Enhanced pathogenicity of Th17 cells due to natalizumab treatment: Implications for MS disease rebound.

After natalizumab (NAT) cessation, some multiple sclerosis (MS) patients experience a severe disease rebound. The rebound pathophysiology is still unclear; however, it has been linked to interleukin-17-producing T-helper (Th17) cells. We demonstrate that during NAT treatment, MCAM+CCR6+Th17 cells gradually acquire a pathogenic profile, including proinflammatory cytokine production, pathogenic transcriptional signatures, brain endothelial barrier impairment, and oligodendrocyte damage via induction of apoptotic pathways. This is accompanied by an increase in Th17 cell frequencies in the cerebrospinal fluid of NAT-treated patients. Notably, Th17 cells derived from NAT-treated patients, who later developed a disease rebound upon treatment cessation, displayed a distinct transcriptional pathogenicity profile associated with altered migratory properties. Accordingly, increased brain infiltration of patient Th17 cells was illustrated in a humanized mouse model and brain histology from a rebound patient. Therefore, peripheral blood-accumulated MCAM+CCR6+Th17 cells might be involved in rebound pathophysiology, and monitoring of changes in Th17 cell pathogenicity in patients before/during NAT treatment cessation might enable rebound risk assessment in the future.

Altered lymphocyte profiles and herpes zoster infections in patients with multiple sclerosis on natalizumab.

Cases of herpes zoster (HZ) in patients with MS on natalizumab (NTZ) have been documented. In this study, we assessed lymphocyte subsets in NTZ-treated patients with HZ compared to matched controls without HZ. Twenty unvaccinated patients developed HZ while on NTZ for an incidence rate of 12.3 per 1000 patient-years. These patients had lower CD8+% and higher CD4+:CD8+ ratios (p ⩽ 0.01) than non-HZ matched controls. Two patients with relapsing-remitting MS developed HZ twice while on NTZ. These findings underscore the importance of pre-NTZ HZ vaccination due to potential HZ risk.

Neuroaxonal damage in natalizumab-treated MS patients: The role of JCV antibody titres.

BACKGROUND: While John Cunningham virus (JCV) is known to cause neuronal damage in progressive multifocal leukoencephalopathy (PML) among natalizumab-treated MS patients, its association with axonal loss in non-PML conditions remains unclear. METHODS: In a cohort of 128 natalizumab-treated MS patients, serum neurofilament (sNfL) levels and JCV antibody titres were measured. RESULTS: Among 128 patients (mean age = 38.4 years, 71.9% female), 51 (40%) were JCV positive. NfL levels increased by 15.3% for JCV index <0.7 (95% confidence interval [CI] = 0.963-1.381), by 18.6% for index 0.7-1.5 (95% CI = 1.009-1.394) and by 21.1% for index >1.5 (95% CI = 1.040-1.409) compared to JCV negative patients. CONCLUSION: These findings indicate a potential link between JCV burden and neuroaxonal degeneration in natalizumab-treated MS patients.

Safety and effectiveness of disease-modifying therapies after switching from natalizumab.

INTRODUCTION: One strategy to mitigate progressive multifocal leukoencephalopathy (PML) risk is to switch to other highly effective disease-modifying therapies (DMTs). However, the optimal switch DMT following natalizumab (NTZ) discontinuation is yet to be determined. OBJECTIVE: The objective of the study is to determine the most effective and tolerable DMTs to switch to following NTZ discontinuation due to John Cunningham virus (JCV) antibody positivity. METHODS: This is a multicenter observational cohort study that included all stable relapsing-remitting multiple sclerosis (MS) patients who were treated with NTZ for at least 6 months before switching therapy due to JCV antibody positivity. RESULTS: Of 321 patients, 255 switched from NTZ to rituximab/ocrelizumab, 52 to fingolimod, and 14 to alemtuzumab, with higher annualized relapse rate (ARR) in fingolimod switchers (0.193) compared with rituximab/ocrelizumab or alemtuzumab (0.028 and 0.032, respectively). Fingolimod switchers also had increased disability progression (p = 0.014) and a higher proportion developed magnetic resonance imaging (MRI) lesions compared with rituximab/ocrelizumab (62.9% vs. 13.0%, p < 0.001, and 66.6% vs. 24.0%, p < 0.001, respectively). Mean drug survival favored rituximab/ocrelizumab or alemtuzumab over fingolimod (p < 0.001). CONCLUSION: Our study shows superior effectiveness of rituximab/ocrelizumab and alemtuzumab compared with fingolimod in stable patients switching from NTZ due to JC virus antibody positivity.

Exploring the effects of extended interval dosing of natalizumab and drug concentrations on brain atrophy in multiple sclerosis.

BACKGROUND: Extended interval dosing (EID) of natalizumab treatment is increasingly used in multiple sclerosis. Besides the clear anti-inflammatory effect, natalizumab is considered to have neuroprotective properties as well. OBJECTIVES: This study aimed to study the longitudinal effects of EID compared to standard interval dosing (SID) and natalizumab drug concentrations on brain atrophy. METHODS: Patients receiving EID or SID of natalizumab with a minimum radiological follow-up of 2 years were included. Changes in brain atrophy measures over time were derived from clinical routine 3D-Fluid Attenuated Inversion Recovery (FLAIR)-weighted magnetic resonance imaging (MRI) scans using SynthSeg. RESULTS: We found no differences between EID (n = 32) and SID (n = 50) for whole brain (-0.21% vs -0.16%, p = 0.42), ventricular (1.84% vs 1.13%, p = 0.24), and thalamic (-0.32% vs -0.32%, p = 0.97) annualized volume change over a median follow-up of 3.2 years. No associations between natalizumab drug concentration and brain atrophy rate were found. CONCLUSION: We found no clear evidence that EID compared to SID or lower natalizumab drug concentrations have a negative impact on the development of brain atrophy over time.

Non-inferiority analysis of subcutaneous versus intravenous 300 mg monthly natalizumab administration: A post hoc analysis of the REFINE study.

To quantify the probability that monthly intravenous (IV) and subcutaneous (SC) natalizumab (NTZ) had similar efficacy in relapsing-remitting multiple sclerosis (RRMS), non-inferiority of efficacy of NTZ-SC versus NTZ-IV on combined MRI unique active lesions number (CUAL) was explored re-analysing the REFINE data set. Non-inferiority margins were selected equal to 25%/33%/50% fractions of the effect size of NTZ-IV versus placebo observed in the AFFIRM study. Ninety-nine RRMS were included. NTZ-SC resulted not inferior to NTZ-IV on CUAL for all margins at 2.5% significance level, and, in worst-case scenario, its effect over NTZ-IV did not exceed 3.5% (or 2.8%) of the effect of NTZ-IV versus placebo.

Natalizumab reduces loss of gray matter and thalamic volume in patients with relapsing-remitting multiple sclerosis: A post hoc analysis from the randomized, placebo-controlled AFFIRM trial.

BACKGROUND: Loss of brain gray matter fractional volume predicts multiple sclerosis (MS) progression and is associated with worsening physical and cognitive symptoms. Within deep gray matter, thalamic damage is evident in early stages of MS and correlates with physical and cognitive impairment. Natalizumab is a highly effective treatment that reduces disease progression and the number of inflammatory lesions in patients with relapsing-remitting MS (RRMS). OBJECTIVE: To evaluate the effect of natalizumab on gray matter and thalamic atrophy. METHODS: A combination of deep learning-based image segmentation and data augmentation was applied to MRI data from the AFFIRM trial. RESULTS: This post hoc analysis identified a reduction of 64.3% (p = 0.0044) and 64.3% (p = 0.0030) in mean percentage gray matter volume loss from baseline at treatment years 1 and 2, respectively, in patients treated with natalizumab versus placebo. The reduction in thalamic fraction volume loss from baseline with natalizumab versus placebo was 57.0% at year 2 (p < 0.0001) and 41.2% at year 1 (p = 0.0147). Similar findings resulted from analyses of absolute gray matter and thalamic fraction volume loss. CONCLUSION: These analyses represent the first placebo-controlled evidence supporting a role for natalizumab treatment in mitigating gray matter and thalamic fraction atrophy among patients with RRMS. CLINICALTRIALS.GOV IDENTIFIER: NCT00027300URL: https://clinicaltrials.gov/ct2/show/NCT00027300.

The impact of social distancing measures on anti-JC virus serostatus changes before and during the COVID-19 pandemic in US patients with multiple sclerosis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic offered an epidemiological opportunity to evaluate if isolation and masking affected John Cunningham (JC) virus transmission. OBJECTIVE: This study aimed to assess the proportion of natalizumab-treated patients who converted to a positive anti-JCV antibody serostatus before and during the pandemic. METHODS: Data from TYSABRI Outreach: Unified Commitment to Health (TOUCH) for 22,375 US patients treated with natalizumab with anti-JCV antibody records were assessed in epochs annually from 2017 to 2022. RESULTS: Pre-pandemic anti-JCV antibody serostatus change was observed for 7.4%-7.7%. During the first and second years of the pandemic, 7.3% and 7.2% of patients' serostatus changed, respectively. CONCLUSION: The proportion of patients with anti-JCV antibody serostatus change did not significantly differ during the first 2 years of the pandemic compared with prior years. In contrast to seasonal influenza, masking and social distancing had no discernable effect on JCV serostatus change.

Rates of John Cunningham virus seroconversion greatly reduced in natalizumab-treated patients during COVID-19-related lockdowns.

BACKGROUND AND PURPOSE: This study was undertaken to retrospectively compare rates of John Cunningham virus (JCV) seroconversion in natalizumab-treated patients before and during COVID-19-related community restrictions. Natalizumab is highly effective therapy for relapsing-remitting multiple sclerosis. Prolonged exposure to natalizumab in JCV-positive patients can cause progressive multifocal leukoencephalopathy, a potentially fatal brain infection. Serial assessment of JCV status is required for patients receiving natalizumab. METHODS: Patients receiving natalizumab at the Royal Melbourne Hospital were assessed for change in JCV serostatus and duration of exposure to natalizumab in two discrete time periods: from 1 February 2012 until 1 February 2017 ("pre-COVID"; n = 128) and from 1 April 2020 until 12 October 2022 ("COVID"; n = 214). A Poisson regression model adjusted for age at natalizumab commencement and sex was used to model seroconversion rate between the two time periods. RESULTS: The pre-COVID JCV seroconversion rate among natalizumab-treated patients at the Royal Melbourne Hospital was 9.08%. Conversely, we found a precipitous decline in JCV seroconversion during COVID lockdown. Annualized seroconversion during COVID-19-related restrictions was 2.01%. The annualized seroconversion rate was 4.7 times higher during the pre-COVID-19 period (95% confidence interval = 2.96-7.45, p < 0.0001) compared to the annualized seroconversion rate during COVID lockdown. Males had a 2× higher rate of seroconversion compared to females. CONCLUSIONS: JCV seroconversion among natalizumab-treated patients was markedly lower during COVID-19-related community restrictions. Restrictions observed in Melbourne were among the longest and most comprehensive implemented worldwide. This suggests the presence of modifiable risk factors that could lower rates of JCV seroconversion among natalizumab-treated patients.

Post-Partum Clinical and Patient-Reported Outcome Changes in Mothers with Multiple Sclerosis: Findings from the NAPPREMS Study.

Background and Objective: Pregnancy in mothers with multiple sclerosis (MS) commonly results in significant changes in disease activity and changes in clinical care, including the discontinuation of disease modifying therapy (DMT). This study aimed at understanding the clinical and patient-reported outcomes (PROs) before, during and 1-year after delivery. Materials and Methods: A total of 30 pregnant mothers with MS were recruited as part of the study. Clinical (relapse activity and disability changes), PRO information and MRI outcomes were collected on four separate visits: one baseline visit-0-30 days post-delivery; and 3 follow-up visits at week 24, week 36 and week 52 from the baseline. PRO was assessed using a validated questionnaire called the Fatigue Scale for Motor and Cognitive Function (FSMC). The MRI scans were analyzed, and the count of new T2 lesions and/or contrast-enhancing lesions was determined. Results: The average time between delivery and the start of DMT was 142.5 days. Relapse activity before the pregnancy was numerically linked with the activity during the pregnancy, where up to 57.1% of the activity during pregnancy occurred in pwMS with previously active disease before conception (statistically trending with p = 0.073). The relapse activity after the pregnancy occurred twice as often in pwMS whose MS was clinically active before conception. All five pwMS who experienced a relapse prior to the pregnancy experienced worsening in their physical PRO domain. Conclusions: Pre-pregnancy activity is crucial in the screening of mothers with MS at risk for post-partum relapses, worsening of clinical disability and/or PRO measures. A post-partum MS period may benefit from the routine PRO utilization and screening for its worsening. The inflammatory activity during pregnancy was not associated with short-term disease progression.

High levels of endothelial ICAM-1 prohibit natalizumab mediated abrogation of CD4+ T cell arrest on the inflamed BBB under flow in vitro.

INTRODUCTION: The humanized anti-α4 integrin blocking antibody natalizumab (NTZ) is an effective treatment for relapsing-remitting multiple sclerosis (RRMS) that is associated with the risk of progressive multifocal leukoencephalopathy (PML). While extended interval dosing (EID) of NTZ reduces the risk for PML, the minimal dose of NTZ required to maintain its therapeutic efficacy remains unknown. OBJECTIVE: Here we aimed to identify the minimal NTZ concentration required to inhibit the arrest of human effector/memory CD4+ T cell subsets or of PBMCs to the blood-brain barrier (BBB) under physiological flow in vitro. RESULTS: Making use of three different human in vitro BBB models and in vitro live-cell imaging we observed that NTZ mediated inhibition of α4-integrins failed to abrogate T cell arrest to the inflamed BBB under physiological flow. Complete inhibition of shear resistant T cell arrest required additional inhibition of ß2-integrins, which correlated with a strong upregulation of endothelial intercellular adhesion molecule (ICAM)-1 on the respective BBB models investigated. Indeed, NTZ mediated inhibition of shear resistant T cell arrest to combinations of immobilized recombinant vascular cell adhesion molecule (VCAM)-1 and ICAM-1 was abrogated in the presence of tenfold higher molar concentrations of ICAM-1 over VCAM-1. Also, monovalent NTZ was less potent than bivalent NTZ in inhibiting T cell arrest to VCAM-1 under physiological flow. In accordance with our previous observations ICAM-1 but not VCAM-1 mediated T cell crawling against the direction of flow. CONCLUSION: Taken together, our in vitro observations show that high levels of endothelial ICAM-1 abrogate NTZ mediated inhibition of T cell interaction with the BBB. EID of NTZ in MS patients may thus require consideration of the inflammatory status of the BBB as high levels of ICAM-1 may provide an alternative molecular cue allowing for pathogenic T cell entry into the CNS in the presence of NTZ.

Comparative effectiveness of natalizumab on cognition in multiple sclerosis: A cohort study.

BACKGROUND: Cognitive impairment occurs in 40%-70% of persons with multiple sclerosis (MS). OBJECTIVE: To examine the effectiveness of natalizumab compared with other disease-modifying treatments (DMTs) on improving cognition as measured by the Symbol Digit Modalities Test (SDMT). METHODS: Data were collected as part of Swedish nationwide phase IV surveillance studies (2007-2020). An increase in SDMT score by ⩾10% of the difference between maximum score possible (110) and the baseline value was defined as cognitive improvement. The likelihood of improvement was compared between natalizumab-treated individuals and individuals treated with other DMTs using mixed effect logistic regression. Trend in odds of improvement was investigated using slope analyses. RESULTS: We included 2100 persons with relapsing-remitting MS treated with natalizumab and 2622 persons treated with other DMTs. At 6 months, 45% reached improvement. The natalizumab group showed largest odds of improvement during follow-up (odds ratio: 2.3, 95% confidence interval (CI): 1.5-3.5). The odds of improvement increased by 7% (95% CI: 6-7) per month of natalizumab treatment. The equivalent estimate was 4% (95% CI: 2-5) for other monoclonal antibodies and nonsignificant for oral or platform therapies. CONCLUSION: Treatment with natalizumab or other monoclonal antibodies is associated with a significantly faster likelihood of cognitive improvement than platform or oral DMTs.

Evaluating the efficacy and safety of transitioning patients with multiple sclerosis from natalizumab to ocrelizumab (OCTAVE).

INTRODUCTION: Natalizumab is associated with a risk of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients infected with John Cunningham virus (JCV). Ocrelizumab has demonstrated efficacy to treat MS; however, its safety in patients previously treated with natalizumab is unclear. OBJECTIVE: To evaluate the safety and efficacy of ocrelizumab in patients with relapsing MS (RMS) previously treated with natalizumab. METHODS: Clinically and radiographically stable RMS patients, ages 18-65 treated with natalizumab for ⩾ 12 months, were enrolled in the study and initiated ocrelizumab 4-6 weeks after their final dose of natalizumab. Relapse assessment, expanded disability status scale, and brain magnetic resonance imaging (MRI) were performed prior to starting ocrelizumab and at months 3, 6, 9, and 12. RESULTS: Forty-three patients were enrolled, and 41 (95%) completed the study. Two patients had a relapse while on ocrelizumab, one at month 9 and the other at month 12, without changes on brain MRI. Two additional patients had new brain MRI lesions detected at month 3, with no new symptoms. Thirteen serious adverse events (SAEs) were recorded, four of which were considered possibly related to ocrelizumab. CONCLUSION: Overall, our study indicates clinical and MRI stability for most patients transitioning from natalizumab to ocrelizumab. CLINICALTRIALS.GOV IDENTIFIER: NCT03157830.

Fingerprick blood samples to measure serum natalizumab concentrations.

BACKGROUND: Natalizumab via subcutaneous administration was recently approved for patients with multiple sclerosis. OBJECTIVE: In light of personalized extended dosing, in which treatment intervals are prolonged to a concentration cut-off, it would be preferable to measure natalizumab drug concentrations in capillary blood. METHODS: In this cross-sectional study in patients treated with intravenous (IV) natalizumab, capillary blood samples by fingerprick and venous blood samples were collected in 30 participants prior to IV administration of natalizumab. RESULTS: Natalizumab concentrations were similar with a mean bias of -0.36 µg/mL (95% CI: 1.3 to -2 µg/mL). CONCLUSIONS: This study shows that physicians can monitor natalizumab drug concentrations by a fingerprick, which could be used for personalized extended dosing.

Serum glial fibrillary acidic protein in natalizumab-treated relapsing-remitting multiple sclerosis: An alternative to neurofilament light.

BACKGROUND: There is a need in Relapsing-Remitting Multiple Sclerosis (RRMS) treatment for biomarkers that monitor neuroinflammation, neurodegeneration, treatment response, and disease progression despite treatment. OBJECTIVE: To assess the value of serum glial fibrillary acidic protein (sGFAP) as a biomarker for clinical disease progression and brain volume measurements in natalizumab-treated RRMS patients. METHODS: sGFAP and neurofilament light (sNfL) were measured in an observational cohort of natalizumab-treated RRMS patients at baseline, +3, +12, and +24 months and at the last sample follow-up (median 5.17 years). sGFAP was compared between significant clinical progressors and non-progressors and related to magnetic resonance imaging (MRI)-derived volumes of the whole brain, ventricle, thalamus, and lesion. The relationship between sGFAP and sNfL was assessed. RESULTS: A total of 88 patients were included, and 47.7% progressed. sGFAP levels at baseline were higher in patients with gadolinium enhancement (1.3-fold difference, p = 0.04) and decreased in 3 months of treatment (adj. p < 0.001). No association was found between longitudinal sGFAP levels and progressor status. sGFAP at baseline and 12 months was significantly associated with normalized ventricular (positively), thalamic (negatively), and lesion volumes (positively). Baseline and 12-month sGFAP predicted annualized ventricle volume change rate after 1 year of treatment. sGFAP correlated with sNfL at baseline (p < 0.001) and last sample follow-up (p < 0.001) but stabilized earlier. DISCUSSION: sGFAP levels related to MRI markers of neuroinflammation and neurodegeneration.

Serum neurofilament light levels in natalizumab-treated patients with multiple sclerosis who switch to extended interval dosing from every-4-week dosing in real-world clinical practice.

BACKGROUND: Serum levels of neurofilament light chain (sNfL) are a potentially useful biomarker for assessing the efficacy of multiple sclerosis (MS) treatments. OBJECTIVE: To compare levels of sNfL in patients with MS who switched from natalizumab every 4 weeks (Q4W) to extended interval dosing (EID) and patients who remained on Q4W dosing in real-world clinical practice. METHODS: This was a retrospective analysis of samples from patients treated with natalizumab from 2010 to 2015 at a single center in the United States. Levels of sNfL were compared in patients who stayed on Q4W dosing or who switched to EID (parallel-arm analyses) and during Q4W and EID periods in patients who switched to EID (pre- and post-switch analyses). RESULTS: The analysis included 139 patients (Q4W: n = 79; EID: n = 60). After adjustment, levels of sNfL did not significantly differ between patients who remained on Q4W dosing and those who switched to EID in parallel-arm analyses (adjusted Q4W-EID difference = 0.51 pg/mL; p = 0.60) or pre- and post-switch analyses (adjusted difference = 0.96 pg/mL; p = 0.10). CONCLUSION: These sNfL biomarker results suggest that the effectiveness of natalizumab is maintained in patients who switch from Q4W dosing to EID.

Long-term effects of natalizumab on MRI activity and clinical outcomes in Japanese patients with relapsing-remitting multiple sclerosis.

BACKGROUND: Relapsing-remitting multiple sclerosis (RRMS) is the most common phenotype of multiple sclerosis (MS), and its active stage is characterized by active T2 lesions with or without gadolinium (Gd) enhancement on magnetic resonance imaging (MRI). Natalizumab is indicated as monotherapy in adults with active RRMS in Japan. The main objective of this study was to investigate the long-term effect of natalizumab on disease progression in Japanese patients with RRMS using MRI data. METHODS: This retrospective, chart review study was conducted at a single center in Japan. The main study outcome was the yearly proportion of patients with active T2-weighted image lesions detected with or without Gd enhancement on brain MRI (incidence rate) after treatment initiation for up to 5 years. Additional endpoints included annual relapse rate (ARR) and expanded disability status scale (EDSS) score. RESULTS: This study included data from 85 patients with RRMS who had received natalizumab for ≥ 1 year; of these, 65 (76.5%) were female and the mean ± standard deviation (SD) age at baseline was 37.5 ± 10.0 years. The incidence rate of active T2 lesions was 52.9% (45/85) in the year prior to natalizumab treatment (Year - 1), which decreased to 2.4% and 1.6% in Year 0.5-1.5 and Year 1.5-2.5, respectively. No active T2 lesions were detected in Year 2.5-5.5 in patients who continued natalizumab treatment. EDSS score was stable, improved, and worsened in 61.8%, 26.3%, and 11.8% of patients, respectively. The median (range) EDSS score was 2.0 (0.0-7.0) at baseline (n = 85) and remained within a similar range (median score between 1.0 and 2.25 during Years 1-5). ARR decreased from 1.12 relapses per year at baseline to 0.12 relapses per year during Year 1 and remained below 0.15 relapses per year up to Year 5. CONCLUSION: The results of this first long-term study evaluating the effect of natalizumab on MRI activity and clinical outcomes in Japanese patients with RRMS suggest that natalizumab markedly reduced disease activity and maintained effectiveness over several years.

Concomitant diagnosis of multiple sclerosis and human immunodeficiency virus (HIV) infection: case report and the review of literature.

BACKGROUND: To date, few cases of multiple sclerosis (MS) patients with concomitant Human Immunodeficiency Virus (HIV) infection have been described. However, none of the previously described cases has been treated with Natalizumab, probably due to the increasing risk of progressive multifocal leukoencephalopathy (PML). CASE: We report the case of a patient concomitantly diagnosed for HIV infection and MS treated with combined antiretroviral therapy (cART) and Natalizumab for 19 months, without clinical or radiological MS activity. CONCLUSIONS: Our case might suggest considering Natalizumab in patients with concomitant HIV infection, especially for those with significant disease activity requiring a high efficacy disease modifying treatment.

The comparative effectiveness of fingolimod, natalizumab, and ocrelizumab in relapsing-remitting multiple sclerosis.

BACKGROUND: Fingolimod, natalizumab, and ocrelizumab are commonly used in the second-line treatment of relapsing-remitting multiple sclerosis (RRMS). However, these have only been compared in observational studies, not in controlled trials, with limited and inconclusive results being reported. A comparison of their effect on relapse and disability in a real-world setting is therefore needed. OBJECTIVES: The objective of this study was to compare the efficacy of fingolimod, natalizumab, and ocrelizumab in reducing disease activity in RRMS. METHODS: This multicenter, retrospective observational study was carried out with prospectively collected data from 16 centers. All consecutive RRMS patients treated with fingolimod, natalizumab, and ocrelizumab were included. Data for relapses, Expanded Disability Status Scale (EDSS) scores, and brain magnetic resonance imaging (MRI) scans were collected. Patients were matched using propensity scores. Annualized relapse rates (ARR), time to first relapse, and disability accumulation were compared. RESULTS: Propensity score matching retained 736 patients in the fingolimod versus 370 in the natalizumab groups, 762 in the fingolimod versus 434 in the ocrelizumab groups, and 310 in the natalizumab versus 310 in the ocrelizumab groups for final analyses. Mean ARR decreased markedly from baseline after treatment in all three treatment groups. Mean on-treatment ARR was lower in natalizumab-treated patients (0.09, 95% confidence interval (CI), 0.07-0.12) than in those treated with fingolimod (0.17, 0.15-0.19, p<0.001), ocrelizumab (0.08, 0.06-0.11), and fingolimod (0.14, 0.12-0.16, p=0.001). No significant difference was observed in mean on-treatment ARR between patients treated with natalizumab (0.08, 0.06-0.11) and ocrelizumab (0.09, 0.07-0.12, p=0.54). Compared to fingolimod, the natalizumab and ocrelizumab groups exhibited a higher percentage of relapse-free patients and a lower percentage of MRI-active patients at year 1. No significance differences in disability accumulation were determined between the therapies. CONCLUSION: Natalizumab and ocrelizumab exhibited similar effects on relapse control, and both were associated with better relapse control than fingolimod. The effects of the three therapies on disability outcomes were similar.

Clinical and economic evaluations of natalizumab, rituximab, and ocrelizumab for the management of relapsing-remitting multiple sclerosis in Saudi Arabia.

INTRODUCTION: The advent of new disease-modifying therapies (DMTs), such as monoclonal antibodies (mAbs), resulted in significant changes in the treatment guidelines for Multiple sclerosis (MS) and improvement in the clinical outcomes. However, mAbs, such as rituximab, natalizumab, and ocrelizumab, are expensive with variable effectiveness rates. Thus, the present study aimed to compare the direct medical cost and consequences (e.g., clinical relapse, disability progression, and new MRI lesions) between rituximab and natalizumab in managing relapsing-remitting multiple sclerosis (RRMS) in Saudi Arabia. Also, the study aimed to explore the cost and consequence of ocrelizumab in managing RRMS as a second-choice treatment. METHODS: The electronic medical records (EMRs) of patients with RRMS were retrospectively reviewed to retrieve the patients' baseline characteristics and disease progression from two tertiary care centers in Riyadh, Saudi Arabia. Biologic-naïve patients treated with rituximab or natalizumab or those switched to ocrelizumab and treated for at least six months were included in the study. The effectiveness rate was defined as no evidence of disease activity (NEDA-3) (i.e., absence of new T2 or T1 gadolinium (Gd) lesions as demonstrated by the Magnetic Resonance Imaging (MRI), disability progression, and clinical relapses), while the direct medical costs were estimated based on the utilization of healthcare resources. In addition, bootstrapping with 10,000 replications and inverse probability weighting based on propensity score were conducted. RESULTS: Ninety-three patients met the inclusion criteria and were included in the analysis (natalizumab (n = 50), rituximab (n = 26), ocrelizumab (n = 17)). Most of the patients were otherwise healthy (81.72%), under 35 years of age (76.34%), females (61.29%), and on the same mAb for more than one year (83.87%). The mean effectiveness rates for natalizumab, rituximab, and ocrelizumab were 72.00%, 76.92%, and 58.83%, respectively. Natalizumab mean incremental cost compared to rituximab was $35,383 (95% CI: $25,401.09- $49,717.92), and its mean effectiveness rate was 4.92% lower than rituximab (95% CI: -30-27.5) with 59.41% confidence level that rituximab will be dominant. CONCLUSIONS: Rituximab seems to be more effective and is less costly than natalizumab in the management of RRMS. Ocrelizumab does not seem to slow the rates of disease progression among patients previously treated with natalizumab.