Figure 2. Mathematical model fit to individual responses to immune checkpoint inhibition.

Open circles represent data points of clinical response in 10 patients extracted from Topalian et al., 2012, while solid lines represent best curve fits of Equation (1) to those data (with α^–1 = 144 days). Each color represents a different patient. Immunotherapy was begun at t = 0, and tumor volume was designated as the relative change in volume from t = 0 (i.e., tumor volume of 1 at t = 0). The dashed line depicts the cutoff used for classifying patients deemed as responders (partial or complete response) versus nonresponders (stable disease or disease progression) according to the RECIST v1.1 criteria.