Hypersensitivity reactions other than anaphylaxis were reported in 72% (204/285) of patients. Management should be based on the severity of the reaction, recurrence, and clinical judgment, and may include dosage adjustment, temporary drug interruption, or treatment with antihistamines, antipyretics, and/or corticosteroids.1
PALYNZIQ can be resumed in patients who experience anaphylaxis—as reported cases were found to be non–IgE-mediated.1*
Consider the risks and benefits of readministering PALYNZIQ following an episode of anaphylaxis. If the decision is made to readminister PALYNZIQ, administer the first dose under the supervision of a healthcare provider equipped to manage anaphylaxis and closely observe the patient for at least 60 minutes following the dose. Subsequent PALYNZIQ dose titration should be based on patient tolerability and therapeutic response.1
*27 of 29 patients who had anaphylaxis were tested for anti–pegvaliase-pqpz IgE antibodies, which recognize the PEGylated protein product. Of those 27 patients, 26 tested negative. The one patient who screened positive for anti–pegvaliase-pqpz IgE had insufficient sample to confirm IgE positivity. This patient tested negative for anti–pegvaliase-pqpz IgE at routine visits before and after the anaphylaxis episode.1
Remind patients and caregivers about the importance of using aseptic injection techniques and rotating injection sites with each dose.
Monitor blood Phe levels periodically during treatment. For Phe levels below 30 µmol/L, dosage may be reduced and/or dietary protein and Phe intake modified.
The most common adverse reactions leading to discontinuation were hypersensitivity reactions (6%), including anaphylaxis (3%), angioedema (1%), arthralgia (4%), generalized skin reactions lasting at least 14 days (2%), and injection site reactions (1%).1
In Part 1 of the adolescent clinical trial, 4 patients taking PALYNZIQ (N=36) experienced one episode of anaphylaxis each, without recurrence or further complications.1,4 Treatment was discontinued due to anaphylaxis in 2 patients, while the remaining 2 were rechallenged with PALYNZIQ.1
Hypersensitivity reactions other than anaphylaxis were reported in 33% (12/36) of adolescent patients. Management should be based on the severity of the reaction, recurrence, and clinical judgment, and may include dosage adjustment, temporary drug interruption, or treatment with antihistamines, antipyretics, and/or corticosteroids.1
Remind patients and caregivers about the importance of using aseptic injection techniques and rotating injection sites with each dose.
Monitor blood Phe levels periodically during treatment and frequently in the pediatric population. For Phe levels below 30 µmol/L, dosage may be reduced and/or dietary protein and Phe intake modified.
6% (2/36) of patients in the adolescent clinical trial discontinued PALYNZIQ due to an adverse reaction—fewer than in the adult clinical trial.1
IgE, immunoglobulin E.
References: 1. PALYNZIQ package insert. Novato, CA: BioMarin Pharmaceutical Inc; February 2026. 2. Thomas J, Levy H, Amato S, et al, for the PRISM investigators. Pegvaliase for the treatment of phenylketonuria: results of a long-term phase 3 clinical trial program (PRISM). Mol Genet Metab. 2018;124(1):27-38. doi:10.1016/j.ymgme.2018.03.006 3. Sacharow S, Northrup H, Whitehall KB, et al. Efficacy and safety of the recommended pegvaliase dosing regimen in adults with phenylketonuria in the phase 3 PRISM studies. Presented at the International Congress of Inborn Errors of Metabolism (ICIEM); November 21-24, 2021; Sydney, Australia. 4. Data on file. Biomarin Pharmaceutical Inc.
BOXED WARNING: ANAPHYLAXIS
WARNINGS AND PRECAUTIONS
Anaphylaxis
Other Hypersensitivity Reactions
Injection Site Infections
Hypophenylalaninemia (HypoPhe)
Some patients have experienced HypoPhe; monitor blood Phe levels periodically during treatment. Frequent blood Phe monitoring is recommended in the pediatric population. For blood Phe concentrations below 30 micromol/L, the dosage of PALYNZIQ may be reduced and/or dietary protein and Phe intake may be modified to maintain blood Phe concentrations within a clinically acceptable range and above 30 micromol/L.
ADVERSE REACTIONS
The most common adverse reactions in clinical trials of primarily adult patients (at least 20% in either treatment phase) were injection site reactions, arthralgia, hypersensitivity reactions, headache, generalized skin reactions lasting at least 14 days, nausea, abdominal pain, vomiting, cough, oropharyngeal pain, pruritus, diarrhea, nasal congestion, fatigue, dizziness, and anxiety.
In the clinical trials, adverse reactions were associated with treatment discontinuation, dosage reduction and temporary drug interruption. In the 285 primarily adult patients exposed to PALYNZIQ in an induction/titration/maintenance regimen in clinical trials, 44 (15%) patients discontinued treatment due to adverse reactions.
Pediatric Patients: In a clinical study of 55 patients aged 12 to less than 18 years of age, the most common adverse reactions (at least 20% and greater than in control) were injection site reactions, arthralgia, headache, pyrexia, hypersensitivity reactions, dizziness, nausea, vomiting, fatigue, and pain in extremity. Two patients (5.6%) discontinued treatment due to adverse reactions.
Blood Phenylalanine Monitoring and Diet
DRUG INTERACTIONS
Effect of PALYNZIQ on Other PEGylated Products
USE IN SPECIFIC POPULATIONS
Pregnancy and Lactation
Available data do not establish an increased risk of adverse developmental outcomes to the fetus exposed to PALYNZIQ.
Pediatric & Geriatric Use: The safety and effectiveness of PALYNZIQ in pediatric patients from birth to less than 12 years have not been established. Clinical studies of PALYNZIQ did not include patients aged 65 years and older.
You are encouraged to report suspected adverse reactions to BioMarin at 1-866-906-6100, or to the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Please see full Prescribing Information, including BOXED WARNING, and the Medication Guide.
INDICATION
PALYNZIQ® (pegvaliase-pqpz) is a phenylalanine (Phe)-metabolizing enzyme indicated to reduce blood Phe concentrations in adult and pediatric patients 12 years of age and older with phenylketonuria (PKU) who have uncontrolled blood Phe concentrations greater than 600 micromol/L (10 mg/dL) on existing management.