Amgen and FDA notified HealthCare Professionals of revision to sections of the prescribing information for Epogen ((Epoetin alfa ).

The revised labeling provides updated safety information on reports of pure red cell aplasia and severe anemia, with or without other cytopenias, associated with neutralizing antibodies to erythropoietin in patients treated with Epoetin alfa.
This has been reported predominantly in patients with CRF ( chronic renal failure ) receiving these products by subcutaneous administration.

Warnings

Cases of pure red cell aplasia ( PRCA ) and of severe anemia,with or without other cytopenias, associated with neutralizing antibodies to erythropoietin have been reported in patients treated with Epogen.
This has been reported predominantly in patients with CRF receiving Epogen by subcutaneous administration.

Any patient who develops a sudden loss of response to Epogen, accompanied by severe anemia and low reticulocyte count, should be evaluated for the etiology of loss of effect,including the presence of neutralizing antibodies to erythropoietin.
If anti-erythropoietin antibody-associated anemia is suspected, Epogen and other erythropoietic proteins should be withheld.

Epogen should be permanently discontinued in patient s with antibody-mediated anemia.
Patients should not be switched to other erythropoietic proteins as antibodies may cross-react.

Adverse reactions

As with all therapeutic proteins, there is a potential for immunogenicity.
Neutralizing antibodies to erythropoietin, in association with PRCA or severe anemia ( with or without other cytopenias ), have been reported in patients receiving Epogen during post-marketing experience.

There has been no systematic assessment of immune responses, i.e., the incidence of either binding or neutralizing antibodies to Epogen, in controlled clinical trials.

Where reported, the incidence of antibody formation is highly dependent on the sensitivity and specificity of the assay.
Additionally, the observed incidence of antibody positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease.
For these reasons,comparison of the incidence of antibodies across products within this class ( erythropoietic proteins ) may be misleading.

Source: FDA, 2005


XagenaMedicine2005