Betaseron (Interferon Beta 1b)

Betaseron (interferon beta-1b) is an anti-inflammatory therapy used to prevent disease relapses and reduce brain lesions in people with multiple sclerosis (MS). It is produced by Bayer.

Betaseron is approved in the U.S. and Europe to treat adults with relapsing forms of MS, including clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), and active secondary progressive MS (SPMS). Outside the U.S., it is marketed under the brand name Betaferon.

How Betaseron works

In MS, the body’s immune system erroneously launches an inflammatory attack that damages healthy parts of the nervous system. The active agent in Betaseron, called interferon beta-1b, is a naturally occurring signaling protein produced by immune cells to communicate with each other, namely to dampen inflammatory immune responses.

Although the exact details of its mechanism of action are unclear, Betaseron is thought to shift the immune system toward an anti-inflammatory response and to reduce the number of immune cells capable of reaching the brain and spinal cord, thus lessening nervous system damage in MS.

Betaseron in clinical trials

Approval of Betaseron was based on data from four clinical trials. One enrolled 372 ambulatory adults with RRMS who were randomly assigned to self-administer one of two doses of Betaseron (0.25 or 0.05 mg), or a placebo, for two years. Results showed that the higher dose of Betaseron significantly reduced the average annual relapse rate compared with a placebo (0.9 vs. 1.31 relapses per year). The treatment also significantly reduced the severity of disease relapses, the number of days of steroid use, and brain lesions.

Two other studies, one conducted in the U.S. and the other in Europe, investigated Betaseron in people with SPMS. The European trial enrolled 718 participants who were randomly assigned to a 0.25 mg dose of Betaseron or a placebo. The 939 patients who took part in the U.S.-based trial were randomly assigned to one of two doses of Betaseron (0.25 mg or 0.16 mg/m² of body surface area), or a placebo. All received their assigned treatment every other day for three years.

Both studies demonstrated a significant reduction in annualized relapse rates and in brain lesions among people receiving Betaseron, compared with those on a placebo. However, only the European study met the primary goal of delaying the progression of disability on the Expanded Disability Status Scale (EDSS).

The final study was a Phase 3 trial, called BENEFIT (NCT00185211), which enrolled 468 people with CIS who had experienced their first onset of MS-like signs and symptoms in the prior 60 days. Participants were treated with 0.25 mg Betaseron or a placebo for two years. Just over half of the patients enrolled in an open-label extension part, in which all continued to receive treatment with Betaseron. Results showed that, with over a decade of follow-up, participants treated with Betaseron right away had lower rates of relapses and were less likely to convert to definitive MS.

Other Information

Betaseron is recommended for use at a dose of 0.25 mg, every two days. It is self-administered via the BetaConnect autoinjector, which was approved for use in the U.S. in late 2015 and delivers Betaseron by subcutaneous injection. The injector can be linked to a smartphone app called myBETAapp, which can help patients track their injection history and has the option of sharing information with healthcare professionals. The app was approved in the U.S. in 2017.

Common side effects associated with Betaseron treatment include injection site reactions, low levels of white blood cells, headache, rash, insomnia, pain, flulike symptoms, and lack of energy.

Betaseron can increase levels of some liver enzymes, and liver health should be monitored while taking the medication. The therapy also carries a warning for mental health problems like depression and suicidal ideation, which should be immediately discussed with a healthcare professional.

Some people may experience an allergic reaction to Betaseron; the medication should not be used in people with a known allergy to any of its components and should be discontinued if an allergic reaction occurs.

There have not been any well-controlled trials of Betaseron used during pregnancy, but available data — which includes prospective observational studies — suggest that the medication is not generally associated with a risk of major birth defects.


Last updated: Jan 20, 2022, by Marisa Wexler MS


Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Dancing Doodle

Did you know some of the news and columns on Multiple Sclerosis News Today are recorded and available for listening on SoundCloud? These audio news stories give our readers an alternative option for accessing information important for them.

Listen Here