4 Things to Know About Immunotherapy for Peritoneal Mesothelioma

Image depicts a hanging bag of intravenous immunotherapy drugs behind the title text: Immunotherapy for Peritoneal Mesothelioma.

Recently, immunotherapy has been making mesothelioma history. One duo of immune checkpoint inhibitor drugs more than doubled survival for some patients. The same treatment worked so well in one difficult case that the patient became eligible for surgery.

These milestones happened in cases of pleural mesothelioma. But what about peritoneal mesothelioma patients? Can immunotherapy help them? Simply put, continuing research suggests it may. The list below covers 4 important facts about immunotherapy for peritoneal mesothelioma patients.

Mesothelioma is an asbestos-linked cancer that occurs in the linings of some tissues and organs. Pleural mesothelioma occurs in the lining around the lungs. Peritoneal mesothelioma arises in the lining surrounding the abdomen. The rarest forms of this cancer can occur in the lining around the heart or the testicles.

1: Immunotherapy Studies Show Promising Results for Peritoneal Mesothelioma

It may seem like pleural immunotherapy studies make the most headlines right now. But some studies have included or focused on peritoneal mesothelioma patients. Some even reported encouraging results.

Study: Immune Checkpoint Inhibitor Combo

Treatment: Opdivo® (nivolumab) and Yervoy® (ipilimumab) after at least 1 other therapy

Study Patients: 100% peritoneal mesothelioma

Key Results:

  • Patients went nearly 6 months without tumor progression.
  • Nearly 70% of patients lived at least 1 year after starting immunotherapy.

Study: Targeted Therapy + Immune Checkpoint Inhibitor

Treatment: Avastin® (bevacizumab) + Tecentriq® (atezolizumab) after at least 2 other therapies

Study Patients: 100% peritoneal mesothelioma

Key Results:

  • Patients went nearly 1.5 years without tumor progression.
  • More than 85% of study patients lived at least 1 year after starting immunotherapy.

The authors of the Opdivo+Yervoy study above say the combo seems to have similar success in pleural and peritoneal cases. These results are good news for peritoneal patients because the Food and Drug Administration (FDA) approved the pair in late 2020. The approval is only for treating inoperable pleural mesothelioma.

But this approval language may not stop Opdivo+Yervoy from becoming a peritoneal mesothelioma treatment.

2: Immunotherapy Drugs Have Become Standard Without Specific FDA Approval

The headline is correct. Some drugs have become standard options without FDA approval for treating peritoneal mesothelioma. Official FDA approval of a cancer drug typically requires large studies. But enrolling hundreds of patients with such a rare cancer can be tough, making major studies a bit scarce.

Only a few studies have looked at systemic treatments for peritoneal mesothelioma. Most of those studies evaluated chemotherapy. None of them resulted in FDA approval of any systemic treatment for peritoneal mesothelioma.

Despite not having approval, medical societies still publish peritoneal mesothelioma treatment guidelines. According to one set, systemic treatments work as well on pleural tumors as they do for peritoneal tumors. So recommended treatments generally come from pleural mesothelioma studies and FDA approvals.

This means some standard treatments are not FDA approved for peritoneal mesothelioma, including:

  • Chemotherapy with pemetrexed and cisplatin
  • Chemotherapy with pemetrexed, cisplatin and Avastin
  • Immunotherapy with Opdivo+Yervoy

Yes, the above list is correct. The Opdivo+Yervoy drug combo is already considered a standard treatment for some peritoneal mesothelioma cases.

3: One Immunotherapy Drug Combo Is Already Recommended for Some Patients

The Opdivo+Yervoy duo is a recommended treatment for inoperable peritoneal mesothelioma. The National Comprehensive Cancer Network (NCCN) includes the drug pair in its treatment guidelines. According to NCCN, Opdivo+Yervoy is 1 of 3 preferred treatments for inoperable peritoneal cases.

The NCCN guidelines mean qualified peritoneal patients already have immunotherapy as an option.

4: Immunotherapy Research Is Ongoing

One immunotherapy approach has already become standard for peritoneal mesothelioma. But research continues, and several clinical trials are enrolling patients. One trial will investigate Opdivo+Yervoy and surgery for peritoneal mesothelioma. Doctors hope to understand the drug combo’s ability to delay or prevent the cancer from returning.

Peritoneal patients considering immunotherapy should discuss it with a mesothelioma specialist. Having this discussion with a true mesothelioma specialist matters. General oncologists may not know how beneficial many treatments can be for mesothelioma. But specialists with plenty of mesothelioma experience usually do. Specialty care can help ensure the patient has access to the best treatments for their unique case.