Federal regulators informed healthcare providers today that monotherapy with Tysabri has been linked to two new European cases of progressive multifocal leukoencephalopathy (PML). The U.S. Food & Drug Administration (FDA) said it is working with Elan and Biogen Idec, the manufacturers of Tysabri, to amend the product labeling to inform prescribers and patients that cases of PML have occurred in patients taking Tysabri as monotherapy.
In the U.S. Tysabri was taken off the market in 2005 after three patients in clinical trials developed PML. But the dug was reapproved in 2006, although it was subject to restrictions. Tysabri is now available only to patients with relapsing multiple sclerosis (MS) or Crohn’s disease (CD) who are enrolled in the risk minimization plan called the TOUCH Prescribing Program. Under the TOUCH Prescribing Program, every Tysabri-treated patient is closely monitored and followed for the occurrence of PML and other serious opportunistic infections.
It was once thought that taking Tysabri alone – known as monotherapy – lessened the risk of developing the brain disorder. But in both European cases, the patients – who were receiving Tysabri to treat multiple sclerosis – were not undergoing any other therapy. According to the FDA, one patient had been treated with Tysabri for 14 months, while the other received it for 17 months.
PML attacks the brain and central nervous system and is usually fatal. It is caused by a polyomavirus, called the JC virus. The JC virus is often acquired during childhood. Most adults have been infected with the JC virus but do not develop PML. The virus appears to remain inactive until something (such as a weakened immune system) allows it to be reactivated and start to multiply. People with a weakened immune system or people taking drugs that suppress their immune system (immunosuppressants) are most likely to get the disease. Symptoms include vision problems, loss of coordination, and memory loss. Patients who survive the disease are often permanently disabled.
In 2005, the law firm Parker Waichman Alonso LLP was retained by the estate of Anita Smith, a patient who died from a confirmed case of PML while taking Tysabri. In 2002, Smith, who had been diagnosed with multiple sclerosis, was enrolled in a clinical trial involving Tysabri along with 1,200 other patients. In November 2004, while her health was rapidly deteriorating, Tysabri gained a coveted “fast-track” approval FDA. Despite her PML symptoms, Smith was allowed to continue receiving treatment in the Tysabri trial, and took her last IV infusion of the drug in January 2005. On February 24, 2005 she died of from PML. Four days later, Tysabri sales were halted.
In its 2005 Annual Report, Elan Inc. informed shareholders that it had entered into settlement talks with the lawyers representing Anita Smith’s estate. When contacted, Jerry Parker, the managing partner of Parker Waichman Alonso LLP said the Anita Smith Tysabri case had been resolved, but that the case was confidential.
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