Short-term evaluation of alemtuzumab to ocrelizumab switch in MS patients with disease activity after alemtuzumab: An Italian multicentric study

Objective: To evaluate efficacy and Safety of multiple sclerosis (MS) patients (pts) who switched to ocrelizumab (OCR) due to persistence of disease activity after two courses of alemtuzumab (ALM) Background: The management of MS pts who show disease activity after 2 ALM courses represents an unsolved issue Design/Methods: MS patients who switched from ALM to OCR from March 2019 to March 2020 were retro-A nd prospectively recruited from different Italian MS Centers. Clinical, immunological and neuroradiological data about ALM treatment period, ALM-OCR interval and OCR treatment period were collected Results: 23 MS pts [mean age: 35.7(6.8);female, 40.1%;Relapsing Remitting, (RR): 75.8%, active Secondary progressive, (aSP): 24.2%;mean time interval (days) from II ALM course 87.4(108);cumulative number of relapses: 21;mean number of new T2 and Gd+ lesions: 4.1(4.5) and 1.6(3.1);median EDSS:3(range 1-7)]. The mean follow-up (FU) from OCR start: 7.9±7.4 months. 4 (17.4%) pts had a relapse after OCR start (1 during the interval between first and the second OCR infusion and 3 pts after 3, 11 and 15 months from OCR start. 4 (17.4%) pts showed only radiological activity at 3 (n=2), 4 (n=1) and 9 months (n=1). Infusion Associated Reactions occurrence was lower than ALM courses (p<0.05) ;mild upper airways (n=1), urinary infections (n=1), appendicectomy (n=1) and fever due to probable Sars-Cov2 infection (n=1). No pts showed T CD4+ cell count <200 cell/mm3 at 3, 6-months and 1-year FU;B CD19+ cell depletion (<5 cell/mm3) was confirmed at 3, 6-months and 1-year FU with the exception of 1 pt (B CD19+ count 12 cells/mm3 at 6 month FU (n=12 pts)). 10 (43.4%) pts developed hypogammaglobulinemia without infectious events. No ALM-related new complications occurred. Conclusions: Short-term FU suggests that the switch to OCR in MS after 2 ALM courses is characterized by a good safety and efficacy profile.