Efficacy and safety of tixagevimab-cilgavimab (Evusheld®) in people with Multiple Sclerosis on Ocrelizumab: preliminary evidence.

Background: Evusheld (EVS) was authorized by FDA and EMA as pre-exposure prophylaxis (PrEP) in people at high risk of severe Covid-19 outcomes, including people with Multiple Sclerosis (pwMS) on B-cell depleting (BCD) therapies-such as Ocrelizumab (OCR). In this population, no data on possible adverse drug reactions (ADRs) to EVS, B-lymphocytes (CD20 +) counts pre- and post-EVS injection, and comparison of percentage increase of IgG antibodies directed against SARS-CoV-2 trimeric spike protein (anti-TSP IgG) post-EVS and Covid-19 vaccine was available. The aim of this study was to better characterize the efficacy and safety profile of EVS in pwMS on BCD agents.

Methods: 17 pwMS on OCR agreed to receive EVS as PrEP for Covid-19. Sera samples were collected before the first dose of Covid-19 vaccine (T0), 4 weeks after the second dose (T1), 4 weeks after third dose (T2), immediately before (T3) and 4 weeks after (T4) EVS.

Results: Covid-19 vaccine ADRs were mild-to-moderate, whereas no ADRs were reported after EVS injection. A significant increase of anti-TSP IgG was found only at T0-T1 (Z = -3.059, p = .002) and T3-T4 (Z = -3.621, p < .001) time-points. The median percentage increase between T3-T4 was significantly higher with respect to the T0-T1(Z = -3.296, p = .001) and T1-T2 (Z = -3.059, p = .002) time-points.

Conclusions: These results further support EVS safety and efficacy in boosting anti-TSP IgG titers in pwMS on OCR, with a statistically greater increase than that observed after completion of a full Covid-19 vaccine cycle, plus a booster dose.