14 results on '"Kurukulasuriya NC"'
Search Results
2. RE-MIND2: comparative effectiveness of tafasitamab plus lenalidomide versus polatuzumab vedotin/bendamustine/rituximab (pola-BR), CAR-T therapies, and lenalidomide/rituximab (R2) based on real-world data in patients with relapsed/refractory diffuse large B-cell lymphoma.
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Nowakowski GS, Yoon DH, Mondello P, Joffe E, Peters A, Fleury I, Greil R, Ku M, Marks R, Kim K, Zinzani PL, Trotman J, Sabatelli L, Waltl EE, Winderlich M, Sporchia A, Kurukulasuriya NC, Cordoba R, Hess G, and Salles G
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- Humans, Adolescent, Adult, Rituximab, Lenalidomide, Bendamustine Hydrochloride therapeutic use, Retrospective Studies, Receptors, Chimeric Antigen, Lymphoma, Non-Hodgkin drug therapy, Lymphoma, Large B-Cell, Diffuse drug therapy
- Abstract
RE-MIND2 (NCT04697160) compared patient outcomes from the L-MIND (NCT02399085) trial of tafasitamab+lenalidomide with those of patients treated with other therapies for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who are autologous stem cell transplant ineligible. We present outcomes data for three pre-specified treatments not assessed in the primary analysis. Data were retrospectively collected from sites in North America, Europe, and the Asia Pacific region. Patients were aged ≥18 years with histologically confirmed DLBCL and received ≥2 systemic therapies for DLBCL (including ≥1 anti-CD20 therapy). Patients enrolled in the observational and L-MIND cohorts were matched using propensity score-based 1:1 nearest-neighbor matching, balanced for six covariates. Tafasitamab+lenalidomide was compared with polatuzumab vedotin+bendamustine+rituximab (pola-BR), rituximab+lenalidomide (R2), and CD19-chimeric antigen receptor T-cell (CAR-T) therapies. The primary endpoint was overall survival (OS). Secondary endpoints included treatment response and progression-free survival. From 200 sites, 3,454 patients were enrolled in the observational cohort. Strictly matched patient pairs consisted of tafasitamab+lenalidomide versus pola-BR (n = 24 pairs), versus R2 (n = 33 pairs), and versus CAR-T therapies (n = 37 pairs). A significant OS benefit was observed with tafasitamab+lenalidomide versus pola-BR (HR: 0.441; p = 0.034) and R2 (HR: 0.435; p = 0.012). Comparable OS was observed in tafasitamab+lenalidomide and CAR-T cohorts (HR: 0.953, p = 0.892). Tafasitamab+lenalidomide appeared to improve survival outcomes versus pola-BR and R2, and comparable outcomes were observed versus CAR-T. Although based on limited patient numbers, these data may help to contextualize emerging therapies for R/R DLBCL. CLINICAL TRIAL REGISTRATION: NCT04697160 (January 6, 2021)., (© 2023. The Author(s).)
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- 2023
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3. Improved Efficacy of Tafasitamab plus Lenalidomide versus Systemic Therapies for Relapsed/Refractory DLBCL: RE-MIND2, an Observational Retrospective Matched Cohort Study.
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Nowakowski GS, Yoon DH, Peters A, Mondello P, Joffe E, Fleury I, Greil R, Ku M, Marks R, Kim K, Zinzani PL, Trotman J, Huang D, Waltl EE, Winderlich M, Kurukulasuriya NC, Ambarkhane S, Hess G, and Salles G
- Subjects
- Adolescent, Adult, Antibodies, Monoclonal, Humanized, Bendamustine Hydrochloride, Cohort Studies, Humans, Lenalidomide administration & dosage, Oxaliplatin therapeutic use, Retrospective Studies, Rituximab administration & dosage, Treatment Outcome, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Antineoplastic Combined Chemotherapy Protocols adverse effects, Lymphoma, Large B-Cell, Diffuse pathology
- Abstract
Purpose: In RE-MIND2 (NCT04697160), patient-level outcomes from the L-MIND study (NCT02399085) of tafasitamab plus lenalidomide were retrospectively compared with patient-level matched observational cohorts treated with National Cancer Care Network (NCCN)/European Society for Medical Oncology (ESMO)-listed systemic therapies for relapsed/refractory diffuse large B-cell lymphoma (DLBCL)., Patients and Methods: Data were collected from health records of eligible patients aged ≥18 years with histologically confirmed DLBCL who had received ≥2 systemic therapies for DLBCL (including ≥1 anti-CD20 therapy). Patients from L-MIND were matched with patients from the RE-MIND2 observational cohort using estimated propensity score-based 1:1 nearest-neighbor matching, balanced for nine covariates. The primary analysis compared tafasitamab plus lenalidomide with patients who received any systemic therapy for R/R DLBCL (pooled in one cohort) or bendamustine plus rituximab (BR) or rituximab plus gemcitabine and oxaliplatin (R-GemOx; as two distinct cohorts). The primary endpoint was overall survival (OS). Secondary endpoints included treatment response and time-to-event outcomes., Results: In RE-MIND2, 3,454 patients were enrolled from 200 sites in North America, Europe, and Asia-Pacific. Strictly matched pairs of patients consisted of tafasitamab plus lenalidomide versus systemic therapies pooled (n = 76 pairs), versus BR (n = 75 pairs), and versus R-GemOx (n = 74 pairs). Significantly prolonged OS was reported with tafasitamab plus lenalidomide versus systemic pooled therapies [hazard ratios (HR): 0.55; P = 0.0068], BR (HR: 0.42; P < 0.0001), and R-GemOx (HR: 0.47; P = 0.0003)., Conclusions: RE-MIND2, a retrospective observational study, met its primary endpoint, demonstrating prolonged OS with tafasitamab plus lenalidomide versus BR and R-GemOx. See related commentary by Cherng and Westin, p. 3908., (©2022 The Authors; Published by the American Association for Cancer Research.)
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- 2022
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4. RE-MIND: Comparing Tafasitamab + Lenalidomide (L-MIND) with a Real-world Lenalidomide Monotherapy Cohort in Relapsed or Refractory Diffuse Large B-cell Lymphoma.
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Zinzani PL, Rodgers T, Marino D, Frezzato M, Barbui AM, Castellino C, Meli E, Fowler NH, Salles G, Feinberg B, Kurukulasuriya NC, Tillmanns S, Parche S, Dey D, Fingerle-Rowson G, Ambarkhane S, Winderlich M, and Nowakowski GS
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- Antibodies, Monoclonal, Humanized, Humans, Lenalidomide, Retrospective Studies, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Lymphoma, Large B-Cell, Diffuse drug therapy
- Abstract
Purpose: Tafasitamab, an Fc-modified, humanized, anti-CD19 monoclonal antibody, in combination with lenalidomide, demonstrated efficacy in transplant-ineligible patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), in the single-arm, phase II L-MIND study (NCT02399085). RE-MIND, a retrospective observational study, generated a historic control for L-MIND to delineate the contribution of tafasitamab to the efficacy of the combination., Patients and Methods: Data were retrospectively collected from patients with R/R DLBCL treated with lenalidomide monotherapy for comparison with tafasitamab + lenalidomide-treated patients (L-MIND). Key eligibility criteria were aligned with L-MIND. Estimated propensity score-based Nearest Neighbor 1:1 Matching methodology balanced the cohorts for nine prespecified prognostic baseline covariates. The primary endpoint was investigator-assessed best overall response rate (ORR). Secondary endpoints included complete response (CR) rate, progression-free survival (PFS), and overall survival (OS)., Results: Data from 490 patients going through lenalidomide monotherapy were collected; 140 qualified for matching with the L-MIND cohort. The primary analysis included 76 patients from each cohort who received a lenalidomide starting dose of 25 mg/day. Cohort baseline covariates were comparable. A significantly better ORR of 67.1% (95% confidence interval, 55.4-77.5) was observed for the combination therapy versus 34.2% (23.7-46.0) for lenalidomide monotherapy [odds ratio, 3.89 (1.90-8.14); P < 0.0001]. Higher CR rates were achieved with combination therapy compared with lenalidomide monotherapy [39.5% (28.4-51.4) vs. 13.2% (6.5-22.9)]. Survival endpoints favored combination therapy. Lenalidomide monotherapy outcomes were similar to previously published data., Conclusions: RE-MIND enabled the estimation of the additional treatment effect achieved by combining tafasitamab with lenalidomide in patients with R/R DLBCL., (©2021 The Authors; Published by the American Association for Cancer Research.)
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- 2021
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5. Long-term effects of delayed-release dimethyl fumarate in multiple sclerosis: Interim analysis of ENDORSE, a randomized extension study.
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Gold R, Arnold DL, Bar-Or A, Hutchinson M, Kappos L, Havrdova E, MacManus DG, Yousry TA, Pozzilli C, Selmaj K, Sweetser MT, Zhang R, Yang M, Potts J, Novas M, Miller DH, Kurukulasuriya NC, Fox RJ, and Phillips TJ
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- Adult, Female, Humans, Magnetic Resonance Imaging methods, Male, Time Factors, Treatment Outcome, Dimethyl Fumarate therapeutic use, Glatiramer Acetate therapeutic use, Immunosuppressive Agents therapeutic use, Multiple Sclerosis drug therapy
- Abstract
Background: Delayed-release dimethyl fumarate (DMF) demonstrated strong efficacy and a favorable benefit-risk profile for patients with relapsing-remitting multiple sclerosis (RRMS) in phase 3 DEFINE/CONFIRM studies. ENDORSE is an ongoing long-term extension of DEFINE/CONFIRM., Objective: We report efficacy and safety results of a 5-year interim analysis of ENDORSE (2 years DEFINE/CONFIRM; minimum 3 years ENDORSE)., Methods: In ENDORSE, patients randomized to DMF 240 mg twice (BID) or thrice daily (TID) in DEFINE/CONFIRM continued this dosage, and those initially randomized to placebo (PBO) or glatiramer acetate (GA) were re-randomized to DMF 240 mg BID or TID., Results: For patients continuing DMF BID (BID/BID), annualized relapse rates were 0.202, 0.163, 0.139, 0.143, and 0.138 (years 1-5, respectively) and 63%, 73%, and 88% were free of new or enlarging T2 hyperintense lesions, new T1 hypointense lesions, and gadolinium-enhanced lesions, respectively, at year 5. Adverse events (AEs; serious adverse events (SAEs)) were reported in 91% (22%; BID/BID), 95% (24%; PBO/BID), and 88% (16%; GA/BID) of the patients. One case of progressive multifocal leukoencephalopathy was reported in the setting of severe, prolonged lymphopenia., Conclusion: Treatment with DMF was associated with continuously low clinical and magnetic resonance imaging (MRI) disease activity in patients with RRMS. These interim data demonstrate a sustained treatment benefit and an acceptable safety profile with DMF.
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- 2017
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6. Effect of Aspirin Pretreatment or Slow Dose Titration on Flushing and Gastrointestinal Events in Healthy Volunteers Receiving Delayed-release Dimethyl Fumarate.
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O'Gorman J, Russell HK, Li J, Phillips G, Kurukulasuriya NC, and Viglietta V
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- Abdominal Pain chemically induced, Abdominal Pain prevention & control, Adult, Aspirin therapeutic use, Constipation chemically induced, Constipation prevention & control, Delayed-Action Preparations administration & dosage, Delayed-Action Preparations therapeutic use, Diarrhea chemically induced, Diarrhea prevention & control, Dimethyl Fumarate administration & dosage, Dimethyl Fumarate therapeutic use, Female, Flushing chemically induced, Flushing prevention & control, Healthy Volunteers, Humans, Immunosuppressive Agents adverse effects, Immunosuppressive Agents therapeutic use, Male, Middle Aged, Multiple Sclerosis, Relapsing-Remitting drug therapy, Random Allocation, Aspirin administration & dosage, Delayed-Action Preparations adverse effects, Dimethyl Fumarate adverse effects, Immunosuppressive Agents administration & dosage
- Abstract
Purpose: In Phase III trials, delayed-release dimethyl fumarate (DMF; also known as gastro-resistant DMF) demonstrated significant efficacy and an acceptable safety profile in patients with relapsing-remitting multiple sclerosis. The purpose of the present study was to examine 2 potential mitigation strategies for flushing and gastrointestinal (GI) events associated with DMF treatment: aspirin (ASA) 325 mg pretreatment for flushing, and slow dose titration of DMF for flushing and GI events., Methods: The 8-week study included 173 healthy volunteers randomized to 4 groups; 172 underwent dosing. The placebo group (n = 44) received placebo ASA 30 minutes before placebo DMF (weeks 1-4), then placebo DMF alone (weeks 5-8). The DMF without ASA group (n = 43) and the DMF with ASA group (n = 43) received placebo ASA or ASA, respectively, 30 minutes before DMF (weeks 1-4), then DMF alone (weeks 5-8); in both groups, DMF was dosed at 120 mg BID (week 1) and 240 mg BID (weeks 2-8). The slow dose titration DMF group (n = 42) received DMF 120 mg once daily (week 1), 120 mg BID (week 2), 240 mg in the morning/120 mg in the evening (week 3), and 240 mg BID (weeks 4-8). Subjects recorded information about flushing and GI-related events by using an eDiary and numerical rating scales., Findings: Flushing and GI-related events were reported in all groups and were mostly rated as mild or moderate in severity. Flushing events were generally ~1 hour in duration and, for most subjects with flushing, initially occurred the first day of study treatment. The duration of GI-related events and time to first GI-related event varied by event type. ASA reduced the incidence, severity, and number of flushing events without affecting duration or time to first flushing event, and had no adverse effect on GI-related events. Dose titration of DMF had no significant effect on flushing or GI events. No subjects discontinued the study due to flushing events. One subject (2%) in the placebo group, 3 subjects (7%) in the DMF without ASA group, 6 subjects (14%) in the DMF with ASA group, and 2 subjects (5%) in the slow dose titration DMF group discontinued treatment because of GI events., Implications: ASA pretreatment may mitigate flushing associated with DMF, with no adverse effect on GI events. Dose titration of DMF did not have a significant effect on flushing or GI events and is being evaluated further in ongoing clinical trials. ClinicalTrials.gov identifier: NCT01568112., (Copyright © 2015 Elsevier HS Journals, Inc. All rights reserved.)
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- 2015
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7. Efficacy and safety of delayed-release dimethyl fumarate in patients newly diagnosed with relapsing-remitting multiple sclerosis (RRMS).
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Gold R, Giovannoni G, Phillips JT, Fox RJ, Zhang A, Meltzer L, and Kurukulasuriya NC
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- Adult, Clinical Trials, Phase III as Topic, Delayed-Action Preparations, Dimethyl Fumarate, Female, Fumarates administration & dosage, Fumarates adverse effects, Humans, Immunosuppressive Agents administration & dosage, Immunosuppressive Agents adverse effects, Magnetic Resonance Imaging, Male, Middle Aged, Multiple Sclerosis, Relapsing-Remitting pathology, Treatment Outcome, Fumarates pharmacology, Immunosuppressive Agents pharmacology, Multiple Sclerosis, Relapsing-Remitting drug therapy
- Abstract
Background: Delayed-release dimethyl fumarate (DMF) demonstrated efficacy and safety in the Phase 3 DEFINE and CONFIRM trials., Objective: To evaluate delayed-release DMF in newly diagnosed relapsing-remitting multiple sclerosis (RRMS) patients, in a post-hoc analysis of integrated data from DEFINE and CONFIRM., Methods: Patients included in the analysis were diagnosed with RRMS within 1 year prior to study entry and naive to MS disease-modifying therapy., Results: The newly diagnosed population comprised 678 patients treated with placebo (n = 223) or delayed-release DMF 240 mg BID (n = 221) or TID (n = 234). At 2 years, delayed-release DMF BID and TID reduced the annualized relapse rate by 56% and 60% (both p < 0.0001), risk of relapse by 54% and 57% (both p < 0.0001), and risk of 12-week confirmed disability progression by 71% (p < 0.0001) and 47% (p = 0.0085) versus placebo. In a subset of patients (MRI cohort), delayed-release DMF BID and TID reduced the mean number of new or enlarging T2-hyperintense lesions by 80% and 81%, gadolinium-enhancing lesion activity by 92% and 92%, and mean number of new non-enhancing T1-hypointense lesions by 68% and 70% (all p < 0.0001 versus placebo). Flushing and gastrointestinal events were associated with delayed-release DMF., Conclusion: Delayed-release DMF improved clinical and neuroradiological outcomes relative to placebo in newly diagnosed RRMS patients., (© The Author(s), 2015.)
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- 2015
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8. Efficacy and safety of BG-12 (dimethyl fumarate) and other disease-modifying therapies for the treatment of relapsing-remitting multiple sclerosis: a systematic review and mixed treatment comparison.
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Hutchinson M, Fox RJ, Havrdova E, Kurukulasuriya NC, Sarda SP, Agarwal S, Siddiqui MK, Taneja A, and Deniz B
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- Antibodies, Monoclonal, Humanized therapeutic use, Crotonates therapeutic use, Dimethyl Fumarate, Disease Progression, Fingolimod Hydrochloride, Fumarates adverse effects, Humans, Hydroxybutyrates, Interferon beta-1a, Interferon beta-1b, Interferon-beta therapeutic use, Natalizumab, Nitriles, Propylene Glycols therapeutic use, Randomized Controlled Trials as Topic, Recurrence, Sphingosine analogs & derivatives, Sphingosine therapeutic use, Toluidines therapeutic use, Fumarates therapeutic use, Multiple Sclerosis, Relapsing-Remitting drug therapy
- Abstract
Objective: Currently, direct comparative evidence or head-to-head data between BG-12 (dimethyl fumarate) and other disease-modifying treatments (DMTs) is limited. This study is a systematic review and data synthesis of published randomized clinical trials comparing the efficacy and safety of existing DMTs to BG-12 for relapsing-remitting multiple sclerosis (RRMS)., Methods: A systematic review was conducted by searching MEDLINE, EMBASE, and the Cochrane Library for English-language publications from 1 January 1960 to 15 November 2012. Clinicaltrials.gov, metaRegister of Controlled Trials, and conference proceedings from relevant annual symposia were also hand searched. Two independent reviewers collected and extracted data, with discrepancies reconciled by a third reviewer. Included studies were randomized controlled trials (RCTs) of DMTs (interferon [IFN] beta-1a, IFN beta-1b, glatiramer acetate [GA], BG-12, fingolimod, natalizumab, and teriflunomide) in adults with RRMS. Mixed treatment comparisons were conducted to derive the relative effect size for the included treatments. Annualized relapse rate (ARR), disability progression, and safety outcomes were assessed., Results: BG-12 240 mg twice a day (BID) significantly reduces ARR compared to placebo (rate ratio: 0.529 [95% CI: 0.451-0.620]), IFNs (0.76 [95% CI: 0.639-0.904]), GA (0.795 [95% CI: 0.668-0.947]), and teriflunomide 7 mg and 14 mg (0.769 [95% CI: 0.610-0.970] and 0.775 [95% CI: 0.614-0.979]), and does not show a significant difference when compared to fingolimod. Only natalizumab was significantly superior to BG-12 in reducing ARR. BG-12 also demonstrated favorable results for disability and safety outcomes., Conclusion: Based on indirect comparison, BG-12 offers an effective oral treatment option for patients with RRMS with an overall promising efficacy and safety profile compared to currently approved DMTs. Key limitations of the systematic review were the large heterogeneity in patients enrolled and the variability in the definition of outcomes in included trials.
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- 2014
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9. Oral BG-12 (dimethyl fumarate) for relapsing-remitting multiple sclerosis: a review of DEFINE and CONFIRM. Evaluation of: Gold R, Kappos L, Arnold D, et al. Placebo-controlled phase 3 study of oral BG-12 for relapsing multiple sclerosis. N Engl J Med 2012;367:1098-107; and Fox RJ, Miller DH, Phillips JT, et al. Placebo-controlled phase 3 study of oral BG-12 or glatiramer in multiple sclerosis. N Engl J Med 2012;367:1087-97.
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Havrdova E, Hutchinson M, Kurukulasuriya NC, Raghupathi K, Sweetser MT, Dawson KT, and Gold R
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- Female, Humans, Male, Fumarates therapeutic use, Immunosuppressive Agents therapeutic use, Multiple Sclerosis, Relapsing-Remitting drug therapy, Peptides therapeutic use
- Abstract
Introduction: Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system involving inflammation, chronic demyelination and axonal loss. MS affects more than 2 million people worldwide., Areas Covered: This article aims to summarize the findings from two pivotal 2-year, randomized, double-blind, placebo-controlled, Phase III studies of BG-12 (dimethyl fumarate) for relapsing-remitting MS (RRMS): DEFINE (Determination of the Efficacy and Safety of Oral Fumarate in RRMS) and CONFIRM (Comparator and an Oral Fumarate in RRMS). Results from both studies demonstrated that BG-12 provides clinical and radiological efficacy over 2 years across a range of outcomes. These results were apparent as early as 12 weeks and sustained over the course of both studies. BG-12 was found to have an acceptable safety profile, with a similar overall incidence of adverse events across all treatment groups., Expert Opinion: The combination of robust efficacy, ease of administration and established safety profile is unique to a new therapy in MS. Findings from the pivotal Phase III studies support BG-12 as a potential initial oral treatment for patients with RRMS or as an alternative to other currently available therapies.
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- 2013
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10. Cladribine tablets for the treatment of relapsing-remitting multiple sclerosis.
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Comi G, Hartung HP, Kurukulasuriya NC, Greenberg SJ, and Scaramozza M
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- Administration, Oral, Cladribine chemistry, Cladribine pharmacokinetics, Clinical Trials, Phase III as Topic, Female, Humans, Immunosuppressive Agents chemistry, Immunosuppressive Agents pharmacokinetics, Lymphocytes drug effects, Male, Safety-Based Drug Withdrawals, Tablets, Cladribine therapeutic use, Immunosuppressive Agents therapeutic use, Multiple Sclerosis, Relapsing-Remitting drug therapy
- Abstract
Introduction: Multiple sclerosis (MS) is a chronic immune-mediated disorder of the central nervous system leading to progressive neurodegeneration and disability. Until 2010, all approved disease-modifying drugs for MS required parenteral administration, which is associated with suboptimal adherence. It was anticipated that new approaches to treatment, including oral agents such as cladribine tablets, may improve adherence. In 2011, the development of cladribine tablets was stopped following negative feedback from the EMA and FDA., Areas Covered: This article provides an overview of the chemistry, mechanism of action and pharmacological properties of cladribine tablets therapy, and highlights the rationale for its development as an oral treatment for MS. Key efficacy and safety data from the pivotal Phase III CLARITY study are presented, providing context for the opinion received from the regulatory agencies., Expert Opinion: Despite the promising efficacy data observed in the cladribine tablets clinical trial program, regulatory agencies identified a potential risk of increased malignancies, and raised concerns about the implications of sustained lymphocyte depletion. Following the feedback received from the regulatory agencies, Merck Serono made the decision to withdraw the agent from the regulatory approval process. The experience gained will benefit other research efforts to address the outstanding unmet treatment needs of patients with relapsing MS.
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- 2013
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11. Cortical feedback to the thalamus is selectively enhanced by nitric oxide.
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Alexander GM, Kurukulasuriya NC, Mu J, and Godwin DW
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- Animals, Animals, Newborn, Arginine pharmacology, Cyclic GMP analogs & derivatives, Cyclic GMP pharmacology, Drug Interactions, Enzyme Inhibitors pharmacology, Excitatory Amino Acid Agonists pharmacology, Excitatory Amino Acid Antagonists pharmacology, Excitatory Postsynaptic Potentials drug effects, Excitatory Postsynaptic Potentials physiology, Excitatory Postsynaptic Potentials radiation effects, Feedback drug effects, Ferrets, In Vitro Techniques, Male, N-Methylaspartate pharmacology, NG-Nitroarginine Methyl Ester pharmacology, Neural Pathways drug effects, Neurons drug effects, Nitric Oxide Donors pharmacology, Penicillamine analogs & derivatives, Penicillamine pharmacology, Superoxide Dismutase pharmacology, Synaptic Transmission drug effects, Synaptic Transmission physiology, Synaptic Transmission radiation effects, Triazoles pharmacology, Cerebral Cortex physiology, Feedback physiology, Geniculate Bodies cytology, Neural Pathways physiology, Neurons physiology, Nitric Oxide physiology
- Abstract
The brain somehow merges visual information with the behavioral context in which it is being processed, a task that is often attributed to the cerebral cortex. We have identified a new role of the gaseous neurotransmitter, nitric oxide (NO), in the early selective enhancement of corticogeniculate communication that may participate in this process at the level of the thalamus. Visual information is dynamically gated through the thalamus by brainstem neurons that release acetylcholine and NO. Using in vitro electrophysiology, we characterized NO effects on excitatory postsynaptic potentials and currents (EPSCs) elicited from retinal and cortical pathways in the lateral geniculate nucleus of the ferret. NO selectively and reversibly increased cortically-evoked postsynaptic responses, and this effect was mimicked by cyclic guanosine 3',5'-monophosphate (cGMP). Conversely, NO inhibited retinally-evoked responses independently of cGMP. We demonstrated that these differential effects were specific to postsynaptic N-methyl-d-aspartate (NMDA) receptors by studying treatment effects on pharmacologically isolated EPSCs from each pathway. We propose that when brainstem activity is increased during behavioral arousal or rapid eye movement sleep, NO may increase the relative sensitivity of relay neurons to corticogeniculate feedback. The net effect of these changes in synaptic processing may be to selectively suppress peripheral information while unifying data carried by reentrant corticogeniculate loops with the behavioral context in which the visual information is processed.
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- 2006
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12. The native T-type calcium current in relay neurons of the primate thalamus.
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Alexander GM, Carden WB, Mu J, Kurukulasuriya NC, McCool BA, Nordskog BK, Friedman DP, Daunais JB, Grant KA, and Godwin DW
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- Animals, Calcium Channels, T-Type classification, Calcium Channels, T-Type genetics, Dose-Response Relationship, Radiation, Electric Stimulation methods, Gene Expression physiology, In Vitro Techniques, Macaca fascicularis, Membrane Potentials physiology, Membrane Potentials radiation effects, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction methods, Calcium Channels, T-Type physiology, Geniculate Bodies cytology, Neurons physiology
- Abstract
The generation of thalamic bursts depends upon calcium currents that flow through transiently open (T)-type calcium channels. In this study, we characterized the native T-type calcium current underlying thalamic burst responses in the macaque monkey. Current clamp recordings from lateral geniculate nucleus (LGN) slices showed characteristic burst responses when relay cells were depolarized from relatively hyperpolarized membrane potentials. These bursts could also be elicited by stimulation of excitatory synaptic inputs to LGN cells. Under voltage clamp conditions, the inactivation kinetics of native currents recorded from primate LGN neurons showed consistency with T-type currents recorded in other mammals and in expression systems. Real-time reverse transcriptase PCR performed on RNA isolated from the LGN (including tissues isolated from magnocellular and parvocellular laminae) detected voltage-dependent calcium channel (Ca(v)) 3.1, Ca(v) 3.2, and Ca(v) 3.3 channel transcripts. Ca(v) 3.1 occurred at relatively higher expression than other isoforms, consistent with in situ hybridization studies in rats, indicating that the molecular basis for burst firing in thalamocortical systems is an important conserved property of primate physiology. Since thalamic bursts have been observed during visual processing as well as in a number of CNS disorders, studies of the expression and modulation of these currents at multiple levels are critical for understanding their role in vision and for the discovery of new treatments for disruptions of thalamic rhythms.
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- 2006
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13. Ethanol influences on native T-type calcium current in thalamic sleep circuitry.
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Mu J, Carden WB, Kurukulasuriya NC, Alexander GM, and Godwin DW
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- Animals, Central Nervous System Depressants pharmacology, In Vitro Techniques, Rats, Thalamus metabolism, Calcium Channel Blockers pharmacology, Calcium Channels, T-Type physiology, Ethanol pharmacology, Sleep drug effects, Thalamus drug effects
- Abstract
Ethanol is known to disrupt normal sleep rhythms; however, the cellular basis for this influence is unknown. This study uses an in vitro slice preparation coupled with electrophysiological recordings to probe neuronal responses to acute ethanol exposure. Recordings were conducted in ferret and rat thalamic slices, since thalamic circuitry is an integral component of sleep/wake cycles and sleep spindles. A key mediator of spindle wave activity is the low-threshold calcium current (T-type current). The T-type current underlies burst responses in the lateral geniculate and thalamic reticular nuclei that are important in spindle propagation. Whole cell patch recordings in thalamic brain slices revealed that ethanol has a differential, dose-dependent effect on the native T-type current in thalamic relay cells. Low concentrations of ethanol (2.5, 5, and 10 mM) enhance T-type current (n = 35), whereas higher concentrations of ethanol (20 and 50 mM) decrease T-type current (n = 27). To address whether this dose-dependent effect was due to variation between cells, in a subset we verified the differential effect within the same cell (n = 7). In an effort to examine whether the biphasic effects on the current were due to the order of ethanol exposures, we varied the order of high and low ethanol concentrations within the same cell. The ability of ethanol to perturb calcium currents in thalamic relay cells may provide a mechanistic framework for the well documented disruptions in sleep/wake behavior in subjects with ethanol exposure.
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- 2003
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14. Transneuronal retrograde transport of attenuated pseudorabies viruses within central visual pathways.
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Moore RJ, Vinsant S, McCauley AK, Kurukulasuriya NC, and Godwin DW
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- Animals, Biological Transport, Active, Cats, Feasibility Studies, Immunohistochemistry, Male, Microscopy, Electron, Rats, Rats, Sprague-Dawley, Herpesvirus 1, Suid physiology, Neurons metabolism, Visual Pathways virology
- Abstract
Pseudorabies virus (PRV) has been shown to be an effective transneuronal tracer within both the peripheral and the central nervous system. The only investigations of this virus in the visual system have examined anterograde transport of PRV from injection sites in the retina. In the present study, we injected attenuated forms of PRV into the primary visual cortex of both rats and cats to determine whether transneuronal retrograde infection would occur back to the retina. In rats, we made small injections into visual cortex of a strain of PRV (Bartha Blu) that contained a beta-galactosidase promoter insert. In cats, we injected PRV-M201 into area V1 of visual cortex. After a 2- to 4-day incubation period, we examined tissue from these animals for the presence of the beta-galactosidase marker (rats) or the virus itself (cats). Cortical PRV injections resulted in transneuronal retrograde infection of the lateral geniculate nucleus (LGN), thalamic reticular nucleus (TRN), and retina. PRV was retinotopically distributed in the pathway. In addition, double-labeling experiments in cats using an antibody against gamma-aminobutyric acid (GABA) were conducted to reveal PRV-labeled interneurons within the LGN and TRN. All TRN neurons were GABA+, as was a subset of LGN neurons. Only the subset of TRN neurons adjacent to the PRV-labeled sector of LGN was labeled with PRV. In addition, a subset of GABA+ interneurons in LGN was also labeled with PRV. We processed some tissue for electron microscopy to examine the morphology of the virus at various replication stages. No mature virions were detected in terminals from efferent pathways, although forms consistent with retrograde infection were encountered. We conclude that the PRV strains we have used produce a local infection that progresses primarily in the retrograde direction in the central visual pathways. The infection is transneuronal and viral replication maintains the intensity of the label throughout the chain of connected neurons, providing a means of examining detailed circuitry within the visual pathway.
- Published
- 2001
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