The Nature of the Drug: Tysabri (natalizumab) is prescribed for the treatment of multiple-sclerosis (MS) symptoms, and for Crohn’s Disease. Tysabri belongs to the class of drugs called immunomodulators, which suppress the immune system and so are useful in treating autoimmune disorders like MS. The drugs prevent certain immune-system cells from attacking nerves and the spinal cord.

In multiple sclerosis the nervous system slowly deteriorates, leading to numbness, loss of muscle control, incontinence, and vision problems. Tysabri is often prescribed for people having flare-ups of MS symptoms, and it also slows the disease’s progression. Crohn’s Disease is another autoimmune disease, and the immune systems of its sufferers attack the intestines, rectum, or mouth. Tysabri helps suppress that immune reaction.

The Hazards of Tysabri: The main risk of Tysabri is progressive multifocal leukoencephalopathy (PML), a brain infection that usually leads to disability or death. As of late 2016, there were at 395 cases recorded. PML is caused by the relatively common JC virus which infects 70%–90% of individuals, and which is generally only a risk for those who have a weak immune system or who are taking immunosuppressive drugs. PML damages myelin, the insulating protein layer that surrounds a neuron; and that leads to brain damage. No cure for PML exists, and it is fatal 50%–60% of the time.
PML symptoms include muscle weakness, clumsiness, vision problems, personality changes, and speech impairments, with the symptoms usually worsening over a few weeks.

Survivors of PML and their families have filed lawsuits against Tysabri’s manufacturer.

To Obtain Legal Relief: If you or a loved one took Tysabi to treat MS or Crohn’s Disease and have experienced side effects of the drug, you may have valuable legal rights. Attorney Stephen A. Katz is available at (800) 251-3529 for a free consultation, or for legal representation.