Many pleural mesothelioma patients do not qualify for surgical treatment. This can be disheartening news because surgery can prolong survival. However, some mesothelioma patients may find hope in a new treatment.
A recently approved immunotherapy combination could provide durable survival for these patients. It is the first treatment in many years to significantly improve survival for inoperable patients.
The CheckMate 743 trial investigated this new immunotherapy combination. The trial compared immunotherapy drugs Yervoy® (ipilimumab) and Opdivo® (nivolumab) to traditional chemotherapy. Early in the study, Yervoy®/Opdivo® patients had superior survival. Newer data shows this immunotherapy combination outperforms chemotherapy for up to three years.
Immunotherapy Improves 3-Year Survival for Inoperable Pleural Mesothelioma
Researchers analyzed early results from CheckMate 743 after following patients for about 2.5 years. The results showed immunotherapy patients lived roughly four months longer than chemotherapy patients. Similarly, immunotherapy yielded higher 1- and 2-year survival rates.
According to the study protocol, participants could only receive immunotherapy for up to two years. Without continued treatment, some may wonder if participants’ bodies would continue fighting the cancer. The most recent study results indicate many patients’ bodies did continue fighting mesothelioma.
After following patients for about three years, researchers determined the 3-year survival rates:
- Opdivo® and Yervoy® Immunotherapy Group: 23.2%
- Platinum and Pemetrexed Chemotherapy Group: 15.4%
Immunotherapy patients had a 3-year survival rate 50% higher than chemotherapy patients. Opdivo® and Yervoy® may have stimulated the body to fight cancer even after the immunotherapy stopped.
It is unclear whether continued immunotherapy treatment could further improve survival. Researchers may investigate this question in the future.
Opdivo®/Yervoy® Combination Even More Effective in Some Patient Subgroups
The researchers in this study compared the results of patients with epithelial cell types versus non-epithelial cells.
The epithelioid type occurs most commonly and has the best prognosis. Non-epithelial cell types are less common and do not respond well to treatment. Historically, systemic treatments have extended survival more effectively in epithelial versus non-epithelial mesothelioma patients.
However, in CheckMate 743, non-epithelial cases responded well to immunotherapy.
The survival difference between immunotherapy and chemotherapy in non-epithelial patients was stark. Immunotherapy more than doubled survival versus chemotherapy for these patients.
Immunotherapy also achieved nearly identical median survival in non-epithelial and epithelial mesotheliomas. This result is notable given the poor performance of other therapies in non-epithelial mesotheliomas.
Note: Pleural mesothelioma can manifest in two different cell types: epithelial and sarcomatoid. Some patients have both types of cells. This is called biphasic mesothelioma. Sarcomatoid and biphasic cases are often grouped together as non-epithelioid mesothelioma.
Immunotherapy Research in Mesothelioma Is Ongoing
Opdivo® and Yervoy® provide a heartening new treatment option for pleural mesothelioma patients. Researchers have also proposed additional studies of this treatment. Suggested lines of investigation include:
- Combining Opdivo® and Yervoy® with chemotherapy
- Combining Opdivo® and Yervoy® with other immunotherapies
- Treating patients with targeted therapies after Opdivo® and Yervoy®
Several clinical trials are investigating new ways to apply this immunotherapy approach. One trial will combine Opdivo® and Yervoy® with a cancer vaccine. Another trial will treat pleural mesothelioma patients with Opdivo® and Yervoy® before surgery.
With all of these studies underway, the near future may bring even better news for mesothelioma patients.
