The European Medicines Evaluation Agency beefed up package insert labeling for Idec Pharmaceuticals Inc.'s Mabthera rituximab following eight fatalities associated with the drug worldwide. The action comes following a change in the package insert for the drug in the U.S. in September, based on off-label treatments of two patients with prolymphocytic leukemia in the U.S., that warned of increased risk of infusion-related events among patients with high numbers of tumor cells circulating in their bloodstreams.

EMEA's action now has prompted both of IDPH's marketing partners - F. Hoffmann-La Roche in Europe and Genentech Inc. in the U.S. - to send "Dear Doctor" letters that will have an unknown effect on sales of rituximab.