Breast cancer is world’s most studied disease for fifth year
8 Jan 2026
Phesi’s annual report on the world’s clinical trials has revealed that breast cancer has maintained its position as the most studied disease for the fifth year in succession.
Meanwhile, obesity studies just failed to enter the top five ranks, placing sixth behind solid tumours, stroke, prostate cancer and non-small cell lung cancer (NSCLC), said the report.
However, Phesi previously concluded that rising use of GLP-1 therapies associated with weight loss and the identification of obesity as a possible co-morbidity for a range of diseases make its inclusion most likely in one to two years.
Data from 65,892 recruiting clinical trials analysed in Phesi’s Trial Accelerator platform revealed a further fall in Phase II trial termination rates.
Although these still stand at some 26%, it represents a marked fall from the 31% recorded in 2024. The percentage remains substantially higher, though, than the 20% achieved prior to the Covid-19 period.
“While it is positive to see trial attrition rates fall, a quarter of Phase II trials ending early is still unacceptably high,” commented Phesi founder and president Dr Gen Li.
He noted that sponsors remained under pressure from macroeconomic constraints, pricing challenges and increased activity in regions such as China, which ranked second behind the USA for recruiting clinical trial investigator sites overall and four of the five most studied diseases.
The exception was prostate cancer, where Canada took second place. China also revealed the greatest growth in investigator site numbers between 2023 and 2025, increasing 51%, ahead of the USA’s 42%.
In addition, France, Italy and Spain comprised the remaining top five countries for recruiting investigator sites.
Li called for sponsors to be led “by insight informed by big data and AI, rather than instinct”, saying this was vital on account of the increase in competition, regulatory changes and acceptance of digital patient data.
“Considerable volumes of contextualised and real-world data exist to power clinical data analytics that overcome these hurdles,” he indicated.
“Although the pandemic is still having lingering effects as a disruptor, sponsors should now be looking ahead to what the next disruptor might be. The broader adoption of GLP-1s, for example, could reshape the clinical development landscape as the focus shifts towards prevention and treating clusters of related disease.”
Click here to read the full report.
Pic: National Cancer Institute
