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Overview: Fayuvi is a one-time gene therapy used to treat Sanfilippo syndrome type A. It works by giving the body a working copy of a faulty gene, which helps the body break down a substance that can build up in cells. Common side effects include increased liver enzymes, nausea or vomiting, fever, decreased appetite, and low levels of certain blood cells. Contact your health care provider right away if you have trouble breathing, chest pain, yellowing of the skin or eyes, unusual bleeding or bruising, urinate less than usual, have a seizure, or have other new or concerning symptoms.

Uses

What is Fayuvi used for?

Fayuvi (rebisufligene etisparvovec-hopf) is used to treat an inherited disorder called Sanfilippo syndrome type A, also known as mucopolysaccharidosis (MPS) type IIIA.

Fayuvi for Sanfilippo Syndrome Type A (MPS IIIA): What to Know

Fayuvi may also be used for other conditions as determined by your health care provider.

How does Fayuvi work (mechanism of action)?

In people with Sanfilippo syndrome, a faulty gene prevents the body from properly breaking down a substance called heparan sulfate. As this substance builds up in cells, it can cause damage, especially in the brain.

Fayuvi is a gene therapy that delivers a working copy of the faulty gene. This allows the body to make an enzyme that breaks down heparan sulfate and reduces its buildup.

How is Fayuvi supplied (dosage forms)?

Fayuvi is available in an injectable form that is given by a health care provider as a one-time treatment.

How should I store Fayuvi?

Fayuvi is usually given by a health care provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of Fayuvi?

The most common side effects of Fayuvi are listed below. Tell your health care provider if you have any of these side effects that bother you.

There may be other side effects of Fayuvi that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Fayuvi?

While less common, the most serious side effects of Fayuvi are described below, along with what to do if they happen.

Severe Allergic Reactions. Fayuvi may cause allergic reactions, which can be serious. Get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Infusion Reactions. Fayuvi can cause reactions when it is given to you. Your infusion may need to be slowed or stopped if you have severe reactions. Tell your health care provider right away if you have any of the following symptoms when you get your infusion.

  • Dizziness
  • Fever or chills
  • Feeling of skipped heartbeats (palpitations)
  • Nausea or vomiting
  • Headache
  • Trouble breathing
  • Chest pain

Increased Liver Enzymes. Changes in liver function tests, including increased liver enzymes, can happen after Fayuvi treatment. Keep all appointments for blood tests to check the health of your liver before and after treatment. Increased liver enzymes can be a sign of liver damage. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Low Platelet Levels. Fayuvi can cause you to have a severely low number of platelets in your blood, also called thrombocytopenia. Platelets help to form blood clots. Having a low level of platelets may increase your risk of bleeding. Tell your health care provider if you have any of the following symptoms of low platelet levels.

  • Easy bruising or bleeding
  • Bleeding that does not stop
  • Nosebleeds

Small Blood Vessel Clots. Fayuvi may cause a life-threatening condition called thrombotic microangiopathy (TMA). This is a condition where small blood clots form in blood vessels and can damage your kidneys. Keep all your appointments to have your blood checked. Tell your health care provider right away if you have any of the following signs or symptoms of TMA.

  • Peeing less than usual
  • Unusual bruising or bleeding
  • High blood pressure
  • Seizures

Cancer. Fayuvi can cause a new cancer to form or cause a previously treated cancer to come back. Tell your health care provider about any new symptoms that you may get. If cancer develops after Fayuvi treatment, you or your health care provider can report it to the drugmaker by calling 888-756-8657. 

Warnings & Precautions

Who should not use Fayuvi?

Allergies to Ingredients. People who are allergic to any of the following should not use Fayuvi.

  • Fayuvi
  • Rebisufligene etisparvovec-hopf
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in Fayuvi.

What should I know about Fayuvi before using it?

Fayuvi is given by a health care provider in a hospital or clinic. It is given as a one-time infusion into a blood vessel.

Your health care provider will take steps to help you prepare for treatment and monitor you afterward. To help reduce the risk of side effects, they will give you certain medicines, including steroids, before and after receiving Fayuvi. It is very important to take these medicines exactly as prescribed and keep all appointments, including blood tests, before and after treatment. If you vomit or miss a steroid dose, contact your health care provider right away.

After receiving Fayuvi, small amounts of the vector (an inactive virus used to carry the gene therapy) can be found in bodily fluids and poop for a short time. This is normal and does not mean you have or are spreading an infection. As a precaution, practice good hand hygiene and place any soiled materials in a sealed bag before throwing them away. You can throw the sealed bag in the regular trash. These precautions are usually needed for 3 months after treatment.

What should I tell my health care provider before using Fayuvi?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if Fayuvi is right for you.

In particular, make sure that you discuss any of the following.

Vaccines. Talk with your health care provider about any vaccines that you may need. Do not get any vaccines before or after treatment with Fayuvi unless your health care provider says it is safe. Your health care provider can help you plan the timing around certain medicines that you will need to take before and after Fayuvi treatment.

Pregnancy. It is not known if or how Fayuvi could affect pregnancy or harm a fetus. If you can get pregnant, you should have a test to make sure you are not pregnant before you receive Fayuvi. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if Fayuvi passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should receive Fayuvi while breastfeeding.

How can I get more information about Fayuvi?

For more information about Fayuvi, you can visit the drugmaker’s website at www.fayuvi.com or call them at 888-756-8657.

Interactions

Does Fayuvi interact with foods or drinks?

There are no known interactions between Fayuvi and foods or drinks.

It is not known whether drinking alcohol will affect Fayuvi.

Does Fayuvi interact with other medicines (drug interactions)?

Fayuvi may interact with certain medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much Fayuvi?

If you or someone else has used too much Fayuvi, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Fayuvi?

Fayuvi is given by a health care provider in a hospital or clinic. Your health care provider will make sure you receive Fayuvi as scheduled.