Breast cancer has maintained its position as the most researched disease in global clinical trials for the fifth consecutive year, according to Phesi’s latest annual report.
The report, which analysed data from 65,892 recruiting clinical trials via Phesi’s Trial Accelerator platform, found that obesity studies narrowly missed the top five, ranking sixth behind solid tumors, stroke, prostate cancer, and non-small cell lung cancer (NSCLC). However, Phesi anticipates obesity will likely enter the top five within one to two years due to the rising adoption of GLP-1 therapies for weight loss and its recognition as a potential co-morbidity for multiple diseases.
Phesi’s analysis also highlighted a continued decline in Phase II trial termination rates, which fell to 26% in 2025 from 31% in 2024. While this marks progress, the rate remains higher than the 20% observed prior to the Covid-19 pandemic. “While it is positive to see trial attrition rates fall, a quarter of Phase II trials ending early is still unacceptably high,” said Dr. Gen Li, Phesi founder and president.
Dr. Li noted that clinical trial sponsors face mounting pressure from macroeconomic constraints, pricing challenges, and growing competition in regions such as China, which ranks second globally behind the USA for recruiting clinical trial investigator sites. China showed the largest growth in investigator site numbers between 2023 and 2025, increasing 51%, compared with 42% in the USA. Among the top five countries, France, Italy, and Spain also ranked prominently, while Canada took second place specifically for prostate cancer trials.
Emphasizing the importance of data-driven decision-making, Dr. Li urged sponsors to rely on insights informed by big data and AI rather than instinct alone. “Considerable volumes of contextualized and real-world data exist to power clinical analytics that overcome these hurdles,” he said.
Looking ahead, Dr. Li highlighted the potential impact of GLP-1 therapies, suggesting that their broader adoption could reshape the clinical development landscape by shifting focus toward disease prevention and the management of clusters of related conditions.
