Medically Reviewed By:
Written By:
Last Modified June 8, 2022
This page features 11 Cited Research Articles
Fact Checked
Our fact-checking process begins with a thorough review of all sources to ensure they are high quality. Then we cross-check the facts with original medical or scientific reports published by those sources, or we validate the facts with reputable news organizations, medical and scientific experts and other health experts. Each page includes all sources for full transparency.
Reviewed is the nation’s most trusted mesothelioma resource

The Mesothelioma Center at has provided patients and their loved ones the most updated and reliable information on mesothelioma and asbestos exposure since 2006.

Our team of Patient Advocates includes a medical doctor, a registered nurse, health services administrators, veterans, VA-accredited Claims Agents, an oncology patient navigator and hospice care expert. Their combined expertise means we help any mesothelioma patient or loved one through every step of their cancer journey.

More than 30 contributors, including mesothelioma doctors, survivors, health care professionals and other experts, have peer-reviewed our website and written unique research-driven articles to ensure you get the highest-quality medical and health information.

About The Mesothelioma Center at

  • Assisting mesothelioma patients and their loved ones since 2006.
  • Helps more than 50% of mesothelioma patients diagnosed annually in the U.S.
  • A+ rating from the Better Business Bureau.
  • 5-star reviewed mesothelioma and support organization.
Learn More About Us


"My family has only the highest compliment for the assistance and support that we received from The Mesothelioma Center. This is a staff of compassionate and knowledgeable individuals who respect what your family is experiencing and who go the extra mile to make an unfortunate diagnosis less stressful. Information and assistance were provided by The Mesothelioma Center at no cost to our family."
Mesothelioma patient’s daughter
  • Google Review Rating
  • BBB Review Rating
Read Our Testimonials

What Is Keytruda?

The immunotherapy drug Keytruda (pembrolizumab) has shown effectiveness in mesothelioma patients through clinical trials and the Merck Access Program. 

In June 2020, the U.S. Food and Drug Administration approved its use as a second-line treatment for cancer patients with high tumor mutation burden, or TMB-H, including late-stage mesothelioma patients.

The FDA concluded that late-stage mesothelioma patients whose disease has progressed following prior treatment and who have no viable alternative options are eligible to receive Keytruda.

Dana-Farber’s Science Illustrated explains how immunotherapy is used to fight cancer.

Patients must also undergo an FDA-approved test to show if they have a high tumor mutation burden. This test ensures that physicians only prescribe Keytruda to patients who will receive the most benefit.

More than half of pleural mesothelioma patients in a completed clinical trial experienced initial tumor reduction during treatment, and 40% had a partial response or stable disease. The average overall survival was 18 months, with several living two years or more following treatment.

Keytruda Information
Name Keytruda
Alternate Names Pembrolizumab
Manufacturer Merck
Dosage 2 mg/kg every three weeks
Medical Code J9271, C9027
Active Ingredient Pembrolizumab
Drug Class Monoclonal antibody
Medical Studies Pembrolizumab in Treating Patients with Malignant Mesothelioma
FDA Warning Pneumonitis, colitis, hepatitis, hormone gland problems, kidney problems, anemia, skin rash, muscle or joint pain, muscle weakness, changes in eyesight

More than a dozen clinical trials involving Keytruda for mesothelioma are ongoing or actively recruiting participants. Most of these trials involve multimodal therapy that combines Keytruda with another therapy such as surgery or radiation therapy. 

How Does Keytruda Work to Treat Mesothelioma?

Keytruda belongs to a class of immunotherapy drugs known as checkpoint inhibitors. Unlike chemotherapy or radiation therapy, Keytruda and other checkpoint inhibitors aim to boost the body’s natural defenses against cancer cells. 

Keytruda helps the immune system fight mesothelioma by obstructing the PD-1 protein pathway. It works by blocking an interaction between PD-1 and another protein called PD-L1, which allows the immune system to recognize mesothelioma cells and attack them. About half of mesothelioma cells carry high expressions of PD-L1 to hide from the immune system, which is why Keytruda works for some mesothelioma patients.

Doctors and researchers are now using Keytruda in combination with traditional mesothelioma treatments such as surgery and chemotherapy with platinum-based drugs. Many patients are turning to immunotherapy drugs after chemotherapy stops working, which it often does.

“It seems to work well in certain cases. We still don’t have enough data to say for sure, but yes, [Keytruda] could become the next big thing for mesothelioma.”
Dr. Tawee Tanvetyanon
Oncologist at the Moffitt Cancer Center in Tampa

Keytruda is a prescription medication administered by IV injection. Like many chemotherapy regimens, treatments with Keytruda are usually given over 30-minute sessions every three weeks.

The recommended Keytruda dosage regimen for TMB-H solid tumors in adults is 200 mg every three weeks or 400 mg every six weeks.

This may vary for mesothelioma patients accessing the immunotherapy drug through a clinical trial or the Merck Access Program. Your doctor or the researcher leading the study will determine the appropriate dosage and how long a patient should stay on Keytruda.

Find a Mesothelioma Cancer Center
Access top mesothelioma cancer centers that have experience treating this rare disease.

Side Effects of Keytruda for Mesothelioma

While essentially unmasking mesothelioma cells, Keytruda can also cause your immune system to attack normal organs and tissues in many areas of the body, affecting the way they work.

This can lead to serious and sometimes life-threatening side effects. However, side effects of Keytruda are minimal compared to those for cancer patients undergoing chemotherapy.

  • Fatigue
  • Nausea
  • Loss of appetite
  • Constipation
  • Dry mouth
  • Low red blood cell count (anemia)
  • Coughing
  • Itching
  • Rashes
  • Diarrhea
  • Shortness of breath
  • Pain in muscles, bones or joints

Pleural mesothelioma patients who took part in a Keytruda clinical trial at the Penn Medicine Abramson Cancer Center reported only dry mouth, fatigue, nausea and loss of appetite. None of the patients had to stop treatment because of side effects.

In the 2021 published results of the ongoing phase 2 KEYNOTE-158 clinical trial, which includes mesothelioma patients, 69% of participants who received Keytruda reported treatment-related side effects. Serious adverse events associated with treatment occurred in 12% of patients.

Serious Side Effects of Keytruda

In rare cases, Keytruda can cause a serious immune reaction. Organs typically affected by these reactions include the lungs, intestinal tract, liver, kidneys and certain hormone glands.

  • Pneumonia
  • Colitis
  • Hepatitis
  • Hormone gland problems
  • Kidney problems

Examples of hormone gland problems include hair loss, muscle aches, rapid heartbeat, recurring headaches and weight loss. Kidney problems may include nephritis (inflammation of the kidneys) and kidney failure.

Some patients may experience adverse intravenous reactions, such as chills, dizziness, fever, itching or rash and shortness of breath or wheezing. Mesothelioma patients taking Keytruda should be aware of these side effects and alert their doctor immediately if they experience these symptoms.

Are All Mesothelioma Patients Eligible for Keytruda?

Mesothelioma patients who have a high tumor mutation burden are eligible for Keytruda. They must also have recurring cancer after undergoing a first round of treatment.

PD-L1 is expressed in 20% to 40% of pleural mesothelioma patients, and these patients tend to experience the best responses in clinical trials. PD-L1 also appears to be more common in nonepithelial mesothelioma tumors.

Keytruda is available through a prescription as a second-line treatment for late-stage mesothelioma patients. It is also available through clinical trials with varying eligibility requirements.

A combination of surgery, chemotherapy and radiation therapy is still the standard first-line treatment for early-stage mesothelioma, but it remains relatively ineffective as a long-term solution.

Success Rate of Keytruda for Mesothelioma

Studies show about 8.5% to 22% of patients with pleural mesothelioma respond to Keytruda. Overall survival has ranged from 10 months to 18.7 months (about a year and a half) in patients with PD-L1–positive mesothelioma.

In 2022, results from a trial known as PROMISE-meso showed that standard chemotherapy outperformed Keytruda. Overall survival was 10.7 months for participants on Keytruda compared to 12.4 months for patients on chemotherapy.

Results from a 2020 study known as KEYNOTE-158 showed an impressive duration of response lasting 14.3 months in pleural patients with a partial response.

Clinical trials investigating Keytruda for mesothelioma are ongoing, and many of them combine the drug with other treatments in hopes of finding the right combination to significantly improve survival.

Walter Merth and his wife Clara
“This therapy has given me a new window. It may not save my life, but it’s certainly buying me some valuable time.”
Walter Merth
Diagnosed with pleural mesothelioma in 2015

Keytruda’s FDA approval as a second-line therapy for cancer patients with high tumor mutation burden, including mesothelioma patients, followed approvals for its use with melanoma, colorectal cancer and lung cancer. Many in the medical community believe the drug represents a potential for future advancements in the long-term management of mesothelioma.

Mesothelioma packet from the Mesothelioma Center
Get Your Free Mesothelioma Treatment Guide
Laptop with screen video conference on kitchen counter
Watch Our Free Mesothelioma Webinars
Technician documenting notes in a lab
Find Active Mesothelioma Clinical Trials

Tell us what you think
Did this article help you?
How did this article help you?
What about this article isn’t helpful for you?
Did this article help you?

Thank you for your feedback. Would you like to speak with a Patient Advocate?