The landscape of investigator-initiated oncology trials conducted in mainland China during the past decade (2010-2019).

The number of clinical trials conducted in mainland China, including investigator-initiated trials (IITs), has increased rapidly in recent years. However, there are few data on the characteristics of cancer-related IITs. We performed a comprehensive analysis of the landscape of cancer-related IITs in mainland China in the past decade. All cancer-related IITs registered on two clinical trial registries in the United States (www.clinicaltrials.gov, CT.gov) and mainland China (www.chictr.org.cn, ChiCTR) from 2010 to 2019 were identified. IITs were reviewed manually to validate classification, subcategorized by cancer type, and stratified by design characteristics to facilitate comparison across cancer types and with other specialties. A total of 8199 cancer-related IITs were identified. The number of trials registered annually increased over time, especially in the last 5 years. Although interventional studies were predominant, randomized double-blind studies accounted for only 8% of IITs. In the past decade, the trend for interventional studies conducted with different drugs increased year on year, although the increase in hormonal therapy IITs was not significant. Additionally, cancer-related IITs were unevenly geographically distributed, with half concentrated in the economically developed cities Shanghai, Beijing, and Guangdong. We also found an increase in registration before participant enrollment (64.9% for trials in conducted in 2015-2019 vs. 40.2% in 2010-2014,