Single pivotal trials with few corroborating characteristics were used for FDA approval of cancer therapies

Novel cancer therapies are often approved with evidence from a single pivotal trial alone. There are concerns about the credibility of this evidence. Higher validity may be indicated by five methodological and statistical characteristics of pivotal trial evidence that were described by the U.S. Food and Drug Administration (FDA), which may corroborate the reliance on a single trial alone for approval decisions. We did a metaepidemiologic evaluation of all single pivotal trials supporting FDA approval of novel drugs and therapeutic biologicals for cancers between 2000 and 2016. For each trial, we determined the presence of these five characteristics, which we operationalized as (1) large and multicenter trial (≥200 patients; more than one center); consistent treatment benefits across (2) multiple patient subgroups (in view of FDA reviewers), (3) multiple endpoints (including overall survival, progression-free survival, response rate, health related quality of life), and (4) multiple treatment comparisons (e.g., multi-arm studies); and (5) “statistically very persuasive” results (P-values