Natalizumab-PML survivors with subsequent MS treatment: Clinico-radiologic outcome

OBJECTIVE: To describe the clinico-radiologic outcome of MS patients with natalizumab-related progressive multifocal leukoencephalopathy (Nz-PML) surviving and receiving disease-modifying therapy (DMT). METHODS: We describe clinical and radiologic evolution of Nz-PML survivors in an observational retrospective multicenter cohort to clarify the effect of different subsequent MS DMT strategies. Twenty-three patients from 11 centers were analyzed. Outcomes were (1) clinical efficacy of post-PML MS DMT, (2) radiologic efficacy of post-PML MS DMT, (3) radiologic evolution of PML lesion, and (4) disability progression. RESULTS: There was no clinical worsening of PML symptoms with a stability of Expanded Disability Status Scale at the last follow-up. No relapse was reported with fingolimod and dimethyl fumarate. No radiologic worsening of Nz-PML lesion was observed at the end of the follow-up. CONCLUSION: In this large cohort of patients with Nz-PML, MS therapies given after Nz discontinuation were not associated with PML worsening. A larger cohort with longer follow-up will be necessary to confirm this therapeutic strategy.