Comparing End Points Between Non-Small Cell Lung Cancer Clinical Trials, Observational Studies

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A study recently published in JAMA Network Open compared response- and progression-based end points in clinical trials and clinical practice settings for patients with stage IV non-small cell lung cancer (NSCLC) receiving first-line platinum plus pemetrexed chemotherapy.¹

Ultimately, the study was aiming to increase confidence in the reliability of observational studies so stakeholders can be well-informed prior to a clinical trial.

“Response Evaluation Criteria in Solid Tumors (RECIST) are commonly used to assess therapeutic response in clinical trials but not in routine care; thus, RECIST-based end points are difficult to include in observational studies,” the study authors wrote. “Clinician-anchored approaches for measuring clinical response have been validated but not widely compared with clinical trial data, limiting their use as evidence for clinical decision-making.”

To conduct the study, the authors used patient-level data from the IMpower132 (NCT02657434) trial, conducted from April 7, 2016, to May 31, 2017, and a nationwide electronic health record (EHR)–derived deidentified database, with data collected from January 1, 2011, to March 31, 2022. All patients in the trial were randomly assigned to receive first-line carboplatin or cisplatin plus pemetrexed. In comparing the trial and observational cohorts, end points included response rates, duration of response, and progression-free survival.

A total of 769 patients met inclusion criteria—494 in the observational cohort and 275 in the trial cohort. The authors found that all three end points were comparable between the study cohorts. Trial patients had a higher number of response assessments compared with patients in the observational cohort. The EHR-derived response rate was higher than the objective response rate after weighting due to higher rates of observed partial response than RECIST-based partial response.

“The consistency between observational and trial end points of EHR-derived response rate and objective response rate as well as EHR-derived progression-free survival and progression-free survival align with previous findings and generate new insights by showing no observed difference between duration of response and EHR-derived duration of response,” the authors wrote of the study results. “The greater proportion of partial response assessments in the observational cohort contributes to the numerically higher EHR-derived response rate as compared with objective response rate.”

The authors achieved their goal of increasing confidence in the reliability of the data, as response rates were consistent. Despite there being fundamental differences between clinical trial and routine practice settings, this study provides valuable insight for interpreting clinical outcomes between trial and observational cohorts.

Looking forward, the authors suggest that this study’s analytic approach could be used to compare end points in other therapeutic areas. Future research could compare end points between multiple studies, potentially enabling the estimation of end points from practice settings to trial settings.

“In conclusion, this study observed consistency between objective response rate and EHR-derived response rate, duration of response and EHR-derived duration of response, and progression-free survival and EHR-derived progression-free survival between trial and clinical practice data in a first-line stage IV NSCLC cohort, despite fundamental differences between clinical trials and routine practice,” the authors concluded. “It provides valuable insight into the relationships and methodological considerations for interpreting clinical outcomes between trial and observational cohorts.”

Reference

1. Lu Y, Langerman SS, McCain E, et al. Response- and Progression-Based End Points in Trial and Observational Cohorts of Patients With NSCLC. JAMA Netw Open. 2024;7(5):e249286. doi: 10.1001/jamanetworkopen.2024.9286