By Steve Bryson PhD on Oct
07, 2021
One year of Ocrevus (ocrelizumab) treatment does not increase the risk for a rare brain infection — called progressive multifocal leukoencephalopathy (PML) — in people with multiple sclerosis (MS), a study suggests.
The study, “Risk Assessment of Progressive Multifocal Leukoencephalopathy in Multiple Sclerosis Patients during 1 Year of Ocrelizumab Treatment,” was published in the journal Viruses.
MS therapies are designed to suppress the immune system and limit the inflammatory damage to the myelin sheath that surrounds nerve fibers, an underlying cause of MS.
PML is a rare and potentially fatal brain infection caused by the common John Cunningham (JC) virus. It has been associated with the extended use of Tysabri (natalizumab), an MS therapy that suppresses the immune response in the brain by limiting the access of immune cells.
Ocrevus is a different MS therapy that also suppresses the immune system, but works by depleting antibody-producing B-cells. Although a few cases of PML have been reported in patients treated with Ocrevus, most had been prescribed other immune-suppressing MS therapies. As such, the risk of PML in those treated with Ocrevus remains unclear.
To investigate further, scientists based at the Sapienza University of Rome, in Italy, collected blood and urine samples from 42 relapsing-remitting MS patients (24 females and 18 males) before Ocrevus treatment (baseline) and at various timepoints over one year of treatment to assess PML risk.
The study included 19 patients who had not been treated with any MS therapy (treatment-naive), four who had previously received Tysabri, and 19 who had switched from other MS treatments, such as Gilenya (fingolimod), Aubagio (teriflunomide), and Tecfidera (dimethyl fumarate).
Before Ocrevus initiation, JC viral DNA was detected in urine samples from 34 (81%) patients, but was absent from all blood samples. Viral DNA was found in all patients who received previous MS treatments and in 11 out of the 19 who were treatment-naive. The results were the same after six months of treatment.