Patient-derived SLC6A1 variant S295L results in an epileptic phenotype similar to haploinsufficient mice.

The solute carrier family 6 member 1 (SLC6A1) gene encodes GAT-1, a γ-aminobutyric acid transporter expressed on astrocytes and inhibitory neurons. Mutations in SLC6A1 are associated with epilepsy and developmental disorders, including motor and social impairments, but variant-specific animal models are needed to elucidate mechanisms. Here, we report electrocorticographic (ECoG) recordings and clinical data from a patient with a variant in SLC6A1 that encodes GAT-1 with a serine-to-leucine substitution at amino acid 295 (S295L), who was diagnosed with childhood absence epilepsy. Next, we show that mice bearing the S295L mutation (GAT-1S295L/+ ) have spike-and-wave discharges with motor arrest consistent with absence-type seizures, similar to GAT-1+/- mice. GAT-1S295L/+ and GAT-1+/- mice follow the same pattern of pharmacosensitivity, being bidirectionally modulated by ethosuximide (200 mg/kg ip) and the GAT-1 antagonist NO-711 (10 mg/kg ip). By contrast, GAT-1-/- mice were insensitive to both ethosuximide and NO-711 at the doses tested. In conclusion, ECoG findings in GAT-1S295L/+ mice phenocopy GAT-1 haploinsufficiency and provide a useful preclinical model for drug screening and gene therapy investigations.

AVACOPAN: A New Adjunctive Therapy for Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Avacopan is a small-molecule complement 5a receptor (CD88) antagonist recently approved by the United States Food and Drug Administration as an adjunct therapy in combination with immunosuppressants and corticosteroids for treatment of ANCA-vasculitis. The selective ability of avacopan to inhibit the C5a receptor blocks neutrophil chemoattraction, activation, and adhesion while maintaining other beneficial complement pathways. Therefore, avacopan's unique selective property provides a breakthrough treatment for ANCA- vasculitis given that current therapies of corticosteroid treatment often lead to a decreased quality of life and a possible relapse. Clinical trials prove that avacopan is an excellent adjunctive treatment option, although it is not approved for the primary treatment of ANCA-vasculitis at this time. Initial clinical trials show substantial promise for avacopan, but additional studies with a longer duration will be needed to test for its durability and safety.

Nipecotic Acid Derivatives as Potent Agents against Neurodegeneration: A Preliminary Study.

Alzheimer's Disease (AD) is a common neurodegenerative disorder characterized by memory loss and cognitive impairment. Its pathology has not been fully clarified and therefore highly effective treatments have not been obtained yet. Almost all the current treatment options aim to alleviate only the symptoms and not to eliminate the disease itself. Acetylcholinesterase inhibitors are the main therapeutic agents against AD, whereas oxidative stress and inflammation have been found to be of great significance for the development and progression of neurodegeneration. In this work, ethyl nipecotate (ethyl-piperidine-3-carboxylate), a heterocyclic carboxylic acid derivative, which acts as a GABA reuptake inhibitor and has been used in research for diseases involving GABAergic neurotransmission dysfunction, was amidated with various carboxylic acids bearing antioxidant and/or anti-inflammatory properties (e.g., ferulic acid, sinapic acid, butylated hydroxycinnamic acid). Most of our compounds have significant antioxidant potency as lipid peroxidation inhibitors (IC50 as low as 20 µΜ), as oxidative protein glycation inhibitors (inhibition up to 57%), and act as DPPH reducing agents. Moreover, our compounds are moderate LOX inhibitors (up to 33% at 100 µΜ) and could reduce rat paw edema induced by carrageenan by up to 61%. Finally, some of them possessed inhibitory activity against acetylcholinesterase (IC50 as low as to 47 µΜ). Our results indicate that our compounds could have the potentiality for further optimization as multi-targeting agents directed against AD.

Avacopan: First Approval.

Avacopan (TAVNEOS™) is a complement 5a receptor (C5aR) antagonist developed by ChemoCentryx for the treatment of autoimmune diseases including anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis. The therapeutic effects of avacopan are attributed to the inhibition of C5aR activity on neutrophils, however, the exact mechanism of therapeutic efficacy in patients with ANCA-associated vasculitis has not been established. In September 2021, avacopan received its first approval in Japan for the treatment of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), the two most common forms of ANCA-associated vasculitis, where it is being commercialized by Kissei Pharmaceutical through a partnership with Vifor Pharma. In October 2021, avacopan was approved in the USA as an adjunctive treatment in adults for severe active ANCA-associated vasculitis (specifically MPA and GPA) in combination with standard therapy including glucocorticoids (avacopan does not eliminate glucocorticoid use). Avacopan has received a positive opinion in the EU, and is also undergoing regulatory review in Switzerland and Canada. Avacopan is being investigated for the treatment of complement component 3 glomerulopathy, hidradenitis suppurativa, lupus nephritis and IgA nephropathy. This article summarizes the milestones in the development of avacopan leading to these first approvals in Japan and the USA.

Avacopan for the Treatment of ANCA-Associated Vasculitis.

BACKGROUND: The C5a receptor inhibitor avacopan is being studied for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. METHODS: In this randomized, controlled trial, we assigned patients with ANCA-associated vasculitis in a 1:1 ratio to receive oral avacopan at a dose of 30 mg twice daily or oral prednisone on a tapering schedule. All the patients received either cyclophosphamide (followed by azathioprine) or rituximab. The first primary end point was remission, defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 (on a scale from 0 to 63, with higher scores indicating greater disease activity) at week 26 and no glucocorticoid use in the previous 4 weeks. The second primary end point was sustained remission, defined as remission at both weeks 26 and 52. Both end points were tested for noninferiority (by a margin of 20 percentage points) and for superiority. RESULTS: A total of 331 patients underwent randomization; 166 were assigned to receive avacopan, and 165 were assigned to receive prednisone. The mean BVAS at baseline was 16 in both groups. Remission at week 26 (the first primary end point) was observed in 120 of 166 patients (72.3%) receiving avacopan and in 115 of 164 patients (70.1%) receiving prednisone (estimated common difference, 3.4 percentage points; 95% confidence interval [CI], -6.0 to 12.8; P<0.001 for noninferiority; P = 0.24 for superiority). Sustained remission at week 52 (the second primary end point) was observed in 109 of 166 patients (65.7%) receiving avacopan and in 90 of 164 patients (54.9%) receiving prednisone (estimated common difference, 12.5 percentage points; 95% CI, 2.6 to 22.3; P<0.001 for noninferiority; P = 0.007 for superiority). Serious adverse events (excluding worsening vasculitis) occurred in 37.3% of the patients receiving avacopan and in 39.0% of those receiving prednisone. CONCLUSIONS: In this trial involving patients with ANCA-associated vasculitis, avacopan was noninferior but not superior to prednisone taper with respect to remission at week 26 and was superior to prednisone taper with respect to sustained remission at week 52. All the patients received cyclophosphamide or rituximab. The safety and clinical effects of avacopan beyond 52 weeks were not addressed in the trial. (Funded by ChemoCentryx; ADVOCATE ClinicalTrials.gov number, NCT02994927.).

New Therapeutic Targets in Antineutrophil Cytoplasm Antibody-Associated Vasculitis.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) is a rare systemic autoimmune disease that is characterized by necrotizing inflammation of predominantly the small blood vessels and the presence of circulating ANCAs directed against myeloperoxidase or proteinase 3. Current treatment strategies for severe disease, supported by the findings of several well-coordinated randomized controlled trials, aim to induce remission with high-dose glucocorticoids and either rituximab or cyclophosphamide, followed by relapse prevention with a period of sustained low-dose treatment. This approach has dramatically improved outcomes in AAV; however, a significant proportion of patients develop serious treatment-related side effects or experience relapse. Recent advances in our understanding of the pathogenesis of AAV have led to the identification of novel therapeutic targets that may address these problems, including strategies directed at the aberrant adaptive autoimmune response (B and T cell-directed treatments) and those targeting innate immune elements (complement, monocytes, and neutrophils). It is anticipated that these novel treatments, used alone or in combination, will lead to more effective and less toxic treatment regimens for patients with AAV.

Management of primary vasculitides with biologic and novel small molecule medications.

PURPOSE OF REVIEW: Vasculitides can affect small, medium and/or large vessels, leading to end-organ damage, decreased quality of life and death. Glucocorticoids remain the backbone of treatment for systemic vasculitis but are associated with numerous toxicities. In recent years, the efficacy of glucocorticoid-sparing biologic and novel small molecule therapies has been demonstrated. RECENT FINDINGS: In giant cell arteritis, tocilizumab was superior to glucocorticoid monotherapy in maintenance remission and cumulative glucocorticoid exposure and is now approved for the treatment of giant cell arteritis. In addition to the previously demonstrated efficacy of rituximab for remission induction in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, recent trials have also demonstrated its superiority for remission maintenance compared to alternative approaches. Mepolizumab is superior to standard of care alone with regard to remission rates and glucocorticoid-sparing effect in refractory eosinophilic granulomatosis with polyangiitis. Avacopan has shown significant promise in ANCA-associated vasculitis as part of a glucocorticoid-free induction regimen in a recently completed phase 3 trial. Use of biologics in rarer vasculitides remains guided by reports from small case series. SUMMARY: Biologics and other novel therapies have an increasingly important role in the management of systemic vasculitis. Additional studies are needed to define their optimal use and to guide their use in more rare forms of vasculitis.

New therapeutic strategies in lung vasculitis.

PURPOSE OF REVIEW: To summarize the latest publications and provide a practical overview of treatment strategies for lung vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs). RECENT FINDINGS: In patients with severe ANCA-associated vasculitis, plasma exchange, as adjunctive therapy to standard treatment, is not associated with improved survival or reduced risk of end-stage kidney disease. A regimen with reduced dose of glucocorticoids is equally effective to induce remission as a standard regimen. In patients without organ or life-threatening disease, mycophenolate mofetil can be used in combination with oral glucocorticoid therapy to induce remission, however, with a higher risk of relapse than when using rituximab or cyclophosphamide. For maintenance of remission, a tailored regimen of rituximab infusion was equivalent to a fixed regimen, with fewer perfusions. Belimumab, a human IgG1(Equation is included in full-text article.)monoclonal antibody against B-lymphocyte stimulator, did not decrease the relapse rate when added to azathioprine and glucocorticoids. Avacopan, a complement C5a receptor inhibitor, was effective in replacing high-dose glucocorticoids in achieving complete remission of vasculitis. SUMMARY: Significant advances have been made in the treatment strategy to both induce remission and maintain remission in patients with ANCA-associated vasculitis. The choice should take into consideration efficacy, cost-effectiveness, safety profile, ease of use, and possibility of individual tailoring of treatment.

Complement inhibition in ANCA vasculitis.

A role for the alternative complement pathway has emerged in the understanding of ANCA vasculitis pathogenesis. Current therapies of ANCA vasculitis are limited by partial efficacy and toxicity and many patients pursue a relapsing course. Improved therapies are needed. Inhibition of the alternative complement pathway component C5a is attractive due to its role in neutrophil activation and migration, and engagement of other inflammatory and thrombotic mechanisms. Two inhibitors of C5a are in clinical development for ANCA vasculitis: avacopan, an oral C5a receptor inhibitor has demonstrated efficacy, safety and steroid sparing in two Phase II trials; and IFX-1, a monoclonal antibody to C5a which is entering Phase II development. Complement inhibition has the potential to contribute to remission induction protocols achieving a higher quality of remission as well as replacing steroids. Confirmation of safety, especially infective risk, and the potential to replace steroids depends on further studies and a role in relapse prevention needs to be explored.

Avacopan in the treatment of ANCA-associated vasculitis.

INTRODUCTION: ANCA-associated vasculitis (AAV) is a rare but potentially life-threatening disease. Currently used induction treatment (cyclophosphamide or rituximab with high-dose corticosteroids) has significantly improved outcome of AAV, but is associated with high toxicity. Alternative complement pathway activation was shown to play a role in the pathogenesis of AAV, thus providing rationale for the use of avacopan, a selective inhibitor of C5a receptor, in the treatment of AAV. Areas covered: Pharmacokinetic and pharmocodynamic properties of avacopan, clinical efficacy and safety and tolerability of avacopan in so far performed clinical trials in patients with AAV are reviewed and discussed. Expert opinion: Avacopan was shown to have at least similar efficacy compared to high dose corticosteroids in patients with active AAV with renal involvement, while there were no major safety issues reported. Replacement of corticosteroids should decrease the corticosteroid-related toxicity and improve long-term outcome of patients with AAV even though this still needs to be confirmed in a larger trial. Data on long-term outcome of avacopan-treated patients are currently lacking and will be eagerly awaited. In the future, avacopan could replace corticosteroids not only in the induction phase, but also in the maintenance treatment of AAV.

Design, Synthesis, Evaluation and Computational Studies of Nipecotic Acid-Acetonaphthone Hybrids as Potential Antiepileptic Agents.

BACKGROUND: Nipecotic acid is considered to be one of the most potent inhibitors of neuronal and glial γ-aminobutyric acid (GABA) uptake in vitro. However, nipecotic acid does not readily cross the blood-brain barrier (BBB) following peripheral administration, owing to its hydrophilic nature. OBJECTIVE: A series of substituted acetonaphthones tethered nipecotic acid derivatives were designed and synthesized with an aim to improve the lipophilicity and the blood-brain barrier (BBB) permeation. METHODS: Synthesized compounds were tested in mice models of PTZ, pilocarpine, and DMCM induced epilepsy, in vivo. The rota-rod test was performed to determine the acute neurotoxicity of the potential leads (4a, 4b, and 4i). These potential hybrids were also evaluated for their ability to cross the BBB by an in vitro parallel artificial membrane permeability BBB assay (PAMPA-BBB). The leads were subjected to in silico molecular docking and dynamics studies on homology modelled protein of human GABA (γ-amino butyric acid) transporter 1 (GAT1) and prediction of their pharmacokinetic properties. RESULT: Amongst the synthesized derivatives, compounds 3a, 3b, 3i, 4a, 4b, and 4i exhibited increased latency of seizures against subcutaneous pentylenetetrazole (scPTZ) induced seizures in mice. Derivatives 4a, 4b, 4i were more effective compared to nipecotic acid ester counterparts 3a, 3b and 3i placing the importance of the presence of free carboxyl group in the centre. The findings revealed that 4i was comparatively more permeable (Pe= 8.89) across BBB than the standard tiagabine (Pe= 7.86). In silico studies proved the consensual interactions of compound 4i with the active binding pocket. CONCLUSION: Some nipecotic acid-acetonaphthone hybrids with considerable anti-epileptic activity, drug like properties and the ability to permeate the BBB have been successfully synthesized.

Disease Modifying Effects of the Spider Toxin Parawixin2 in the Experimental Epilepsy Model.

(1) Background: Temporal lobe epilepsy (TLE) is the most common type of epilepsy in adults. It is also the one with the highest percentage of drug-resistance to the current available anti-epileptic drugs (AED). Additionaly, most antiepileptic drugs are only able to control seizures in epileptogenesis, but do not decrease the hippocampal neurodegenerative process. TLE patients have a reduced population of interneuronal cells, which express Parvalbumin (PV) proteins. This reduction is directly linked to seizure frequency and severity in the chronic period of epilepsy. There is therefore a need to seek new therapies with a disease-modifying profile, and with efficient antiepileptic and neuroprotective properties. Parawixin2, a compound isolated from the venom of the spider Parawixia bistriata, has been shown to inhibit GABA transporters (GAT) and to have acute anticonvulsant effects in rats. (2) Methods: In this work, we studied the effects of Parawixin2 and Tiagabine (an FDA- approved GAT inhibitor), and compared these effects in a TLE model. Rats were subjected to lithium-pilocarpine TLE model and the main features were evaluated over a chronic period including: (a) spontaneous recurrent seizures (SRS), (b) neuronal loss, and (c) PV cell density in different regions of the hippocampus (CA1, CA3, DG and Hilus). (3) Results: Parawixin2 treatment reduced SRS frequency whereas Tiagabine did not. We also found a significant reduction in neuronal loss in CA3 and in the hilus regions of the hippocampus, in animals treated with Parawixin2. Noteworthy, Parawixin2 significantly reversed PV cell loss observed particularly in DG layers. (4) Conclusions: Parawixin2 exerts a promising neuroprotective and anti-epileptic effect and has potential as a novel agent in drug design.

Preclinical Comparison of Mechanistically Different Antiseizure, Antinociceptive, and/or Antidepressant Drugs in a Battery of Rodent Models of Nociceptive and Neuropathic Pain.

The series of experiments herein evaluated prototype drugs representing different mechanisms of antiseizure, antinociceptive or antidepressant action in a battery of preclinical pain models in adult male CF#1 mice (formalin, writhing, and tail flick) and Sprague Dawley rats partial sciatic nerve ligation (PSNL). In the formalin assay, phenytoin (PHT, 6 mg/kg), sodium valproate (VPA, 300 mg/kg), amitriptyline (AMI, 7.5 and 15 mg/kg), gabapentin (GBP, 30 and 70 mg/kg), tiagabine (TGB, 5 and 15 mg/kg), and acetominophen (APAP, 250 and 500 mg/kg) reduced both phases of the formalin response to ≤ 25% of vehicle-treated mice. In the acetic acid induced writhing assay, VPA (300 mg/kg), ethosuximide (ETX, 300 mg/kg), morphine (MOR, 5 & 10 mg/kg), GBP (10, 30, and 60 mg/kg), TGB (15 mg/kg), levetiracetam (LEV, 300 mg/kg), felbamate (FBM, 80 mg/kg) and APAP (250 mg/kg) reduced writhing to ≤ 25% of vehicle-treated mice. In the tail flick test, MOR (1.25-5 mg/kg), AMI (15 mg/kg) and TGB (5 mg/kg) demonstrated significant antinociceptive effects. Finally, carbamazepine (CBZ, 20 and 50 mg/kg), VPA, MOR (2 and 4 mg/kg), AMI (12 mg/kg), TPM (100 mg/kg), lamotrigine (LTG, 40 mg/kg), GBP (60 mg/kg), TGB (15 mg/kg), FBM (35 mg/kg), and APAP (250 mg/kg) were effective in the PSNL model. Thus, TGB was the only prototype compound with significant analgesic effects in each of the four models, while AMI, GBP, APAP, and MOR each improved three of the four pain phenotypes. This study highlights the importance evaluating novel targets in a variety of pain phenotypes.

Randomized Trial of C5a Receptor Inhibitor Avacopan in ANCA-Associated Vasculitis.

Alternative C activation is involved in the pathogenesis of ANCA-associated vasculitis. However, glucocorticoids used as treatment contribute to the morbidity and mortality of vasculitis. We determined whether avacopan (CCX168), an orally administered, selective C5a receptor inhibitor, could replace oral glucocorticoids without compromising efficacy. In this randomized, placebo-controlled trial, adults with newly diagnosed or relapsing vasculitis received placebo plus prednisone starting at 60 mg daily (control group), avacopan (30 mg, twice daily) plus reduced-dose prednisone (20 mg daily), or avacopan (30 mg, twice daily) without prednisone. All patients received cyclophosphamide or rituximab. The primary efficacy measure was the proportion of patients achieving a ≥50% reduction in Birmingham Vasculitis Activity Score by week 12 and no worsening in any body system. We enrolled 67 patients, 23 in the control and 22 in each of the avacopan groups. Clinical response at week 12 was achieved in 14 of 20 (70.0%) control patients, 19 of 22 (86.4%) patients in the avacopan plus reduced-dose prednisone group (difference from control 16.4%; two-sided 90% confidence limit, -4.3% to 37.1%; P=0.002 for noninferiority), and 17 of 21 (81.0%) patients in the avacopan without prednisone group (difference from control 11.0%; two-sided 90% confidence limit, -11.0% to 32.9%; P=0.01 for noninferiority). Adverse events occurred in 21 of 23 (91%) control patients, 19 of 22 (86%) patients in the avacopan plus reduced-dose prednisone group, and 21 of 22 (96%) patients in the avacopan without prednisone group. In conclusion, C5a receptor inhibition with avacopan was effective in replacing high-dose glucocorticoids in treating vasculitis.

Effects of Tiagabine on Slow Wave Sleep and Arousal Threshold in Patients With Obstructive Sleep Apnea.

Introduction: Obstructive sleep apnea (OSA) severity is markedly reduced during slow-wave sleep (SWS) even in patients with a severe disease. The reason for this improvement is uncertain but likely relates to non-anatomical factors (i.e. reduced arousability, chemosensitivity, and increased dilator muscle activity). The anticonvulsant tiagabine produces a dose-dependent increase in SWS in subjects without OSA. This study aimed to test the hypothesis that tiagabine would reduce OSA severity by raising the overall arousal threshold during sleep. Aims and Methods: After a baseline physiology night to assess patients' OSA phenotypic traits, a placebo-controlled, double-blind, crossover trial of tiagabine 12 mg administered before sleep was performed in 14 OSA patients. Under each condition, we assessed the effects on sleep and OSA severity using standard clinical polysomnography. Results: Tiagabine increased slow-wave activity (SWA) of the electroencephalogram (1-4 Hz) compared to placebo (1.8 [0.4] vs. 2.0 [0.5] LogµV2, p = .04) but did not reduce OSA severity (apnea-hypopnea index [AHI] 41.5 [20.3] vs. 39.1 [16.5], p > .5). SWS duration (25 [20] vs. 26 [43] mins, p > .5) and arousal threshold (-26.5 [5.0] vs. -27.6 [5.1] cmH2O, p = .26) were also unchanged between nights. Conclusions: Tiagabine modified sleep microstructure (increase in SWA) but did not change the duration of SWS, OSA severity, or arousal threshold in this group of OSA patients. Based on these findings, tiagabine should not be considered as a therapeutic option for OSA treatment.

Pharmacokinetic optimitzation of CCG-203971: Novel inhibitors of the Rho/MRTF/SRF transcriptional pathway as potential antifibrotic therapeutics for systemic scleroderma.

We recently reported the development of a novel inhibitor of Rho-mediated gene transcription (1, CCG-203971) that is efficacious in multiple animal models of acute fibrosis, including scleroderma, when given intraperitoneally. The modest in vivo potency and poor pharmacokinetics (PK) of this lead, however, make it unsuitable for long term efficacy studies. We therefore undertook a systematic medicinal chemistry effort to improve both the metabolic stability and the solubility of 1, resulting in the identification of two analogs achieving over 10-fold increases in plasma exposures in mice. We subsequently showed that one of these analogs (8f, CCG-232601) could inhibit the development of bleomycin-induced dermal fibrosis in mice when administered orally at 50mg/kg, an effect that was comparable to what we had observed earlier with 1 at a 4-fold higher IP dose.

Breaking down the complement system: a review and update on novel therapies.

PURPOSE OF REVIEW: The complement system represents one of the more primitive forms of innate immunity. It has increasingly been found to contribute to pathologies in the native and transplanted kidney. We provide a concise review of the physiology of the complement cascade, and discuss current and upcoming complement-based therapies. RECENT FINDINGS: Current agents in clinical use either bind to complement components directly or prevent complement from binding to antibodies affixed to the endothelial surface. These include C1 esterase inhibitors, anti-C5 mAbs, anti-CD20 mAbs, and proteasome inhibitors. Treatment continues to show efficacy in the atypical hemolytic uremic syndrome and antibody-mediated rejection. Promising agents not currently available include CCX168, TP10, AMY-101, factor D inhibitors, coversin, and compstatin. Several new trials are targeting complement inhibition to treat antineutrophilic cystoplasmic antibody (ANCA)-associated vasculitis, C3 glomerulopathy, thrombotic microangiopathy, and IgA nephropathy. New agents for the treatment of the atypical hemolytic uremic syndrome are also in development. SUMMARY: Complement-based therapies are being considered for targeted therapy in the atypical hemolytic uremic syndrome and antibody-mediated rejection, C3 glomerulopathy, and ANCA-associated vasculitis. A few agents are currently in use as orphan drugs. A number of other drugs are in clinical trials and, overall, are showing promising preliminary results.