OBJECTIVES: Surrogate endpoints, such as progression-free survival (PFS) and time-to-progression (TTP), are frequently used to evaluate the clinical benefits of new anticancer drugs. However, the surrogacy of these endpoints for overall survival (OS) is not validated in all cancer settings. The main objective of this study was to evaluate the relationship between median PFS/TTP and median OS in the context of chronic lymphocytic leukemia (CLL) using a trial-based approach. METHODS: A systematic review of the literature was conducted using the PICO method: Population consisted of patients with CLL; Interventions and Comparators (when applicable) were standard therapies for CLL and Outcomes were median PFS/TTP and median OS. Two independent reviewers screened titles, abstracts, and full papers for eligibility, and then extracted data from selected studies. Correlation coefficient was calculated to assess the relationship between median PFS/TTP and median OS. Subgroup correlation analyses were also conducted according to characteristics of selected studies such as line of treatment and type of treatment under investigation. RESULTS: Among the 1,263 potentially relevant studies identified by the literature search, 23 articles were included. The mean number of patients included in these studies was 118 patients (min: 30, max: 724). On average, median PFS/TTP was 14.0 months (sd=12.4) and median OS was 35.0 months (sd=31.2). Results of the correlation analysis indicated that median PFS/TTP is highly correlated with median OS, with a Spearman’s correlation coefficient of 0.813 (p≤0.001). A significant correlation between median PFS/TTP and median OS was observed in the second-line and subsequent-line therapies, but not in the first-line setting. CONCLUSIONS: The present results demonstrate a very strong correlation between median PFS/TTP and median OS in the context of CLL, which reinforce the hypothesis that PFS/TTP would be adequate surrogate endpoints for OS in this cancer setting.