What drives time-to-randomization in oncology trials?

In the United States, approximately 2 million 41 thousand new cases of cancer were diagnosed in 2025, with only 7.1% of cancer patients participating in clinical research. The main challenge in recruiting patients for oncology trials is strict eligibility criteria that exclude many patients based on age, comorbidities, or biomarkers. According to GlobalData data, patient enrollment in single-country oncology trials takes an average of 36 months, while multinational trials take 30.8 months. In North America, enrollment takes 32.5 months compared to 21.7 months in the Asia-Pacific region. In Phase II studies, an average of 89 patients were planned to be enrolled, but only 64 were actually enrolled, representing an enrollment efficiency of 79.4%. The number of eligibility criteria has increased over time, rising from a median of 17 criteria in 1986-1995 to 28 in 2006-2016.