Recombinant Human Erythropoiesis Stimulating Agents in Cancer Patients: Individual Patient Data Meta-Analysis on Behalf of the EPO IPD Meta-Analysis Collaborative Group

Background: Erythropoiesis stimulating agents (ESAs) consistently have been shown to decrease transfusions in anemic oncology patients. However, whether they increase mortality in cancer patients is under debate. Results from individual studies conflict, and results from literature based meta-analyses are inconclusive. We conducted a meta-analysis based on individual patient data (IPD) from all available randomized controlled trials (RCTs). Meta-analyses with individual patient data offer several advantages over study-level analysis, including the ability to gain statistical power and increase validity using time-to-event analyses, to adjust for prognostic variables that may have confounded the original treatment comparisons and to investigate subgroups in which treatment may be either more or less effective or harmful.

Methods: An international collaboration conducted an individual patent data meta-analysis of ESA effects on mortality in cancer patients. With guidance from an independent steering committee of international experts in hematology, oncology, radiotherapy, epidemiology, medical statistics and a consumer representative, we developed a detailed protocol and statistical analysis plan. Independent RCT investigators and representatives from pharmaceutical companies who submitted data provided additional input through the project’s advisory board. IPD from RCTs of ESA plus red blood cell transfusion (RBCT) (as needed) versus placebo or no ESA plus RBCT (as needed), for prophylaxis or treatment of anemia in cancer patients with or without concurrent antineoplastic therapy, were included. Hazard ratios and 95% confidence intervals (CIs) were calculated per study and meta-analyzed with fixed-effects and random-effects models. Primary endpoints were overall survival (during active study phase and for the longest follow-up available) for patients receiving chemotherapy, and for all cancer patients regardless of anticancer treatment. Stratified multivariable Cox-regression analyses were conducted to assess the impact of baseline imbalances and to identify potential effect modifiers. Duplicate main statistical analyses were conducted independently at two academic statistical departments.

Results: Data on 13933 patients enrolled in 53 studies were included in the analysis. Data were provided by the companies Amgen Inc., Johnson & Johnson Pharmaceutical Research & Development, L.L.C., and F. Hoffmann-La Roche Ltd.; and by five independent investigators. Results are currently undergoing internal verification and final evaluation and will be presented at the meeting.

Conclusion: Final conclusions will be presented at the meeting. Future analyses using IPD will be conducted to estimate the risks (clots, tumor progression) and potential benefits (transfusion needs and quality of life/fatigue) from other outcomes.