Pronunciation: Pal-lin-zeek
Generic name: pegvaliase-pqpz
Dosage form: single-dose prefilled syringe for subcutaneous use (2.5 mg/0.5 mL, 10 mg/0.5 mL, 20 mg/mL)
Drug class: Miscellaneous metabolic agents

Medically reviewed by Carmen Pope, BPharm. Last updated on Jul 11, 2025.

What is Palynziq?

Palynziq is used to lower blood levels of phenylalanine in adults with PKU (phenylketonuria) who have uncontrolled blood phenylalanine levels above 600 micromol/L (10 mg/dL) on their current treatment. It is given by subcutaneous injection 1 time a week for 4 weeks initially, before being titrated over several weeks based on the person's tolerability to achieve a once-daily dose.

Palynziq works by breaking down phenylalanine into ammonia and trans-cinnamic acid. It is a modified version of an enzyme called phenylalanine ammonia lyase (PAL) that has been enhanced with PEG to make it work better in the body. When given to PKU patients, it substitutes for the deficient phenylalanine hydroxylase (PAH) enzyme activity in adults with PKU and reduces blood phenylalanine concentrations. Palynziq is a phenylalanine (Phe)-metabolizing enzyme.

Palynziq gained FDA approval on May 24, 2018. There is no generic.

Warnings

Palynziq carries a Boxed Warning for the risk of anaphylaxis.

Palynziq can cause a severe allergic reaction (anaphylaxis) that may be life-threatening and can happen any time during treatment with Palynziq. Severe allergic reactions are a serious but common side effect of Palynziq.

• You will receive your first injection of Palynziq in a healthcare setting where you will be closely watched for at least 1 hour after your injection for a severe allergic reaction.
• If you have a severe allergic reaction during treatment with Palynziq, you will need to receive an auto-injection of epinephrine immediately and get emergency medical help right away.
• Your healthcare provider will decide if you (or your caregiver) can give the Palynziq injections, recognize the signs and symptoms of a severe allergic reaction, give an injection of epinephrine and call for emergency medical help, if needed.
• Your healthcare provider may recommend that an adult observer (or your caregiver) be with you when you give your Palynziq injection, and for at least 1 hour after your injection, to watch you for signs and symptoms of a severe allergic reaction and, if needed, give you an injection of epinephrine and call for emergency medical help.

Stop injecting Palynziq and get emergency medical care right away if you have any of the following symptoms of a severe allergic reaction during treatment with Palynziq:

• • fainting (passing out)
  • swelling of your face, lips, eyes, or tongue
  • dizziness or lightheadedness
  • throat tightness
  • sudden confusion
  • flushed skin
  • trouble breathing or wheezing
  • skin rash, itching, or raised bumps on skin
  • chest discomfort or chest tightness
  • nausea, vomiting, or diarrhea
  • fast heart rate
  • losing control of urine or stools.
• Your healthcare provider will prescribe an auto-injectable epinephrine for you and will teach you (or your caregiver) and your observer, if needed, when and how to use it if you have a severe allergic reaction. Keep the auto-injectable epinephrine with you at all times during treatment with Palynziq. Read the Patient Information that comes with the auto-injectable epinephrine that your healthcare provider prescribes for you for more information.
• If you have a severe allergic reaction, do not continue to take Palynziq until you talk with your healthcare provider. Tell your healthcare provider that you had a severe allergic reaction. Your healthcare provider will tell you if you can continue treatment with Palynziq.
  • Your healthcare provider may prescribe other medicines to take before your Palynziq injection that may help reduce the symptoms of an allergic reaction.
  • If your healthcare provider decides that you can continue treatment with Palynziq after a severe allergic reaction, you will receive your next injection of Palynziq in a healthcare setting where you will be closely watched for at least 1 hour after your injection for a severe allergic reaction.
• Your healthcare provider will give you a Palynziq Patient Wallet Card that describes symptoms that you (or your caregiver), or your observer, should know that require you to get emergency medical care right away. Carry this card with you at all times during treatment with Palynziq. It is important to show your Palynziq Patient Wallet Card to any other healthcare provider who treats you.

Palynziq is only available through a restricted program called the Palynziq Risk Evaluation and Mitigation Strategy (REMS) Program. Before you can receive Palynziq, you must:

• Enroll in this program.
• Receive education about the risk of a severe allergic reaction (anaphylaxis) by a healthcare provider certified in the Palynziq REMS to be sure that you understand the risks and benefits of treatment with Palynziq.
• Fill the prescription your healthcare provider gives you for the auto-injectable epinephrine and carry it with you at all times during treatment with Palynziq.
• Carry the Palynziq Patient Wallet Card with you at all times.

Talk to your healthcare provider for more information about the Palynziq REMS and how to enroll.

It is not known if Palynziq is safe and effective in children.

Side effects

The most common side effects of Palynziq include:

• injection site reactions, such as redness, itching, pain,
• cough
• bruising, rash, swelling, tenderness
• mouth and throat pain
• joint pain
• itching
• headache
• diarrhea
• skin reactions that spread on your skin and last at least 14 days, such as itching, rash, redness
• stuffy nose
• feel very tired
• nausea
• dizziness
• stomach pain
• anxiety
• vomiting
• low levels of phenylalanine in your blood.

Other allergic reactions to Palynziq can happen during treatment with Palynziq. Contact your healthcare provider right away if you have any of the following symptoms of an allergic reaction including: rash, itching, or swelling of the face, lips, eyes, or tongue. Your healthcare provider may change your dose of Palynziq, stop your treatment with Palynziq for a period of time, or prescribe medicine for you to take before your Palynziq injection to help reduce the symptoms of an allergic reaction.

These are not all the possible side effects of Palynziq. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before receiving

Before injecting Palynziq, tell your healthcare provider about all of your medical conditions, including if you:

• cannot or are not willing to use auto-injectable epinephrine to treat a severe allergic reaction.
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

Palynziq may harm your unborn baby. Tell your healthcare provider right away if you become pregnant or think you might be pregnant while taking Palynziq.

• If your phenylalanine levels are too high or too low during pregnancy, this may also affect your unborn baby. You and your healthcare provider can decide the best way for you to manage your blood phenylalanine levels and discuss the risks and benefits of taking Palynziq during pregnancy to you and your unborn baby. It is very important to keep your phenylalanine levels at the levels your healthcare provider recommends during pregnancy.
• Pregnancy Surveillance Program. There is a pregnancy surveillance program for females who take Palynziq during pregnancy, or who become pregnant while receiving Palynziq or within 1 month after their last dose of Palynziq. The purpose of this program is to collect information about the health of you and your baby while taking Palynziq. Talk to your healthcare provider about how you can take part in this program or call BioMarin at 1-866-906-6100.

Breastfeeding

It is not known if Palynziq passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby if you take Palynziq.

How do I administer Palynziq?

Your healthcare provider will give you the Palynziq injection until they decide that you (or your caregiver) can give it.

• Your healthcare provider may prescribe medicine for you to take before your Palynziq injection to help reduce the symptoms of an allergic reaction.
• If your healthcare provider decides that you (or your caregiver) can give your Palynziq injections, you (or your caregiver) will be shown how to prepare and give your Palynziq injections. See the “Instructions for Use” for detailed instructions on how to prepare and give an injection of Palynziq.

Use Palynziq exactly as your healthcare provider tells you to. Your healthcare provider will tell you how much Palynziq to inject and when to inject it.

• Palynziq comes in prefilled syringes with 3 different strengths (2.5 mg, 10 mg, or 20 mg). You may need more than 1  prefilled syringe for your prescribed dose.
• Palynziq is administered subcutaneously (under the skin).
• The recommended injection sites for Palynziq are:
  • the front middle of the thighs
  • the abdomen at least 2 inches (five centimeters) away from the navel.
• If a caregiver is giving the injection, the top of the buttocks and the back of the upper arms are also appropriate injection sites.
• Do not inject Palynziq into moles, scars, birthmarks, bruises, rashes, or areas where the skin is
  hard, tender, red, damaged, burned, inflamed, or tattooed. Check the injection site for redness,
  swelling, or tenderness.
• Rotate sites for subcutaneous injections of Palynziq. If more than one injection is needed for a
  single dose of Palynziq, the injection sites should be at least 2 inches away from each other. The
  second injection site can be on the same part of the body or a different part of the body.

Monitor the amount of protein and phenylalanine that you eat or drink. Your healthcare provider may change the amount of protein and phenylalanine you should have in your diet during treatment with Palynziq, depending on the levels of phenylalanine in your blood. Follow your healthcare provider’s instructions about the amount of protein and phenylalanine you should have in your diet.

Dosing information

• Obtain baseline blood Phe concentration before initiating treatment.

Dose of Palynziq for PKU in Adults

• Initial dosage: 2.5 mg subcutaneously once weekly for 4 weeks.
• Titration: Titrate the dosage in a step-wise manner over at least 5 weeks based on tolerability to achieve a dosage of 20 mg once daily. See full prescribing information for the titration regimen.

Assess patient tolerability, blood Phe concentration, and dietary protein and Phe intake throughout treatment.

• Consider increasing the dosage to 40 mg once daily in patients who have been on 20 mg once daily continuously for at least 24 weeks and who have not achieved blood Phe control (blood phenylalanine concentration less than or equal to 600 micromol/L).
• Consider increasing the dosage to a maximum of 60 mg once daily in patients who have been on 40 mg once daily continuously for at least 16 weeks and who have not achieved blood Phe control.
• Discontinue Palynziq in patients who have not achieved an adequate response after 16 weeks of continuous treatment with the maximum dosage of 60 mg once daily.
• Reduce the dosage and/or modify dietary protein and Phe intake, as needed, to maintain blood Phe concentrations within a clinically acceptable range and above 30 micromol/L.

Blood Phenylalanine Monitoring and Diet

• Obtain blood Phe concentrations every 4 weeks until a maintenance dosage is established.
• Periodically monitor blood Phe concentrations during maintenance therapy.
• Counsel patients to monitor dietary protein and Phe intake, and adjust as directed by their healthcare provider.

Premedication

• Consider premedication for hypersensitivity reactions.

What happens if I miss a dose?

If you miss a dose, take your next dose at the regular time. Do not take 2 doses of Palynziq to make up for a missed dose.

What other drugs will affect Palynziq?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, or herbal supplements

Storage

Store Palynziq in the refrigerator at 36°F to 46°F (2°C to 8°C).

If needed, you may store Palynziq at room temperature between 68°F to 77°F (20°C to 25°C) for up to 30 days.

• Write the date that you remove Palynziq from the refrigerator on the carton.
• If stored at room temperature, do not put Palynziq back in the refrigerator.
• Keep Palynziq in the original carton to protect it from light.
• Do not freeze or shake Palynziq.
• Throw away Palynziq if it has been kept at room temperature for 30 days and has not been used, or after the expiration date on the carton, whichever comes first.

Keep Palynziq and all medicines out of the reach of children

Ingredients

Active ingredients: pegvaliase-pqpz

Inactive ingredients: sodium chloride, trans-cinnamic acid, tromethamine, and tromethamine hydrochloride.

Palynziq is available as prefilled syringes with 3 different strengths (2.5 mg, 10 mg, or 20 mg).

Manufacturer

Palynziq is manufactured by BioMarin Pharmaceutical Inc. Novato, CA 94949

Palynziq Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Palynziq.

Frequently asked questions

• What is Palynziq used to treat?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer