Interferons 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:




Avonex® (Interferon beta-1a)

It is thought that Avonex acts by reducing both inflammation and the immune response that is attacking the body’s own myelin.

Avonex® was first extensively studied in the 1990s in a two-year trial involving 301 people with relapsing remitting MS. Compared to the placebo group the participants taking Avonex were significantly less likely to increase their disability. After two years 35% of those on placebo increased their disability compated to 22% of those on Avonex, a 37% reduction compared to placebo. Participants using Avonex also reduced their relapse rate by 32% compared to placebo and saw a reduction in the number of new brain lesions on MRI.


How is Avonex administered?
Avonex is a weekly intramuscular (directly into the muscle) injection.

Before starting Avonex, you should have blood tests to measure blood cell counts and check liver function. You should have regular blood tests to monitor blood cell counts and liver function every three months for the first year, then less frequently. Your neurologist will advise whether this should be done within the hospital clinic or through your local GP practice.


Betaferon® (Interferon beta-1b)

Betaferon® was first studies in the early 1990’s with a multi-year international clinical trial involving 372 patients with relapsing-remitting MS. Compared with placebo, the higher dose of the two doses of Betaferon trailed showed a reduction in the relapse rate by 31%.  The higher dose of Betaferon also showed fewer, smaller or no new areas of active MS lesions on MRI scans. Betaferon may also slow down the build-up of disability associated with MS.


How  is Betaferon administered?
Betaferon is self administered every other day as a subcutaneous (under the skin) injection

Your MS nurse will show you how to do the injections as well as giving advice and on-going training and support should you need it.

For some patients Betaferon is initially started on a lower dose. Your specialist will advise the recommended dosage for you.


What are the important considerations when taking an interferon

You should tell your doctor if:

  • you have a history of or experience severe depression or suicidal thoughts;
  • for women of childbearing age, it is essential that you use reliable and effective contraception. For more information on effective contraception, contact your healthcare professional or family planning association;
  • if you become pregnant or wish to have children, speak to your doctor straight away. This includes men whose partner plans to become pregnant;
  • you have any health problems or are taking other medicines;
  • if you have any allergies or experience an allergic reaction.


Side effects

The most common side effects are:

  • flu-like symptoms;  which may include headache, muscle ache and stiffness, chills or fever, following an injection
  • injection site reactions
  • injection site fatigue with prolonged use
  • blood cell abnormalities
  • weakness or tiredness
  • difficulty sleeping
  • diarrhoea, nausea and vomiting
  • muscular or joint pain
  • infections

You are more likely to have these side effects when you first start taking an interferon and they should subside over time. Speak to your health professional to discuss ways to reduce the side effects. These may include:

  • Changing the time of day of injection in order to sleep through the worst of the side effects; and/or
  • Taking paracetamol or ibuprofen before the injection and at four to six hour intervals after the injection, as required, to reduce fever symptoms.

Less common side effects can include:

  • changes in menstruation (periods)
  • neurological symptoms, mood changes, depression
  • liver abnormalities
  • allergic reactions
  • heart problems and hypertension
  • hair thinning or loss
  • damage to small blood vessels leading to kidney problems

If you are concerned about any reactions and side effects you should discuss these with your relevant health professional.



Special Authority must be approved by the Multiple Sclerosis Treatment Assessment Committee (MSTAC) before funding is approved. Applications will be considered by MSTAC at its regular meetings and approved subject to eligibility according to the Entry and Stopping criteria.

For details of the current criteria and how to apply for funded treatment see Disease Modifying Treatment Special Authority Criteria

Treatment with glatiramer acetate is permitted only if treatment with both natalizumab and fingolimod is not tolerated or treatment with both would beclinically inappropriate. Glatiramer acetate will not be funded as second line treatment if EDSS progression has occurred on treatment with natalizumab or fingolimod. Patients who have an increasing relapse rate over 12 months of treatment(compared with the relapse rate on starting treatment) and who do not meet the EDSS Stopping Criteria at annual review may switch from either of the beta-interferon’s [interferonbeta-1-beta or interferonbeta-1-alpha] to glatiramer acetate or vice versa. Patients may switch from either of the beta-interferon’s [interferonbeta-1-beta or interferonbeta-1-alpha] to glatiramer acetate or vice versa for increased relapses only once, after which they will be required to stop funded treatment if they meet any of the Stopping Criteria at annual review(including the criterion relating to increasing relapse rate over 12 months of treatment). If a relapse has resulted in an increased EDSS score that potentially may lead to discontinuation of treatment according to stopping criteria, a period of 6 months is allowed from the start of the relapse for recovery to occur. In this setting anti-JCV antibody positive status maybe accepted as a clinically inappropriate reason for treatment with natalizumab.


Feedback from other patients

It is often helpful to review how other people with MS have liked or tolerated a treatments and the benefits and side effects they have experienced.

Patients Like Me – Avonex

Patients Like Me – Betaferon


What to do about a bad reaction to medication

Reports from health professionals are preferred as doctors and other prescribers, pharmacists and nurses usually are able to provide more detailed information about the medications in use and other medical history from patient records that are helpful in evaluating the adverse reaction. However anyone may report a suspected adverse event or reaction to medication taken to the Centre for Adverse Reactions Monitoring (CARM).

For instructions and further information


Further Information

Further information about Avonex can be found on the Medsafe Data Sheet

Further information about Betaferon can be found on the Medsafe Data Sheet

An introduction to modern MS treatments – Current MS therapy has changed the lives of thousands of people living with MS for the better. This brochure explains the mechanism of action and protective effects of Betaferon® on the nerve cells.

Betaferon® The benefits of modern MS therapy – In this brochure you will find information about Betaferon®, a treatment that can modify the course of your MS.

A FREE service for people taking BetaferonThe Betaferon® Reminder Service. All you need to do is complete the form attached registering either a mobile number or email address for your Betaferon injection reminder and pop it in the mail. After you register, you will receive a text message and/or email to confirm your registration. Please post form to: Bayer NZ Limited, PO Box 2825, Auckland 1140.