Impact of rituximab in Mexican patients with Multiple Sclerosis-A single-center retrospective study.

BACKGROUND: Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS). B cells have an essential role in the disease pathogenesis and therefore selective B-cell depletion are commonly used to treat the disease. Rituximab (RTX), a chimeric anti-CD20 monoclonal antibody had demonstrated reduced inflammatory activity and radiological activity in MS patients. Due to economic constrains and treatment access limitations, RTX is often used as a treatment alternative in these patients. Here, we described our center experience in RTX -treated MS patients. METHODS: A single-center observational retrospective study was conducted in a Mexican cohort MS during 2010 to 2020. All patients had a confirmed MS diagnosis.All patients received fixed scheme involving induction with 1 g on day one and day 15, followed by 500 mg-1 g every six months for maintenance. Annual Relapse Rate (ARR), Progression index (PI), Expanded Disability Status Scale (EDSS) and MRI activity of the disease were evaluated. Comparison between naïve and non-naïve patients was also conducted. RESULTS: A total of 85 patients were included. The mean age at diagnosis was 33.13 (±8.90) years with 73 (85.9%) being RRMS. 39 (34.1%) were treatment-naïve. While treated with RTX, 62(72.9%) patients reached a free-of-relapse status, with statistically significant decrease in the mean ARR from 0.82 to 0.36 [0.14 (95%CI: 0.09-0.20), p = 0.0001 and EDSS [0.25 CI 0-0.5 (p = 0.034)] and a decrease in their T1 Gd-enhancing MRI lesions (1.64 vs. 0.12 CI 0.70-2.30, p = 0.004. 29 (29.4%) patients achieved NEDA-3. Among all patients, only 2 (2.4%) experienced infusion-related mild adverse events. No serious adverse events were reported. CONCLUSION: We found significant clinical and radiological improvement in naïve and non-naïve MS patients treated with RTX.

Clinical experience of plasmapheresis for neuromyelitis optica patients in Mexico.

BACKGROUND: Neuromyelitis optica spectrum disorders (NMOSDs) are a group of chronic immune-mediated demyelinating diseases of the central nervous system. Their pathophysiology dependent on humoral mediated responses caused by autoreactive IgG antibodies against aquaporin-4 water channels (AQP4-IgG) or myelin oligodendrocyte glycoprotein (MOG-IgG). Plasma exchange (PLEX) has proved to be a beneficial therapy in patients with severe relapses. We present the largest series of Latin American patients treated with PLEX for acute NMOSDs relapses. METHODS: A retrospective study was conducted. Selection included patients diagnosed with NMOSDs who received PLEX between 2010-2019, irrespective of their AQP4-IgG serostatus. All patients received 5 grams of IV methylprednisolone. PLEX therapy could be initiated simultaneously or after IV steroids. Baseline and post-PLEX therapy Expanded Disability Status Scale (EDSS) was measured to identify acute response to therapy. Comparison between responders and non-responders was also conducted. Subgroup analysis stratified response by serostatus, type of clinical relapse and time to PLEX. RESULTS: A total of 89 patients were included. Mean age at onset was 38 ± 12.97 years. 49 (55.1%) patients were AQP4-IgG seropositive. Most patients had unilateral optic neuritis (34.8%) or longitudinally extensive transverse myelitis (33.7%). Mean time from onset to PLEX initiation was 20.9 ± 18.1 days. Response rate was 39.3% and mean decline in EDSS was 0.7 ± 0.9 (p <0.001). Decline in EDSS and response rate were independent of serostatus, type of clinical relapse or time to PLEX initiation. CONCLUSION: PLEX appears to be an effective therapy for NMOSDs relapses even in limited resources setting where treatment initiation may be delayed. The benefit seems to be independent of the type of clinical relapse and AQP4 IgG serostatus.

Rituximab efficacy at different initial and maintenance doses in neuromyelitis optica spectrum disorder: Experience from a national health institute in México.

BACKGROUND: NMOSD is an inflammatory disorder of the central nervous system that primarily affects the optic nerves and spinal cord. Rituximab (RTX) is a monoclonal antibody directed against CD20, an epitope expressed on pre-B and mature B cells. It has of wide use in several antibody-mediated autoimmune diseases. OBJECTIVES: To demonstrate RTX clinical efficacy at different initial and maintenance doses administered in patients with NMOSD. METHODS: In this retrospective/observational study we recruited subjects with NMOSD with at least one RTX infusion. Annual relapse rates (ARR) were compared in several induction and maintenance regimens with RTX in 66 patients with NMOSD. RESULTS: Fifty-four (81.8%) were female and two thirds (66.7%) had positive anti-AQP4 antibodies. The most prevalent induction and maintenance regimens were 1000 mg on days 1 and 15 (51.5%) and 1000 mg every 6 months (40.9%), respectively. Overall, the annual relapse rate (ARR) decreased from 1.15 to 0.46 with RTX (p < 0.001). In patients with persistent relapses, the ARR decreased from 1.66 to 1.22, representing a relative risk reduction of 24%. Treatment with RTX decreased the ARR from 1.36 to 0.4 in the 500 mg induction and maintenance dose subgroup, and from 0.7 to 0.4 in the 1000 mg induction and maintenance dose subgroup. CONCLUSION: RTX treatment in patients with NMOSD demonstrated a marked and sustained reduction in the ARR, regardless of induction and maintenance regimens. EDSS stability was observed, even in patients with active and severe NMOSD.