Immunotherapy Leads to Lasting Response for Peritoneal Mesothelioma Patient

A case of peritoneal mesothelioma showed incredible benefit from receiving two immunotherapy drugs, further proving that this treatment can work for this type of mesothelioma.

The case report published in Frontiers in Oncology details a 74-year-old woman diagnosed with peritoneal mesothelioma, which forms in the lining of the abdominal cavity. She received two immunotherapy drugs – Opdivo (nivolumab) and Yervoy (ipilimumab).

Opdivo and Yervoy granted the patient a durable 12-month anti-tumor response – meaning the cancer either shrunk or disappeared completely – before it stopped working and tumors began spreading again. The average survival for people with peritoneal mesothelioma who do not have surgery is approximately 1 year, so the immunotherapies extended the patient’s survival.

 

How Mesothelioma Escapes the Immune System

Mesothelioma is a rare and aggressive cancer diagnosed in approximately 2,500 people in the United States each year.

Mesothelioma tumor cells have biological capabilities to subdue the immune system, which is tasked with detecting and eliminating cancer cells when present in the body. Mesothelioma cells can deactivate the immune system’s T cells by linking sets of proteins:

• PD-L1 on the surface of mesothelioma cells links with PD-1 on the surface of T cells.
• B7 on the surface of mesothelioma cells links with CTLA-4 on the surface of T cells.

 

How Mesothelioma Immunotherapy Works

Mesothelioma immunotherapy activates the immune system to overcome these proteins to more effectively attack tumors. Immunotherapy drugs called immune checkpoint inhibitors can block these sets of proteins from linking. This keeps the immune system active and allows T cells to identify mesothelioma tumor cells as dangerous.

The immunotherapy drugs Opdiivo (PD-1/PD-L1 inhibitor) and Yervoy (CTLA-4/B7 inhibitor) are the main options for mesothelioma. Opdivo and Yervoy are approved by the U.S. Food and Drug Administration (FDA) for pleural mesothelioma, which is the type of mesothelioma forming in the lining of the lungs.

The FDA has not approved Opdivo and Yervoy for peritoneal mesothelioma, but cases like the one described here provide hope for a future approval. Currently, people with peritoneal mesothelioma can access immunotherapy through clinical trials.

 

History of Immunotherapy Working for Peritoneal Mesothelioma

While cases of immunotherapy for peritoneal mesothelioma are rare, this case is not the first.

A study at MD Anderson Cancer Center tested Opdivo and Yervoy for people with peritoneal mesothelioma. The average survival was 19 months, and the 1-year survival rate was 68%. Both of these statistics were improvements from chemotherapy or no treatment.

Another immunotherapy drug, Keytruda (pembrolizumab), led to an average survival of 21 months in a separate study. Keytruda is another immune checkpoint inhibitor for the proteins PD-1 and PD-L1. One case of a 59-year-old man led to a complete response (no sign of cancer in imaging scans), and the patient was cancer-free for four years as of 2024.

Anyone interested in receiving immunotherapy for mesothelioma should contact the patient advocates at Mesothelioma Guide. Our experts will help find a treatment center providing FDA-approved immunotherapies for mesothelioma or a clinical trial testing novel, promising approaches. Email registered nurse Karen Ritter at karen@mesotheliomaguide.com.