Treatment
Avonex (Interferon Beta-1a) ( refT3 )
Avonex (interferon beta-1a) belongs to a group of substances that help regulate your body's immune system.
Avonex is used to treat relapsing-remitting multiple sclerosis (RR-MS). It has been shown to be effective in slowing the progression of the disease and reducing the frequency of clinical relapses.
Avonex is a suitable treatment for people with RR-MS who are able to walk, who have had at least two relapses in the preceding 3 years, and who do not have evidence of progressive disease. Avonex may also be given to people who have had a single, severe episode of demyelination and inflammation in the CNS. In this case, however, Avonex is suitable only if other diagnoses have been excluded and there is a high risk of developing MS.
Avonex has not been investigated in people with secondary progressive MS. Therefore, the use of Avonex should be discontinued in people who show evidence of progressive disease.
Avonex is provided in two presentations. The pre-filled syringe is a ready-to-use solution for injection. Each box of Avonex contains four pre-filled syringes of 0.5 ml of solution. Each syringe is packed in a sealed plastic tray which also contains one injection needle for intramuscular (IM) use. Avonex vials (BIO-SET) are presented in a package of four individual doses. Each contains a clear glass vial with BIO-SET device and stopper, syringe of solvent for reconstitution and injection needle.
Avonex is given once a week as an injection into a muscle - eg the thigh. The dose is 30 µg (micrograms). The injection site should be varied with each dose to avoid soreness. Injections should also be accompanied with an anti-fever drug, because the use of Avoenx can be associated with flu-like symptoms including fever.
It is not known for how long treatment with Avonex should be given. People taking Avonex should therefore be assessed by their physician every 2 years. Treatment decisions about longer-term treatment can then be made on an individual basis.
Avonex is intended for use under the guidance and supervision of a doctor. Patients may self-inject if their doctor determines that it is appropriate and after proper training in intramuscular (IM) injection technique has been given.
Do Not Use Avonex:
If you are hypersensitive (allergic) to interferon beta or any other of the ingredients of the
formulation.
If you are pregnant or intend to become pregnant.
If you suffer from severe depressive disorders and/or suicidal ideation.
If you have epileptic seizures that are not adequately controlled by treatment.
Take Special Care with Avonex:
If you have to visit the hospital or family doctor for any treatment or for a blood test,
remember to tell the health professional/doctor that you are receiving Avonex. Avonex may
affect the results of these tests.
Avonex is not recommended for use in patients under 16 years of age.
People with certain forms of cardiac disease (angina, heart failure or arrhythmia) should be more closely monitored while taking Avonex. People with a condition called myelosuppression (which results in a low white blood cell count) should also be more closely monitored.
Avonex is associated with some common side effects including flu-like symptoms (fever, chills, sweating, muscle aches, tiredness) early on during the course of treatment.
Other, less-common side effects include anorexia (loss of appetite), weight problems, skin reactions, diarrhoea, anxiety, dizziness, pain and muscle weakness, alopecia (hair loss) and breathlessness.
Very rarely, some people may experience a hypersensitivity reaction to Avonex.
People taking Avonex may develop neutralising antibodies. This is because Avonex is a foreign protein and the body's immune system naturally produces antibodies against foreign proteins. Neutralising antibodies have been detected in 8% of people with MS who had been taking Avonex for up to 2 years. Neutralising antibodies bind to foreign proteins and therefore these antibodies may reduce the effectiveness of Avonex.
Licensed for the treatment of MS in 1997, Avonex is marketed by Biogen Idec Ltd.
More detailed prescribing information on Avonex can be found by going to www.medicines.org.uk. Typing Avonex in the search box and pressing Go will bring you to a patient information leaflet on Avonex.
The Association of British Neurologists provides guidelines on the use of interferon beta drugs (refT4). Among its recommendations are the suitability of people with MS for the treatment and the criteria that should be used to stop therapy.
Suitability of Patients:
Inteferon beta is an appropriate treatment for people with RR-MS provided they fulfil the following criteria:
1. Are able to walk independently.
2. Have had at least two clinically significant relapses in the last 2 years.
3. Are aged >18 years.
4. Have no contraindications (ie there is no medical reason why the patient should not
receive the treatment).
Stopping Criteria:
Treatment should be stopped in people taking interferon beta if there are intolerable side effects or if a pregnancy is planned. The treatment should also be stopped if it does not appear to be effective - for example, if:
1. The person experiences two disabling relapses within 12 months, as certified by a
neurologist.
2.
Secondary progressive MS and disability occur over a period of 6 months.
3. There is a loss of ability to walk, with or without assistance, for at least 6
months.