Tyruko (natalizumab-site) is an injectable integrin receptor antagonist that is a biosimilar to Tysabri (natalizumab) that may be used to treat adults with relapsing forms of multiple sclerosis (including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease) or moderate to severe Crohn's disease (usually after other treatments have been tried).

A biosimilar is a biological product that is like a reference biologic (in this case Tysabri) and for which there are no clinically meaningful differences in terms of safety, purity, and potency. A biosimilar is not considered a “generic” because they are made from living cells rather than chemicals, making them naturally variable, and they are expensive to make. Generic drugs contain identical medicinal ingredients to their reference products and are cheap to make.

Tyruko was FDA-approved on August 24, 2023. It covers all the same indications as the reference product, Tysabri.

Tyruko increases the risk of progressive multifocal leukoencephalopathy (PML), a viral infection of the brain that usually occurs in immunosuppressed people. This can lead to severe disability and death. Risk factors include using presence of John Cunningham Virus (JCV) antibodies, duration of treatment beyond 2 years, and prior use of immunosuppressants. Because of this risk, Tyruko is only available through a restricted distribution program called the Tyruko REMS Program. Call your doctor right away if you have a sudden fever, severe headache, confusion, memory problems, vision changes, eye pain, weakness on one side of your body, or problems with using your arms or legs. These symptoms may start gradually and get worse quickly.

Life-threatening infections, including herpes encephalitis, meningitis, and acute retinal necrosis have occurred in patients receiving natalizumab. Call your doctor right away if you have any change in your mental state, decreased vision, weakness on one side of your body, or problems with speech or walking. These symptoms may start gradually and get worse quickly.

Significant liver injury, including liver failure requiring transplant, has occurred. Call your doctor at once if you develop any symptoms of liver damage, such as nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

Tyruko can increase your risk of infection. Call your doctor right away if you develop any signs of infection such as fever, chills, sore throat, cough, stuffy nose, redness, pain, swelling, or painful urination.

There is a risk of severe hypersensitivity reactions, such as anaphylaxis, with Tyruko. It should be permanently discontinued if these occur.

Thrombocytopenia (very low platelet counts) can occur with natalizumab. Your doctor will conduct regular blood tests and monitor you for bleeding abnormalities.

In Crohn’s disease, this drug should not be used with concomitant immunosuppressants (such as 6-mercaptopurine, azathioprine, cyclosporine, and methotrexate) or inhibitors of TNF-alpha.

Tyruko is given as an IV infusion into a vein, over one hour, usually once every 4 weeks. A healthcare provider will give you this injection.

The usual dose is 300mg and Tyruko must be given slowly, which is why the  IV infusion can take at least 1 hour to complete. You will be watched closely for at least 1 hour after receiving the infusion, to make sure you do not have an allergic reaction to the medication. An allergic reaction can occur up to 2 hours or longer after your infusion.

Before your first dose, your doctor may recommend an MRI to make sure you do not have any signs of a brain infection.

Tyruko can weaken your immune system. You may get infections more easily, even serious or fatal infections.

You will need frequent blood tests. You may also need a brain scan or spinal tap (lumbar puncture) if you develop signs of a brain infection.

Your doctor must check you every 3 to 6 months for signs of serious infection. Your doctor may also want to check you for several weeks after you stop using this medicine.

Tell any doctor who treats you that you are using Tyruko.

Your doctor will determine every 6 months whether you should continue on treatment, and if so, will authorize treatment for another 6 months.

Tyruko is given as an IV infusion into a vein, over one hour, usually once every 4 weeks. A healthcare provider will give you this injection.

The usual dose is 300mg and Tyruko must be given slowly, which is why the  IV infusion can take at least 1 hour to complete. You will be watched closely for at least 1 hour after receiving the infusion, to make sure you do not have an allergic reaction to the medication. An allergic reaction can occur up to 2 hours or longer after your infusion.

Before your first dose, your doctor may recommend an MRI to make sure you do not have any signs of a brain infection.

Tyruko can weaken your immune system. You may get infections more easily, even serious or fatal infections.

You will need frequent blood tests. You may also need a brain scan or spinal tap (lumbar puncture) if you develop signs of a brain infection.

Your doctor must check you every 3 to 6 months for signs of serious infection. Your doctor may also want to check you for several weeks after you stop using this medicine.

Tell any doctor who treats you that you are using Tyruko.

Your doctor will determine every 6 months whether you should continue on treatment, and if so, will authorize treatment for another 6 months.

You should not receive Tyruko if you are allergic to natalizumab, or if you have ever had PML.

Your doctor will test you for antibodies to the John Cunningham Virus (JCV). This is a common virus that has infected almost half of the population, although most people are unaware that they have had it. It does not usually cause problems for healthy people but it can be dangerous for those with a weakened immune system.

Tyruko is only available from a certified pharmacy under a special program called the Tyruko REMS Program. You must be registered in the program and understand the risks and benefits of taking this medicine.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

• A fever, or an active infection
• Herpes or shingles
• Leukemia or lymphoma
• HIV, AIDS, or other conditions that can weaken your immune system
• Liver disease
• An organ transplant or
• Hives, itching, or trouble breathing after a dose of Tyruko.

Tyruko can cause harm to an unborn baby and it should not be used while pregnant. Tell your doctor if you are pregnant or plan to become pregnant. Call your doctor right away if you inadvertently become pregnant.

It may not be safe to breastfeed while using Tyruko because it has been detected in human milk. Ask your doctor about any risks.

Tyruko is not approved for use by anyone younger than 18 years old.

Call your doctor for instructions if you miss an appointment for your Tyruko injection.

Since this medicine is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Keep all your regular appointments with your doctor.

Get emergency medical help if you have signs of an allergic reaction to Tyruko such as hives, a rash, wheezing, difficulty breathing, or swelling of your face, lips, tongue, or throat.

Some allergic reactions may occur during the injection. Tell your caregiver right away if you feel dizzy, nauseated, light-headed, itchy, cold, or sweaty, or if you have chest pain, trouble breathing, or swelling in your face.

Tyruko may cause serious viral infections of the brain or spinal cord that can lead to disability or death. Call your doctor right away if you have any of the following symptoms during treatment with Tyruko or up to 6 months after your last dose (these symptoms may start gradually and get worse quickly):

• Sudden fever or severe headache
• Confusion, memory problems, or other changes in your mental state
• Weakness on one side of your bodyVision changes, eye pain, or redness
• Problems with speech or walking or
• Trouble using your arms and legs.

Also, call your doctor at once if you have:

• Fever, chills, cough with yellow or green mucus
• Easy bruising, unusual bleeding (nosebleeds, bleeding gums, heavy menstrual periods), purple or red spots under your skin
• Any bleeding that will not stop
• Pain or burning when you urinate or
• Liver problems - nausea, upper stomach pain, itching, tiredness, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

Common Tyruko side effects may include:

• Headache
• Fatigue
• Depression
• Nausea, diarrhea, stomach pain
• Cold symptoms such as stuffy nose, sneezing, sore throat
• Joint pain, pain in your arms and legs
• A Rash
• Urinary tract infections, gastroenteritis, or lower respiratory tract infections
• Vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your doctor about all your current medicines and any you start or stop using, especially drugs that weaken the immune system such as cancer medicine, steroids, and medicines to prevent organ transplant rejection.

Other drugs may interact with natalizumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.