Background and purpose: Temporary discontinuation of natalizumab/Tysabri is sometimes considered because of the observed risk of progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS). However, interruption of natalizumab may result in a re-start of disease activity.
Methods: In this prospective post-marketing study, 23 patients with MS treated with natalizumab elected a trial of treatment interruption (90-150 days) because of safety concerns on the risk of developing PML. To reduce the risk of disease activity return, patients received monthly intravenous (i.v.) steroid pulses before natalizumab re-start.
Figure - mode of action: Natalizumab works by coating white blood cells and preventing them from entering the brain and spinal cord. By doing this it prevents relapses, but also put treated subjects at risk of infection; we need white blood cells to traffic through the nervous system to clear infections.
Results: Despite the steroid coverage, seven patients (30.4%) had an active scan during the natalizumab interruption period; of these, four also had a concomitant clinical exacerbation.
Conclusions: Our findings suggest that i.v. steroids are not currently recommendable as drug coverage during a scheduled treatment interruption period.
"The conclusions say it all, we need to find an alternative"