A third Rituxan patient has developed a serious and often fatal brain infection called progressive multifocal leukoencephalopathy (PML). According to a statement posted on the Food & Drug Administration (FDA) Web site, this is the first case of PML in a patient with rheumatoid arthritis treated with Rituxan who has not previously received treatment with a TNF antagonist.
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.
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.
According to a “Dear Healthcare Provider” letter issued by Genentech, the third Rituxan PML case occurred in a 73-year old woman with a diagnosis of seronegative rheumatoid arthritis of 3 years who had received a course of Rituxan in February 2009. The letter did not say whether the woman was still alive, but two other PML victims who had taken Rituxan have died.
According to the letter, the overall reporting incidence of PML in patients with rheumatoid arthritis receiving Rituxan is rare (3 reports in approximately 100,000 rheumatoid arthritis patients that have been exposed). However, the information to date suggests that patients with rheumatoid arthritis who receive Rituxan have an increased risk of PML
The letter advises physicians to consider PML in any patient being treated with Rituxan who presents with new onset neurologic manifestations. Consultation with a neurologist, brain MRI, and lumbar puncture should be considered as clinically indicated. In patients who develop PML, Rituxan should be discontinued.
In June, the FDA announced that it was investigating a possible Rituxan-PML link. At the time, The Wall Street Journal reported that doctors at the FDA were 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.