Overall Survival and Quality-of-Life Superiority in Modern Phase 3 Oncology Trials

Importance: Alternative end points, such as progression-free survival, are increasingly used in phase 3 randomized clinical trials (RCTs). However, alternative end points are often not valid surrogates for overall survival and quality of life (QOL) and may be less relevant to patients. Objective: To determine the proportion of phase 3 RCTs with overall survival or QOL superiority. Design and Setting: Meta-epidemiological study of 2-group, superiority-design, interventional phase 3 oncology RCTs screened from ClinicalTrials.gov and published between 2002 and 2024. Main Outcomes and Measures: Alternative end-point, overall survival, and QOL superiority in the experimental group vs the reference/control group according to prespecified statistical criteria for each RCT. A secondary goal was to evaluate the quality of QOL analyses, since approaches unadjusted for baseline scores may bias results. Results: A total of 791 RCTs representing 555 580 enrolled patients were included. Alternative primary end points were most common (n = 495 [63%]). The primary end point was met in 53% of the RCTs (n = 420); alternative end-point superiority was shown in 55% (n = 434). Overall survival superiority was shown in 28% (n = 221). Patient-reported outcomes were collected in 61% of the RCTs (n = 482), but global QOL results were published in only 34% (n = 271). Most between-group global QOL analyses did not adjust for baseline scores (223 [82%]). Global QOL superiority was shown in 11% (n = 84). Among all RCTs, 32% (n = 257) demonstrated either overall survival or global QOL superiority. Superiority of both overall survival and global QOL was shown in 6% (n = 48). Among 434 RCTs with a positive alternative end point, only a minority showed superiority of either overall survival (185 [43%]) or global QOL (67 [15%]). Conclusions and Relevance: Findings of superiority-design phase 3 oncology RCTs are commonly interpreted as positive. However, this is mostly based on improvements in alternative end points. Gains in either overall survival or QOL are uncommon, even when alternative end-point findings are positive. QOL appears both underevaluated and underreported; furthermore, the majority of phase 3 QOL analyses are unadjusted for baseline scores, which lose efficiency and add bias compared with adjusted analyses. To increase the meaningfulness of late-phase research, future trial designs and regulatory processes should be refocused toward overall survival and QOL improvements.