Immune checkpoint therapy stimulates tumor infiltration by CD8 T cells to facilitate an antitumor response, but many advanced solid tumors do not respond to treatment. In the AMADEUS trial, researchers led by Padmanee Sharma, M.D., Ph.D., aimed to identify biomarkers that predict treatment response in patients with advanced solid tumors. The trial enrolled 39 patients who were divided into two groups based on pre-treatment levels of CD8 T cells.
Those with low CD8 levels received a combination of nivolumab plus ipilimumab, while those with high CD8 levels received nivolumab alone. The disease control rate for low-CD8 and high-CD8 patients was 25% and 14.3%, respectively, and 39.5% of tumors that initially were low-CD8 had an influx of CD8 T cells after treatment. Treatment improved the inflammatory tumor microenvironment in low-CD8 responders, leading to better outcomes. These results provide insights into more efficient ways to stratify patients using immunological features to personalize treatment.