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The information on this website should be discussed with your healthcare professional and does not replace their advice.

Questions about KEYTRUDA® (pembrolizumab)

How does KEYTRUDA work?

KEYTRUDA is an immunotherapy, which is a type of cancer treatment that works with your immune system to help fight cancer.

Is KEYTRUDA an immunotherapy?

Yes, KEYTRUDA is an immunotherapy. It may be used to treat certain cancers by working with your immune system.

How is KEYTRUDA given?

Your treatment team will give you KEYTRUDA through an intravenous (IV) line for about 30 minutes.

How often will I receive KEYTRUDA?

Most people get KEYTRUDA every 3 weeks or every 6 weeks, depending on the dose you are given. Your doctor will decide how many treatments you need.

What are the side effects of KEYTRUDA?

Like all medicines, KEYTRUDA can cause side effects, although not everybody gets them. Your doctor will discuss these with you and will explain the risks and benefits of your treatment.

KEYTRUDA can cause some serious side effects. These side effects can sometimes become life-threatening and can lead to death. These side effects may happen anytime during treatment or even after your treatment has ended. You may experience more than one side effect at the same time.

Side effects with immunotherapy are different to the side effects of other cancer treatments and are managed differently.

Questions about biomarkers

Do I need a biomarker test before taking KEYTRUDA?

Everyone’s cancer is different. To help develop a treatment plan that’s right for you, your doctor may order biomarker tests.

These tests can measure your tumour for different biomarkers. These include biomarkers known as MSI-H or dMMR and another biomarker called PD-L1.

Biomarker tests may be used to help predict your response to certain treatments, such as KEYTRUDA.

Talk to your doctor to see if a biomarker test is right for you.

What are PD-1 and PD-L1?

PD-1 and PD-L1 are called biomarkers. They are types of proteins found on cells in your body.

PD-1 protein is found on immune cells called T cells. It normally acts as a type of “off switch” that helps keep the T cells from attacking other cells in the body.

PD-L1 protein is present on some healthy cells and certain cancer cells. When PD-L1 connects with PD-1 on T cells, it prevents the T cells from attacking and destroying cells that have PD-L1, including cancer cells. Some cancer cells have large amounts of PD-L1, which helps them hide from the immune system.

What are MSI-H and dMMR?

MSI-H/dMMR are biomarkers that can be found in many different types of cancer.

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Patient Resources



Cancer Council Australia. 2021. Understanding Immunotherapy. A guide for people affected by cancer.
Available at:
Accessed on 02/06/2022

KEYTRUDA Consumer Medicine Information

National Cancer Institute. NCI Dictionary of Cancer Terms. Biomarker.
Available at:
Accessed on 17/12/2019

National Cancer Institute. NCI Dictionary of Cancer Terms. MSI-H cancer.
Available at:
Accessed on 17/12/2019

National Cancer Institute. NCI Dictionary of Cancer Terms. Mismatch repair deficiency.
Available at:
Accessed on 17/12/2019

National Cancer Institute. NCI Dictionary of Cancer Terms. PD-L1.
Available at:
Accessed on 17/12/2019

NZ-KEY-00868. TAPS DA 2339KN TAPS NP20132. First Issued February 2024.