Over the past 25 years, the use of Overall Survival as the primary endpoint in oncology clinical trials has steadily declined to be replaced by event free survival but response rate continues to be evaluated as primary end point specially in early phases of clinical trials.* Although OS remains the gold standard, it has been more difficult to measure due to the confounding influence of other therapies and the fact that patients are living longer, which extends the trial timeline.
Thus, the evidence goals of many oncology trials today hinge on having a definitive measure of treatment response that is a predictor of overall survival. The response criteria covered here are predominantly used in Phase II trials, but if they can be shown to correlate with overall survival, they can be used in Phase III trials. (The fact is, sometimes they correlate, and sometimes they don’t!)
In this e-book, we review the history of response evaluation in cancer trials, detailing how measures have evolved along with technology; explain the principles of response evaluation; and share our view of its future. Our discussion is limited to solid tumors and so does not include response criteria for leukemia.