ABSTRACT
BACKGROUND: Severe cases of lymphopenia have been reported during siponimod clinical trials, which may negatively impact its benefit/risk profile. OBJECTIVE: We aimed to evaluate the incidence of lymphopenia following the initiation of siponimod treatment in clinical practice. The secondary objectives included the analysis of factors predisposing to and the clinical relevance of lymphopenia events. METHODS: In this multicenter retrospective cohort study, information collected from the medical records of 129 patients with MS from 15 tertiary hospitals in Spain who initiated treatment with Siponimod were followed-up for at least 3 months, including at least one lymphocyte count evaluation per patient. RESULTS: Of the 129 patients, 121 (93.6%) reported lymphopenia events, including 110 (85.3%) with grade ≤ 3 and 11 (8.5%) with grade 4 lymphopenia, higher than those reported in the pivotal clinical trial (73.3% and 3.3% for grade ≤ 3 and grade 4 lymphopenia, respectively). The study included an unexpectedly high proportion of male subjects (72.9%), which might have led to an underestimation of the actual magnitude of the risk. CONCLUSIONS: In this study, the incidence and severity of lymphopenia after starting siponimod treatment were higher than those reported in previous clinical trials. Therefore, our results reinforce the need for the closer monitoring of novel MS drugs in clinical practice, as well as larger and longer follow-up studies to properly characterize this risk.
ABSTRACT
The humoral immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern elicited by vaccination was evaluated in COVID-19 recovered individuals (Rec) separated 1-3 months (Rec2m) or 4-12 months (Rec9m) postinfection and compared to the response in naïve participants. Antibody-mediated immune responses were assessed in 66 participants by three commercial immunoassays and a SARS-CoV-2 lentiviral-based pseudovirus neutralization assay. Immunoglobulin (Ig) levels against SARS-CoV-2 spike were lower in naïve participants after two doses than in Rec after a single dose (p < 0.05). After two doses in Rec, levels of total Ig to receptor-binding domain were significantly increased in Rec9m compared to Rec2m (p < 0.001). The neutralizing potency observed in Rec9m was consistently higher than in Rec2m against variants of concern (VOCs) Alpha, Beta, Delta, and BA.1 sublineage of Omicron with 2.2-2.8-fold increases. Increasing the interval between SARS-CoV-2 infection and the vaccination with messenger RNA-based vaccines to more than 3 months generates a more efficient heterologous humoral immune response against VOCs by allowing enough time to mount a strong recall memory B cell response.
