By John Gever, Senior Editor, MedPage Today

A pen-type intramuscular injector that allows multiple sclerosis patients to self-administer interferon-beta-1a (Avonex) has won FDA approval, the drug’s manufacturer said.

Biogen Idec said the device is the first intramuscular autoinjector to be approved for MS. It uses a thinner and shorter needle (25 gauge, 5/8 inch length) than the prefilled syringes that have been the company’s mainstay for administering the drug.