What is the most important information I should know about pembrolizumab?

Pembrolizumab can change the way your immune system works, which may cause certain side effects that can lead to serious medical problems.

What is pembrolizumab?

Pembrolizumab is a cancer medicine that interferes with the growth and spread of cancer cells in the body.

Pembrolizumab is used to treat:

• advanced skin cancer (melanoma) that has spread to other parts of the body or cannot be surgically removed;
• a certain type of non-small cell lung cancer, if your tumor has a specific genetic marker for which your doctor will test;
• head and neck cancer that has spread to other parts of the body, or has come back after prior treatment;
• classical Hodgkin lymphoma in adults and children;
• a certain type of bladder and urinary tract cancer that has spread to other parts of the body or cannot be surgically removed; and
• a type of cancer that laboratory testing proves to be a microsatellite instability-high or a mismatch repair deficiency solid tumor.

Pembrolizumab is often given after other cancer medicine has been tried without success.

Pembrolizumab was approved by the US Food and Drug Administration (FDA) on an "accelerated" basis to treat lung cancer or head and neck cancer. In clinical studies, tumors responded to this medicine. However, it has not been shown that pembrolizumab can improve symptoms or lengthen survival time.

Pembrolizumab may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before receiving pembrolizumab?

To make sure pembrolizumab is safe for you, tell your doctor if you have:

• a lung disease or a breathing disorder;
• liver or kidney disease;
• diabetes;
• a thyroid disorder;
• an autoimmune disorder such as lupus, Crohn's disease, or ulcerative colitis; or
• if you have ever had an organ transplant.

How is pembrolizumab given?

Before you start treatment, your doctor will perform tests to make sure pembrolizumab is the best treatment for your type of cancer.

Pembrolizumab is injected into a vein through an IV. A healthcare provider will give you this injection.

Pembrolizumab is usually given once every 3 weeks. Your doctor will determine how long to treat you with this medicine. Follow your doctor's dosing instructions.

Pembrolizumab can cause certain side effects by changing the way your immune system works. These side effects can cause symptoms in many different parts of your body. Some side effects may need to be treated with other medicine, and your cancer treatments may be delayed or stopped altogether.

What happens if I miss a dose?

What happens if I overdose?

What should I avoid while receiving pembrolizumab?

This medicine can pass into body fluids (urine, feces, vomit). For at least 48 hours after you receive a dose, avoid allowing your body fluids to come into contact with your hands or other surfaces. Caregivers should wear rubber gloves while cleaning up a patient's body fluids, handling contaminated trash or laundry or changing diapers. Wash hands before and after removing gloves. Wash soiled clothing and linens separately from other laundry.

What are the possible side effects of pembrolizumab?

Some side effects may occur during the injection. Tell your caregiver right away if you feel dizzy, light-headed, itchy, hot or cold, sweaty, tingly, feverish, or if you have trouble breathing.

Pembrolizumab can change the way your immune system works, which may cause certain side effects that can lead to serious medical problems.

• new or worsening cough, chest pain, feeling short of breath;
• pale skin, easy bruising or bleeding;
• severe muscle weakness, severe or ongoing muscle aches, joint pain;
• diarrhea or increased stools, severe stomach pain, bloody or tarry stools;
• low levels of sodium in the body --confusion, slurred speech, severe weakness, loss of coordination, feeling unsteady;
• signs of a hormonal disorder --frequent or unusual headaches, vision problems, feeling light-headed or very tired, rapid heartbeats, mood or behavior changes, hoarse or deepened voice, increased hunger or thirst, increased urination, constipation, hair loss, sweating, feeling cold, weight gain, or weight loss;
• symptoms of a kidney problem --urinating more or less than usual, pelvic pain, vomiting, swelling in your ankles or feet, pain or burning when you urinate, bloody or cloudy urine; or
• liver problems --loss of appetite, right-sided stomach pain, easy bruising or bleeding, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

• nausea, vomiting, stomach pain, loss of appetite, diarrhea, constipation;
• low sodium levels, abnormal liver function tests;
• itching or rash;
• fever, cough, feeling short of breath;
• pain in your muscles, bones, or joints; or
• feeling tired.

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.

What other drugs will affect pembrolizumab?

Other drugs may interact with pembrolizumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Where can I get more information?

Your pharmacist can provide more information about pembrolizumab.