Rituxan Side Effects Linked to Progressive Multifocal Leukoencephalopathy (PML)

On Thursday, the FDA notified oncologists, rheumatologists and other healthcare providers that the rheumatoid arthritis drug Rituxan has been linked to a fatal case of progressive multifocal leukoencephalopathy (PML). An update will be made to the prescription information about the risk of developing the rare brain disease.

Rituxan is a powerful immunosuppressant used for the treatment of rheumatoid arthritis and non-Hodgkin’s lymphoma. The drug is made by Genentech Inc. and Biogen Idec Inc., with annual sales of about $2.3 billion last year.

Warnings were placed on the label in 2006 about potential Rituxan side effects which could cause several viral infections, including progressive multifocal leukoencephalopathy. In 2007, the FDA warned that two people died after using Rituxan for lupas treatment, which is not an approved use.

Progressive multifocal leukoencephalopathy, commonly referred to as PML, is caused by a polyomavirus called the JC virus. It is a progressive inflammation of the central nervous system and the brain, which could cause symptoms such as confusion, blurred vision, speech difficulties, movement problems, dizziness and loss of balance.

Although PML is rare, the brain infection can worsen over time and there is no known cure. In many cases it ultimately leads to death.

Genentech and Biogen have sent a letter to physicians notifying them about the label changes that will be made about the potential side effects of Rituxan. An update will be made to the prescribing information about a woman treated for arthritis with the drug who developed PML about 18 months after the therapy was stopped. She ultimately died from the brain disease.

This is the third alert issued by the FDA this year involving a drug linked to progressive multifocal leukoencephalopathy. The other drugs include Biogen Idec and Elan Inc.’s multiple sclerosis drug Tysabri, and the organ transplant drugs CellCept and Myfortic.

Tysabri was recalled in 2005 after a number of patients developed PML. It was subsequently reintroduced in 2006 with restrictions on how it can be prescribed.