The recommended dose is 350 mg every 3 weeks, given as an infusion that takes 30 minutes.

Cemiplimab is an antineoplastic medication. It is a type of protein designed to help your own body’s immune system target cancer cells to stop them from growing.

More common side effects that don't require medical attention unless they are bothersome:

• Pain or tenderness where the needle is placed
• Nause and vomiting
• Reduced immune system, meaning you are at higher risk of getting an infection.
• Constipation
• Loss of appetite / weight loss
• Tiredness

Check with your healthcare team or get emergency help immediately if you have:

• Signs of an allergic reaction soon after treatment such as dizziness, fast heartbeat, face swelling, or breathing problems
• An infection, which may cause fever (over 38°C or 100°F by an oral thermometer), shaking chills; severe sore throat, productive cough (coughing up thick or green sputum); cloudy or foul smelling urine; painful, tender, or swollen red skin wounds or sores
• Changes in your bowel movements such as diarrhea, black tarry stools, blood or mucus in the stool, abdominal pain
• Eye changes such as eyesight, pain, or redness
• Breathing problems such as new or worsening cough, new or worsening cough, shortness of breath, difficulty in breathing, coughing blood
• Heart problems such as chest pain, irregular heartbeat, swelling of feet or lower legs
• Signs of liver problems such as yellow eyes or skin, white or clay-coloured stools
• Signs of kidney problems such as lower back or side pain, blood in the urine, swelling of feet or lower legs, or change in amount or colour of urine
• Problems with muscles such as weakness or trouble using arms or leg muscles
• Skin rash with blisters

Check with your healthcare team as soon as possible if you have:

• Unusual tiredness or weakness, which could be low red blood cells or hemoglobin
• Blood sugar problems, which  may cause thirst and frequent need to urinate
• Skin rash or itching (if blisters seek medical attention immediately)
• Thyroid problems, which may cause unusual weight gain or loss, feeling hot or cold, deepened voice, or unusual tiredness or weakness
• Numbness or tingling in the extremities (feet or hands)
• Dry  mouth or difficulty swallowing

Cemiplimab causes a reduction in your immune system. Discuss vaccines with your healthcare team before starting treatment and do not receive any vaccines before discussing with your doctor.  

Drug interactions: How cemiplimab interacts with other medications is not well understood and little information is available. Speak to your pharmacist about potential interactions.

Use in pregnancy:  There is a possibility of birth defects with cemiplimab. Effective birth control should be practiced while using this medication and for 4 months after treatment. 

Use in breastfeeding:  At this time, breastfeeding is not recommended during treatment and for 4 months after treatment has ended.