Raising the bar for antineoplastic agents: how to choose threshold values for superiority trials in advanced solid tumors.

Abstract

To establish the concept of minimum clinically meaningful outcome (mCMO) of treatment in advanced solid tumors, to establish its threshold and evaluate how many superiority trials of new antineoplastic agents pass this threshold. We chose overall survival as the primary indicator of patient benefit. Four conceptually different types of treatment effect can be identified in OS curves: HR, gains in median OS, proportional, and absolute increases at long-term OS. We postulated threshold levels for these four parameters defining the mCMO and set the bar at three different levels of required benefit: high, medium, and low. The postulated values were then studied by comparing our thresholds with the actual results of the pivotal superiority phase III trials on new drugs reporting on mature OS data. Forty-three trials on 35,419 patients in 12 cancer types on 23 novel agents met these criteria. Only two trials reached the postulated "high" thresholds for HR and median OS. The number of "positive trials" increased to eight and 15 when the bar was lowered to the "medium" and "low" levels, respectively. The same analysis was done for proportional and absolute increases in long-term OS. No trial satisfied the criteria for long-term benefit, whereas only two and nine trials satisfied both parameters for the "medium and low" required benefit levels, respectively. All four OS-related parameters contribute to define the mCMO. If the bar for the mCMO is raised too much, positive trials are exceptional.