Frankfurt - Merck KGaA, the drugmaker that markets Genentech's psoriasis drug Raptiva in Europe, said it is working with European Union regulators after a second Raptiva patient died of a rare brain infection in the United States.

"We are aware of both cases. We are working with the European Medicines Agency and with other authorities to update the product information and are seeking to determine if further action is needed," Phyllis Carter, a spokeswoman for Germany's Merck said.

Genentech said last month that a 70-year-old patient who had used Raptiva for four years died of a rare brain infection known as progressive multifocal leukoencephalopathy (PML), prompting U.S. regulators to order warnings alerting doctors to the risk.

Genentech, a biotech company controlled by Swiss drug maker Roche ROGN.VX, on Monday reported a second case of PML, resulting in the death of a 73-year old woman who had been given Raptiva for about four years.

A panel of healthcare experts advising the EU Commission recommended changing the product information for Raptiva after the first PML case in the U.S., Merck's Carter said, adding that a ruling on the part of the Commission was outstanding.

In the meantime, Merck is keeping doctors informed about the latest development and is reminding them to report any side effects linked to the Raptiva injection.

Merck generated 76 million euros ($95.94 million) in sales from Raptiva last year, about 1.6 percent of its total pharmaceuticals revenue of 4.9 billion euros. It has not published an annual peak sales potential for the injection.

Genentech, in turn, derived $107 million in sales from the drug in 2007.

The German company's shares slid 1.5 percent to 65.5 euros at 1038 GMT, compared with a 0.5 percent decline in the European DJ Stoxx Health Care Index .