Genentech has decided to pull Raptiva from the market in the USA over links between the psoriasis drug and a rare but deadly brain infection.

The US biotechnology giant has announced what it calls a “phased voluntary withdrawal” of Raptiva (efalizumab) from the US market based on the association of the drug with an increased risk of progressive multifocal leukoencephalopathy. To date, three cases of diagnosed PML have been reported in patients receiving Raptiva and one patient treated with the drug who developed progressive neurologic symptoms died of unknown causes.

Raptiva will no longer be available after June 8 and Genentech, which is now fully-owned by Roche, said this transition is necessary because of the potential for severe psoriasis worsening with abrupt discontinuation of the drug, thus giving patients time to talk with their doctor before stopping treatment.

Hal Barron, Genentech's chief medical officer, said that “although we believe that many psoriasis patients are benefiting from Raptiva, the balance between benefit and risk in the psoriasis population…has significantly changed." The company estimates that 2,000 patients in the USA may currently be receiving Raptiva for chronic plaque psoriasis and 46,000 patients have been treated worldwide the drug was approved by the US Food and Drug Administration in 2003.

The removal of Raptiva and resultant excess inventories of the drug will result in a one-time charge of $125 million in the first half of this year. The product had sales of $108 million in the USA in 2008.

Genentech added that it is collaborating with licensee Merck Serono to inform regulatory authorities outside of the USA of its decision. In February, the European Medicines Agency recommended that marketing authorisation for Raptiva be suspended, saying the benefits of the drug no longer outweigh its risks.