Globalization of clinical trials in oncology: a worldwide quantitative analysis

Over the past two decades, the globalization of oncology clinical trials has expanded, yet significant disparities persist across countries. This study aimed to evaluate these geographical inequalities, the evolution of trial phases, and the adherence to ethical standards according to the World Bank's income group.

The ClinicalTrials.gov database was searched and recorded in June 2024. We analyzed data from 87 748 oncology clinical trials conducted between 2000 and 2021, across high-income (HICs), upper-middle-income (UMICs), lower-middle-income (LMICs), and low-income countries. Key metrics included trial density, funding sources, registration timing, and trial phase distribution.

The number of oncology trials increased significantly, with a mean absolute annual rise of 266.6 trials, with China currently being the leading site of early- and validation-phase trials. While HICs still present the highest trial densities, UMICs showed a notable increase in early-phase trials, reflecting a shift in research dynamics. However, despite these advances, 76.4% of countries still had no new trials initiated by 2024. Additionally, ethical practices saw improvement from 2005 to 2021 with an increase in pre-commencement registration (from 9.2% to 58%, P < 0.0001), and more validation-phase trials with a survival variable as the primary outcome (from 40% to 59.6%, P < 0.0001).

Despite the growth in oncology clinical trials, significant disparities in trial distribution and access remain, especially in LMICs. Continued investments in research infrastructure and adherence to ethical standards are crucial to ensure that clinical research benefits are equitably distributed, particularly in regions with the greatest need for advanced cancer therapies.