Figure 1.

Hypothetical examples of Kaplan–Meier overall survival curves comparing drug developments in a selected patient population based on biomarkers vs unselected patient population. A) Like many drug trials directed at specific populations of patients based on biomarker selection, the initial part of the curve separates early in the targeted agent group (Drug X) compared with the standard of care (SOC) arm, but eventually resistance develops in the majority of these patients. B) For a trial testing the efficacy of Drug X in an unselected group of patients, practically no real separation is seen in the curves between the experimental (Drug X + SOC) and SOC arms early on; the curves eventually split, and a statistically significant separation occurs later in the trial, with some patients having durable responses.