1070PD - Relationship between progression-free survival and overall survival in chronic lymphocytic leukemia

Date 01 October 2012
Event ESMO Congress 2012
Session Hematological malignancies
Topics Leukaemia
Presenter Catherine Beauchemin
Authors C. Beauchemin1, J.B. Johnston2, M. Lapierre3, F. Aissa4, J. Lachaine1
  • 1Faculty Of Pharmacy, University of Montreal, H3C3J7 - Montreal/CA
  • 2Cancer Research, Manitoba Institute of Cell Biology, Winnipeg/CA
  • 3Faculty Of Pharmacy, University of Montreal, Montreal/CA
  • 4Market Access And Health Outcome Department, Lundbeck Canada Inc., Montreal/CA

 

Abstract

Objectives

Overall survival (OS) represents a universally recognized measure to evaluate clinical benefits for a new anti-cancer drug. Due to the limitations of this measure of survival, surrogate endpoints are frequently used, such as progression-free survival (PFS) and time-to-progression (TTP). However, the surrogacy of these endpoints for OS is not validated in all cancer settings. The main objective 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). The median age was 63.0 years and the median follow-up period was 33.7 months. On average, median PFS/TTP was 14.0 months (sd =12.4) and median OS was 35.0 months (sd = 31.2). The results of the correlation analysis demonstrated 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 therapy, but not in the first-line setting.

Conclusion

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. These findings would strongly support the use of PFS/TTP in the appreciation of the clinical efficacy of new drugs in CLL.

Disclosure

All authors have declared no conflicts of interest.