Use of PALFORZIA has been associated with:

  * Anaphylaxis [see Warnings and Precautions (5.1)] 
  * Eosinophilic esophagitis [see Warnings and Precautions (5.4)] 



Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in clinical trials of a drug cannot be directly compared with the adverse reaction rates in clinical trials of another drug and may not reflect the rates observed in practice.

The clinical data for PALFORZIA reflect exposure in 709 peanut-allergic subjects enrolled in two phase 3, double-blind, placebo-controlled trials (Study 1 and Study 2), and in long-term, open-label, follow-on studies. In Study 1, subjects were Up-Dosed for 20-40 weeks followed by Maintenance dosing for 24-28 weeks. In Study 2 subjects were Up-Dosed for 20-40 weeks up to a 300 mg daily dose with no extended Maintenance dosing. In these studies, subjects recorded adverse reactions daily in an electronic diary card throughout the study duration.

Study 1 (NCT02635776) was a randomized, double-blind, placebo-controlled efficacy and safety study conducted in the United States, Canada, and Europe evaluating PALFORZIA versus placebo in 555 subjects aged 4 through 55 years with peanut allergy. Subjects were required to have serum IgE to peanut ≥ 0.35 kUA/L within 12 months before study entry and/or a mean wheal diameter on skin prick test to peanut ≥ 3 mm greater than the negative control. The primary analysis population was aged 4 through 17 years, 78% white and 57% male. At study entry, subjects reacted at 100 mg or less of peanut protein in a double-blind, placebo-controlled food challenge (DBPCFC). The primary analysis was conducted in 496 subjects aged 4 through 17 years (PALFORZIA, N = 372; placebo, N = 124). Of the subjects aged 4 through 17 years treated with PALFORZIA, 72% had a medical history of anaphylactic reactions to peanut, 66% reported multiple food allergies, 63% had a medical history of atopic dermatitis, and 53% had a present or previous diagnosis of asthma. Subjects with severe persistent or uncontrolled asthma were excluded.

Study 2 (NCT03126227) was a randomized, double-blind, placebo-controlled safety study conducted in the United States and Canada evaluating PALFORZIA versus placebo in 506 subjects aged 4 through 17 years with peanut allergy. Subjects were required to have a clinical history of peanut allergy including onset of characteristic allergic signs and symptoms within 2 hours of known oral exposure to peanut, serum IgE to peanut of ≥ 14 kUA/L and a mean wheal diameter on skin prick test ≥ 8 mm greater than the negative control at screening. Subjects were not required to complete a DBPCFC for study entry. The study duration was approximately 6 months and compared the safety and tolerability of PALFORZIA (N = 337) with placebo (N = 168). Most subjects were male (63%) and white (79%). Of the subjects treated with PALFORZIA, 60.5% had a medical history of anaphylactic reactions, 65.0% reported multiple food allergies, 57.9% had a medical history of atopic dermatitis, and 52.2% had a present or previous diagnosis of asthma. Subjects with severe persistent or uncontrolled asthma were excluded.

Across these two phase 3, double-blind, placebo-controlled, randomized clinical studies the most common adverse reactions in subjects treated with PALFORZIA (incidence ≥ 5% and at least 5 percentage points greater than in subjects treated with placebo) were gastrointestinal, respiratory, and skin symptoms commonly associated with allergic reactions, as shown in Table 4.

A total of 155 (21.9%) PALFORZIA-treated subjects and 19 (6.5%) placebo-treated subjects discontinued for any reason in Studies 1 and 2. Adverse reactions led to study discontinuation in 9.2% PALFORZIA-treated subjects and 1.7% placebo-treated subjects during Initial Dose Escalation and Up-Dosing combined in Studies 1 and 2, and 1.0% PALFORZIA-treated subjects and no placebo-treated subjects during Maintenance dosing in Study 1. Gastrointestinal reactions were the most common reason leading to discontinuation of study product during Initial Dose Escalation and Up-Dosing combined (6.5% PALFORZIA, 1.0% placebo), followed by respiratory disorders (2.3% PALFORZIA, 1.0% placebo) in Studies 1 and 2.

The timing of symptoms relative to exposure to PALFORZIA was evaluated for dosing that occurred within a clinical setting during Initial Dose Escalation and on the day of initiation of each new dose level during the Up-Dosing phase (every 2 weeks) and during monthly Maintenance visits. Symptoms occurring in the clinic following any dose of PALFORZIA had a median time to onset of 4 minutes for 502 subjects (70.8%). The median time to resolution of the last symptom was 37 minutes.