Jedd D. Wolchok, MD, PhD (Damon Runyon-Lilly Clinical Investigator ‘03-‘08) at Memorial Sloan Kettering Cancer Center, New York, and colleagues, reported that matching the size of a tumor to the body's immune response could help doctors tailor immunotherapy treatments for melanoma patients whose disease has spread. Immunotherapy activates tumor-fighting T cells to target cancer, but these immune cells can lose their effectiveness or become “exhausted.” The study identified three different ways by which PD-1 blocking immunotherapies can fail: the drug doesn't re-invigorate exhausted T-cells, an immune response is not strong enough for the size of the tumor, and the drug is off target. Using these factors, the researchers developed a scoring system to more accurately predict how likely it is a treatment will work. The study was published in the scientific journal Nature.