFORZIA-treated patients and 0% of placebo-treated patients.

These results indicate that treatment with PALFORZIA in young children resulted in a clinically meaningful change in the amount of peanut they could tolerate during oral challenge. Currently, there is a high unmet need for these young children with peanut allergy who rely on avoidance alone, and treatment at this early age presents a unique window of opportunity to actively manage their peanut allergy near the time of diagnosis. Peanut allergy is one of the most common food allergies in the world, affecting more than 1.6 million children and teens in the U.S.i Reactions to peanut are potentially life-threatening, accounting for the majority of deaths related to food allergy.

PALFORZIA is currently approved by the FDA as an oral immunotherapy (OIT) for the mitigation of allergic reactions, including anaphylaxis, that may occur with accidental exposure to peanut in patients aged 4 through 17 years with a confirmed diagnosis of peanut allergy. Aimmune plans to submit the full POSEIDON study results for publication in a peer-reviewed journal and submit these study results to the FDA in the first half of 2023 to support the use of PALFORZIA in appropriate peanut-allergic children aged 1-3 years, subject to review and approval by FDA. POSEIDON Results: POSEIDON enrolled 146 patients, with 98 randomized to PALFORZIA and 48 randomized to placebo.

Overall, 84.7% of patients on PALFORZIA and 93.8% of patients on placebo completed the study. Efficacy results: 73.5% and 68.4% of patients treated with PALFORZIA tolerated a single dose of 600 mg and 1,000 mg of peanut protein compared with 6.3% and 4.2% of patients in the placebo group, respectively, with a treatment difference of 67.2% and 64.2% (p); 61.2% of PALFORZIA-treated patients tolerated the highest dose level in the exit DBPCFC of 2,000 mg (cumulative 4,043 mg) compared with 2.1% of placebo-treated patients, with a treatment difference of 59.1% (p). Key safety results: The most common AEs related to PALFORZIA treatment involved the skin and subcutaneous tissues (urticaria, erythema), the gastrointestinal system (abdominal pain, vomiting), and the respiratory, thoracic and mediastinal system (cough, sneezing).

5.1% of PALFORZIA-treated patients versus 2.1% of placebo-treated patients experienced early withdrawal due to AEs. 6.1% of PALFORZIA-treated patients versus 4.2% of placebo-treated patients experienced serious AEs. None were related to treatment.

2% of PALFORZIA-treated patients versus 0% of placebo-treated patients experienced systemic allergic reactions (SARs; anaphylactic reactions of any severity) related to treatment. SARs are de?ned according to the National Institute of Allergy and Infectious Disease criteria and graded using the 3-point Muraro (European Academy of Allergy and Clinical Immunology) grading scale. SARs were similar between PALFORZIA-treated and placebo-treated patients (8.1% and 8.3%, respectively).

There were no severe or serious systemic allergic reactions. 3.1% of PALFORZIA-treated patients versus 0% of placebo-treated patients used epinephrine for a treatment-related AEs. Abstracts to be presented by Aimmune at the ACAAI conference include: Oral Immunotherapy In Children Aged 1 To 3 to =300 mg in a positive double-blind, placebo-controlled food challenge (DBPCFC).

In POSEIDON, patients underwent a dose-escalation period of approximately 22 weeks to reach a dose of 300 mg per day of PALFORZIA or placebo, then continued on that dose for approximately six months. At the end of the trial, patients underwent an exit DBPCFC. PALFORZIA«[Peanut (Arachis hypogaea) AllergenPowder-dnfp]: PALFORZIA was approved in January 2020 by the U.S. Food and Drug Administration (FDA) as an oral immunotherapy (OIT) for the mitigation of allergic reactions, including anaphylaxis, that may occur with accidental exposure to peanut in patients aged 4 through 17 years with a confirmed diagnosis of peanut allergy.

PALFORZIA was approved on December 17, 2020 by the European Commission (EC), on April 7, 2021 by the Medicines and Healthcare products Regulatory Agency (MHRA) in the U.K., and on May 4, 2021 by Swissmedic. Use of PALFORZIA may be continued in patients 18 years of age and older. PALFORZIA is not indicated for the emergency treatment of allergic reactions, including anaphylaxis and must always be used in conjunction with a peanut-avoidant diet.

Boxed WARNING: PALFORZIA can cause anaphylaxis, which may be life threatening and can occur at any time during PALFORZIA therapy. Prescribe injectable epinephrine, instruct and train patients on its appropriate use, and instruct patients to seek immediate medical care upon its use. Do not administer PALFORZIA to patients with uncontrolled asthma.