Tysabri (natalizumab) is in a class of medications known as immunomodulators and is an immunosuppressant.Manufacturer Biogen reports that it may help prevent worsening symptoms or slow progression of disability for patients with relapsing multiple sclerosis (MS), as well as those with moderate to severe Crohn’s disease.
Multiple sclerosis is a progressive disease, with different forms of multiple sclerosis affecting people in different ways. Relapsing-remitting multiple sclerosis is identified by flare-ups, or relapses, of the disease. A majority of people diagnosed with multiple sclerosis initially present with the relapsing-remitting type.
Lymphocytes are a type of white blood cell in the immune system that includes B cells (which produce antibodies) and T cells (which provide defense against viruses and harmful bacteria). In cases of relapsing MS, some of these blood cells may enter the central nervous system and attack nerves, leading to numbing, tingling, muscle fatigue or weakness, vision problems, and loss of bowel or bladder control.
Tysabri (natalizumab) is a monotherapy antibody prescribed for the treatment of patients with relapsing forms of multiple sclerosis. It works by targeting and attaching to a protein called integrin; the treatment is thought to block these cells from an inflammatory attack on the brain or spinal cord where damage to nerve cells can occur. It is often recommended for MS patients who are unable to tolerate other therapies.
Biogen reports that in a two-year clinical trial of relapsing MS patients, 627 people were treated with 300 mg Tysabri versus 315 with placebo. Treatment with Tysabri showed significant results:
- Tysabri decreased the average number of relapses per year by 67%
- 83% of patients who received Tysabri had no progression of disability, compared to 71% taking placebo
- 97% of people treated with Tysabri showed no Gd+ lesions on an MRI scan, compared to 72% of people taking placebo
- 57% of patients administered Tysabri had no new T2 lesions on an MRI scan, compared with 15% of people taking placebo
Does Tysabri suppress your immune system?
Immunosuppressants prevent the immune system from damaging healthy cells. Immunomodulators such as Tysabri may act by targeting only specific areas of the immune system in an effort to reduce risk of complications.
Treatment with Tysabri can weaken the immune system, resulting in increased risk of serious infection.
How long you can stay on Tysabri for MS
Individuals can take Tysabri for as long as their healthcare provider determines it is beneficial in preventing relapses or reducing symptoms, is well tolerated, and does not place patients at increased risk of side effects. In the US, more than 40% of people being treated with Tysabri have been on it for more than 5 years.
Biogen cautions that long-term treatment, especially over two years, may increase the risk of progressive multifocal leukoencephalopathy (PML), a rare viral brain infection that can lead to severe disability. Risk of PML is higher for those infected by John Cunningham Virus (JCV), a common virus which may cause PML in patients with weakened immune systems, including those taking Tysabri.
Prior to receiving Tysabri or while receiving treatments, a doctor may order blood tests to ensure blood cells have not been infected by JC Virus (JCV).
Only those who have been infected by the JC Virus (JCV) can develop PML; however, it is important to understand that testing positive for the John Cunningham Virus antibody does not mean that PML will develop. The estimated risk of developing PML is less than 1%.
Higher risk factors may be present for those who have received medications that weakened the immune system prior to starting Tysabri.
In recent years, research has shed light on possible vaccine treatment for JCV; this will have important implications for those undergoing treatment for MS.
Due to the risk of PML, Tysabri is only available through a distribution program called the TOUCH® Prescribing Program. Only prescribers, infusion centers such as Local Infusion, and pharmacies associated with infusion centers registered with the program may prescribe and distribute the product. Patients must be enrolled in and meet criteria for the TOUCH® Prescribing Program.
Healthcare professionals are advised to monitor patients on Tysabri for signs or symptoms of PML.
While receiving Tysabri, and for six months after treatment, patients should inform their healthcare professional of new or worsening medical conditions or concerns.
Side effects of Tysabri
Patients considering Tysabri (natalizumab) treatment should discuss the potential benefits and side effects with their physician. Refer to the FDA-approved Prescribing Information (PI) for safety and effectiveness information.
Adverse events may include:
- Herpes infections, encephalitis, or meningitis
- Liver damage, nausea, fatigue, vomiting
- Allergic reactions (hives, itching, trouble breathing)
- Low platelet counts, bruising of the skin, bleeding that is hard to stop
- Urinary tract infection, vaginitis, respiratory tract infection, or other opportunistic infections occurring in people with weakened immune systems
- Headache, joint pain, depression, diarrhea
Suspected adverse reactions can be reported directly to Biogen or the Food and Drug Administration at 1-800-FDA-1088.
Difference between Tysabri and other immunosuppressants
Disease-modifying therapies are prescribed to modify or influence the underlying course of relapsing forms of MS. Various immunomodulatory therapies work to target the inflammatory process, reduce relapses, and slow the progression of disease.
- Fingolimod is an immunomodulating medication taken in tablet form. The prescribed dosage is generally taken orally once daily by adults and children over 10 years who experience relapsing-remitting forms of MS.
- Azathioprine is an immunosuppressive medication taken in tablet form. It is usually taken once or twice daily and is prescribed for those with Crohn’s disease, rheumatoid arthritis, ulcerative colitis, and in kidney organ transplants to prevent rejection.
- Interferon therapy is immunosuppressive and administered as a shot under the skin, in muscle or vein, or directly into a skin lesion. It eases inflammation in the brain and spinal cord.
- Corticosteroids are considered a relapse management therapy and are used to decrease the severity or duration of multiple sclerosis relapses. Available as tablets, injections or inhalers, they are generally considered safe for short-term use. Over the long term, these drugs may impact liver or kidney function, so frequent long-term use should be avoided.
Tysabri (natalizumab) may be an effective long-term treatment for patients with relapsing MS and patients with moderate to severe Crohn’s disease. It can be considered for those who have not responded to other medications, when medication cannot be taken by mouth, or when stomach acid impacts oral prescriptions.
How Tysabri is administered
A healthcare professional administers an intravenous infusion every four weeks, and the procedure generally takes one hour. Patients are advised to stay in the clinic for an additional 60 minutes for routine observation.
How long it takes Tysabri to work
Tysabri (natalizumab) begins working after the first dose; however, many patients feel the beneficial effects within 12 weeks. Fewer relapses may occur over time.
Interested in learning more about Tysabri infusion at Local Infusion?
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