Evobrutinib Recipients With RMS Mount Humoral Responses to COVID-19 Vaccines

Patients who received evobrutinib for relapsing multiple sclerosis (RMS) had humoral responses to mRNA COVID-19 vaccines, according to study results presented at the 2023 Consortium of Multiple Sclerosis Centers (CMSC) Annual Meeting, held from May 31 to June 3 in Aurora, Colorado.

Evobrutinib is a highly selective covalent Bruton tyrosine kinase inhibitor that is under investigation for the treatment of RMS.

In a post hoc analysis, researchers evaluated data from the open-label extension period of a phase II clinical trial (ClinicalTrials.gov Identifier: NCT02975349). Patients (N=45) with RMS who received 75 mg evobrutinib twice daily and an mRNA (n=37), non-mRNA (n=8), or booster (n=14) COVID-19 vaccine were evaluated for antibody responses. The outcome of interest in this analysis was immunoglobulin G (IgG) anti-SARS-CoV-2 spike protein domain (S1/S2) antibodies. Seropositivity was defined as anti-S1/S2 IgG antibody levels of 15.0 AU/ml or greater.

The patients were mean age, 46.0 (SD, 9.6) years; 68.9% were women; and, they had been exposed to evobrutinib for an average of 105.2 weeks.

All but 2 patients developed increased S1/S2 IgG antibody levels postvaccination from a geometric mean of 8.5 AU/ml to 247.7 AU/ml among those who received the mRNA vaccine and from 12.1 AU/ml to 197.1 AU/ml for those who received the non-mRNA vaccine.

Stratified by seropositivity status at baseline, those who were seronegative (n=32) had increased S1/S2 IgG antibody levels from a geometric mean of 4.3 AU/ml to 133.6 AU/ml and those who were seropositive (n=13) from 55.4 AU/ml to 984.4 AU/ml.

Overall, 36 of the patients had a 10- to 100-fold increase in S1/S2 IgG antibody levels postvaccination.

Similarly, the group who received a booster vaccination also exhibited increased SARS-CoV-2 antibody responses.

The limitations of this study included the small sample size and the unbalanced groups.

The researchers concluded, “These results provide additional evidence that evobrutinib-treated persons with RMS can mount a humoral response to COVID-19 vaccinations and that, with boosters, antibody levels increase further than after the first vaccination cycle.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.