Clinical outcomes in patients who discontinue natalizumab therapy after 2 years in the Tysabri® Observational Program (TOP).

Patients who stayed on natalizumab had better clinical outcomes than those who switched to an oral or injectable therapy after ⩾2 years on natalizumab. These results highlight modifiable risk factors for disease activity return (e.g. natalizumab treatment duration and washout duration) to consider when making treatment decisions.