NEW ORLEANS—Now that testing for John Cunningham virus (JCV) antibody status is recommended for all patients with multiple sclerosis (MS) receiving infusions of natalizumab, the decision of whether to switch to another agent if the antibody status is positive might seem straightforward. However, the potential for relapsing and worsening MS might cause some patients to weigh the risks of natalizumab treatment, including progressive multifocal leukoencephalopathy (PML), a bit differently.
Researchers from Winthrop Comprehensive MS Care Center in Mineola, New York, presented findings from a study on patient decision-making and JCV antibody status at the 64th Annual Meeting of the American Academy of Neurology. Malcolm Gottesman, MD, and colleagues studied 71 patients who had initiated natalizumab therapy without knowing their JCV status. After antibody testing, patients were followed for six months and evaluated based on whether they elected to continue or discontinue natalizumab therapy. Of the 39 patients who were JCV negative, all continued on therapy and two (5%) experienced a relapse within the six-month period. Of the 32 patients who tested positive for JCV, nine elected to stop natalizumab therapy, but five patients (56%) had a relapse during the follow-up period. Of the 23 who continued, one patient (4%) relapsed. Of the nine patients who discontinued natalizumab after learning their JCV status, all but one (80%) resumed the treatment after they experienced an MS relapse.