Changes in John Cunningham Virus Index in Multiple Sclerosis Patients Treated with Different Disease-Modifying...

Progressive Multifocal Leukoencephalopathy (PML) is an opportunistic infection caused by John Cunningham virus (JCV) reactivation, potentially associated with natalizumab (NTZ) treatment for Multiple Sclerosis (MS). The anti-JCV antibodies titre (JCV index) increases during NTZ treatment; however, the effects of other disease-modifying therapies (DMTs) on the JCV index have not been fully explored.

The aim of the study was to evaluate changes in the JCV index during treatment with several DMTs.

This longitudinal study evaluated the JCV index before starting DMT (T0) and during treatment with DMT (T1).

A total of 260 participants (65.4 % females, mean age 43 ± 11.3 ) were enrolled: 68 (26.2 %) treated with fingolimod (FTY), 65 (25 %) rituximab or ocrelizumab (RTX/OCR), 37 (14.2 %) dimethyl-fumarate (DMF), 29 (11.2 %) cladribine (CLD), 23 (8.8 %) teriflunomide (TFM), 20 (7.7 %) interferon or glatiramer acetate (IFN/GA), and 18 (6.9 %) alemtuzumab (ALM). At T1, the percentage of patients with JCV index <0.90 was found to be significantly increased in the ALM group (16.7 % versus 66.7 %, p = 0.05), while the percentage of patients with JCV index >1.51 was found to be significantly reduced in the RTX/OCR group (51.6 % versus 37.5 %, p = 0.04). In the FTY group, a significant reduction in the percentage of patients with JCV index <0.90 was also found (23.5 % versus 1.4 %, p = 0.0006). The mean JCV index was reduced in the RTX/OCR and ALM groups, while a significant increase was observed in the FTY group.

DMTs with a T and/or B depleting mechanism of action induced a significant reduction in the JCV index. These results may suggest new possible sequencing strategies potentially maximizing disease control while reducing the PML risk.