Fig. 1.

Flowchart of the study procedure. SID was defined as a regular maintenance interval of OCR infusions every 6 months, whereas EID was defined an OCR infusion delay of at least 4 weeks (6 months + ≥ 4 weeks delay). Infusion A was the last ocrelizumab infusion (second 300 mg cycle or 600 mg maintenance infusion) before January 2020, while infusions B and C (always 600 mg standard maintenance dose) were the subsequent infusions. Infusion C was the last OCR infusion. The observation period in which either SID or EID took place (always maintenance cycle, 600 mg) was from January 2020 to June 2021. We considered a single interval from infusions A to C, defined as the A-C interval. EID, extended interval dosing; SID, standard interval dosing