Mogamulizumab-kpkc injection is used to treat mycosis fungoides and Sézary syndrome, two types of cutaneous T-cell lymphoma ([CTCL], a group of cancers of the immune system that first appear as skin rashes), in adults whose disease has not improved, has gotten worse, or has come back after taking other medications. Mogamulizumab-kpkc injection is in a class of medications called monoclonal antibodies. It works by activating the immune system to attack cancer cells.

Mogamulizumab-kpkc injection comes as a solution (liquid) to be injected intravenously (into a vein) over at least 60 minutes by a doctor or nurse in a hospital or medical office. It is usually given once a week for the first four doses, and then once every other week for as long as your treatment continues. The length of treatment depends on how well your body responds to the medication and the side effects that you experience.

You may experience a serious or life-threatening reaction while you receive a dose of mogamulizumab-kpkc injection. These reactions are more common with the first dose of mogamulizumab-kpkc injection but may occur at any time during treatment. Your doctor may tell you to take certain medications before receiving your dose to prevent these reactions. Your doctor will monitor you carefully while you are receiving the medication. If you experience any of the following symptoms during or after your infusion, tell your doctor immediately: chills, shaking, nausea, vomiting, flushing, itching, rash, fast heartbeat, shortness of breath, coughing, wheezing, dizziness, feeling like passing out, tiredness, headache, or fever. If you experience any of these symptoms, your doctor will slow down or stop your infusion and treat the symptoms of the reaction. If your reaction is severe, your healthcare provider may decide not to give you any more infusions of mogamulizumab-kpkc.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Before receiving mogamulizumab-kpkc injection,

• tell your doctor and pharmacist if you are allergic (such as a skin reaction or infusion reaction) to mogamulizumab-kpkc, any other medications, or any of the ingredients in mogamulizumab-kpkc injection. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have had or plan to have a stem cell transplant using cells from a donor, and if you have or have ever had any type of autoimmune disease, liver disease including Hepatitis B virus infection, or any type of lung or breathing problems.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you are able to become pregnant, your doctor will do a pregnancy test before you start treatment with mogamulizumab-kpkc injection. You should use birth control to prevent pregnancy during your treatment with mogamulizumab-kpkc injection and for at least 3 months after your last dose of medication. Talk to your doctor about methods of birth control that will work for you. If you become pregnant while receiving mogamulizumab-kpkc injection, call your doctor.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are receiving mogamulizumab-kpkc injection.

If you miss an appointment to receive a dose of mogamulizumab-kpkc injection, call your doctor as soon as possible.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Unless your doctor tells you otherwise, continue your normal diet.

Mogamulizumab-kpkc injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• constipation
• muscle spasms or pain
• tiredness or fatigue
• headache
• swelling of the hands, feet, ankles, or lower legs
• decreased appetite
• changes in weight
• difficulty falling asleep or staying asleep
• depression
• dry skin
• hair loss

Some side effects can be serious. If you experience any of these symptoms or those in the HOW section, call your doctor immediately or get emergency medical treatment:

• rash, skin pain, itching, blistering, or peeling
• painful sores or ulcers in the mouth, nose, throat, or genital area
• fever, cough, sore throat, chills, flu-like symptoms, or other signs of infection
• nausea, diarrhea, or stomach pain
• painful or frequent urination
• easy bruising or bleeding

Mogamulizumab-kpkc injection may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to mogamulizumab-kpkc injection.

Ask your pharmacist any questions you have about mogamulizumab-kpkc injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.