Long-Term Follow-Up of Recombinant Human Erythropoietin (epoetin)Induced Pure Red Cell Aplasia (PRCA): A Comparison of Data Collected through Active and Passive Pharmacovigilance Efforts.

Background: Follow-up reports describing the long-term prognosis of 47 patients with epoetin induced PRCA have been confined to a single study from France, England, and Germany, investigated through active surveillance efforts. There is concern that reporting quality may differ between active versus voluntary reporting efforts.

Methods: Investigators from the Research on Adverse Drug reactions And Reports (RADAR) program compared clinical findings for epoetin-associated PRCA cases reported by voluntary surveillance efforts (n= 47) versus active surveillance (n= 47). (Verhelst et at, Lancet 2004). Recovery from PRCA was defined as transfusion independence, normalized reticulocyte count, and/or disappearance of anti-erythropoietin antibody.

Results: Baseline characteristics of age and gender were similar in both the MEDWatch and active surveillance groups. The two groups were similar with respect to median age similar (67 years) and gender (70%) and follow-up duration for patients who recovered (mean of 3 months). Median follow-up was shorter for passive surveillance patients who did not recover (6 versus 11 months). Recovery rates with immunosuppression differed (39.5% for MedWatch versus 21.6% for active surveillance).

Conclusions: Follow-up of active versus passive pharmacovigilance differed markedly for epoetin-associated PRCA cases in France, Germany, and the UK, in part due to differences in follow-up time. Active pharmacovigilance efforts should be supported by national health authorities.