Rituxan - PML Link Could Spark FDA ActionJun 1, 2009 | Parker Waichman LLP U.S. health regulators are taking a look at the lymphoma drug Rituxan because of its possible association with progressive multifocal leukoencephalitis (PML), an often fatal brain infection. According to The Wall Street Journal, the Food & Drug Administration (FDA) is trying to determine if patients should take Rituxan for shorter periods, or take breaks from therapy to lessen the risk that they will develop PML.
Rituxan, a powerful medication that suppresses the immune system, is the most important and widely used cancer drug for lymphoma. It is also approved as a therapy for rheumatoid arthritis, and is used off-label to treat multiple sclerosis, lupus erythematosus and autoimmune anemias.
In February 2006, the labeling of Rituxan was updated to include information about the risks of patients contracting several viral infections, including PML. At present, the Rituxan PML warning is contained in a "Black Box", the FDA's strongest safety alert, The Wall Street Journal said.
PML is a viral infection that affects the white matter of the brain. Patients with PML exhibit neurological symptoms like confusion, dizziness or loss of balance, difficulty talking or walking, and vision problems. PML gets worse over time, and is usually fatal. There is no treatment or cure for the disease. It is often associated with drugs that suppress the immune system.
As we reported last month, a study published in the journal Blood found that 57 patients taking Rituxan had developed PML between 1997 and 2008. The study, conducted by researchers with the Northwestern University Feinberg School of Medicine RADAR (Research on Adverse Drug Events and Reports) project, also found that on average, average, these PML patients died just two months after being diagnosed. In many cases, PML patients taking Rituxan were misdiagnosed with disease like dementia and Alzheimer’s.
The PML patients in the RADAR study were using Rituxan as a treatment for anemia, rheumatoid arthritis or lymphoma. While it is known that a small number of lymphoma patients will develop PML regardless of the treatment they undergo, it is not typically seen in anemia or arthritis patients, the researchers said.
According to The Wall street Journal, doctors at the FDA are trying to determine if long-term, uninterrupted Rituxan therapy may play a role in the development of PML. The agency has discussed whether a "drug holiday" - an interruption in therapy - might mitigate the risk of PML, the report said. But that could be a problem for many lymphoma patient, as a break could lead to a recurrence of the disease that is more difficult to treat. In such a case, higher doses of Rituxan are needed to bring the cancer under control, the Journal said.
The doctor who led the RADAR study, Charles Bennett, told the Journal that he believes that Rituxan should only be used for life-threatening ailments like lymphoma until more conclusion can be drawn about its link to PML. A co-author of the study, Kenneth Carson, is of the opinion that the FDA should consider imposing special prescribing conditions on Rituxan, similar to those imposed on Tysabri, a drug for MS that has been liked to PML.
One thing no one is advocating is the withdrawal of Rituxan from the market because it is often the best option for patients with life-threatening cancer. However, other drugs have been withdrawn because of associations with PML. As we reported in April, the psoriasis drug Raptiva was voluntary withdrawn from the market after three patients died from PML. Tysabri was withdrawn for a time because of its PML link, but reintroduced under current prescribing restrictions.