Trends in endpoint selection and result interpretation in advanced non-small cell lung cancer clinical trials published between 2000 and 2012: A retrospective cohort study

Abstract

Background: The objective of this review was to investigate trends in clinical trial design, specifically, the primary outcomes used, interpretation of results, and the magnitude of the benefits described in phase III controlled clinical trials in the first-line treatment of patients with advanced non-small cell lung cancer (NSCLC). Methods: Seventy-six trials published between 2000 and 2012 were selected from a total of 122 identified in a structured search. Results: Overall survival (OS) was evaluated as the primary study endpoint in 50 (65.8%) trials, followed by progression-free survival (PFS) in 15 (19.7%), and other variables, such as toxicity, quality of life (QoL), and response rate in 11 (14.5%). Ten (66.7%) out of 15 clinical trials using PFS as the primary endpoint were published between 2010 and 2012. Median overall survival (mOS) was 9.90 months (interquartile range: 3.5) with an increase of 0.384 months per year of publication (P < 0.001). A statistically significant improvement in mOS was obtained in only 13 (18.8%) trials. A total of 41 (53.9%) studies concluded that the result was positive. Of these, only 16 (39.1%) showed a statistically significant benefit in OS. QoL was assessed in 46 trials (60.5%) and of these, 10 (21.7%) reported significant improvements. Conclusions: These findings raise important questions about how clinical benefits are measured in clinical trials in advanced NSCLC. Appropriate clinically relevant outcome variables should be established and validated, and post-marketing studies should be requested by regulatory authorities to ensure meaningful clinical benefits in OS and QoL.