European regulators have recommended that sales of the psoriasis drug Raptiva be suspended after it was linked to three cases of the fatal brain infection progressive multifocal leukoencephalopathy (PML)   The recommendation came the same day that the U.S. Food & Drug Administration (FDA) announced a review of Raptiva because of its association with PML.

Following these developments, one analyst told Reuters that it is becoming. “increasingly likely” Raptiva would be pulled from the U.S. market.  In October 2008, the FDA had already required Genentech to place a Boxed Warning on the Raptiva label regarding the drugs’ risk of PML and other infectious diseases.

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. Symptoms include vision problems, loss of coordination, and memory loss. Patients who survive the disease are often permanently disabled.

Yesterday, the FDA said that it had confirmed three fatal cases of PML in Raptiva patients.  The agency also said that it had learned of a suspected PML death in a fourth person treated with Raptiva.  The FDA said it was currently reviewing the latest information regarding Raptiva and PML, and is taking action to ensure that the risks of Raptiva do not outweigh its benefits.

Meanwhile, the European Medicines Agency (EMEA) Committee for Medicinal Products for Human Use said yesterday it had conducted a benefit/risk review of the drug, and concluded Raptiva’s benefits no longer outweigh its risks.  It recommended that sales of the drug be suspended in the European Union.   The European Commission – which usually follows EMEA recommendations – will now take up the issue.

Raptiva is an injectable drug that was approved by the FDA in 2003 to treat moderate to severe plaque psoriasis.  Raptiva works by blocking the activation of certain immune cells called T cells, and the migration of those cells into the skin. However, by suppressing the body’s natural defense system, it can also increase the risk of serious infections and malignancies in patients.

Other drugs that suppress the immune system have also been linked to PML. Last summer, the FDA warned that the same brain disease had been associated with Tysabri, a drug for multiple sclerosis.  The FDA warning was prompted by reports of two European MS patients undergoing Tysabri monotherapy had developed PML. In the U.S., Tysabri was taken off the market in 2005 after three patients in clinical  trials developed PML.  But the drug was reapproved in 2006, although it was subject to restrictions.

Last September, Genentech revised a warning on Rituxan to reflect the case of a rheumatoid arthritis patient who was treated with the medicine and died from PML.