Biogen Idec Inc said on Thursday that a late-stage clinical trial of an experimental multiple sclerosis treatment showed it to be safe and effective in cutting the annual rate of relapse in patients with MS. The injectable treatment, peginterferon beta-1a, is designed to reduce the dosing schedule typical of standard interferon drugs.

Biogen said the results “support peginterferon beta-1a as a potential treatment dosed every two weeks or every four weeks for relapsing-remitting multiple sclerosis.”

The study included more than 1,500 patients with relapsing-remitting multiple sclerosis. Both schedules of use worked at about the same rate to reduce the progression of disability with MS, an autoimmune disease that affects the brain and spinal cord, the company said.

Still, analysts are mainly focused on another multiple sclerosis drug in development by Biogen, BG-12, a pill that some expect could become the leading treatment for the disease.

Biogen said it plans to submit the drug for approval in 2013 and Mark Schoenebaum, a research analyst at ISI Group, said in a note that he expects approval in 2014.