Stallergenes Greer announces publication of positive results for Palforzia® phase III study in peanut-allergic children aged 1 to 3 years

  • Full POSEIDON (Peanut Oral Immunotherapy Study of Early Intervention for Desensitization) study data published in New England Journal of Medicine Evidence.
  • 73.5% of patients treated with PALFORZIA met the primary endpoint of tolerating the 600 mg single dose of peanut protein at 12 months compared with 6.3% of patients receiving placebo.
  • No serious or severe treatment-related adverse events were reported with the use of PALFORZIA. Only 2% of patients experienced systemic allergic reactions related to the trial treatment.
  • Evidence of progression of peanut allergy in patients receiving placebo but not in patients treated with PALFORZIA.  

Baar, SwitzerlandNovember 20, 2023 – Stallergenes Greer, a leading global healthcare company specialising in allergen immunotherapy (AIT), announces the publication of results from the Phase 3 POSEIDON (Peanut Oral Immunotherapy Study of Early Intervention for Desensitization) study in the New England Journal of Medicine Evidence. The study evaluated the efficacy and safety of PALFORZIA [defatted powder of Arachis hypogaea L., semen (peanuts)] in peanut-allergic children aged 1 to 3 years.

The study met the primary endpoint, with the majority of patients treated with PALFORZIA tolerating at least a 600 mg single dose (1,043 mg cumulative) or a 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 this proportion was higher for the youngest age group.

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, and systemic allergic reactions due to any cause were similar between PALFORZIA and placebo-treated patients (8.2% and 8.3%, respectively). Treatment-related systemic allergic reactions occurred in 2% of PALFORZIA-treated patients and 0% of placebo-treated patients.

A 3.5-fold increase in peanut allergy prevalence has been reported in recent years, with 1 to 2% of children in Western countries affected1. Reactions to peanut are potentially life-threatening, accounting for the majority of deaths related to food allergy2.  

Through the Poseidon study, we have witnessed a significant shift in how peanut allergy can be managed in the youngest patients,” said George du Toit, M.B., B.Ch., Professor of Pediatric Allergy at Evelina London Children’s Hospital, Guy's and St Thomas' NHS Foundation Trust, King’s College London and study investigator in PALFORZIA clinical trials. “These findings highlight the potential benefit of early intervention for peanut-allergic children aged 1 to 3 years, offering a glimpse of hope for a future where we can alleviate the burden of this condition.”

We are delighted about the results which underscore the clinical significance of PALFORZIA for peanut-allergic toddlers. The results, published in the New England Journal of Medicine Evidence, are truly promising and potentially life-changing for young patients. The recent addition of PALFORZIA, the first standardised treatment for peanut-allergic toddlers, to Stallergenes Greer’s portfolio is testimony to our unwavering commitment to provide patients and the medical community with innovative AIT treatments,” says Amer Jaber, Chief Innovation Officer of Stallergenes Greer.

To read the publication:



POSEIDON (Peanut Oral Immunotherapy Study of Early Intervention for Desensitization, number NCT03736447) is an international, randomized (2:1), double-blind, placebo-controlled Phase 3 study that evaluated the efficacy and safety of PALFORZIA in peanut-allergic children aged 1 to <4 years of age in North America and Europe. The POSEIDON study was completed by Aimmune Therapeutics, part of Nestlé Health Science before Nestlé divested PALFORZIA to Stallergenes Greer in September 2023. Enrollment was based on several entry criteria, including a documented clinical history of peanut allergy, positive skin prick tests and/or elevated blood levels of peanut antibodies, and dose-limiting symptoms after consuming single doses of peanut protein >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 that dose for approximately six months. At the end of the trial, patients underwent an exit DBPCFC.


PALFORZIA is a complex biologic drug used with a structured dosing approach that builds on a century of oral immunotherapy (OIT) research. With OIT, the specific allergenic proteins are ingested initially in very small quantities, followed by incrementally increasing amounts, that can result in the ability to mitigate allergic reactions to the allergen over time. PALFORZIA is a rigorously developed, pharmaceutical-grade OIT for peanut allergy with a well-defined allergen profile to assure the consistency of every dose, from 0.5 mg (equivalent to 1/600th of a peanut) to 300 mg.

PALFORZIA is not intended for, and does not provide, immediate relief of allergic symptoms. Therefore, this medicinal product is not to be used for emergency treatment of allergic reactions, including anaphylaxis. Self-injectable adrenaline (epinephrine) must be available to the patient at all times.

PALFORZIA is approved by the U.S. Food and Drug Administration (FDA) by the European Medicine Agency (EMA), by the Medicines and Healthcare products Regulatory Agency (MHRA) in the U.K., and by Swissmedic in Switzerland.


Headquartered in Baar (Switzerland), Stallergenes Greer International AG is a global healthcare company specialising in the diagnosis and treatment of respiratory and food allergies through the research, development and commercialisation of allergen immunotherapy products and services. Stallergenes Greer International AG is the parent company of Greer Laboratories, Inc. (whose registered office is in the United States) and Stallergenes SAS (whose registered office is in France). For more information, visit




Catherine Kress 

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  1. Lange L, Klimek L, Beyer K, et al. White paper on peanut allergy. Part 1: epidemiology, burden of disease, health economic aspects. Allergo j Int 2021;30:261-269. DOi: 10.1007 / s40629-021-00189-z.
  2. Bock SA, Muñoz-Furlong A, Sampson HA. Fatalities due to anaphylactic reactions to foods. J Allergy Clin Immunol. 2001;107:191-193.


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