Article: Interferon beta-1a

Image:Interferon beta-1a.png
Interferon beta-1a
Systematic (IUPAC) name
Human interferon beta
CAS number 145258-61-3
ATC code L03AB07
PubChem  ?
DrugBank BTD00093
Chemical data
Formula C908H1408N246O252S7
Mol. weight 20027.0 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism  ?
Half life 10 hrs
Excretion  ?
Therapeutic considerations
Pregnancy cat.


Legal status
Routes  ?

Interferon beta-1a is a drug in the interferon family used to treat multiple sclerosis. It is produced by mammalian cells while Interferon beta-1b is produced in modified E. coli bacteria. It is the pioneering treatment for multiple sclerosis with, as of 2005, 16 years of data demonstrating its safety and efficacy. Interferons have been shown to have about a 30-35% reduction in the rate of MS relapses, and to slow the progression of disability in MS patients. None of the products on the market is a cure, but patients today who start early on Inteferons can curb the disease enough that they are much less likely today to end up in a wheelchair than they were 10 years ago, before these treatments were known.

It is believed that Interferon-Beta based drugs achieve their beneficial effect on MS progress via their anti-inflammatory properties. Studies have also determined that Interferon-Beta improves the integrity of the blood-brain barrier (BBB)-- which generally breaks down in MS patients, allowing increasing amounts of undesirable substances to reach the brain. This strengthening of the BBB may be a contributing factor to Interferon-Beta's beneficial effects. These studies were carried out in vitro (outside a living organism - a "petri dish" experiment), so it does not necessarily mean it works the same in people.

Nonetheless, Interferons have side effects. The two main ones are flu-like symptoms, and injection-site reactions. The flu-like symptoms tend to happen immediately after the injection, and last for about half a day. In many patients, these symptoms diminish over time, but some patients continue to experience them over the long term. One can mitigate these symptoms by using a dose that's injected less frequently, and by taking the medication before bedtime. The injection-site reactions can be mitigated by rotating injection sites, or also by using one of the medications that is injected less frequently. These side effects are onerous enough that many patients take Interferons (or Copaxone, the other disease-modifying therapy that is available) for six months or a couple years and then decide to drop off treatment.

Most commonly reported side effects are injection site disorders, flu-like symptoms, elevation of liver enzymes and blood cell abnormalities. Patients with depression, seizure disorders, or liver problems, should discuss treatment with Rebif with their doctors.

While these drugs improve certain diagnostic test results, many patients report no perceived improvement, along with serious side-effects that substantially reduce quality of life. It is important to recognize that these drugs are intended to treat symptoms but do not cure multiple sclerosis, and it is debatable whether they provide meaningful benefit in the short or long term. Furthermore, tolerance develops over time in some patients, due to the development of "neutralizing antibodies," which reduce the effectiveness of these drugs while side effects may persist even after discontinuation. See patient ratings of Rebif and Avonex, below.

There are two principal competitors in the market for this drug:

  • Biogen Idec's Avonex®
  • Serono's Rebif®


Avonex is a once a week intramuscular injection using a 27 gauge needle (thicker than Rebif). It is produced by the Biogen Idec biotechnology company. Originally it was under competition protection in the US under the Orphan Drug Act.

Avonex was approved in USA in 1996, and in Europe in 1997, and is registered in more than 80 countries worldwide. It is the leading MS therapy in the US, with around 40% of the overall market, and in Europe, with around 30% of the overall market.

Biogen Idec markets Avonex in two formulations: the original powder form, which requires the patient to reconstitute it before administration; and a newer pre-reconstituted "liquid Avonex" syringe kit.


Rebif is a subcutaneous injection 3 times a week. It comes in pre-filled syringes with a 29 gauge needle, thinner than the needle supplied with Avonex. It can be used with the Rebiject II autoinjector.

Rebif is a disease-modifying drug used to treat relapsing forms of multiple sclerosis and is similar to the interferon beta protein produced by the human body. Interferon helps modulate the body’s immune system, fight disease and reduce inflammation. It is comarketed by Serono and Pfizer in the US under an exception to the Orphan Drug Act.

Rebif, which was approved in Europe in 1998 and in the U.S. in 2002, is registered in more than 80 countries worldwide. Rebif is available in a 22 mcg and 44 mcg ready-to-use pre-filled syringe and can be stored at room temperature for up to 30 days if a refrigerator is not available.

Related Drugs

Closely related is Interferon beta-1b, also indicated for Multiple Sclerosis, and with a very similar drug profile. Interferon beta-1b is marketed only by Berlex in the US as Betaseron and outside the US as Betaferon by Schering AG.

See also

  • Interferon beta-1b
  • Multiple sclerosis