Keytruda Improves Pleural Mesothelioma Survival in Phase 3 Clinical Trial

The immunotherapy drug Keytruda combined with chemotherapy improved survival for people with pleural mesothelioma compared to standard of care chemotherapy.

Keytruda, which is the brand name for the mesothelioma immunotherapy treatment pembrolizumab, was the feature treatment in a phase 3 clinical trial. It was a first-line treatment paired with chemotherapy as a combination therapy, and researchers compared it to using chemotherapy as a standalone first-line treatment.

Merck, which is the manufacturer of Keytruda, and the Canadian Cancer Trials Group announced the results during the 2023 American Society of Clinical Oncology Annual Meeting. The clinical trial was called KEYNOTE-483.

If you’d like to learn more about Keytruda for mesothelioma or another immunotherapy option, please contact our patient advocate staff. Karen Ritter, the registered nurse at Mesothelioma Guide, can help you find a clinical trial or cancer center offering immunotherapy for mesothelioma. Email karen@mesotheliomaguide.com to start.

 

Results of the Important Mesothelioma Study

The trial was for patients diagnosed with unresectable advanced pleural mesothelioma, meaning a stage 3 or stage 4 cancer. “Unresectable” means the patient’s cancer is not treatable with surgery.

Most people in the study who received Keytruda had a boost in their survival:

• 17.3 months median survival for Keytruda plus chemotherapy
• 16.1 months median survival for chemotherapy alone

“Patients with pleural mesothelioma are usually diagnosed at an advanced stage, when the 5-year survival rate is only 12% and curative surgery is not an option,” said Dr. Lesley Seymour, Director of the Investigational New Drug program at the Canadian Cancer Trials group and Senior Investigator for the clinical trial.

He added that the addition of Keytruda to chemotherapy led to a “significantly improved overall survival, progression-free survival, and objective response rates” compared to just chemotherapy.

“This regimen represents a potential new treatment option for patients with advanced pleural mesothelioma.”

There were 440 patients in the study. Half received Keytruda every three weeks plus chemotherapy for six cycles. The other half received chemotherapy alone.

The addition of Keytruda helped the progression-free survival. After a year, the PFS rate was:

• 26% for Keytruda plus chemotherapy
• 17% for chemotherapy alone

The overall response rate was 62% for the Keytruda group and 38% for the chemotherapy group.

 

More About Keytruda for Mesothelioma

Pleural mesothelioma is a rare cancer forming in the lining of the lungs. It can spread quickly from this lining, called the pleura, to the nearby lungs. There are 2,500 cases of mesothelioma diagnosed in the U.S. each year, and the majority of them are pleural mesothelioma. The average survival for patients is 12-14 months because most are diagnosed when the cancer is already advanced.

Keytruda is an immune checkpoint inhibitor, which is a type of immunotherapy drug that helps the patient’s immune system attack cancer cells. Immune checkpoint inhibitors block specific proteins from connecting.

Mesothelioma cancer cells often have a protein called PD-L1. The immune system’s T cells have a protein called PD-1. When these two proteins connect, the T cells are subdued from attacking the cancer cells.

Keytruda is a PD-L1/PD-1 checkpoint inhibitor. It breaks apart the two proteins and prevents them from linking. Keytruda is already approved by the U.S. Food and Drug Administration (FDA) to treat very specific cases of pleural mesothelioma. This latest clinical trial may expand the approval to make Keytruda available for more patients with this cancer.

There are other immune checkpoint inhibitors for pleural mesothelioma. Opdivo, the brand name for nivolumab, is another PD-L1 checkpoint inhibitor. Yervoy, the brand name for ipilimumab, is a CTLA-4 checkpoint inhibitor. Opdivo and Yervoy are approved by the FDA to treat unresectable pleural mesothelioma.