Analysis Group Researchers Examine Surrogate Measurements for Overall Survival in Bladder Cancer Studies

January 26, 2026

In clinical trials, overall survival (OS) is the gold standard of primary endpoints for evaluating novel cancer therapies. However, as novel treatments for various types of bladder cancer rapidly advance, there is an increasing need for clinical endpoints that allow for more efficient evaluation of survival outcomes. Endpoints such as event-free survival (EFS) and complete response rate (CRR) have been recommended by the International Bladder Cancer Group and the Society for Immunotherapy of Cancer to facilitate drug evaluation and accelerate patient access to novel treatments, but their validity as surrogate measurements for OS remains under study.  

To help bridge this gap, Analysis Group teams collaborated with academic and industry researchers to conduct a pair of studies assessing the surrogacy relationship between EFS and OS and between CRR and OS among patients with bladder cancer.

In the first study, a group led by Vice President Yan Song, Manager Aozhou Wu, and Associate Yipeng Gao, collaborated with researchers from Merck and Weill Cornell Medicine to evaluate EFS as a surrogate endpoint for OS in neoadjuvant-treated muscle-invasive bladder cancer (MIBC). In an article on their research, the authors indicate that EFS may be used to assist regulatory and reimbursement decision making regarding new and existing MIBC therapies.

In the second study, a team headed by Vice Presidents Kalé Kponee-Shovein and Yan Song and Associates Yipeng Gao and Jingyi Liu worked with collaborators from Merck and The University of Texas MD Anderson Cancer Center on first-of-its-kind research examining the surrogacy between both EFS and OS and CRR and OS among patients with high-risk non-muscle-invasive bladder cancer (HR NMIBC). Detailing their findings in an article, the authors conclude that EFS could reliably predict treatment effects on OS among Bacillus Calmette-Guérin (BCG) vaccine-naïve or -remote patients with HR NMIBC. They also found an association between OS and CRR, noting that further evidence from larger clinical trials will be critical going forward to help understand CRR’s role.

Read the MIBC article
Read the HR NMIBC article