Network Meta-analysis of Ravulizumab and Alternative Interventions for the Treatment of Neuromyelitis Optica Spectrum Disorder.

INTRODUCTION: Anti-aquaporin-4 antibody-positive (AQP4-Ab+) neuromyelitis optica spectrum disorder (NMOSD) is a complement-mediated autoimmune disease in which unpredictable and relapsing attacks on the central nervous system cause irreversible and accumulating damage. Comparative efficacy of new NMOSD therapies, such as ravulizumab, with established therapies is critical in making informed treatment decisions. METHODS: Efficacy of ravulizumab relative to established AQP4-Ab+ NMOSD treatments, such as eculizumab, inebilizumab, and satralizumab, was evaluated in a Bayesian network meta-analysis (NMA). Data were extracted from trials identified by a systematic literature review. The final evidence base consisted of 17 publications representing five unique and global studies (PREVENT, N-MOmentum, SAkuraSky, SAkuraStar, and CHAMPION-NMOSD). The primary endpoint was time-to-first relapse; other outcomes included annualized relapse rates (ARRs). RESULTS: For patients receiving monotherapy (monoclonal antibody only), ravulizumab was associated with a lower risk of relapse than inebilizumab (hazard ratio [HR] 0.09, 95% credible interval [CrI] 0.02, 0.57) or satralizumab (HR 0.08, 95% CrI 0.01, 0.55) and was comparable to eculizumab (HR 0.86, 95% Crl 0.16, 4.52). Ravulizumab + immunosuppressive therapy (IST) was associated with a lower risk of relapse than satralizumab + IST (HR 0.15, 95% CrI 0.03, 0.78); the comparison with eculizumab + IST suggested no difference. No patients treated with inebilizumab received background IST and were thus excluded from analysis. The ARR with ravulizumab monotherapy was 98% lower compared with inebilizumab (rate ratio [RR] 0.02, 95% Crl 0.00, 0.38) and satralizumab (RR 0.02, 95% Crl 0.00, 0.42) monotherapies. The ARR with ravulizumab ± IST showed the strongest treatment-effect estimates compared with other interventions. CONCLUSION: In the absence of head-to-head randomized controlled trials, NMA results suggest ravulizumab, a C5 inhibitor, is likely to be more effective in preventing NMOSD relapse in patients with AQP4-Ab+ NMOSD when compared with other treatments having different methods of action.

Anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder, also called AQP4-Ab+ NMOSD, is a rare autoimmune disease that causes repeated episodes of symptoms such as blindness, arm/leg weakness, painful spasms, vomiting, and hiccups, among other symptoms. Each episode can cause nervous system damage to worsen, making it more difficult to recover back to regular abilities. Repeated episodes are likely to cause permanent damage, such as blindness and paralysis. Medical treatments that reduce episodes also reduce the damage and the chances symptoms will become permanent. One treatment, ravulizumab, is being studied to treat adults with AQP4-Ab+ NMOSD. This analysis looked at information from published clinical studies to compare ravulizumab with three other treatments (eculizumab, inebilizumab, and satralizumab) to determine how well each treatment reduced NMOSD episodes. There are no studies that have tested all four treatments in one study. Here, the treatments were compared by a method used to estimate the likelihood of a treatment being better than the others. While all four treatments successfully reduced episodes in their own studies, this analysis predicts that ravulizumab would likely be best in preventing episodes compared with inebilizumab or satralizumab when used alone or in combination with other immunosuppressive treatments. These findings, in consideration along with other relevant factors such as cost, safety, dosing delivery method, and frequency of treatment, may help doctors and patients decide what is the best treatment option for each individual patient to prevent attacks in adults with AQP4-Ab+ NMOSD.

Safety and efficacy of daclizumab beta in patients with relapsing multiple sclerosis in a 5-year open-label study (EXTEND): final results following early termination.

BACKGROUND: EXTEND (NCT01797965), an open-label extension study, evaluated the safety and efficacy of daclizumab beta in participants with relapsing multiple sclerosis (MS) who had completed the randomized DECIDE study. METHODS: Eligible participants who received either daclizumab beta or interferon beta-1a in DECIDE received daclizumab beta 150 mg subcutaneously every 4 weeks for up to 5 years in EXTEND, followed by 24 weeks of post-dosing follow-up. Safety and tolerability were evaluated, as were clinical efficacy and magnetic resonance imaging (MRI). EXTEND was terminated ahead of schedule by the sponsors. RESULTS: The total safety population (N = 1203) received at least one dose of daclizumab beta in EXTEND. In the DECIDE and EXTEND combined periods, the median number of doses of daclizumab beta was 53; median time on treatment was 196 weeks. By 24 September 2018, the end of the study, 110/1203 (9%) participants had completed the protocol-specified treatment period and 1101/1203 (92%) had experienced an adverse event (AE). The most commonly reported AEs were MS relapse, nasopharyngitis, and upper respiratory tract infection. Hepatic events (18%), cutaneous events (45%), and infections (62%) were common treatment-related AEs. The incidence of serious AEs was 29%, most commonly MS relapse and infections. The incidence of immune-mediated disorders was 2%; three of seven were encephalitis. Two of six deaths were considered treatment related. In participants who received continuous daclizumab beta throughout DECIDE and EXTEND, the treatment effects on clinical and MRI outcomes were maintained for up to 6 years. CONCLUSION: Results from the combined DECIDE-EXTEND study elucidate outcomes of longer-term treatment with daclizumab beta in the clinical trial setting and underscore the importance of pharmacovigilance with immunomodulatory therapies in the real-world setting.

Long-term safety and efficacy of daclizumab beta in relapsing-remitting multiple sclerosis: 6-year results from the SELECTED open-label extension study.

OBJECTIVE: SELECTED, an open-label extension study, evaluated daclizumab beta treatment for up to 6 years in participants with relapsing multiple sclerosis who completed the randomized SELECT/SELECTION studies. We report final results of SELECTED. METHODS: Eligible participants who completed 1-2 years of daclizumab beta treatment in SELECT/SELECTION received daclizumab beta 150 mg subcutaneously every 4 weeks for up to 6 years in SELECTED. Safety assessments were evaluated for the SELECTED treatment period; efficacy data were evaluated from first dose of daclizumab beta in SELECT/SELECTION. RESULTS: Ninety percent (410/455) of participants who completed treatment in SELECTION enrolled in SELECTED. Within SELECTED, 69% of participants received daclizumab beta for > 3 years, 39% for > 4 years, and 9% for > 5 years; 87% of participants experienced an adverse event and 26% a serious adverse event (excluding multiple sclerosis relapse). No deaths occurred. Overall, hepatic events were reported in 25% of participants; serious hepatic events in 2%. There were no confirmed cases of immune-mediated encephalitis. Based on weeks from the first daclizumab beta dose in SELECT/SELECTION, adjusted annualized relapse rate (95% confidence interval) for weeks 0-24 was 0.21 (0.16-0.29) and remained low on continued treatment. Overall incidence of 24-week confirmed disability progression was 17.4%. Mean numbers of new/newly enlarging T2 hyperintense lesions remained low; percentage change in whole brain volume decreased over time. CONCLUSIONS: The effects of daclizumab beta on clinical and radiologic outcomes were sustained for up to ~ 8 years of treatment. No new safety concerns were identified in SELECTED. TRIAL REGISTRATION: Clinicaltrials.gov NCT01051349; first registered on January 15, 2010.

Lymphocyte reconstitution after DMF discontinuation in clinical trial and real-world patients with MS.

BACKGROUND: Delayed-release dimethyl fumarate (DMF) has demonstrated robust efficacy in treating patients with relapsing-remitting multiple sclerosis. Decreases in absolute lymphocyte count (ALC) are a well-known pharmacodynamic effect of DMF treatment, but lymphocyte recovery dynamics are not well characterized after discontinuation of DMF. METHODS: Data sources included the Biogen DMF integrated clinical trial data set, a retrospective US chart abstraction study, and data from MSBase. We assessed rate and time course of lymphocyte reconstitution after DMF discontinuation. RESULTS: The majority of patients who developed lymphopenia while treated with DMF and subsequently discontinued treatment experienced ALC reconstitution. The median time to reach ALC ≥0.8 × 109/L was 2-4 months after discontinuation for patients treated in real-world data sets; the median time to reach ALC ≥0.91 × 109/L was 2 months after discontinuation in DMF clinical trials. Severity of lymphopenia on treatment and decline in ALC within the first 6 months did not affect the ALC reconstitution rate after DMF discontinuation; rather, on-treatment lymphopenia duration influenced the reconstitution rate. In patients with severe, prolonged lymphopenia for ≥3 years, lymphocyte reconstitution to ≥0.91 × 109/L was 12-18 months vs 2-3 months in patients with lymphopenia persisting <6 months. CONCLUSIONS: The majority of patients who discontinued DMF due to lymphopenia experienced ALC reconstitution within 2-4 months following DMF discontinuation. This may help guide clinicians in managing patients who develop lymphopenia during DMF treatment. Prolonged lymphopenia on DMF treatment is associated with slow lymphocyte recovery after DMF discontinuation.

GABAB receptor association with the PDZ scaffold Mupp1 alters receptor stability and function.

gamma-Aminobutyric acid, type B (GABA(B)) receptors are heterodimeric G protein-coupled receptors that mediate slow inhibitory synaptic transmission in the central nervous system. To identify novel interacting partners that might regulate GABA(B) receptor (GABA(B)R) functionality, we screened the GABA(B)R2 carboxyl terminus against a recently created proteomic array of 96 distinct PDZ (PSD-95/Dlg/ZO-1 homology) domains. The screen identified three specific PDZ domains that exhibit interactions with GABA(B)R2: Mupp1 PDZ13, PAPIN PDZ1, and Erbin PDZ. Biochemical analysis confirmed that full-length Mupp1 and PAPIN interact with GABA(B)R2 in cells. Disruption of the GABA(B)R2 interaction with PDZ scaffolds by a point mutation to the carboxyl terminus of the receptor dramatically decreased receptor stability and attenuated the duration of GABA(B) receptor signaling. The effects of mutating the GABA(B)R2 carboxyl terminus on receptor stability and signaling were mimicked by small interference RNA knockdown of endogenous Mupp1. These findings reveal that GABA(B) receptor stability and signaling can be modulated via GABA(B)R2 interactions with the PDZ scaffold protein Mupp1, which may contribute to cell-specific regulation of GABA(B) receptors in the central nervous system.

The PDZ scaffold NHERF-2 interacts with mGluR5 and regulates receptor activity.

The two members of the group I metabotropic glutamate receptor family, mGluR1 and mGluR5, both couple to G(q) to mediate rises in intracellular calcium. The alternatively spliced C termini (CT) of mGluRs1 and 5are known to be critical for regulating receptor activity and to terminate in motifs suggestive of potential interactions with PDZ domains. We therefore screened the CTs of both mGluR1a and mGluR5 against a PDZ domain proteomic array. Out of 96 PDZ domains examined, the domain that bound most strongly to mGluR5-CT was the second PDZ domain of the Na(+)/H(+) exchanger regulatory factor 2 (NHERF-2). This interaction was confirmed by reverse overlay, and a single point mutation to the mGluR5-CT was found to completely disrupt the interaction. Full-length mGluR5 robustly associated with full-length NHERF-2 in cells, as assessed by co-immunoprecipitation and confocal microscopy experiments. In contrast, mGluR1a was found to bind NHERF-2 in vitro with a weaker affinity than mGluR5, and furthermore mGluR1a did not detectably associate with NHERF-2 in a cellular context. Immunohistochemical experiments revealed that NHERF-2 and mGluR5 exhibit overlapping patterns of expression in mouse brain, being found most abundantly in astrocytic processes and postsynaptic neuronal elements. In functional experiments, the interaction of NHERF-2 with mGluR5 in cells was found to prolong mGluR5-mediated calcium mobilization and to also potentiate mGluR5-mediated cell death, whereas coexpression of mGluR1a with NHERF-2 had no evident effects on mGluR1a functional activity. These observations reveal that NHERF-2 can selectively modulate mGluR5 signaling, which may contribute to cell-specific regulation of mGluR5 activity.

P2Y1 receptor signaling is controlled by interaction with the PDZ scaffold NHERF-2.

P2Y(1) purinergic receptors (P2Y(1)Rs) mediate rises in intracellular Ca(2+) in response to ATP, but the duration and characteristics of this Ca(2+) response are known to vary markedly in distinct cell types. We screened the P2Y(1)R carboxyl terminus against a recently created proteomic array of PDZ (PSD-95/Drosophila Discs large/ZO-1 homology) domains and identified a previously unrecognized, specific interaction with the second PDZ domain of the scaffold NHERF-2 (Na(+)/H(+) exchanger regulatory factor type 2). Furthermore, we found that P2Y(1)R and NHERF-2 associate in cells, allowing NHERF-2-mediated tethering of P2Y(1)R to key downstream effectors such as phospholipase Cbeta. Finally, we found that coexpression of P2Y(1)R with NHERF-2 in glial cells prolongs P2Y(1)R-mediated Ca(2+) signaling, whereas disruption of the P2Y(1)R-NHERF-2 interaction by point mutations attenuates the duration of P2Y(1)R-mediated Ca(2+) responses. These findings reveal that NHERF-2 is a key regulator of the cellular activity of P2Y(1)R and may therefore determine cell-specific differences in P2Y(1)R-mediated signaling.

alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype glutamate receptor (AMPAR) endocytosis is essential for N-methyl-D-aspartate-induced neuronal apoptosis.

Excessive activation of the N-methyl-d-aspartate subtype glutamate receptor (NMDAR) is thought to be involved in mediating programmed cell death (apoptosis) in numerous central nervous diseases. However, the underlying mechanisms remain unknown. We report here that stimulation of NMDARs activates intracellular signaling cascades leading to apoptosis and facilitates clathrin-dependent endocytosis of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype glutamate receptors (AMPARs). Both broad spectrum inhibitors of clathrin-dependent endocytotic processes and a specific inhibitor of AMPAR endocytosis selectively inhibit NMDA-induced apoptosis without affecting apoptosis produced by staurosporine. These results demonstrate that clathrin-dependent endocytosis of AMPARs is an essential step in NMDAR-mediated neuronal apoptosis. Our study not only identifies a previously unsuspected step in NMDA-induced apoptosis but also demonstrates that AMPAR endocytosis, in addition to attenuating synaptic strength as previously demonstrated in models of synaptic plasticity, may play a critical role in mediating other important intracellular pathways.

Unique domain anchoring of Src to synaptic NMDA receptors via the mitochondrial protein NADH dehydrogenase subunit 2.

Src is the prototypic protein tyrosine kinase and is critical for controlling diverse cellular functions. Regions in Src define structural and functional domains conserved in many cell signaling proteins. Src also contains a region of low sequence conservation termed the unique domain, the function of which has until now remained enigmatic. Here, we show that the unique domain of Src is a protein-protein interaction region and we identify NADH dehydrogenase subunit 2 (ND2) as a Src unique domain-interacting protein. ND2 is a subunit of complex I in mitochondria, but we find that ND2 interacts with Src outside this organelle at excitatory synapses in the brain. ND2 acts as an adapter protein anchoring Src to the N-methyl-d-aspartate (NMDA) receptor complex, and is crucial for Src regulation of synaptic NMDA receptor activity. By showing an extramitochondrial action for a protein encoded in the mitochondrial genome, we identify a previously unsuspected means by which mitochondria regulate cellular function, suggesting a new paradigm that may be of general relevance for control of Src signaling.

Differential frequency dependence of P2Y1- and P2Y2- mediated Ca 2+ signaling in astrocytes.

ATP is a key extracellular messenger that mediates the propagation of Ca 2+ waves in astrocyte networks in various regions of the CNS. ATP-mediated Ca 2+ signals play critical roles in astrocyte proliferation and differentiation and in modulating neuronal activity. The actions of ATP on astrocytes are via two distinct subtypes of P2Y purinoceptors, P2Y1 and P2Y2 receptors (P2Y1Rs and P2Y2Rs), G-protein coupled receptors that stimulate mobilization of intracellular Ca 2+ ([Ca 2+]i) via the phospholipase Cbeta-IP3 pathway. We report here that P2Y1R-mediated and P2Y2R-mediated Ca 2+ responses differentially show two forms of activity-dependent negative feedback. First, Ca 2+ responses mediated by either receptor exhibit slow depression that is independent of stimulation frequency. Second, responses mediated by P2Y1Rs, but not those mediated by P2Y2Rs, show rapid oscillations after high-frequency stimulation. We demonstrate that the oscillations are mediated by recruiting negative feedback by protein kinase C, and we map the site responsible for the effect of protein kinase C to Thr339 in the C terminus of P2Y1R. We propose that frequency-dependent changes in ATP-mediated Ca 2+ signaling pathways may modulate astrocyte function and astrocyte-neuron signaling in the CNS.