Why can clinical trials for chronic diseases last for decades without useful surrogate endpoints?

In the context of translational medicine, clinical trials for chronic diseases can last for decades primarily due to the lack of useful surrogate endpoints.1

Surrogate endpoints are biological markers—such as specific proteins or genetic mutations—that can be measured to assess the benefits of a treatment during the early stages of clinical testing. When these markers are unavailable, researchers cannot quickly determine if a therapy is effectively altering the course of a disease. Consequently, trials must rely on long-term clinical outcomes to demonstrate efficacy, which significantly extends the duration of the study.12

Translational medicine aims to address this challenge by facilitating the incorporation of novel endpoints into clinical testing, thereby shortening the time required to validate new treatments for chronic conditions.1