Avonex (Interferon beta 1a)
Avonex® (Interferon beta 1a) is a medication manufactured by a biotechnological process from one of the naturally-occurring interferons (a type of protein). It is made up of exactly the same amino acids (major components of proteins) as the interferon beta found in the human body. In controlled clinical trials in relapsing MS, those taking the medication had a reduced risk of disability progression, experienced fewer exacerbations, and showed a reduction in number and size of active lesions in the brain (as shown on MRI) when compared with the group taking a placebo. In a subsequent study of patients who had experienced a single demyelinating event in the optic nerve, spinal cord, or brainstem, and had lesions typical of MS on brain MRI, Avonex significantly delayed the time to a second exacerbation, and thus to a clinically definite diagnosis of MS.
Avonex is approved by the U.S. Food and Drug Administration (FDA) in 1996 for the treatment of patients with relapsing forms of MS to slow the accumulation of physical disability and decrease the frequency of clinical exacerbations. Patients with MS in whom efficacy has been demonstrated include those who have experienced a first clinical episode and have MRI features consistent with MS.
The recommended dose is 30 micrograms once a week. To reduce the incidence and severity of flu-like symptoms that may occur when initiating Avonex therapy at a dose of 30 micrograms, Avonex may be started at a dose of 7.5 micrograms and the dose may be increased by 7.5 micrograms each week for the next three weeks until the recommended dose of 30 micrograms is achieved (see Table below). An AVOSTARTGRIP™ kit containing 3 titration devices can be used for titration and is to be used only with Avonex Prefilled Syringes.
1 Dosed once a week, intramuscularly
|AVONEX Dose1||Recommended Dose|
|Week 1||7.5 micrograms||1/4 dose|
|Week 2||15 micrograms||1/2 dose|
|Week 3||22.5 micrograms||3/4 dose|
|Week 4+||30 micrograms||full dose|
All Avonex dosage forms are single-use (injection of reconstituted solution, prefilled syringe, and prefilled autoinjector).
The first Avonex injection should be performed under the supervision of an appropriately qualified health care professional. If patients or caregivers are to administer Avonex, train them in the proper intramuscular injection technique and assess their ability to inject intramuscularly to ensure the proper administration of Avonex.
- Rotate sites for intramuscular injections with each injection to minimize the likelihood of injection site reactions
- NOT inject into an area of the body where the skin is irritated, reddened, bruised, infected or scarred in any way
- Check the injection site after 2 hours for redness, swelling, or tenderness
- Contact their healthcare provider if they have a skin reaction and it does not clear up in a few days
In order to determine how effective AVONEX® (interferon beta-1a) is in treating relapsing MS, 2 studies were conducted:
In the first study, which was initiated in 1990 and took place over 2 years, 158 people with relapsing MS taking Avonex by intramuscular injection were compared with 143 people with relapsing MS in the placebo group. In the second study, which was conducted from April 1996 until March 2000, 193 people with relapsing MS who had recently experienced a first flare-up were given Avonex by intramuscular injection and compared with 190 people in the placebo group. These patients were followed for up to 3 years
In people who took Avonex for the full 2 years of a study, Avonex reduced relapses by 32% compared with placebo.
The annual relapse rate was 0.61 per patient-year in the Avonex-treated group and 0.90 per patient-year in the placebo-treated group (P=0.002)
When including the people enrolled in the study who didn’t take Avonex for the full 2 years, Avonex reduced relapses by 18% compared with placebo.
The annual relapse rate was 0.67 per patient-year in the Avonex-treated group and 0.82 per patient-year in the placebo-treated group (P=0.04)
In a study of people who had only experienced one flare-up,* people taking Avonex were 44% less likely to have a relapse at 3 years, compared with people in the placebo group.
In a 2-year clinical study, it took significantly longer for people with relapsing MS taking Avonex to have increased physical disability compared with people in the placebo group.
People taking Avonex were 37% less likely to have increased physical disability at 2 years. At the end of this study, 78% of people (67 out of 85) taking Avonex had no increase in physical disability, compared with 66% of people (58 out of 87) in the placebo group
In a 2-year study, Avonex reduced the number of gadolinium (Gd)-enhanced lesions by 75%, compared with the beginning of the study. †
At the start of the study, people in the Avonex group had 3.2 Gd-enhanced lesions vs 0.8 lesions after 2 years on Avonex
In a 3-year study, Avonex reduced the size of T2 lesions by 91% compared with placebo at 18 months.
Before beginning treatment, you should discuss with your healthcare provider the potential benefits and risks associated with Avonex.
Avonex can cause serious side effects. Tell your healthcare provider right away if you have any of the symptoms listed below while taking Avonex.
- Behavioral health problems including depression, suicidal thoughts or hallucinations. Some people taking Avonex may develop mood or behavior problems including irritability (getting upset easily), depression (feeling hopeless or feeling bad about yourself), nervousness, anxiety, aggressive behavior, thoughts of hurting yourself or suicide, and hearing or seeing things that others do not hear or see (hallucinations).
- Liver problems, or worsening of liver problems including liver failure and death. Symptoms may include nausea, loss of appetite, tiredness, dark colored urine and pale stools, yellowing of your skin or the white part of your eye, bleeding more easily than normal, confusion, and sleepiness. During your treatment with Avonex you will need to see your healthcare provider regularly and have regular blood tests to check for side effects.
- Serious allergic reactions and skin reactions. Symptoms may include itching, swelling of the face, eyes, lips, tongue or throat, trouble breathing, anxiousness, feeling faint, and skin rash, hives, sores in your mouth, or your skin blisters and peels.
Avonex will not cure your MS but may decrease the number of flare-ups of the disease and slow the occurrence of some of the physical disability that is common in people with MS. MS is a life-long disease that affects your nervous system by destroying the protective covering (myelin) that surrounds your nerve fibers.
The way Avonex works in MS is not known. It is not known if Avonex is safe and effective in children.
Do not take Avonex if you are allergic to interferon beta, albumin (human), or any of the ingredients in Avonex.
Before taking Avonex, tell your healthcare provider if you:
- are being treated for a mental illness, or had treatment in the past for any mental illness, including depression and suicidal behavior.
- have or had bleeding problems or blood clots, have or had low blood cell counts, have or had liver problems, have or had seizures (epilepsy), have or had heart problems, have or had thyroid problems, have or had any kind of autoimmune disease (where the body’s immune system attacks the body’s own cells), such as psoriasis, systemic lupus erythematosus, or rheumatoid arthritis.
- drink alcohol.
- are pregnant or plan to become pregnant. It is not known if Avonex will harm your unborn baby. Tell your healthcare provider if you become pregnant during your treatment with Avonex.
- are breastfeeding or plan to breastfeed. It is not known if Avonex passes into your breast milk. You and your healthcare provider should decide if you will use Avonex or breastfeed. You should not do both.
Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Avonex can cause serious side effects including:
- Heart problems, including heart failure. While Avonex is not known to have any direct effects on the heart, a few patients who did not have a history of heart problems developed heart muscle problems or congestive heart failure after taking Avonex. If you already have heart failure, Avonex may cause your heart failure to get worse. Call your healthcare provider right away if you have worsening symptoms of heart failure such as shortness of breath or swelling of your lower legs or feet while using Avonex.
- Some people using Avonex may have other heart problems including low blood pressure, fast or abnormal heart beat, chest pain, and heart attack or heart muscle problem (cardiomyopathy).
- Blood problems. Avonex can affect your bone marrow and cause low red and white blood cell, and platelet counts. In some people, these blood cell counts may fall to dangerously low levels. If your blood cell counts become very low, you can get infections and problems with bleeding and bruising.
- Seizures. Some patients have had seizures while taking Avonex, including patients who have never had seizures before.
- Infections. Some people who take Avonex may get an infection. Symptoms of an infection may include fever, chills, pain or burning with urination, urinating often, bloody diarrhea, and coughing up mucus.
- Thyroid problems. Some people taking Avonex develop changes in their thyroid function. Symptoms of thyroid changes include problems concentrating, feeling cold or hot all the time, weight changes, and skin changes.
Tell your healthcare provider right away if you have any of the symptoms listed above.
The most common side effects of Avonex include:
- Flu-like symptoms. Most people who take Avonex have flu-like symptoms early during the course of therapy. Usually, these symptoms last for a day after the injection. You may be able to manage these flu-like symptoms by taking over-the-counter pain and fever reducers. For many people, these symptoms lessen or go away over time. Symptoms may include muscle aches, fever, tiredness, and chills.
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