Tysabri lessens disease activity and reduces relapses in paediatric-onset multiple sclerosis Published: 01 April 2021 Tysabri (natalizumab) significantly reduces disease activity and the number of relapses in people with paediatric-onset multiple sclerosis (POMS), new real-world study from Portugal has found.  Tysabri is an off-label treatment, which means it hasn’t been