New research suggests that, in the battle against malignant pleural mesothelioma, a treatment combining immunotherapy drugs with radiotherapy may be a powerful new weapon.
Researchers at the University of Pennsylvania reached that conclusion after reviewing the few existing studies on this emerging multimodal mesothelioma treatment for an article in Translational Lung Cancer Research.
Current available treatments for pleural mesothelioma, an aggressive lung-related cancer, include surgical resection, radiotherapy, and systemic chemotherapy. Certain investigational drugs, including new immunotherapy agents, are available through clinical trials.
But the Penn Medicine researchers have found evidence that immunotherapy drugs and radiation, when used in combination for pleural mesothelioma, may be able jumpstart the immune system’s anti-cancer mechanisms like no other single treatment.
Immunotherapy in Mesothelioma
Immune checkpoint inhibitors are the most prominent type of immunotherapy drugs to be tested for malignant mesothelioma in the last five years.
While there are several different types of immune checkpoint inhibitors, a number of studies have suggested that the most effective are those that block PD-1, a cell surface protein expressed by up to 40 percent of mesothelioma tumors.
Examples of PD-1 inhibitors are Keytruda (pembrolizumab), avelumab, and nivolumab, all of which have made headlines in the past two years for their potential to improve mesothelioma survival.
Radiation and the Immune System
Because the immune system plays such a pivotal role in allowing the body to recognize and fight tumors, many mesothelioma researchers are focusing on new ways to manipulate it.
Immunotherapy drugs are one way to “trick” the immune system into recognizing mesothelioma as a threat and going after it; Radiotherapy may be another.
“Radiation therapy may itself be immunomodulatory,” writes Dr. Evan W. Alley of the Hematology and Oncology Division at Penn Presbyterian Medical Center, noting that radiotherapy has been shown to activate cancer-fighting cells.“The combination of immunotherapy and radiation therapy may allow for complimentary immunologic effects that can enhance antitumor response.”
While Dr. Alley and his colleagues say early evidence suggests that the treatment combination of radiation and immunotherapy is promising, clinical trial data in mesothelioma patients is lacking. In their conclusion, they call for more clinical trials on the efficacy of the combination in the treatment of malignant mesothelioma.
Malignant pleural mesothelioma is a rare and highly invasive cancer that is closely related to asbestos exposure. The current median survival time with standard cancer treatments is less than 12 months.
Alley, EW, et al, “Immunotherapy and radiation therapy for malignant pleural mesothelioma”, April 2017, Translational Lung Cancer Research, pp. 212-219