PML & Multiple Sclerosis

Multiple sclerosis (MS) is a disease affecting the brain and spinal cord. Patients with early symptoms of MS suffer from:

  • Weakness
  • Tingling sensations
  • Numbness
  • Blurred vision

Other symptoms and warning signs of the disease are:

  • Muscle stiffness
  • Problems thinking
  • Urinary problems
  • Trouble balancing
  • Muscle spasms

MS Treatment: Tysabri®

Tysabri®, a monoclonal antibody, received accelerated approval in November 2004 to treat relapsing MS, the most common form of the disease. The U.S. Food and Drug Administration (FDA) called it a new approach to treating these patients. In February 2005, however, the FDA suspended marketing the drug while the agency and the drug manufacturer Biogen, Idec evaluated two serious adverse events reported by patients.

On Feb. 18, 2005, the FDA received a report from the drug maker, confirming one death from progressive multifocal leukoencephalopathy (PML) and later confirmed another case of PML in patients receiving Tysabri® to treat MS. Ultimately three patients were diagnosed with PML. PML is a lethal viral infection of the brain that kills its victims within six months of diagnosis, on average.

Tysabri® was pulled from the market. Patients were told to stop taking the drug and physicians stopped prescribing it. Patients were supposed to talk with their doctors about alternative treatments for MS.

By the time it was withdrawn from the market, Tysabri® had been taken by about 3,000 patients in clinical trials. Outside of clinical trials about 5,000 MS patients had received Tysabri® from their primary care physicians. At that time, because of the drug's recent approval, patients had received at most only a few doses of the drug.

Tysabri® Linked to an Increase in the Risk of PML

In June 2006, the FDA lifted its hold on the drug after reviewing data, and Tysabri® went back on the market, but it was prescribed only to patients who had previously been receiving the drug in a special study. The study was designed to closely monitor patients being given the drug. Only patients enrolled in a special risk management restricted access program were allowed to receive the medication.

In a paper presented at an April 2011 annual meeting of the American Academy of Neurology, three risk factors were said to cause a one in 100 incidence of developing PML. These risk factors are:

  • Taking Tysabri® for more than two years
  • Receiving immunosuppressive therapy prior to taking Tysabri®
  • Having a positive test showing the presence of the JC virus infection

Data kept by Biogen indicated the risk of PML in Tysabri®-treated patients was:

  • 8.1 per 1,000 patients having all three risk factors compared to
  • 0.11 per 1,000 for patients with no risk factors

Early diagnosis of PML is important for the survival of MS patients. However, the early symptoms of PML and the symptoms of MS are quite similar, making a differential diagnosis difficult.

Compensation forTysabri® Patients with PML

If you or someone you love has been diagnosed with PML after being prescribed Tysabri®, you might be eligible for financial compensation. To learn more about your legal rights, contact our PML lawyers today. We will review your case for free and let you know if you qualify for compensation.

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