A retrospective study found that patients on ocrelizumab and rituximab had a higher risk of contracting SARS-CoV-2 compared to those on ofatumumab, despite all patients being fully or partially vaccinated.

Recent reports have indicated that B-cell–depleting disease-modifying therapies (B-DMTs) may increase the risk of infections, including SARS-CoV-2. The risk of infection varies among different DMTs and is influenced by factors such as age, disabilities, and comorbidities. Limited studies have examined the incidence of SARS-CoV-2 infection in individuals on B-DMT following the introduction of the vaccine in late 2020. The objective of this study is to compare the incidence of SARS-CoV-2 infection among different B-cell–depleting therapies in patients who have received the SARS-CoV-2 vaccine.

A retrospective chart review was conducted on clinic patients with MS receiving B-DMT from January 1, 2021, to November 15, 2023. Patients were required to have been on B-DMT for at least 2 months at the beginning of the study or at the time of SARS-CoV-2 infection. Confirmation of SARS-CoV-2 infection was based on a positive test result accompanied by clinical symptoms.

A total of 145 patients were included in the study, with 69 on ocrelizumab, 69 on ofatumumab, and 7 on rituximab. All patients were fully or partially vaccinated against SARS-CoV-2. Among those on ocrelizumab, 40.58% contracted SARS-CoV-2, compared to 21.74% on ofatumumab and 71.43% on rituximab. 

The average age of patients with SARS-CoV-2 was around 48 years for ocrelizumab and ofatumumab, and 47 years for rituximab. The average Expanded Disability Status Scale score for patients with SARS-CoV-2 was 2.2 on ocrelizumab, 2.4 on ofatumumab, and 2.1 on rituximab. Patients on ocrelizumab had a higher percentage of vascular or respiratory comorbidities at 50%, compared to 27% on ofatumumab and 20% on rituximab. The average body mass index for patients infected with SARS-CoV-2 was 24.5 kg/m2 on ocrelizumab, 24 kg/m2 on ofatumumab, and 24.2 kg/m2 on rituximab.

“In our series, patients on ocrelizumab and rituximab appeared to have an increased risk of SARS-CoV-2 infection compared with patients on ofatumumab,” said researchers. “Demographic variables were not different among the 3 groups, except for a higher prevalence of comorbidities in patients on ocrelizumab.” 

Reference 
Quinn K S, Giesser B S. SARS-CoV-2 infection in vaccinated persons with multiple sclerosis on B-Cell–Depleting therapies; CMSC 2024; May 29-June 1, 2024; Nashville, TN; Abstract CS11.