ABSTRACT
Introduction: In March 2020, to prevent the risk of infection from SARS-CoV-2 in people with multiple sclerosis (MS) on Ocrelizumab, notably associated with an immunosuppressed state, the Association of British Neurologists (ABN) advised delaying the infusions until the recovery of CD19+ cells to over 1% of the total lymphocyte population. The indication is based on observations from multinational experience using Rituximab, suggesting that an Ocrelizumab infusion may remain effective at controlling MS for longer than 6 months. Objective(s): We will analyse data on the delayed time intervals between Ocrelizumab infusions, the rate of relapses and signs of disease activity or progression reported for 209 patients in the audited period. Aim(s): We aim at assessing the efficacy of dosing Ocrelizumab according to CD19+ cell count in terms of MS control. Method(s): The study was designed as a clinical audit. 209 patients under the care of the MS centre of the Queen Elisabeth Hospital Birmingham were included in the audit. The protocol suggested by the ABN was applied to all of them from mid-March 2020 onwards. 2 years after, we collected data on the time intervals between the infusions, the relapses and radiological findings reported for the 209 subjects in the audited period. Result(s): A total of 424 Ocrelizumab infusions were administered. 123 (29%) were first infusions. 301 (71%) were either second, third, fourth, fifth or sixth infusions. Of those 301 infusions, 235 (78,07%) were administered after 8 months or more from the preceding one, whereas 66 (21,92%) were performed at a time interval of 6-7 months. Of 209 patients, 8 (3,82%) experienced a clinical relapse not supported by radiological signs of disease activity or progression. 4 patients (1,91%) presented clinical manifestations of a relapse confirmed by radiological findings of disease activity or progression. For 1 patient (0,47%) the magnetic resonance imaging showed evidence of increased lesion load not associated with any new clinical sign or symptom. In addition, 4 patients (1,91%) reported subjective feelings of worsening MS that they attributed to infusions being delayed and were re-established on standard sixth-month interval infusions. Conclusion(s): Ocrelizumab dosing according to CD19+ cell count monitoring remained effective at controlling MS in the majority of the 209 patients included in the audit while preventing unnecessary exposure to SARS-CoV-2 infection related to hospital attendance.