Disparities in cancer clinical trials among low- and middle-income countries: A 20-year analysis

There are suspected disparities in clinical research (CR) development among low- and middle-income countries (LMICs). This study investigated differences in number and complexity of clinical trials (CTs) and how economic growth (EG) might contribute to these disparities.

For countries classified as LMICs in 2000, number, proportion of phase 1-2/3 and independent/pharma-sponsored CTs were documented. For correlations with EG, correlation coefficients (CC) were produced, indicating very weak, weak, moderate, strong, and very strong correlation.

A total of 16,977 CTs were identified. Asian countries China and South Korea experienced strong EG and increases in CTs (very strong CC). South/Southeast Asian countries had strong EG but modest increases in CTs (variable CC). Most East European countries and West Asian/Southeast European Turkey experienced robust EG and increases in CTs (moderate to strong and very strong CC, respectively). South/North American Argentina, Brazil, and Mexico had inconsistent EG but increases in CTs (weak to moderate CC). Among African countries, Egypt showed strong EG with a corresponding increase in CTs (strong CC), whereas South Africa had a weak CC. Most LMICs, except for China and South Korea, relied heavily on pharma-sponsored CTs, with a persistently low proportion of early-phase (1-2) compared to late-phase (3) CTs.

CR development has been unequal among LMICs. Strong EG could be a contributing factor but only to some extent. Only China and South Korea meaningfully developed independent and high-complexity CR. These data reinforce the need for initiatives to support cancer research in LMICs.