Table of Contents
- What is Pembrolizumab?
- How Does Pembrolizumab Work?
- What Types of Cancers Does Pembrolizumab Treat?
- How is Pembrolizumab Administered?
- Pembrolizumab in Combination Therapies
- Potential Side Effects
- Ongoing Research and Future Directions
What is Pembrolizumab?
Pembrolizumab is a type of cancer treatment known as immunotherapy. It’s also referred to by its brand name Keytruda[1]. This medication is designed to help your body’s own immune system fight cancer cells. Pembrolizumab is a monoclonal antibody, which is a type of protein made in a laboratory that can bind to specific targets in the body, such as cancer cells[2].
How Does Pembrolizumab Work?
Pembrolizumab works by targeting a protein called PD-1 (programmed death 1) that is found on certain immune cells called T cells. Normally, PD-1 acts as a type of “off switch” that helps prevent T cells from attacking other cells in the body. Some cancer cells can take advantage of this by expressing PD-L1, which binds to PD-1 and turns off the T cells, allowing the cancer to hide from the immune system.
Pembrolizumab blocks the interaction between PD-1 and its ligands (PD-L1 and PD-L2). By doing this, it allows the T cells to remain active and detect and attack cancer cells[1]. In simpler terms, pembrolizumab helps “unmask” the cancer cells so that your immune system can recognize and destroy them.
What Types of Cancers Does Pembrolizumab Treat?
Pembrolizumab has shown effectiveness in treating various types of cancers. Based on the clinical trials information provided, it is being studied or used to treat:
- Melanoma: A type of skin cancer[1]
- Non-small cell lung cancer (NSCLC)[3]
- Head and neck squamous cell carcinoma: Cancers that start in the mouth, nose, or throat[4]
- Ovarian clear cell carcinoma: A rare type of ovarian cancer[5]
- Breast cancer: Specifically, hormone receptor-positive, HER2-negative breast cancer[2]
- Thymic carcinoma: A rare cancer of the thymus gland[6]
It’s important to note that research is ongoing, and pembrolizumab may be effective for other types of cancers as well.
How is Pembrolizumab Administered?
Pembrolizumab is typically given as an intravenous (IV) infusion. This means it’s administered directly into your bloodstream through a vein. The usual dose is 200 mg, given once every three weeks[1]. Each treatment cycle is generally 21 days long. The infusion usually takes about 30 minutes to complete.
The duration of treatment can vary depending on how well the cancer responds and how well you tolerate the medication. In some cases, treatment may continue for up to two years if the cancer is responding well and side effects are manageable[3].
Pembrolizumab in Combination Therapies
Researchers are exploring the use of pembrolizumab in combination with other cancer treatments to potentially enhance its effectiveness. Some combinations being studied include:
- Pembrolizumab with lenvatinib: This combination is being studied for various cancers, including ovarian clear cell carcinoma and thymic carcinoma[5].
- Pembrolizumab with radiation therapy: This combination is being investigated for breast cancer[2].
- Pembrolizumab with chemotherapy: This combination is being studied for lung cancer[3].
- Pembrolizumab with other targeted therapies: For example, combination with crizotinib for certain types of lung cancer[7].
Potential Side Effects
Like all medications, pembrolizumab can cause side effects. Because it works by stimulating your immune system, many of the side effects are related to an overactive immune response. Some potential side effects include:
- Fatigue
- Skin rash or itching
- Nausea or diarrhea
- Joint pain
- Decreased appetite
- Fever
More serious side effects can occur, though they are less common. These may include inflammation in various parts of the body, such as the lungs (pneumonitis), intestines (colitis), or hormone-producing glands (endocrinopathies)[7]. It’s important to report any new symptoms to your healthcare team promptly.
Ongoing Research and Future Directions
Research on pembrolizumab is ongoing, with many clinical trials exploring its use in different types of cancers and in combination with other treatments. Some areas of current research include:
- Identifying biomarkers to predict which patients will respond best to pembrolizumab. For example, some studies are looking at the levels of a protein called PD-L1 in tumor cells[7].
- Investigating the effectiveness of pembrolizumab in cancers that have spread to the brain or spinal cord (leptomeningeal metastases)[8].
- Exploring the use of pembrolizumab earlier in the course of cancer treatment, including as a first-line therapy for some cancers[1].
- Studying how pembrolizumab might be used to treat cancers that have become resistant to other forms of treatment[4].
These ongoing studies aim to improve our understanding of how pembrolizumab works and how it can be used most effectively to help patients with various types of cancer.


