Tysabri® is a monoclonal antibody bioengineered in the laboratory and designed to hamper the movement of potentially damaging immune cells from the bloodstream, across the “blood brain barrier,” and into the brain and spinal cord. The monoclonal antibody was first approved by the FDA in November 2004 for the treatment of relapsing forms of MS and later withdrawn by the manufacturer in February 2005 after three patients developed progressive multifocal leukoencephalopathy (PML) during clinical trials. PML is a rare and frequently fatal demyelinating disease of the central nervous system that primarily affects immunocompromised patients and is caused by the activation of a polyomavirus, which is latent in 80% of healthy adults. Tysabri® was re-approved by the FDA in June 2006 and is indicated for the treatment of patients with relapsing forms of MS to reduce the frequency of clinical exacerbations. In January 2008 the FDA approved Tysabri for the treatment of moderate-to-severe CD in patients with evidence of inflammation who have had an inadequate response to, or are unable to tolerate, conventional CD therapies.
Tysabri® is given intravenously every four weeks and is only available to prescribing physicians and patients through a distribution program known as TOUCH® administered by Biogen Idec, Inc. TOUCH® is a distribution program designed to assess the risk of progressive multifocal leukoencephalopathy (PML) associated with Tysabri, minimize the risk of PML, minimize death and disability due to PML, and promote informed risk-benefit decisions regarding Tysabri use. The risks of Tysabri treatment are addressed through the distribution program, along with education of prescribers, pharmacists, infusion center staff, and patients about potential PML infection associated with Tysabri treatment. Safety and efficacy of treatment with Tysabri beyond two years are not known.
Multiple sclerosis (MS) is a chronic, often disabling disease of the brain and spinal cord. According to the MS Association of America, approximately 350,000 individuals have been diagnosed with MS in the U.S., with an estimated 10,000 diagnosed each year. The most common form of MS at the time of initial diagnosis is a relapsing-remitting form (RRMS), in which acute symptoms or worsening of neurologic function (referred to as “relapses”, “attacks”, or “exacerbations”) occur intermittently.
Prior to receiving treatment for MS with Tysabri, a MRI brain scan must be obtained for each patient to aid in the differentiation of potential MS symptoms from PML. To enable early identification of potential cases, periodic follow-ups are required at three and six months after the initial infusion and then every six months thereafter.
NOTE: Patient must be enrolled in and meet all the criteria of the MS TOUCH Prescribing Program.
Crohn's disease (CD) is a chronic, inflammatory bowel disease that affects both men and women. There is no cure. CD can cause diarrhea, fever, rectal bleeding, malnutrition, narrowing of the intestinal tract, obstructions, abscesses, cramping, and abdominal pain. The disease also can lead to abnormal connections (fistulas) leading from the intestine to the skin or internal organs. Its cause is unknown. There are more than one million people with CD worldwide.
In CD patients, a baseline brain MRI may be helpful to distinguish pre-existent lesions from newly developed lesions, but brain lesions at baseline that could cause diagnostic difficulty while on Tysabri therapy are uncommon.
NOTE: Patient must be enrolled in and meet all the criteria of the CD TOUCH Prescribing Program.