Early-phase vs. late-phase clinical trials in gynecologic oncology: Trends in trial completion, reporting, and...

To compare early- vs. late-phase gynecologic oncology trials with respect to rates of trial completion and enrollment of racial and ethnic minority groups (REMGs).

Gynecologic oncology studies registered on ClinicalTrials.gov between 2007 and 2020 were identified and compared between early- and late- phase trials. Reporting and publication rates were compared. Trials with published results were analyzed based on reporting of race/ethnicity in relation to disease site and trial characteristics.

Of 223,690 trials identified, 2146 (0.9%) were focused on gynecologic oncology. Most gynecologic oncology trials investigated ovarian cancer (n = 1092, 50.8%), followed by cervical cancer (n = 350, 16.3%), and uterine cancer (n = 334, 15.6%). Only 22.1% (n = 474) of trials either reported results or led to publication. Early-phase trials were more likely to be published than late-phase trials (18.4% vs. 8.6%, p < 0.001). Among US-based trials which published (n = 252), 199 were early-phase (79.0%; phase I, phase I/II, or phase II), and 45 late-phase (17.9%; phase II/III, III or phase IV). 33.7% of early-phase trials (n = 67) reported race/ethnicity data compared to 64.4% of late-phase trials (n = 29, p < 0.0001). Of those trials which reported race/ethnicity, more patients identified as White (85.7%) in late-phase trials as compared to early-phase trials (72.0%, p < 0.001).

In clinical trials in gynecologic oncology, early-phase trials were more likely to reach publication than late-phase trials. While late-phase trials were more likely to report race/ethnicity data compared to early-phase trials, early-phase trials were more likely to enroll REMGs. Further research must be conducted to determine reasons for the overall low publication rates of gynecologic oncology trials and relative under-enrollment of REMGs in late-phase trials, in order to work towards reducing these inequities in the future.