Tagraxofusp-erzs injection may cause a serious and life-threatening reaction called capillary leak syndrome (CLS; a serious condition in which parts of the blood leak out of the blood vessels and can result in death). Tell your doctor right away if you experience sudden weight gain; swelling of the face, arms, legs, feet, or any other place on the body; shortness of breath; or dizziness. Your doctor may interrupt or stop your treatment with tagraxofusp-erzs, and may treat you with other medications. Be sure to weigh yourself each day to see if you are gaining weight.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests before and during your treatment to be sure it is safe for you to receive tagraxofusp-erzs and to check your body’s response to the medication.

Tagraxofusp-erzs injection is used to treat blastic plasmacytoid dendritic cell neoplasm (BPDCN; a blood cancer that causes skin lesions, and may spread to the bone marrow and lymphatic system) in adults and children 2 years of age and older. Tagraxofusp-erzs is in a class of medications called CD123 cytotoxin. It works by killing cancer cells.

Tagraxofusp-erzs injection comes as a solution (liquid) to be diluted and injected intravenously (into a vein) over 15 minutes. It is usually given once a day on days 1, 2, 3, 4 and 5 of a 21 day treatment cycle. For the first treatment cycle you will need to stay in the hospital until 24 hours after your last (5th) dose so that the doctors and nurses can watch you carefully for any side effects. For the following treatment cycles you will probably only need to stay in the hospital for 4 hours after each dose.

Your doctor will probably treat you with other medications about one hour before each dose to help prevent certain side effects. Be sure to tell the doctor how you are feeling during your treatment with tagraxofusp-erzs. Your doctor may need to delay or stop your treatment if you experience certain side effects.

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

Before receiving tagraxofusp-erzs,

• tell your doctor and pharmacist if you are allergic to tagraxofusp-erzs, any other medications, or any of the ingredients in tagraxofusp-erzs injection. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what 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 are pregnant, or plan to become pregnant. You must take a pregnancy test within 7 days before starting treatment. You should not become pregnant during your treatment with tagraxofusp-erzs. Use effective birth control during treatment and for 7 days after your final dose. If you become pregnant while receiving tagraxofusp-erzs, call your doctor.
• tell your doctor if you are breastfeeding. You should not breastfeed during your treatment with tagraxofusp-erzs and for 7 days after your final dose.

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

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

• nausea
• vomiting
• constipation
• diarrhea
• extreme tiredness
• headache
• decreased appetite
• sore throat
• pain in back, arms, or legs
• cough
• difficulty falling asleep or staying asleep
• feeling nervous or confused
• nose bleed
• small red, brown, or purple spots on the skin

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

• rash, itching, difficulty breathing, mouth sores or swelling
• extreme tiredness, yellowing of skin or eyes, loss of appetite, pain in the upper right part of the stomach
• fever, chills
• fast heartbeat
• blood in urine

Tagraxofusp-erzs may cause other side effects. Call your doctor if you have any unusual problems while receiving 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).

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.

• Elzonris^®