Interferon beta-1b injection site reactions and necroses.

We conducted a comprehensive review of selected adverse event reports that were submitted to the Food and Drug Administration (FDA) for interferon beta-1b during the first 30 months following licensure. The adverse events reviewed were injection site reactions, injection site necroses, and non-injection site necroses. These adverse events were selected because of the relative frequency of injection site reactions and because of the severity and sequelae of certain injection site and non-injection site necroses. Our review enabled us to characterize the clinical presentation and the treatment received, which were not described in the package insert or by the IFN beta (interferon beta-1b) Multiple Sclerosis Study Group publication. The time of onset of the adverse events ranged from 1-29 months after initiation of interferon beta-1b treatment, with a mean of 1 month. In general, the more clinically significant adverse events (i.e., injection site necrosis and non-injection site necrosis) developed more slowly than the injection site reactions. Greater than 85% of the adverse events presented with one or two signs/symptoms, although the number of signs/ symptoms ranged from 1-8. No predominance of treatments for the adverse events was observed. The most striking finding was that the overall sex ratio, which could be due to reporting artifacts, was 8.1:1 female:male.