ABSTRACT
The FDA is preparing guidance about using real-world evidence (RWE) to support decisions about product effectiveness. Several ongoing efforts aim to replicate randomized clinical trial (RCT) results using RWE with the intent of identifying circumstances and methods that provide valid evidence of drug effects. Lack of agreement may not be due to faulty methods but rather to the challenges with emulating RCTs, differences in healthcare settings and patient populations, differences in effect measures and data analysis, bias, and/or the efficacy-effectiveness gap. In fact, for some decisions, RWE may lead to better understanding of how treatments work in usual care settings than a more constrained view from RCTs. Efforts to reconcile the role and opportunities for generating complementary evidence from RWE and RCTs will advance regulatory science.