These are a group of proteins that are normally produced by cells in the immune system in response to viral infection and other foreign bodies and conditions. Interferons were named for their ability to interfere with viruses that are replicating themselves in the body.

One type of interferon (beta) has a variety of effects on the immune system, including a reduction in those immune responses directed at the myelin. There are two forms of interferon beta: interferon beta 1a (Avonex®) and interferon beta 1b (Betaferon®). Each is manufactured through the use of recombinant DNA technology (the technique by which genetic material from one organism is inserted into a foreign cell in order to mass produce the protein encoded by the inserted genes).

The following provides background about the clinical evidence for each: