Keytruda (generic name: pembrolizumab) is one of the most significant advancements in cancer treatment in the last decade. As a checkpoint inhibitor immunotherapy, Keytruda empowers the body’s immune system to recognize and attack cancer cells across a wide range of cancers. It has earned FDA approvals for more than 15 different types of cancer and counting.
In this article, we’ll explain how Keytruda works, the types of cancer it treats, what patients can expect during treatment, and why it has become a leading option in modern oncology.
What Is Keytruda (Pembrolizumab)?
Keytruda is a type of immunotherapy drug known as a PD-1 inhibitor. It works by blocking the programmed death-1 (PD-1) receptor, which some cancer cells use to evade detection by the immune system.
By blocking PD-1, Keytruda reactivates immune T-cells, enabling them to recognize and destroy cancer cells that would otherwise remain hidden.
How Keytruda Works in Cancer Treatment
Cancer cells often express PD-L1, a protein that binds to the PD-1 receptor on immune cells, effectively turning off the immune response. This allows cancer to grow unchecked.
Keytruda disrupts this process by:
- Blocking the PD-1/PD-L1 interaction
- Reactivating T-cell function
- Allowing the immune system to identify and eliminate cancer cells
Unlike chemotherapy, which kills cells directly, Keytruda stimulates the body’s natural defenses to target cancer, making it part of a treatment category called immune checkpoint inhibitors.
Cancers Treated with Keytruda
Keytruda is approved for use in numerous cancers, often in combination with other therapies or after failure of traditional treatments. As of 2024, Keytruda is FDA-approved for the treatment of:
1. Non-Small Cell Lung Cancer (NSCLC)
Keytruda is used:
- As a first-line treatment for metastatic NSCLC with high PD-L1 expression
- In combination with chemotherapy regardless of PD-L1 status
2. Melanoma
Keytruda is a frontline treatment for advanced or unresectable melanoma and can be used alone or in combination with other agents.
3. Head and Neck Squamous Cell Carcinoma (HNSCC)
Approved for both initial and recurrent or metastatic disease, particularly in patients with high PD-L1 expression.
4. Bladder Cancer (Urothelial Carcinoma)
Keytruda is used in advanced bladder cancer after failure of platinum-based chemotherapy or as first-line treatment in patients who can’t tolerate cisplatin.
5. Kidney Cancer (Renal Cell Carcinoma)
Often used in combination with axitinib or lenvatinib for first-line treatment of advanced disease.
6. Triple-Negative Breast Cancer (TNBC)
Approved for PD-L1–positive metastatic TNBC in combination with chemotherapy.
7. Cervical Cancer
Keytruda is used for PD-L1–positive recurrent or metastatic cervical cancer after chemotherapy.
8. Gastric and Esophageal Cancers
Approved for specific patients with advanced gastric, gastroesophageal junction, or esophageal cancer, often combined with chemotherapy.
9. Hepatocellular Carcinoma (Liver Cancer)
Approved after prior sorafenib therapy.
10. Colorectal Cancer
For patients with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) tumors, regardless of tumor location.
11. Hodgkin Lymphoma
Used in classical Hodgkin lymphoma in both adult and pediatric patients after prior treatment.
12. Endometrial Cancer
Approved for MSI-H or dMMR advanced endometrial cancer in select patients.
13. Merkel Cell Carcinoma
An aggressive skin cancer treated with Keytruda in the metastatic setting.
14. Cutaneous Squamous Cell Carcinoma
Approved for recurrent or metastatic forms of the disease not curable by surgery or radiation.
15. Tumor-Agnostic Indications
Keytruda is also approved for any solid tumors that are:
- MSI-H (microsatellite instability-high)
- dMMR (mismatch repair deficient)
- TMB-H (tumor mutational burden-high)
These approvals are not limited to a specific cancer type, making Keytruda one of the first tumor-agnostic treatments in oncology.
How Keytruda Is Given
Keytruda is administered via intravenous (IV) infusion, typically:
- Once every 3 to 6 weeks
- In a hospital or infusion center
- Over approximately 30 minutes
The treatment schedule varies based on cancer type, stage, and combination therapies.
Common Side Effects of Keytruda
While Keytruda is often better tolerated than chemotherapy, it can still cause side effects—mostly due to immune system activation.
Common side effects include:
- Fatigue
- Diarrhea or constipation
- Skin rash or itching
- Joint or muscle pain
- Fever or chills
Immune-related side effects (serious but less common):
- Inflammation of the lungs (pneumonitis)
- Hepatitis
- Colitis
- Endocrine disorders (e.g., thyroid or adrenal issues)
Patients receiving Keytruda require regular blood tests and imaging to monitor for side effects and assess treatment response.
How Long Can You Stay on Keytruda?
Many patients remain on Keytruda for up to 2 years, depending on response and side effect tolerance. If the cancer remains stable or improves, therapy may continue, but some patients may stop after achieving remission and still benefit from long-term immune memory.
Cost and Financial Assistance
Keytruda is a high-cost specialty drug, with treatment courses potentially exceeding $150,000 annually. However, patients may be eligible for:
- Manufacturer copay assistance (for those with commercial insurance)
- Patient assistance programs (for uninsured or underinsured patients)
- Medicare/Medicaid support and foundation grants
Work with your oncology team or a specialty pharmacy to explore cost-saving options.
Conclusion
Keytruda (pembrolizumab) represents a major breakthrough in cancer treatment, offering hope across a wide range of cancers, especially for those with high PD-L1 expression, MSI-H status, or advanced disease. As research continues, Keytruda’s role in oncology is expanding rapidly, helping more patients access the benefits of immunotherapy.
If you or a loved one is exploring treatment options, talk to your oncologist about whether Keytruda is right for your cancer type, and how biomarker testing can help determine eligibility.
