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Keytruda (Pembrolizumab)

What is Keytruda?

Keytruda (pembrolizumab) is an immunotherapy drug that can be used to treat some patients with advanced or metastatic bladder cancer.1,2 It was approved for bladder cancer by the U.S. Food and Drug Administration in 2017. Patients receive treatment with pembrolizumab through an intravenous (IV) infusion. Most patients receive treatment with pembrolizumab every three weeks and pembrolizumab is typically given over half an hour.

How does it work?

Pembrolizumab is a type of immunotherapy drug called a PD-1 inhibitor, that has been approved to treat advanced or metastatic bladder cancer and other types of cancers.1,2 The body’s immune system consists of a group of organs and cells that work to protect the body from diseases and infections. In a patient with cancer, immunotherapy drugs work by affecting the way the immune system functions to help it fight cancer cells more effectively.

Pembrolizumab works by blocking the function of a specific protein called PD-1. PD-1 is a checkpoint protein present on T cells (immune system cells) that can attach to the PD-L1 protein on certain cancer cells and help disguise them from the immune system. Because the immune system cannot detect and attack them, cancer cells can grow more easily when PD-1 is allowed to bind to PD-L1.

Patients with advanced or metastatic bladder cancer took part in clinical trials to research the effectiveness of treatment with pembrolizumab. Some patients’ tumors became smaller and treatment helped some patients to live longer.

Who can receive Pembrolizumab?

Only patients who have bladder cancer that is advanced or metastatic can be treated with pembrolizumab.1,3 Advanced or metastatic bladder cancer means that the cancer cells have spread beyond the bladder and/or to other parts of the body. Pembrolizumab is generally prescribed for patients who have already tried treatment with a chemotherapy that contains platinum, but the chemotherapy was not effective against the cancer or it was initially effective, but has stopped working. Pembrolizumab may also be used for patients with advanced or metastatic bladder cancer who are unable to receive certain platinum-containing chemotherapy. If you have advanced or metastatic bladder cancer, your healthcare providers can discuss whether treatment with pembrolizumab may be suitable.

Before prescribing pembrolizumab, healthcare providers need to know if a patient has certain other health conditions that may be made worse by taking pembrolizumab. These include:

  • Immune system problems, such as Crohn’s disease or ulcerative colitis
  • Having had an organ transplant
  • Lung or breathing problems
  • Liver or kidney problems
  • Endocrine disorders such as diabetes or thyroid disorders

It is very important for women who are pregnant, planning to become pregnant, or breastfeeding to let their healthcare provider know before starting treatment with pembrolizumab because of the serious side effects that treatment can cause. Women who are able to become pregnant should use effective birth control during pembrolizumab treatment and for at least four months after the last dose of pembrolizumab.

What are the possible side effects?

The side effects that are most common in patients treated with pembrolizumab include 1:

Treatment with a PD-1 inhibitor such as pembrolizumab can help a patient’s immune system to fight cancer cells, but it can also cause the immune system to attack healthy cells. This can cause very serious side effects in some patients. Before starting treatment with pembrolizumab, healthcare providers will speak with patients about the relative benefits and risks of treatment. If a patient chooses to begin treatment with pembrolizumab, healthcare providers will explain the signs and symptoms of serious side effects so that the patient can recognize them quickly and seek treatment. Such serious side effects can include:

  • Lung problems
  • Intestinal problems
  • Liver problems
  • Hormone gland problems
  • Kidney problems
  • Problems in other organs
  • Severe infusion reactions
  • Skin reactions

Patients who experience any symptoms of severe side effects should contact their healthcare providers right away to seek immediate treatment. This is not an exhaustive list of all potential side effects of pembrolizumab. Talk to your healthcare provider or pharmacist for further information.

Written by Anna Nicholson | Last review date: July 2019.
  1. Keytruda. Accessed September 2017.
  2. KEYTRUDA Prescribing Information. Merck, 2017.
  3. Beasly, Deena. Merck says test shows Keytruda improves survival for bladder cancer patients. Accessed September 2017.