Psoriasis drug may be linked to fatal infection

The Food and Drug Administration (FDA) warned U.S. patients last week that it is investigating the possibility of a link between the psoriasis drug marketed as Raptiva, or efalizumab, and at least three deaths caused by a rare brain infection called progressive multifocal leukoencephalopathy. The agency is looking into a fourth, unconfirmed, report of the deadly infection in a patient taking Raptiva.

All four patients had been taking the medication approved by the FDA for the treatment of psoriasis, an often-chronic condition characterized by skin pain, itching and bleeding.

The FDA announcement Thursday was the latest blow for a drug that yielded its maker, Genentech, relatively modest sales — $108 million — in 2008.

In October 2008, the FDA required Genentech to include on Raptiva's patient information sheet a "black box" warning indicating that the drug carries the risk of a number of opportunistic infections, including bacterial sepsis, viral meningitis and invasive fungal disease.

In a presentation prepared for the FDA in 2003, Genentech reported that "ongoing therapy with Raptiva provides extended benefit, with no increase in adverse events as exposure is prolonged."

That is a claim that FDA will likely explore, given that those patients who succumbed to progressive multifocal leukoencephalopathy had been on the medication for at least three years.

Progressive multifocal leukoencephalopathy is considered an opportunistic infection, seen most often in those with compromised immune systems, including cancer and transplant patients and those with AIDS.