Escalation to Anti-CD20 Treatment for Multiple Sclerosis Following Natalizumab-Associated Progressive Multifocal Leukoencephalopathy.

Objectives: Disease-modifying therapy (DMT) for multiple sclerosis (MS) after natalizumab-associated progressive multifocal leukoencephalopathy (PML) is controversial due to concern for recurrent PML. We describe DMT utilization for over a decade in a patient with MS who survived PML. Methods: Case report. Results: A 36-year-old woman was diagnosed with MS in 2002 and treated with interferon beta-1a until 2006, when she transitioned to natalizumab due to relapses. She presented in 2012 with 2 months of progressive cognitive and gait concerns and was diagnosed with PML by positive CSF JC virus testing with concordant clinical and MRI findings. She was treated with plasma exchange and then corticosteroids for PML immune reconstitution inflammatory syndrome before starting glatiramer acetate for DMT. She transitioned to dimethyl fumarate in 2013 after MS activity on MRI with negative CSF JC virus testing. Owing to worsening footdrop consistent with progression, she transitioned to ocrelizumab in 2017 and then to ofatumumab in 2020 due to logistics of medication administration. There has been no clinicoradiographic or CSF evidence of recurrent PML. Discussion: DMT selection is challenging for patients with MS who survive PML. We used an escalation approach extending to ocrelizumab and ofatumumab due to MS progression. Anti-CD20 DMTs are a high-efficacy option post-PML. Classification of Evidence: This provides Class IV evidence. It is a single observational study without controls.