The European Medicines Agency (EMEA) Friday suspended sales of Genentech/Merck KGaA’s psoriasis treatment, Raptiva, (efalizumab) amid new reports linking the medication to the deadly brain infection progressive multifocal leukoencephalopathy (PML).

The EMEA Committee for Medicinal Products for Human Use (CHMP) concluded that the benefits of Raptiva (A once-weekly injection used to treat psoriasis) no longer outweigh its risks.

On Monday, sales were also halted in Canada. EMD Serono Canada Inc., an affiliate of Merck Serono that markets Raptiva in Canada, suspended the drug from the marketplace after a recommendation from Health Canada.

Last Thursday, the FDA issued a public health advisory concerning three confirmed, and one possible report of PML in patients using Raptiva for more than three years.

Opressed Immune System
PML is a neurological disorder caused by the JC Virus that destroys the nerve cell protecting substance myelin. Up to 85 percent of the adult population carries the JC Virus, but it only becomes active when the immune system is severely oppressed. PML leads to a decline in neurologic function and eventually death. No preventative therapy or cure currently exists.

Raptiva works by suppressing T-cells that cause inflammation connected to psoriasis. T-cells are part of the immune system, and according to an FDA press release “By suppressing T-cells, Raptiva decreases the function of the immune system which increases a patient’s susceptibility to infections.”

The FDA said it would evaluate the new information, and that patients should be informed of PML signs and symptoms while being closely monitored by their doctors.

Safety Plan
In October, Raptiva was relabeled with a Boxed Warning that alerted users of the risk of developing infections, including PML. The FDA also directed Genentech to design a patient medication guide outlining the risks as a part of a risk evaluation and mitigation strategy (REMS).

Genentech said they are working on a safety plan with the FDA to minimize Raptiva’s risk. “We take the risk of PML very seriously and are working diligently with the FDA to put the right plans in place that will help protect patient safety,” said Tara Cooper, a Genentech Spokeswoman. “We are evaluating all possible approaches to address the risk of PML with Raptiva use including a risk minimization plan. It is premature to disclose the scope of our plans until we’ve reached a formal agreement on these plans with FDA.”

Although Genentech/Merck KGaA will face an obvious sales loss due to the pull, the damage won’t be dire. According to Merck, 2008 sales totaled about $119 million, with a negative impact on profit. And Genentech reported only $108 million in 2008 Raptiva sales, a small fraction of their $9.5 billion total US product sales.

Raptiva is not the first drug to be linked to PML. Drugs used to treat autoimmune disorders, cancer, and organ transplant patients also suppress the immune system and may lead to PML.