What is Tysabri?
Tysabri a concentrate which must be diluted to make a solution for infusion (drip into a vein). Contains the active substance natalizumab.
What is Tysabri used for?
Tysabri is used to treat adults with multiple sclerosis (MS). It is indicated for the treatment of the form of MS known as "relapsing-remitting", ie when the patient suffers from neurological attacks (relapses), followed by periods of recovery without symptoms (remissions). The medicine is used in the following cases:
high disease activity, despite treatment with interferon-beta (another type of medicine used in MS) or severe and rapidly worsening disease.
The medicine can only be obtained with a prescription.
How is Tysabri used?
Treatment with Tysabri should be initiated and supervised by a physician experienced in the diagnosis and treatment of diseases of the nervous system, who has easy access to a particular diagnostic equipment: magnetic resonance (MRI) equipment. This equipment will allow the doctor to check for brain changes caused by MS or the rare brain infection called progressive multifocal leukoencephalopathy (PML). Tysabri is given by infusion over a one-hour period every four weeks. Since the infusion can trigger an allergic reaction, the patient should be monitored both during the infusion and for the next hour. If the patient does not show clear signs of therapeutic benefit after six months, the physician should consider continuing. the cure. Patients being treated with Tysabri must be given a special alert card, which summarizes the key information on the safety of the medicine. Patients should have their partner or carer read the alert card, as well as other doctors treating them, as they may notice symptoms of PLM that patients are unaware of, such as changes in their mood and behavior or speech changes.
How does Tysabri work?
The active substance in Tysabri, natalizumab, is a monoclonal antibody. A monoclonal antibody is an antibody (type of protein) created to recognize and attach to a specific structure (called an antigen) found on certain cells in the body. Natalizumab was created to attach to a specific part of an integrin, called _4_1 integrin , which is found on the surface of most leukocytes (white blood cells, which are involved in the inflammatory process).
Multiple sclerosis is a nerve disease in which inflammation destroys the protective sheath surrounding nerve cells. By blocking integrin, Natalizumab prevents leukocytes from reaching the brain via the blood. In this way the inflammation is reduced, as is the nerve damage caused by MS.
How has Tysabri been studied?
The effects of Tysabri were first tested in experimental models before being studied in humans. Two studies, both lasting two years, looked at the effectiveness of Tysabri in treating MS. One study compared Tysabri alone (monotherapy) with placebo (a dummy treatment) in 942 patients. The other study looked at the effect of using Tysabri in combination with interferon beta-1a (another medicine used in the treatment of MS) on 1,171 patients. The main measures of effectiveness were the reduction in the number of relapses and changes in the level patient's disability as measured on a standard scale (the Expanded Disability Status Scale).
What benefit has Tysabri shown during the studies?
In the monotherapy study, Tysabri was more effective than placebo in reducing the number of relapses. After one year, there was an approximately two-thirds drop in the number of MS attacks in patients treated with Tysabri compared to patients treated with placebo. Tysabri was also more effective than placebo for the disabling effects of MS: over two years, the risk of disability progression was reduced by 42% compared to the placebo group.
In the complementary study with interferon beta-1a, the risk of worsening disability and the number of relapses were reduced. However, the way the study was designed did not allow to clearly identify whether these results were due to Tysabri alone. or to the combination.
What are the risks associated with Tysabri?
Patients, their families, and physicians should be aware that Tysabri can cause infections, including PML. PML has symptoms similar to those of an MS attack and usually causes severe disability or death. If PML is suspected, the doctor should stop treatment until he is satisfied that the patient does not have the infection. In the studies conducted, the most common side effects of Tysabri (seen between 1 and 10 out of 100 patients) were urinary tract infections (infections of the organs through which urine flows), nasopharyngitis (inflammation of the nose and throat), hives, headache, dizziness, vomiting, nausea (malaise), arthralgia (pain in the joints), chills, pyrexia (fever) and fatigue. For the full list of side effects reported with Tysabri, see the package leaflet. About 6% of the patients who participated in the studies developed long-lasting antibodies against natalizumab, resulting in a decline in the medicine's effectiveness.
Tysabri should not be used in patients who may be hypersensitive (allergic) to natalizumab or any of the other ingredients. The medicine should not be given to patients with PML or at risk of infection, including patients suffering from a weakened system
immune system due to an illness or other medicines taken as part of an ongoing or finished therapy. Furthermore, Tysabri should not be given at the same time as interferon beta or glatiramer acetate (other long-term medicines for MS). basal cells ") or to patients under the age of 18. See the package insert for the full list of restrictions.
Why has Tysabri been approved?
The Committee for Medicinal Products for Human Use (CHMP) concluded that the efficacy of Tysabri in the treatment of MS, in terms of both relapse and disability, was clearly demonstrated. However, due to the safety profile of the medicine, the medicine It should only be used in patients who really need it. The Committee decided that the benefits of Tysabri are greater than its risks as a single disease-modifying therapy in highly active relapsing-remitting multiple sclerosis in patients unresponsive to beta-treatment. Interferon or in patients whose disease progresses rapidly The Committee therefore recommended the granting of a marketing authorization.
What measures are being taken to ensure the safe use of Tysabri?
The company that makes Tysabri guarantees that all doctors responsible for prescribing the medicine will receive an educational packet containing all the information necessary to ensure proper use of the medicine and that all patients will be closely monitored.
Learn more about Tysabri
On June 27, 2006, the European Commission granted Elan Pharma International Ltd a "Marketing Authorization" for Tysabri, valid throughout the European Union.
For the full evaluation version (EPAR) of Tysabri, click here.
Last update of this summary: 11-2008
The information on Tysabri - natalizumab published on this page may be out of date or incomplete. For a correct use of this information, see the Disclaimer and useful information page.
