Immune checkpoint inhibitor (ICI) therapy is relatively new, but a recent research paper suggests it could provide more effective, less toxic treatment for some malignant pleural mesothelioma (MPM) patients. Specifically, the therapy increased median overall survival for some MPM patients who also received chemotherapy.
The idea behind ICI therapy is basically to stop the cancer cells from expressing PD-L1. PD-L1 causes immunosuppression that relates only to the local tumor. In other words, it keeps the immune system from recognizing the local tumor as cancer and attacking it.
The expression of PD-L1 in MPM tumors is considered moderate. However, the nonepithelioid histolic subtypes are associated with greater expression of PD-L1. This tracks with the observation that nonepithelioid MPM is associated with a poorer outcome for patients.
This is a lot of medical jargon to get through, but the upshot is that keeping MPM tumors from expressing PD-L1 could make the immune system better recognize and fight the tumor.
For the recent paper, doctors pored over real-world patient reports. They used a collection of patient reports for 426 MPM patients around the country. These patients had been diagnosed with MPM between January 2011 and December 2019.
All of these patients had received the treatments that 2017 guidelines recommended, which included chemotherapy and sometimes radiation. During the period the doctors examined, 144 of the patients also received second-line ICI, while 282 patients received second-line chemotherapy.
Previous clinical trials had indicated that ICI was more effective than a placebo. However, it was still unclear whether it would be better than a second round of traditional chemotherapy.
Ultimately, the doctors found a statistically significant improvement in overall survival in the ICI group. Specifically, the median survival rate in the group that received ICI was 8.7 months, versus only 5.0 months in the chemotherapy group.
The medical community is actively working on new, better therapies for people with malignant mesothelioma. Although the disease is not yet curable, it may be possible to extend life and comfort for significant periods.
Keep talking to your doctor about what therapies may be promising. You may be a candidate for off-label or experimental therapies too.