Recombinant erythropoietin (Epo)/darbepoetin (Darb) associated venous thromboembolism (VTE) in the oncology setting: Findings from the Research on Adverse Drug Events And Reports (RADAR) project

Abstract

2552 Background: Cancer patients are at increased risk for VTE as compared to the general population, making VTE as a sADR difficult to detect in the oncology setting. In 2004, two phase III trials identified higher mortality rates among epo-treated cancer patients who were receiving chemotherapy in “off-label” settings- with these studies identifying higher VTE rates in the treatment arms. We reviewed data on epo/darb-associated VTE in the oncology setting. Methods: Data sources were meta-analyses and the FDA’s MedWatch database. Results: Since 1996, only 259 VTE reports (darb: n=30, epo: n=229) of VTE in the setting of chemotherapy and epo/darb were reported to MedWatch. Meta-analyses findings are tabulated below: Conclusions: In 2004, package inserts for Epo/Darb were revised, identifying increased risks of VTE with these agents in the oncology setting. Identification of this adverse drug reaction thirteen years after Epo received FDA approval for this indication (and had been prescribed to > 500,000 cancer patients) illustrates difficulties inherent with current pharmacovigilance efforts. [Table: see text] No significant financial relationships to disclose.