Assessing global disparities in clinical trial availability for renal cell carcinoma (RCC).
Authors: Barragán Carrillo Regina , Zugman Miguel , Castro Daniela V. , Li Xiaochen , Shah Koral , Lau Lily , Agarwal Ruchi , Lee Aaron B , Reid Skylar , Chaudhary Nasr , Kooner Shivanee , Jaime-Casas Salvador , Ebrahimi Hedyeh , Regalado Porras Gabriela Olivia , Choi Sharon H. , Sobrevilla Nora , Ruiz-Garcia Erika , McKay Rana R. , Pal Sumanta Kumar 
Published: February 2025

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Background:
Clinical trials are the cornerstone for developing novel therapies and diagnostic tools. Due to advancements from clinical trials, the median overall survival (OS) of patients with metastatic RCC has increased 4-fold in the last 20 years (Lancet 2024). However, clinical trial availability remains disproportionately concentrated in high-income regions, limiting the inclusion of a diverse patient population (JCO CCI 2020). We aimed to assess the current state of the global availability of clinical trials for RCC.
Methods:
Using the National Clinical Trials database, we identified all clinical trials enrolling patients with RCC from 6/1/2019 to 6/1/2024. We initially screened all trials and excluded those involving non-interventional studies, pediatric patients, and non-RCC neoplasms. Per trial, we annotated which countries had at least one active site. We classified them based on income using the World Bank Ranking (WBR) into high-income (HICs), upper-middle-income (UMICs), lower-middle-income (LMICs), and low-income (LICs) countries. Additionally, we registered information on RCC type, sponsor, phase, cancer stage, and primary and secondary endpoints. We used descriptive statistics to summarize the characteristics of each trial. The association between RCC trial availability and WBR was assessed using the Kruskal-Wallis test. We applied Poisson regression analysis to evaluate the association between clinical trial availability and incidence, mortality, WBR, health expenditure, and gross national income (GNI).
Results:
Out of 558 identified RCC trials, 357 met the eligibility criteria and 201 were exclude. The median number of countries per trial was 2.6. Most trials were conducted exclusively in HICs (76%), with fewer trials available in UMICs (23%), LMICs (3%), and none in LICs. The majority of trials included patients with clear cell RCC (52%) and metastatic disease (80%). Furthermore, 47% of trials were sponsored by academic institutions and 81% were early-phase trials. We found that the WBR was significantly associated with RCC clinical trial availability (p < .001). UMICs, LMICs, and LICs had significantly lower odds of hosting RCC clinical trials than HICs (OR 0.2, 0.05, and 0.013, respectively). Moreover, trials in non-HICs were more frequently funded by pharma (64% vs 40%), were part of multinational trials (45% vs 16%) and were late-phase trials (25% vs 8%). Poisson regression analysis revealed that GNI, health expenditure, and mortality rates were significantly associated with the number of clinical trials in a country.
Conclusions:
RCC clinical trials are disproportionately concentrated in HICs, with a direct association between GNI, health expenditures and trial availability. Expanding access to a broader range of trials, including early-phase and academic-sponsored studies, in underserved regions will promote more equitable advancements for all RCC patients.