Gavreto is a tyrosine kinase inhibitor that may be used to treat adults with non-small cell lung cancer (NSCLC) that has spread to other parts of the body (metastatic). It is only used if your cancer has a specific genetic marker (an abnormal "RET" gene fusion). Your doctor will test you for this gene fusion using an FDA-approved test.

Gavreto is also used to treat adults and children 12 years of age and older with advanced or metastatic RET fusion-positive thyroid cancer who require a medicine by mouth or injection (systemic therapy) and who are radioactive iodine-refractory (in cases where radioactive iodine is appropriate).

Gavreto was first approved on September 4, 2020, by the US Food and Drug Administration (FDA) on an "accelerated" basis for metastatic RET fusion-positive NSCLC, and it received accelerated approval for metastatic RET fusion-positive thyroid cancer on December 1, 2020.

On 9 August 2023, it received full approval for metastatic RET fusion-positive NSCLC.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use. Gavreto may affect the way other medicines work, and other medicines may affect how it works. Coadministration with strong or moderate CYP3A inhibitors, P-gp inhibitors, or strong or moderate CYP3A inducers is not recommended.

There are no contraindications to the use of Gavreto.

Treatment with Gavreto should be withheld in patients who develop Grade 1 or Grade 2 interstitial lung disease (ILD)/pneumonitis, then resumed at a lower dose once resolved. If the ILD recurs, or ILD Grade 3 or 4 occurs, Gavreto should be permanently discontinued.

Gavreto should not be given to patients with uncontrolled high blood pressure. Blood pressure should be optimized before starting treatment and then monitored after the first week of treatment, then monthly thereafter or as indicated. The dosage may be reduced, withheld, or permanently discontinued if blood pressure increases.

Gavreto can be toxic to the liver. Your doctor will monitor your liver function (specifically ALT and AST enzymes) before initiating Gavreto, then every 2 weeks for the first 3 weeks, then monthly thereafter or as indicated. The dosage may be reduced, withheld, or permanently discontinued if liver toxicity occurs.

Gavreto may increase your risk of bleeding (hemorrhage) and may need to be permanently discontinued if severe or life-threatening events occur.

There is also a risk of tumor lysis syndrome.

Gavreto can impair the ability of wounds to heal. It should be withheld at least 5 days before elective surgery and should not be administered for 2 weeks following major surgery or until a wound has adequately healed.

Females of reproductive potential should be advised that Gavreto can cause fetal harm and they should use adequate forms of non-hormonal contraception.

The growth plates of children taking Gavreto should be monitored and the medication withheld or discontinued if abnormalities occur.

Take Gavreto exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Take Gavreto on an empty stomach, at least 1 hour before or 2 hours after a meal.

If you vomit shortly after taking Gavreto, do not take another dose. Wait until your next scheduled dose time to take the medicine again.

Your blood pressure will need to be checked often and you will need frequent blood tests.

If you need surgery, tell your surgeon you currently use this medicine. You may need to stop for a short time.

Do not change your dose or stop using a medicine without your doctor's advice.

Store at room temperature away from moisture and heat.

Take Gavreto exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Do not change your dose or stop using the medicine without your doctor's advice. Your doctor will conduct a RET gene fusion test to determine if Gavreto is right for you.

Gavreto is an oral medication that is taken by mouth.

The recommended dosage for adults and children 12 and over is 400mg orally once daily. Each capsule is 100mg, which means you will take 4 capsules. Gavreto should be taken on an empty stomach, at least 1 hour before or 2 hours after a meal.

If you vomit shortly after taking Gavreto, do not take another dose. Wait until your next scheduled dose time to take the medicine again.

Your blood pressure will need to be checked often and you will need frequent blood tests.

If you need surgery, tell your surgeon you currently use this medicine. You may need to stop for a short time.

Duration of therapy: Continue until disease progression or unacceptable toxicity occurs.

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

• lung or breathing problems other than lung cancer

• bleeding problems, or

• high blood pressure.

Gavreto can harm an unborn baby.  A pregnancy test should be conducted before initiating Gavreto in females of reproductive potential. Use effective non-hormonal birth control to prevent pregnancy while using this medicine and for at least 2 weeks after your last dose. If you inadvertently become pregnant, tell your doctor right away.

If you are a man prescribed Gavreto, use effective birth control if your sex partner can get pregnant. Keep using birth control for at least 1 week after your last dose. Tell your doctor right away if a pregnancy occurs in your partner while using Gavreto.

Gavreto can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. To prevent pregnancy while using Gavreto, use a barrier form of birth control: condom, diaphragm, cervical cap, or contraceptive sponge.

Do not breastfeed while using this medicine, and for at least 1 week after your last dose.

Gavreto may impair fertility.

Gavreto is only approved for adults with NSCLC, and for adults and children 12 years of age and older with RET fusion-positive thyroid cancer.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction to Gavreto: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• fever, chills;

• new or worsening cough, shortness of breath, or chest pain;

• severe headache, dizziness, confusion, trouble speaking;

• any wound that will not heal;

• unusual bleeding - bruising, nosebleeds, bleeding gums, abnormal vaginal bleeding, any bleeding that will not stop;

• signs of bleeding inside your body - weakness, drowsiness, pink or brown urine, bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;

• low blood cell counts - fever, tiredness, sore throat, mouth sores, skin sores, pale skin, cold hands and feet, feeling light-headed or short of breath; or

• liver problems - nausea, vomiting, loss of appetite, stomach pain (upper right side), tiredness, dark urine, jaundice (yellowing of the skin or eyes).

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common Gavreto side effects may include:

• muscle or joint pain
• constipation or diarrhea
• high blood pressure
• low blood cell counts or other abnormal laboratory tests
• feeling tired
• edema
• fever
• cough
• low sodium levels and other electrolyte changes.

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 FDA at 1-800-FDA-1088.

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Tell your doctor about all your current medicines including prescription medicines, over-the-counter drugs, vitamins, and herbal products. Many drugs can interact with Gavreto, especially:

• some antibiotic or antifungal medicines
• antiviral medications used to treat HIV or hepatitis C
• some cancer medications
• certain cholesterol medications
• seizure medications.

Avoid administering Gavreto with strong or moderate CYP3A inhibitors and/or P-gp inhibitors such as clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil, goldenseal, and grapefruit. Your doctor may reduce the dosage of Gavreto if coadministration is unavoidable.

Avoid administering Gavreto with strong or moderate CYP3A inducers such as phenobarbital, phenytoin, rifampicin, St. John's Wort, and glucocorticoids. Your doctor may increase the dosage of Gavreto if coadministration is unavoidable.

This list is not complete and many other drugs may interact with pralsetinib. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.