April 29, 2004
FDA/Center for Drug Evaluation and Research
Re: Avonex (Interferon beta-1a) Prefilled Syringes (NDC #59627-002-05)
Dear Healthcare Professional:
Biogen Idec may experience shortages in supply of the liquid formulation of AVONEX in prefilled syringes. We are, therefore, making more lyophilized AVONEX available to assure that we meet patients’ needs.
The liquid in prefilled syringes and the lyophilized powder are bioequivalent and can be substituted for one another. In the event of a short supply of liquid AVONEX, prescriptions may be filled with the lyophilized formulation. We encourage you to prescribe lyophilized AVONEX for your new patients instead of prefilled syringes until this situation is resolved. We appreciate your cooperation as this will help to maintain patients on one formulation in the event of a shortage.
We recognize the medical importance of AVONEX therapy for patients with MS. To assist patients, Biogen Idec is providing free preparation and administration training. If you have any questions or if your patients need to be trained to administer AVONEX, please contact us at 1-800-456-2255.
The possible short supply of AVONEX is due to some prefilled syringes containing more than expected levels of aggregates. Currently, Biogen Idec is performing additional evaluations on manufactured lots of the prefilled syringes for aggregates. Nevertheless, until the manufacturing issue is fully resolved, some liquid AVONEX syringes released for distribution may contain increased levels of aggregates. In theory, the presence of increased aggregate levels could lead to increased immunogenicity and increased production of antibodies. This has the potential for immunogenicity-related events such as those listed in the AVONEX package insert including allergic reactions, anaphylaxis, dyspnea, orolingual edema, skin rash and/or urticaria or increased incidence of neutralizing antibodies which may result in decreased efficacy.
Following the introduction of liquid AVONEX, a review of postmarketing data has suggested an increase in the frequency, but not severity, of flu-like symptoms.
Reports of adverse events relating to AVONEX should be directed to Biogen
1-800-456-2255 or to FDA’s MED Watch Program by phone (1-800-FDA-1088), by fax
(1-800-FDA-0178), by mail (5600 Fishers Lane, Rockville, MD 20852-9787) or via www.accessdata.fda.gov/scripts/medwatch.
We are working closely with the Food and Drug Administration to address and resolve supply issues for AVONEX liquid in prefilled syringes. We appreciate your cooperation with our efforts to assure that your patients’ needs are met. We will update you as the supply of AVONEX liquid is fully re-established.
Alfred Sandrock, M.D., Ph.D.
Vice President, Medical Research
Copyright © 2004, FDA/Center for Drug Evaluation and Research