Scientists and researchers from Merck announced an update on their findings for the Phase 1b KEYNOTE-28 study that involves the investigation of the immunotherapy treatment called KEYTRUDA ® (pembrolizumab). The purpose of this study was to evaluate the safety, tolerability, and the anti-tumor activity of KEYTRUDA ® and focused on patients with small cell lung cancer (SCLC) and malignant pleural mesothelioma. Those given the treatment showed overall response rates of 33.3% and 20%, respectively.
The surface on some human cells carries proteins that allow the cells to not be affected by the body’s immune system. This protein is called PD-1 and when paired with a cancer cell, the cell is able to survive and multiply without being threatened by the immune system. KEYTRUDA ® blocks PD-1 and its ligands, PD-L1 and PD-L2 so that the immune system can hopefully kill the cancer cell. KEYTRUDA ® was given to over 450 patients with PD-L1 positive tumors across 20 types of cancer.
Pre-treated patients with advanced SCLC showed one complete response and seven partial responses totaling a 33% response rate to KEYTRUDA ®. The median response rate was 19.4 months and the median overall survival was 9.7 months. Those suffering from malignant pleural mesothelioma had a 20% overall response rate, all of which were partial responses. After KEYTRUDA ® was administered, the overall survival rate was documented as 18 months – 83.5% for 6 months and 62.6% for 12 months.
Mesothelioma and lung cancer are just two of the many diseases and illnesses that are related to asbestos exposure. The small, thin, friable asbestos fibers are easily inhaled and the odds of developing lung cancer because of heavy asbestos exposure are increased up to five times. Malignant mesothelioma is a cancer of the mesothelium, which is the area that surrounds the lung and the abdomen that allows organs to move easily in the body (i.e., lungs expanding and contracting, or food moving through the intestines through the digestive system). The asbestos fibers that become embedded in the mesothelium can cause scarring and tumors which leads to a mesothelioma diagnosis.
A mesothelioma diagnosis and a lung cancer diagnosis due to asbestos exposure are grim, and there is no known cure. However, the relatively new alternative to chemotherapy, immunotherapy, uses the body’s immune system to fight the cancer within the body. Clinical trials were introduced to evaluate immunotherapy treatments on patients who are suffering. This latest development with KEYTRUDA ® has scientists and researchers optimistic in moving forward with the treatment since results were generally positive.
Phase 2 of the trial has been initiated by Merck (Keynote-158) for KEYTRDA ® to test on more advanced tumors in small cell lung cancer and pleural mesothelioma.
Sources:
Business Wire, “Updated KEYTRUDA® (pembrolizumab) Data in Small Cell Lung Cancer and Mesothelioma Presented at 17th World Conference on Lung Cancer,” (December 6, 2016). [Link]
Dana-Farber, “What is the Science of PD-1 and Immunotherapy?” Dana-Faber Cancer Institute (July 6, 2016). [Link]
