O’Connor PW, et al Neurology. 2011 May 4.
Due to a heightened risk of progressive multifocal leukoencephalopathy (PML) with increased natalizumab exposure, some neurologists interrupt treatment of patients with MS despite a lack of data regarding the safety of treatment interruption. The aim of this study was to determine the effects of natalizumab treatment interruption on clinical and MRI measures of disease activity in RRMS. Findings: a consistent return of disease activity was observed regardless of overall natalizumab exposure, whether or not patients received alternative MS therapies, and in patients with highly active MS disease.
“Hopefully, risk stratification as proposed in a previous post will help neurologists make informed decisions and prevent abrupt withdrawal.”
COI: I was the Chief Investigator in the UK on the AFFIRM study and have received consulting fees from Biogen-Idec in relation to Natalizumab.
If disease activity resumes while on Natalizumab and treatment is stopped because of neutralising antibodies: will stopping treatment cause further worsening or any other effect?
Re: "If disease activity resumes while on Natalizumab and treatment is stopped because of neutralising antibodies: will stopping treatment cause further worsening or any other effect?"Not necessarily. If yo have neutralizing antibodies to Natalizumab they stop the drug from working. In other words you MS is untreated. Stopping the drug in this situation will have no effect; i.e. your MS will be active and remain so unless you go onto another drug. You need to remember that MS is a disease that has relapses and remissions; in other words an MS'er on Natalizumab with neutralizing antibodies may have no disease activity detectable. This is based on the natural history of the disease, i.e. remission, which has nothing to do with being on the drug.