A patient in Germany treated with the new multiple sclerosis (MS) drug ocrelizumab (Ocrevus, Roche) has been diagnosed with progressive multifocal leukoencephalopathy (PML), a potentially deadly brain infection, after switching from natalizumab (Tysabri, Biogen) following three years of treatment, according to a Reuters report. The patient received a single dose of ocrelizumab in February.
According to Roche, however, the case of PML was reported as a carry-over from natalizumab by the patient’s attending physician. The patient had previously tested positive for John Cunningham virus, a common virus that is normally harmless but can lead to PML in MS patients with weakened immune systems.
Dozens of patients receiving treatment with natalizumab have been diagnosed with PML. Use of the drug was temporarily halted in 2005, but was resumed after patients for whom the medication was effective demanded its return and regulators added restrictions to its use.
Roche has said no cases of PML emerged during its trials of ocrelizumab, but the company included warnings to patients taking the medication that there was a risk they could develop the disease.
Ocrelizumab was approved by the FDA in March 2017. It is the only disease-modifying therapy indicated for the primary progressive form of MS, Roche said. Ocrelizumab is a monoclonal antibody designed to target CD20-positive B cells, a specific type of immune cell thought to be a key contributor to myelin and axonal damage.
Natalizumab, another immunomodulator, was approved for use in MS patients in 2004.
Sources: Reuters; May 25, 2017; and BioSpace; May 25, 2017.