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Cell-cell interactions in the central nervous system play important roles in neurologic diseases. However, little is known about the specific molecular pathways involved, and methods for their systematic identification are limited. Here, we developed a forward genetic screening platform that combines CRISPR-Cas9 perturbations, cell coculture in picoliter droplets, and microfluidic-based fluorescence-activated droplet sorting to identify mechanisms of cell-cell communication. We used SPEAC-seq (systematic perturbation of encapsulated associated cells followed by sequencing), in combination with in vivo genetic perturbations, to identify microglia-produced amphiregulin as a suppressor of disease-promoting astrocyte responses in multiple sclerosis preclinical models and clinical samples. Thus, SPEAC-seq enables the high-throughput systematic identification of cell-cell communication mechanisms.

Multiple sclerosis is a chronic inflammatory disease of the central nervous system1. Astrocytes are heterogeneous glial cells that are resident in the central nervous system and participate in the pathogenesis of multiple sclerosis and its model experimental autoimmune encephalomyelitis2,3. However, few unique surface markers are available for the isolation of astrocyte subsets, preventing their analysis and the identification of candidate therapeutic targets; these limitations are further amplified by the rarity of pathogenic astrocytes. Here, to address these challenges, we developed focused interrogation of cells by nucleic acid detection and sequencing (FIND-seq), a high-throughput microfluidic cytometry method that combines encapsulation of cells in droplets, PCR-based detection of target nucleic acids and droplet sorting to enable in-depth transcriptomic analyses of cells of interest at single-cell resolution. We applied FIND-seq to study the regulation of astrocytes characterized by the splicing-driven activation of the transcription factor XBP1, which promotes disease pathology in multiple sclerosis and experimental autoimmune encephalomyelitis4. Using FIND-seq in combination with conditional-knockout mice, in vivo CRISPR-Cas9-driven genetic perturbation studies and bulk and single-cell RNA sequencing analyses of samples from mouse experimental autoimmune encephalomyelitis and humans with multiple sclerosis, we identified a new role for the nuclear receptor NR3C2 and its corepressor NCOR2 in limiting XBP1-driven pathogenic astrocyte responses. In summary, we used FIND-seq to identify a therapeutically targetable mechanism that limits XBP1-driven pathogenic astrocyte responses. FIND-seq enables the investigation of previously inaccessible cells, including rare cell subsets defined by unique gene expression signatures or other nucleic acid markers.

BackgroundMagnetic resonance imaging (MRI) measurements of gray matter (GM) atrophy and magnetization transfer ratio (MTR; correlate of myelination) may provide better insights than conventional MRI regarding brain tissue integrity/myelination in multiple sclerosis (MS).ObjectiveTo examine the effect of siponimod in the EXPAND trial on whole-brain and GM atrophy, newly formed normalized magnetization transfer ratio (nMTR) lesions, and nMTR-assessed integrity of normal-appearing brain tissue (NABT), cortical GM (cGM), and normal-appearing white matter (NAWM).MethodsPatients with secondary progressive multiple sclerosis (SPMS) received siponimod (2 mg/day; n =1037) or placebo (n = 523). Endpoints included percentage change from baseline to months 12/24 in whole-brain, cGM, and thalamic volumes; change in nMTR from baseline to months 12/24 in NABT, cGM, and NAWM; MTR recovery in newly formed lesions.ResultsCompared with placebo, siponimod significantly reduced progression of whole-brain and GM atrophy over 12/24 months, and was associated with improvements in brain tissue integrity/myelination within newly formed nMTR lesions and across NABT, cGM, and NAWM over 24 months. Effects were consistent across age, disease duration, inflammatory activity subgroups, and disease severity.ConclusionSiponimod reduced brain tissue damage in patients with SPMS as evidenced by objective measures of brain tissue integrity/myelination. This is consistent with central nervous system (CNS) effects observed in preclinical models. ClinicalTrials.gov number: NCT01665144.

BackgroundSiponimod is a sphingosine 1-phosphate receptor modulator approved for active secondary progressive multiple sclerosis (aSPMS) in most countries; however, phase 3 EXPAND study data are from an SPMS population with/without disease activity. A need exists to characterize efficacy/safety of siponimod in aSPMS.MethodsPost hoc analysis of participants with aSPMS (≥ 1 relapse in 2 years before study and/or ≥ 1 T1 gadolinium-enhancing [Gd +] magnetic resonance imaging [MRI] lesions at baseline) receiving oral siponimod (2 mg/day) or placebo for up to 3 years in EXPAND.Endpoints3-month/6-month confirmed disability progression (3mCDP/6mCDP); 3-month confirmed ≥ 20% worsening in Timed 25-Foot Walk (T25FW); 6-month confirmed improvement/worsening in Symbol Digit Modalities Test (SDMT) scores (≥ 4-point change); T2 lesion volume (T2LV) change from baseline; number of T1 Gd + lesions baseline-month 24; number of new/enlarging (N/E) T2 lesions over all visits.ResultsData from 779 participants with aSPMS were analysed. Siponimod reduced risk of 3mCDP/6mCDP vs placebo (by 31%/37%, respectively; p

BackgroundSiponimod significantly reduced the risk of confirmed disability progression (CDP), worsening in cognitive processing speed (CPS), relapses, and magnetic resonance imaging (MRI) measures of brain atrophy and inflammation versus placebo in secondary progressive multiple sclerosis (SPMS) patients in the Phase 3 EXPAND study.ObjectiveThe aim of this study was to assess long-term efficacy and safety of siponimod 2 mg/day from the EXPAND study including the extension part, up to > 5 years.MethodsIn the open-label extension part, participants receiving placebo during the core part were switched to siponimod (placebo-siponimod group) and those on siponimod continued the same treatment (continuous siponimod group).ResultsContinuous siponimod reduced the risk of 6-month CDP by 22% (hazard ratio (HR) (95% confidence interval (CI)): 0.78 (0.66-0.92) p = 0.0026) and 6-month confirmed worsening in CPS by 23% (HR (95% CI): 0.77 (0.65-0.92) p = 0.0047) versus the placebo-siponimod group. Sustained efficacy on annualized relapse rate, total and regional brain atrophy, and inflammatory disease activity was also observed. No new, unexpected safety signals for siponimod were identified over the long term.ConclusionThe sustained efficacy and consistent long-term safety profile of siponimod up to > 5 years support its clinical utility for long-term treatment of SPMS. Benefits in the continuous siponimod versus placebo-siponimod group highlight the significance of earlier treatment initiation.Trial registration numberNCT01665144.

Background and purposeReaching Expanded Disability Status Scale (EDSS) ≥7.0 represents the requirement for a wheelchair. Here we (i) assess the effect of ocrelizumab on time to EDSS ≥7.0 over the ORATORIO (NCT01194570) double-blind and extended controlled periods (DBP+ECP), (ii) quantify likely long-term benefits by extrapolating results, and (iii) assess the plausibility of extrapolations using an independent real-world cohort (MSBase registry; ACTRN12605000455662).MethodsPost hoc analyses assessing time to 24-week confirmed EDSS ≥7.0 in two cohorts of patients with primary progressive multiple sclerosis (baseline EDSS 3.0-6.5) were investigated in ORATORIO and MSBase.ResultsIn the ORATORIO DBP+ECP, ocrelizumab reduced the risk of 24-week confirmed EDSS ≥7.0 (hazard ratio = 0.54, 95% confidence interval [CI]: 0.31-0.92; p = 0.022). Extrapolated median time to 24-week confirmed EDSS ≥7.0 was 12.1 and 19.2 years for placebo and ocrelizumab, respectively (7.1-year delay [95% CI: -4.3 to 18.4]). In MSBase, the median time to 24-week confirmed EDSS ≥7.0 was 12.4 years.ConclusionsCompared with placebo, ocrelizumab significantly delayed time to 24-week confirmed wheelchair requirement in ORATORIO. The plausibility of the extrapolated median time to reach this milestone in the placebo group was supported by observed real-world data from MSBase. Extrapolated benefits for ocrelizumab over placebo could represent a truly meaningful delay in loss of ambulation and independence.

Background and purposeRequiring a walking aid is a fundamental milestone in multiple sclerosis (MS), represented by an Expanded Disability Status Scale (EDSS) score ≥6.0. In the present study, we assess the effect of ocrelizumab (OCR) on time to EDSS score ≥6.0 in relapsing MS.MethodsTime to EDSS score ≥6.0 confirmed for ≥24 and ≥48 weeks was assessed over the course of 6.5 years (336 weeks) in the double-blind period (DBP) and open-label extension (OLE) period of the OPERA I (NCT01247324) and OPERA II (NCT01412333) studies.ResultsTime to reach EDSS score ≥6.0 was significantly delayed in those initially randomized to OCR versus interferon. Over 6.5 years, the risk of requiring a walking aid confirmed for ≥24 weeks was 34% lower among those who initiated OCR earlier versus delayed treatment (average hazard ratio [HR] DBP + OLE 0.66, 95% confidence interval [CI] 0.45-0.95; p = 0.024); the risk of requiring a walking aid confirmed for ≥48 weeks was 46% lower (average HR DBP+OLE 0.54, 95% CI 0.35-0.83; p = 0.004).ConclusionThe reduced risk of requiring a walking aid in earlier initiators of OCR demonstrates the long-term implications of earlier highly effective treatment.

BackgroundIn multiple sclerosis, impact of treatment on disability progression can be confounded if treatment also reduces relapses.ObjectiveTo distinguish siponimod's direct effects on disability progression from those on relapses in the EXPAND phase 3 trial.MethodsThree estimands, one based on principal stratum and two on hypothetical scenarios (no relapses, or equal relapses in both treatment arms), were defined to determine the extent to which siponimod's effects on 3- and 6-month confirmed disability progression were independent of on-study relapses.ResultsPrincipal stratum analysis estimated that siponimod reduced the risk of 3- and 6-month confirmed disability progression by 14%-20% and 29%-33%, respectively, compared with placebo in non-relapsing patients. In the hypothetical scenarios, risk reductions independent of relapses were 14%-18% and 23% for 3- and 6-month confirmed disability progression, respectively.ConclusionBy controlling the confounding impact of on-study relapses on confirmed disability progression, these statistical approaches provide a methodological framework to assess treatment effects on disability progression in relapsing and non-relapsing patients. The analyses support that siponimod may be useful for treating secondary progressive multiple sclerosis in patients with or without relapses.

BackgroundIn multiple sclerosis, impact of treatment on disability progression can be confounded if treatment also reduces relapses.ObjectiveTo distinguish siponimod's direct effects on disability progression from those on relapses in the EXPAND phase 3 trial.MethodsThree estimands, one based on principal stratum and two on hypothetical scenarios (no relapses, or equal relapses in both treatment arms), were defined to determine the extent to which siponimod's effects on 3- and 6-month confirmed disability progression were independent of on-study relapses.ResultsPrincipal stratum analysis estimated that siponimod reduced the risk of 3- and 6-month confirmed disability progression by 14%-20% and 29%-33%, respectively, compared with placebo in non-relapsing patients. In the hypothetical scenarios, risk reductions independent of relapses were 14%-18% and 23% for 3- and 6-month confirmed disability progression, respectively.ConclusionBy controlling the confounding impact of on-study relapses on confirmed disability progression, these statistical approaches provide a methodological framework to assess treatment effects on disability progression in relapsing and non-relapsing patients. The analyses support that siponimod may be useful for treating secondary progressive multiple sclerosis in patients with or without relapses.

Artificial intelligence (AI)-based diagnostic algorithms have achieved ambitious aims through automated image pattern recognition. For neurological disorders, this includes neurodegeneration and inflammation. Scalable imaging technology for big data in neurology is optical coherence tomography (OCT). We highlight that OCT changes observed in the retina, as a window to the brain, are small, requiring rigorous quality control pipelines. There are existing tools for this purpose. Firstly, there are human-led validated consensus quality control criteria (OSCAR-IB) for OCT. Secondly, these criteria are embedded into OCT reporting guidelines (APOSTEL). The use of the described annotation of failed OCT scans advances machine learning. This is illustrated through the present review of the advantages and disadvantages of AI-based applications to OCT data. The neurological conditions reviewed here for the use of big data include Alzheimer disease, stroke, multiple sclerosis (MS), Parkinson disease, and epilepsy. It is noted that while big data is relevant for AI, ownership is complex. For this reason, we also reached out to involve representatives from patient organizations and the public domain in addition to clinical and research centers. The evidence reviewed can be grouped in a five-point expansion of the OSCAR-IB criteria to embrace AI (OSCAR-AI). The review concludes by specific recommendations on how this can be achieved practically and in compliance with existing guidelines.

ObjectiveNo evidence of progression or active disease (NEPAD) is a novel combined endpoint defined by the absence of both progression and inflammatory disease activity in primary progressive multiple sclerosis (PPMS). In the placebo-controlled phase III ORATORIO study (NCT01194570), we investigated the effect of ocrelizumab on this comprehensive outcome and its components in a post-hoc analysis.MethodsThe proportion of patients with NEPAD (no evidence of progression [NEP; no 12-week confirmed progression of ≥1/≥0.5 points on the Expanded Disability Status Scale if the baseline score was ≤5.5/>5.5 points, respectively; no 12-week confirmed progression of ≥20% on the Timed 25-Foot Walk test and 9-Hole Peg Test], no brain magnetic resonance imaging activity [no new/enlarging T2 lesions and no T1 gadolinium-enhancing lesions], and no protocol-defined relapse) from baseline to week 120 was determined in ocrelizumab- (600 mg; n = 465) and placebo-treated (n = 234) patients.ResultsThe majority of ORATORIO study patients with PPMS experienced clinical progression or evidence of disease activity. From baseline to week 120, 29.9% and 42.7% ocrelizumab-treated compared to 9.4% and 29.1% placebo-treated patients maintained NEPAD (relative risk [95% confidence interval {CI}], 3.15 [2.07-4.79]; p

ObjectiveNo evidence of progression or active disease (NEPAD) is a novel combined endpoint defined by the absence of both progression and inflammatory disease activity in primary progressive multiple sclerosis (PPMS). In the placebo-controlled phase III ORATORIO study (NCT01194570), we investigated the effect of ocrelizumab on this comprehensive outcome and its components in a post-hoc analysis.MethodsThe proportion of patients with NEPAD (no evidence of progression [NEP; no 12-week confirmed progression of ≥1/≥0.5 points on the Expanded Disability Status Scale if the baseline score was ≤5.5/>5.5 points, respectively; no 12-week confirmed progression of ≥20% on the Timed 25-Foot Walk test and 9-Hole Peg Test], no brain magnetic resonance imaging activity [no new/enlarging T2 lesions and no T1 gadolinium-enhancing lesions], and no protocol-defined relapse) from baseline to week 120 was determined in ocrelizumab- (600 mg; n = 465) and placebo-treated (n = 234) patients.ResultsThe majority of ORATORIO study patients with PPMS experienced clinical progression or evidence of disease activity. From baseline to week 120, 29.9% and 42.7% ocrelizumab-treated compared to 9.4% and 29.1% placebo-treated patients maintained NEPAD (relative risk [95% confidence interval {CI}], 3.15 [2.07-4.79]; p

BackgroundNo evidence of disease activity (NEDA; defined as no 12-week confirmed disability progression, no protocol-defined relapses, no new/enlarging T2 lesions and no T1 gadolinium-enhancing lesions) using a fixed-study entry baseline is commonly used as a treatment outcome in multiple sclerosis (MS).ObjectiveThe objective of this paper is to assess the effect of ocrelizumab on NEDA using re-baselining analysis, and the predictive value of NEDA status.MethodsNEDA was assessed in a modified intent-to-treat population (n = 1520) from the pooled OPERA I and OPERA II studies over various epochs in patients with relapsing MS receiving ocrelizumab (600 mg) or interferon beta-1a (IFN β-1a; 44 μg).ResultsNEDA was increased with ocrelizumab vs IFN β-1a over 96 weeks by 75% (p