Rituxan Side Effects a Concern for Some

Washington, DCIt has been almost six years exactly since the US Food and Drug Administration (FDA) issued a serious warning about the risks of Rituxan side effects. At the time, the FDA noted that Rituxan adverse events could include an increased risk of progressive multifocal leukoencephalopathy (PML). Although Rituxan remains on the market, patients must still be careful to watch for signs that they are suffering an adverse reaction.

On December 18, 2006, the FDA issued its Public Health Advisory about Rituxan, warning about the risk of PML and advising patients of the reports of two deaths in patients who used Rituxan to treat systemic lupus erythematosus (SLE) and developed PML. Rituxan at the time was approved for patients with non-Hodgkin's lymphoma and rheumatoid arthritis when other treatments did not work. It was not approved to treat SLE, although off-label use of a medication is not illegal.

Progressive multifocal leukoencephalopathy is a life-threatening brain infection for which there are no known effective treatments. It is caused when the JC virus--which can be found in most adults--is reactivated. Symptoms of PML include confusion, dizziness, loss of balance, difficulty walking and vision problems. In February 2006, the warning label for Rituxan was updated to include information about the potential link between Rituxan and PML.

Meanwhile, a study published in the journal Blood (5/14/09), and presented in part to the 49th annual meeting of the American Society of Hematology (12/10/07) found a potential link between Rituxan and PML. According to researchers, a literature review of studies from 1997 to 2008 found that of patients who used rituximab (the generic version of Rituxan) and developed PML, 52 were diagnosed with lymphoproliferative disorders, two were diagnosed with SLE and three were diagnosed with a different condition. Of those who developed PML, 90 percent died. The median time from the final dose of rituximab to the diagnosis of PML was 5.5 months, while the median time to death after the diagnosis was 2.0 months.

Researchers concluded that the use of rituximab may increase the risk of developing PML, although the absolute risk of developing it was still low. They recommended that patients and clinicians should be aware of the risks of PML after use of rituximab.