Biogen Idec, Inc., the manufacturer of the drug, Rituxan, just issued to an alert to doctors, warning that two patients taking Rituxan died of the fatal brain disease, “progressive multifocal leukoencephalopathy” (PML). Both patients who died were being treated experimentally with the drug, for lupus. While Rituxan is approved by the Food and Drug Administration, only for treatment of rheumatoid arthritis and non-Hodgkins lymphoma, doctors are permitted to use it for other purposes at their discretion.
Medication deaths are always a concern for the FDA, particularly when a drug is often used for purposes for which it is not officially approved. Such use is not automatically wrong, but carries extra risk because the quantity and quality of the data relating to the drug’s risk, will generally be less than for an approved drug. One recent study estimated that medication errors cause 7,000 deaths each year.
PML is a disorder that typically strikes only people with compromised immune systems. Nearly two dozen patients are known to have contracted PML while taking Rituxan; all of those patients were being treated for cancer of the blood. Biogen has already included a label warning regarding the risk of Rituxan-related PML in blood cancer patients. A Biogen spokesman, Tim Hunt, stated that he did not believe the two lupus-patient deaths were caused by Rituxan.
It is worth questioning how Mr. Hunt could have any opinion on Rituxan’s role, given that the FDA is still investigating the deaths. Biogen’s quick dismissal of the role of its drug in the two deaths can also be scrutinized, given that Rituxan generated $1.8 billion dollars in sales worldwide in 2005, $709 million of which was earned by Biogen. It is too early to say at this point, whether use of Rituxan for lupus is dangerous or whether its prescription for non-approved uses is negligent. In its alert, Biogen advised doctors prescribing Rituxan to be watchful for early signs of PML, such as speech difficulties, dizziness, and vision problems.