Comparative Effect of Standard Versus Extended Interval Dosing of Rituximab or Ocrelizumab in Multiple Sclerosis

We aimed to investigate the comparative effectiveness of standard versus personalized extended interval dosing of anti-CD20 therapy on clinical and sub-clinical outcomes in multiple sclerosis.

Clinical information was collected prospectively on Research Electronic Data Capture. Patients with age ≥ 18 years old, confirmed diagnosis of multiple sclerosis, treatment with B-cell depleting drug (Rituximab and Ocrelizumab), and minimum follow-up of 12 months with at least 3 clinical visits and at least 3 infusions of medication were included and divided into an extended interval dosing group, a standard interval dosing group, and a converters group who switched from standard to extended interval dosing. Retinal measures were obtained using spectral domain Optical Coherence Tomography. Magnetic resonance imaging acquisitions were performed in two centers using a standardized conventional imaging protocol for multiple sclerosis.

Patients had a median clinical follow-up of 3.5 (0.44-7.3) years, retinal OCT follow-up of 2.6 (1.4) years, and MRI follow-up of 2.6 (1.1) years. Annualized changes in clinical measures, retinal measures, and brain volumetric measures were similar between the 3 groups. Multivariate regression analyses also showed no differences.

We found no differences in clinical or sub-clinical outcomes between patients treated with standard interval dosing, patients converting from standard to extended interval dosing, and patients on extended interval dosing of B-cell depleting drugs.