Cosibelimab

Cosibelimab is used in adults to treat specific skin cancers.

Cosibelimab is often used when the cancer has spread to other areas of the body (metastatic) or cannot be treated with other cancer medications, radiation, or surgery.

Your doctor will confirm that you have the right type of tumor to be treated with cosibelimab.

Cosibelimab may also be used for reasons not mentioned in this medication guide.

Your doctor will do tests to confirm that cosibelimab is the right treatment for you.

Cosibelimab is given as an infusion into a vein, usually once every 3 weeks. A healthcare provider will give you this injection.

After receiving an infusion, you will be monitored closely to ensure you do not have an allergic reaction.

Your doctor will need to check your progress regularly.

You will need frequent medical tests, and your next dose may be delayed depending on the results.

You may receive other medications to help prevent serious side effects or allergic reactions. Continue taking these medications for as long as your doctor has prescribed.

Cosibelimab helps your immune system target tumor cells, but it might also affect healthy organs and tissues in your body. This could result in serious or life-threatening side effects affecting your lungs, liver, pancreas, kidneys, intestines, thyroid, or adrenal glands. Some side effects might require treatment with other medicines, and your cancer treatments could be postponed.

Tell your doctor if you have or have ever had:

• a stem cell transplant that uses donor stem cells or plan to have one;
• an organ transplant (including corneal transplant);
• radiation treatment to your chest;
• an autoimmune disorder like lupus, ulcerative colitis, or Crohn's disease; or
• a nerve-muscle disorder like myasthenia gravis or Guillain-Barré syndrome.

You may need to take a pregnancy test before starting this treatment.

May harm an unborn baby. Do not use if you are pregnant. Use effective birth control while using cosibelimab and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Do not breastfeed while using cosibelimab, and for at least 4 months after your last dose.

Get emergency medical help if you notice signs of an allergic reaction (hives, trouble breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Some side effects may happen during the injection. Let your medical caregiver know if you feel dizzy, nauseous, light-headed, itchy, sweaty, or have a headache, chest tightness, back pain, trouble breathing, or swelling in your face.

Cosibelimab makes your immune system attack tumor cells, but it could also attack healthy organs and tissues in your body. This could result in serious or life-threatening side effects affecting your lungs, liver, pancreas, kidneys, intestines, skin, thyroid, or adrenal glands.

Cosibelimab may cause serious side effects. Contact your doctor immediately if you experience:

• fever or flu-like symptoms, severe nausea or vomiting, swollen glands;
• severe headache, feeling light-headed or extremely tired, drowsiness;
• severe muscle cramps, pain or weakness, neck pain or stiffness, swelling, numbness or tingling in your arms or legs, hoarse or deepened voice, hair loss, increased sweating, feeling cold;
• new or worsening skin rash, itching, blistering, or ulcers;
• chest pain, rapid or irregular heartbeats, new or worsening cough, feeling short of breath, bleeding, bruising, anemia (low red blood cells);
• changes in appetite including loss of appetite or increased hunger or thirst, weight gain, or weight loss;
• vision changes, confusion, mood or behavior changes, memory issues, balance problems;
• severe pain in your upper stomach (that may spread to your back), jaundice (yellowing of skin or eyes), or dark urine;
• diarrhea, constipation, bloody or tarry stools, decreased or increased urination, or blood in your urine; or
• (if you have had a stem cell transplant) feeling sick or uneasy, with pain or swelling.

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

Common side effects of cosibelimab may include:

• nausea, constipation, diarrhea;
• abnormal blood tests;
• bone or muscle pain;
• rash, itching, or swelling;
• infection;
• pain and burning when you urinate; or
• headache, feeling weak or tired.

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

Call your doctor for guidance if you miss an appointment for your cosibelimab injection.

In a medical setting, an overdose will be treated quickly.

Follow your doctor's instructions regarding any restrictions on food, drinks, or activities.

Other drugs may affect cosibelimab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you take.