1
|
Peng JJ, Lin SH, Liu YT, Lin HC, Li TN, Yao CK. A circuit-dependent ROS feedback loop mediates glutamate excitotoxicity to sculpt the Drosophila motor system. eLife 2019; 8:47372. [PMID: 31318331 PMCID: PMC6682402 DOI: 10.7554/elife.47372] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022] Open
Abstract
Overproduction of reactive oxygen species (ROS) is known to mediate glutamate excitotoxicity in neurological diseases. However, how ROS burdens can influence neural circuit integrity remains unclear. Here, we investigate the impact of excitotoxicity induced by depletion of Drosophila Eaat1, an astrocytic glutamate transporter, on locomotor central pattern generator (CPG) activity, neuromuscular junction architecture, and motor function. We show that glutamate excitotoxicity triggers a circuit-dependent ROS feedback loop to sculpt the motor system. Excitotoxicity initially elevates ROS, thereby inactivating cholinergic interneurons and consequently changing CPG output activity to overexcite motor neurons and muscles. Remarkably, tonic motor neuron stimulation boosts muscular ROS, gradually dampening muscle contractility to feedback-enhance ROS accumulation in the CPG circuit and subsequently exacerbate circuit dysfunction. Ultimately, excess premotor excitation of motor neurons promotes ROS-activated stress signaling that alters neuromuscular junction architecture. Collectively, our results reveal that excitotoxicity-induced ROS can perturb motor system integrity through a circuit-dependent mechanism.
Collapse
Affiliation(s)
- Jhan-Jie Peng
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Shih-Han Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yu-Tzu Liu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Hsin-Chieh Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Tsai-Ning Li
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Chi-Kuang Yao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China.,Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan, Republic of China
| |
Collapse
|
2
|
Xu Y, Halievski K, Katsuno M, Adachi H, Sobue G, Breedlove SM, Jordan CL. Pre-clinical symptoms of SBMA may not be androgen-dependent: implications from two SBMA mouse models. Hum Mol Genet 2019; 27:2425-2442. [PMID: 29897452 DOI: 10.1093/hmg/ddy142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 04/16/2018] [Indexed: 12/31/2022] Open
Abstract
A distinguishing aspect of spinal and bulbar muscular atrophy (SBMA) is its androgen-dependence, possibly explaining why only males are clinically affected. This disease, which impairs neuromuscular function, is linked to a polyglutamine expansion mutation in the androgen receptor (AR). In mouse models of SBMA, motor dysfunction is associated with pronounced defects in neuromuscular transmission, including defects in evoked transmitter release (quantal content, QC) and fiber membrane excitability (based on the resting membrane potential, RMP). However, whether such defects are androgen-dependent is unknown. Thus, we recorded synaptic potentials intracellularly from adult muscle fibers of transgenic (Tg) AR97Q male mice castrated pre-symptomatically. Although castration largely protects both QC and the RMP of fibers, correlating with the protective effect of castration on motor function, significant deficits in QC and RMP remained. Surprisingly, comparable defects in QC and RMP were also observed in pre-symptomatic AR97Q males, indicating that such defects emerge early and are pre-clinical. Exposing asymptomatic Tg females to androgens also induces both motor dysfunction and comparable defects in QC and RMP. Notably, asymptomatic Tg females also showed significant deficits in QC and RMP, albeit less severe, supporting their pre-clinical nature, but also raising questions about the androgen-dependence of pre-clinical symptoms. In summary, current evidence indicates that disease progression depends on androgens, but early pathogenic events may be triggered by the mutant AR allele independent of androgens. Such early, androgen-independent disease mechanisms may also be relevant to females carrying the SBMA allele.
Collapse
Affiliation(s)
- Youfen Xu
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | | | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environment Health School of Medicine, Yahatanishi-ku, Kitakyushu Fukuoka, Japan
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - S Marc Breedlove
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Cynthia L Jordan
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
3
|
de Wilde S, de Jong MGH, Lipka AF, Guchelaar HJ, Schimmel KJM. The possibility of obtaining marketing authorization of orphan pharmaceutical compounding preparations: 3,4-DAP for Lambert-Eaton Myasthenic Syndrome. Eur J Pharm Sci 2018; 114:24-29. [PMID: 29191521 DOI: 10.1016/j.ejps.2017.11.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND Pharmaceutical compounding preparations, produced by (hospital) pharmacies, usually do not have marketing authorization. As a consequence, some of these pharmaceutical compounding preparations can be picked-up by a pharmaceutical company to obtain marketing authorization, often leading to price increases. An example is the 3,4-diaminopyridine slow release (3,4-DAP SR) tablets for Lambert-Eaton Myasthenic Syndrome (LEMS). In 2009 marketing authorization was given for the commercial immediate release phosphate salt of the drug, including a fifty-fold price increase compared to the pharmaceutical compounding preparation. Obtaining marketing authorization for 3,4-DAP SR by academia might have been a solution to prevent this price increase. To determine whether the available data of a pharmaceutical compounding preparation with long-term experience in regular care are adequate to obtain marketing authorization, 3,4-DAP SR is used as a case study. METHODS A retrospective qualitative case-study was performed. Initially, document analysis was executed by collecting the required data for marketing authorization in general and whether data of Firdapse® and 3,4-DAP SR met these requirements. Secondly, the (non-) available data of the two formulations were compared with each other to determine the differences in availability. RESULTS At the time of approval, almost all data were available for both Firdapse® and 3,4-DAP SR. Conversely, much of the data used for the approval of Firdapse® originated from the 3,4-DAP immediate release (3,4-DAP IR) formulation. Only two bioequivalence studies and one pharmacology safety study was performed with Firdapse® before marketing authorization application. CONCLUSIONS In conclusion, at time Firdapse® obtained approval, the data available did not differ substantially from 3,4-DAP SR, indicating that approval with 3,4-DAP SR would have been possible. We make a plea for approval of orphan medicinal products developed and manufactured by academic institutions as to keep utilization of these products affordable.
Collapse
Affiliation(s)
- Sofieke de Wilde
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Maria G H de Jong
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands.
| | - Alexander F Lipka
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Henk-Jan Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Kirsten J M Schimmel
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
4
|
Dooms M, Carvalho M. Compounded medication for patients with rare diseases. Orphanet J Rare Dis 2018; 13:1. [PMID: 29301541 PMCID: PMC5753439 DOI: 10.1186/s13023-017-0741-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 12/11/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND When there is no authorized on- or in absence even no off-label treatment for patients with rare diseases, pharmacists have to compound medicinal products to meet the patients special needs. However it is important that there is evidence in the medical and/or pharmaceutical literature for such compounded medications. POSITION STATEMENT Pharmaceutical compounding must be performed in the best possible circumstances by certified practitioners (pharmacists) using validated standard operating procedures (standardized formulations) in order to obtain medicinal products of the highest quality to assure patient safety. More than 60 compounding procedures were identified in 17 on-line pharmaceutical compounding reference sources worldwide but more operating procedures still need to be validated. All ingredients used in the preparation of the compounded medication must be accompanied by a certificate of analysis and full records of the pharmaceutical production process need to be kept for full traceability and accountability.
Collapse
Affiliation(s)
- Marc Dooms
- University Hospitals Leuven, Herestraat, B 3000 Leuven, Belgium
| | | |
Collapse
|
5
|
Portaro S, Brizzi T, Sinicropi S, Cacciola A, De Cola MC, Bramanti A, Milardi D, Lupica A, Bramanti P, Toscano A, Rodolico C. Five years experience on 3,4-diaminopyridine phosphate in Lambert-Eaton syndrome: Case reports. Medicine (Baltimore) 2017; 96:e7839. [PMID: 28930822 PMCID: PMC5617689 DOI: 10.1097/md.0000000000007839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/27/2022] Open
Abstract
RATIONALE To report our experience on 7 patients (4 males and 3 females), affected by nonparaneoplastic Lambert-Eaton myasthenic syndrome, treated with 3,4-diaminopyridine phosphate (3,4-DAPP) either alone or in combination with other immunosuppressants or steroids. PATIENT CONCERNS Patients have been evaluated at specific timepoints (ie, baseline and last 5 year follow-up), with neurological examination, autoantibodies against presynaptic voltage-gated Cav2.1 (P/Q type) calcium ion channel (VGCC) dosage, neurophysiological evaluation focusing on the increased amplitude of the compound muscle action potential (cMAP) after maximum voluntary effort, quantitative myasthenia gravis (QMG) and activities of daily living scales, and autonomic nervous system involvement evaluation. OUTCOMES Five out of 7 patients presented a clinical improvement persisting at last 5-year follow-up; 2 out of them improved taking only 3,4-DAPP at the maximal dosage, whereas the remaining received concomitant medications, such as prednisone and azathioprine. However, the clinical amelioration was not statistically significant. No one of the patients reported severe adverse events, except one, complaining of transient chin and perioral paresthesias. A significant association between QMG and the type of pharmacological drugs therapy (P = .028) emerged. Indeed, we observed an improvement of the clinical condition in all 3 subjects treated with 3,4-DAPP and prednisone. CONCLUSIONS In this study, we confirm 3,4-DAPP treatment efficacy on muscle strength, but minor evidence of drug effectiveness have been demonstrated on the autonomic nervous system involvement and on the deep tendon reflexes reappearance, a part from patients who received 3,4-DAPP associated to prednisone.
Collapse
Affiliation(s)
- Simona Portaro
- IRCSS Centro Neurolesi “Bonino-Pulejo”, Neuromuscular Disease Laboratory
| | - Teresa Brizzi
- Department of Clinical and Experimental Medicine, University of Messina, Messina
- DIBIMIS, University of Palermo, Palermo, Italy
| | - Stefano Sinicropi
- Department of Clinical and Experimental Medicine, University of Messina, Messina
| | - Alberto Cacciola
- IRCSS Centro Neurolesi “Bonino-Pulejo”, Neuromuscular Disease Laboratory
| | | | - Alessia Bramanti
- IRCSS Centro Neurolesi “Bonino-Pulejo”, Neuromuscular Disease Laboratory
| | - Demetrio Milardi
- IRCSS Centro Neurolesi “Bonino-Pulejo”, Neuromuscular Disease Laboratory
| | - Antonino Lupica
- Department of Clinical and Experimental Medicine, University of Messina, Messina
| | - Placido Bramanti
- IRCSS Centro Neurolesi “Bonino-Pulejo”, Neuromuscular Disease Laboratory
| | - Antonio Toscano
- Department of Clinical and Experimental Medicine, University of Messina, Messina
| | - Carmelo Rodolico
- Department of Clinical and Experimental Medicine, University of Messina, Messina
| |
Collapse
|
6
|
Acetylator Status Impacts Amifampridine Phosphate (Firdapse™) Pharmacokinetics and Exposure to a Greater Extent Than Renal Function. Clin Ther 2017. [DOI: 10.1016/j.clinthera.2017.05.353] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
7
|
Schoser B, Eymard B, Datt J, Mantegazza R. Lambert–Eaton myasthenic syndrome (LEMS): a rare autoimmune presynaptic disorder often associated with cancer. J Neurol 2017; 264:1854-1863. [DOI: 10.1007/s00415-017-8541-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/06/2017] [Accepted: 06/07/2017] [Indexed: 10/19/2022]
|
8
|
Perez EE, Orange JS, Bonilla F, Chinen J, Chinn IK, Dorsey M, El-Gamal Y, Harville TO, Hossny E, Mazer B, Nelson R, Secord E, Jordan SC, Stiehm ER, Vo AA, Ballow M. Update on the use of immunoglobulin in human disease: A review of evidence. J Allergy Clin Immunol 2016; 139:S1-S46. [PMID: 28041678 DOI: 10.1016/j.jaci.2016.09.023] [Citation(s) in RCA: 368] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 09/12/2016] [Accepted: 09/23/2016] [Indexed: 12/20/2022]
Abstract
Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.
Collapse
Affiliation(s)
- Elena E Perez
- Allergy Associates of the Palm Beaches, North Palm Beach, Fla.
| | - Jordan S Orange
- Department of Pediatrics, Section of Immunology Allergy and Rheumatology, Center for Human Immunobiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Tex
| | - Francisco Bonilla
- Department of Pediatrics, Clinical Immunology Program, Children's Hospital Boston and Harvard Medical School, Boston, Mass
| | - Javier Chinen
- Department of Pediatrics, Section of Immunology Allergy and Rheumatology, Center for Human Immunobiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Tex
| | - Ivan K Chinn
- Department of Pediatrics, Section of Immunology Allergy and Rheumatology, Center for Human Immunobiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Tex
| | - Morna Dorsey
- Department of Pediatrics, Allergy, Immunology and BMT Division, Benioff Children's Hospital and University of California, San Francisco, Calif
| | - Yehia El-Gamal
- Department of Pediatrics, Pediatric Allergy and Immunology Unit, Children's Hospital and Ain Shams University, Cairo, Egypt
| | - Terry O Harville
- Departments of Pathology and Laboratory Services and Pediatrics, University of Arkansas, Little Rock, Ark
| | - Elham Hossny
- Department of Pediatrics, Pediatric Allergy and Immunology Unit, Children's Hospital and Ain Shams University, Cairo, Egypt
| | - Bruce Mazer
- Department of Pediatrics, Allergy and Immunology, Montreal Children's Hospital and McGill University, Montreal, Quebec, Canada
| | - Robert Nelson
- Department of Medicine and Pediatrics, Division of Hematology and Oncology and Stem Cell Transplantation, Riley Hospital, Indiana University School of Medicine and the IU Melvin and Bren Simon Cancer Center, Indianapolis, Ind
| | - Elizabeth Secord
- Department of Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit, Mich
| | - Stanley C Jordan
- Nephrology & Transplant Immunology, Kidney Transplant Program, David Geffen School of Medicine at UCLA and Cedars-Sinai Medical Center, Los Angeles, Calif
| | - E Richard Stiehm
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, Calif
| | - Ashley A Vo
- Transplant Immunotherapy Program, Comprehensive Transplant Center, Kidney Transplant Program, Cedars-Sinai Medical Center, Los Angeles, Calif
| | - Mark Ballow
- Department of Pediatrics, Division of Allergy & Immunology, University of South Florida, Morsani College of Medicine, Johns Hopkins All Children's Hospital, St Petersburg, Fla
| |
Collapse
|
9
|
Ng F, Lee DC, Schrumpf LA, Mazurek ME, Lee Lo V, Gill SK, Maselli RA. Effect of 3,4-diaminopyridine at the murine neuromuscular junction. Muscle Nerve 2016; 55:223-231. [PMID: 27251582 DOI: 10.1002/mus.25208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/19/2016] [Accepted: 05/31/2016] [Indexed: 11/09/2022]
Abstract
INTRODUCTION We investigated the effects of 3,4-diaminopyridine (3,4-DAP) and its acetylated metabolite, N-(4-amino-pyridin-3-yl) acetamide (3-Ac), at the mammalian neuromuscular junction. METHODS Quantal release of acetylcholine was studied in diaphragm muscles of mice, using in vitro intracellular microelectrode recordings. RESULTS Under conditions of low probability of release, 3,4-DAP produced a 1,000% increase in quantal release, but 3-Ac had no effect. Under conditions of normal probability of release, the effect of 3,4-DAP was modest and limited by concurrent depletion of synaptic vesicles, especially with high concentrations of 3,4-DAP and high frequencies of nerve stimulation. CONCLUSIONS These findings predict 3,4-DAP is most effective in conditions with low probability of quantal release, such as Lambert-Eaton myasthenic syndrome. A beneficial effect is also expected in disorders of neuromuscular transmission in which the effect of 3,4-DAP on quantal release is not limited by depletion of synaptic vesicles, such as postsynaptic congenital myasthenic syndromes. Muscle Nerve, 2016 Muscle Nerve 55: 223-231, 2017.
Collapse
Affiliation(s)
- Fiona Ng
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Diana C Lee
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Leah A Schrumpf
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Mary E Mazurek
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Victoria Lee Lo
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Sharleen K Gill
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Ricardo A Maselli
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| |
Collapse
|
10
|
Oh SJ, Shcherbakova N, Kostera-Pruszczyk A, Alsharabati M, Dimachkie M, Blanco JM, Brannagan T, Lavrnić D, Shieh PB, Vial C, Meisel A, Komoly S, Schoser B, Sivakumar K, So Y. Amifampridine phosphate (Firdapse®) is effective and safe in a phase 3 clinical trial in LEMS. Muscle Nerve 2016; 53:717-25. [DOI: 10.1002/mus.25070] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Shin J Oh
- Department of Neurology; University of Alabama at Birmingham; Birmingham Alabama USA
| | | | | | - Mohammad Alsharabati
- Department of Neurology; University of Alabama at Birmingham; Birmingham Alabama USA
| | | | | | | | - Dragana Lavrnić
- Clinical Center of Serbia, Clinic of Neurology; Belgrade Serbia
| | - Perry B Shieh
- Department of Neurology, University of California; Los Angeles California USA
| | - Christophe Vial
- Hospital of Lyon, ENMG Service and Neuromuscular Pathology Hospital; Lyon France
| | - Andreas Meisel
- Charite Universitatsmedizin Berlin-NeuroCure Clinical Research Center; Berlin Germany
| | - Samuel Komoly
- University of Pécs, Department of Neurology; Pécs Hungary
| | - Benedikt Schoser
- Ludwig-Maximilians-University Munich Friedrich-Baur-Institute; Munich Germany
| | | | - Yuen So
- Stanford University; Stanford California USA
| | | |
Collapse
|
11
|
Haroldsen PE, Musson DG, Hanson B, Quartel A, O'Neill CA. Effects of Food Intake on the Relative Bioavailability of Amifampridine Phosphate Salt in Healthy Adults. Clin Ther 2015; 37:1555-63. [PMID: 26101174 DOI: 10.1016/j.clinthera.2015.05.498] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/30/2015] [Accepted: 05/15/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Amifampridine (3,4-diaminopyridine) has been approved in the European Union for the treatment of Lambert-Eaton myasthenic syndrome. Amifampridine has a narrow therapeutic index, and supratherapeutic exposure has been associated with dose-dependent adverse events, including an increased risk for seizure. This study assessed the effect of food on the relative bioavailability of amifampridine in healthy subjects and informed on conditions that can alter exposure. METHODS This randomized, open-labeled, 2-treatment, 2-period crossover study enrolled 47 healthy male and female subjects. Subjects were randomly assigned to receive 2 single oral doses of amifampridine phosphate salt (20 mg base equivalents per dose) under fed or fasted conditions separated by a washout period. Blood and urine samples for pharmacokinetic analyses were taken before and after dosing. Plasma concentrations of amifampridine and an inactive 3-N-acetyl metabolite were determined. The relative bioavailability values of amifampridine and metabolite were assessed based on the plasma PK parameters AUC0-∞, AUC0-t, and Cmax in the fed and fasted states using noncompartmental pharmacokinetic analysis. Parent drug and metabolite excretion were calculated from urinary concentrations. A food effect on bioavailability would be established if the 90% CI of the ratio of population geometric mean value of AUC0-∞, AUC0-t, or Cmax between fed and fasted administration was not within the bioequivalence range of 80% to 125%. Tolerability was assessed based on adverse-event reporting, clinical laboratory assessments, physical examination including vital sign measurements, 12-lead ECG, and concurrent medication use. FINDINGS Food slowed and somewhat decreased the absorption of amifampridine. There was a decrease in exposure (Cmax, 44%; AUC, 20%) after oral administration of amifampridine phosphate salt in the presence of food, and mean Tmax was 2-fold longer in the fed state. The extent of exposure and plasma elimination half-life of the major metabolite was greater than those of amifampridine in the fed and fasted conditions. Mean AUCs in the fed and fasted states were slightly greater in women than men, with no difference in mean Cmax. Orally administered amifampridine was renally eliminated (>93%) as the parent compound and metabolite within 24 hours. Single oral doses of 20 mg of amifampridine phosphate salt were considered well tolerated in both the fed and fasted conditions. High intersubject variability (%CVs, >30%) in amifampridine pharmacokinetic parameter values was observed. IMPLICATIONS At the intended dose under fasting conditions, amifampridine exposure may be increased. European Union Drug Regulating Authorities Clinical Trials identifier: 2011-000596-13.
Collapse
Affiliation(s)
| | | | - Boyd Hanson
- BioMarin Pharmaceutical Inc, Novato, California
| | | | | |
Collapse
|
12
|
Haroldsen PE, Garovoy MR, Musson DG, Zhou H, Tsuruda L, Hanson B, O'Neill CA. Genetic variation in aryl N-acetyltransferase results in significant differences in the pharmacokinetic and safety profiles of amifampridine (3,4-diaminopyridine) phosphate. Pharmacol Res Perspect 2014; 3:e00099. [PMID: 25692017 PMCID: PMC4317230 DOI: 10.1002/prp2.99] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 12/16/2022] Open
Abstract
The clinical use of amifampridine phosphate for neuromuscular junction disorders is increasing. The metabolism of amifampridine occurs via polymorphic aryl N-acetyltransferase (NAT), yet its pharmacokinetic (PK) and safety profiles, as influenced by this enzyme system, have not been investigated. The objective of this study was to assess the effect of NAT phenotype and genotype on the PK and safety profiles of amifampridine in healthy volunteers (N = 26). A caffeine challenge test and NAT2 genotyping were used to delineate subjects into slow and fast acetylators for PK and tolerability assessment of single, escalating doses of amifampridine (up to 30 mg) and in multiple daily doses (20 mg QID) of amifampridine. The results showed that fast acetylator phenotypes displayed significantly lower C max, AUC, and shorter t 1/2 for amifampridine than slow acetylators. Plasma concentrations of the N-acetyl metabolite were approximately twofold higher in fast acetylators. Gender differences were not observed. Single doses of amifampridine demonstrated dose linear PKs. Amifampridine achieved steady state plasma levels within 1 day of dosing four times daily. No accumulation or time-dependent changes in amifampridine PK parameters occurred. Overall, slow acetylators reported 73 drug-related treatment-emergent adverse events versus 6 in fast acetylators. Variations in polymorphic NAT corresponding with fast and slow acetylator phenotypes significantly affects the PK and safety profiles of amifampridine.
Collapse
Affiliation(s)
| | | | | | - Huiyu Zhou
- BioMarin Pharmaceutical Inc. Novato, California, 94949
| | | | - Boyd Hanson
- BioMarin Pharmaceutical Inc. Novato, California, 94949
| | | |
Collapse
|
13
|
Sioka C, Fotopoulos A, Kyritsis AP. Paraneoplastic immune-mediated neurological effects of systemic cancers. Expert Rev Clin Immunol 2014; 10:621-30. [PMID: 24665890 DOI: 10.1586/1744666x.2014.901151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cancer patients may develop paraneoplastic neurological conditions associated with autoantibodies directed against neural or neuromuscular tissues. These syndromes are frequently manifested in advance of the cancer presentation by several months or years necessitating a detailed and expensive investigation to search for the presence of a malignancy. In such cases additional assistance may be obtained by the early employment of whole body 18F flurodeoxyglucose positron emission tomography as a cancer screening imaging procedure for early cancer diagnosis and potential therapy. Effective therapy of the primary cancer consists the best current therapy for a given paraneoplastic syndrome. However, other forms of immune modulation, such as plasma exchange, intravenous gamma globulin, other immune therapies and symptomatic treatment for certain PNS may have additional benefit.
Collapse
Affiliation(s)
- Chrissa Sioka
- Neurosurgical Research Institute, University of Ioannina, Ioannina, Greece
| | | | | |
Collapse
|
14
|
Asadi M, Torabi S, Mohammadi K. Synthesis, characterization, and thermodynamics of some new unsymmetrical Schiff bases of salicylaldehyde with 3,4-diaminopyridine and their cobalt(III) complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 122:676-681. [PMID: 24342295 DOI: 10.1016/j.saa.2013.09.098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/08/2013] [Accepted: 09/26/2013] [Indexed: 06/03/2023]
Abstract
Some new Schiff bases derived from 3,4-diaminopyridine (3,4-DAP) and their new unsymmetrical Co(III) five coordinate complexes described as [Co(Chel)(L)]ClO4⋅H2O where (Chel) is the deprotonated form of a series of unsymmetric ligands containing 3,4-diaminopyridine (3,4-DAP) and substituted salicylaldehyde moieties and a new Co(III) six coordinate Co(III) complex, were synthesized and characterized by (1)H NMR, IR, UV-Vis, and elemental analysis. For the new synthesized five coordinate complexes, the formation constants of the interaction of the Co(III) Schiff bases with various donors were measured spectrophotometrically. The trend of the formation constants of the five coordinate Co(III) Schiff base complexes toward a given phosphine is as follow: 5-H>5-Br and the formation constants trend of these donors are as follow: PBu3>PPh2Me. Furthermore the adduct formation of the five coordinate [Co(3,4-Salpyr)(PBu3)] ClO4⋅H2O, with aromatic amines shows the following binding trend: Im>2-MeIm>2-EtIm>BzIm. The trend of the formation constants of Co(III) Schiff base complexes toward a given donor according to the phosphine axial ligand is as follow: PBu3>PPh2Me.
Collapse
Affiliation(s)
- Mozaffar Asadi
- Chemistry Department, College of Sciences, Shiraz University, Shiraz 71454, Islamic Republic of Iran.
| | - Susan Torabi
- Chemistry Department, College of Sciences, Shiraz University, Shiraz 71454, Islamic Republic of Iran; International Branch, Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran
| | - Khosro Mohammadi
- Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran
| |
Collapse
|
15
|
Lindquist S, Stangel M. 3,4-Diaminopyridine (amifampridine) for the treatment of Lambert–Eaton myasthenic syndrome. Expert Opin Orphan Drugs 2014. [DOI: 10.1517/21678707.2014.887464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
16
|
van Sonderen A, Wirtz PW, Verschuuren JJGM, Titulaer MJ. Treatment options for Lambert–Eaton myasthenic syndrome. Expert Opin Orphan Drugs 2014. [DOI: 10.1517/21678707.2014.872559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
17
|
Claassen J, Spiegel R, Kalla R, Faldon M, Kennard C, Danchaivijitr C, Bardins S, Rettinger N, Schneider E, Brandt T, Jahn K, Teufel J, Strupp M, Bronstein A. A randomised double-blind, cross-over trial of 4-aminopyridine for downbeat nystagmus--effects on slowphase eye velocity, postural stability, locomotion and symptoms. J Neurol Neurosurg Psychiatry 2013; 84:1392-9. [PMID: 23813743 DOI: 10.1136/jnnp-2012-304736] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE The effects of 4-aminopyridine (4-AP) on downbeat nystagmus (DBN) were analysed in terms of slow-phase velocity (SPV), stance, locomotion, visual acuity (VA), patient satisfaction and side effects using standardised questionnaires. METHODS Twenty-seven patients with DBN received 5 mg 4-AP four times a day or placebo for 3 days and 10 mg 4-AP four times a day or placebo for 4 days. Recordings were done before the first, 60 min after the first and 60 min after the last drug administration. RESULTS SPV decreased from 2.42 deg/s at baseline to 1.38 deg/s with 5 mg 4-AP and to 2.03 deg/s with 10 mg 4-AP (p<0.05; post hoc: 5 mg 4-AP: p=0.04). The rate of responders was 57%. Increasing age correlated with a 4-AP-related decrease in SPV (p<0.05). Patients improved in the 'get-up-and-go test' with 4-AP (p<0.001; post hoc: 5 mg: p=0.025; 10 mg: p<0.001). Tandem-walk time (both p<0.01) and tandem-walk error (4-AP: p=0.054; placebo: p=0.059) improved under 4-AP and placebo. Posturography showed that some patients improved with the 5 mg 4-AP dose, particularly older patients. Near VA increased from 0.59 at baseline to 0.66 with 5 mg 4-AP (p<0.05). Patients with idiopathic DBN had the greatest benefit from 4-AP. There were no differences between 4-AP and placebo regarding patient satisfaction and side effects. CONCLUSIONS 4-AP reduced SPV of DBN, improved near VA and some locomotor parameters. 4-AP is a useful medication for DBN syndrome, older patients in particular benefit from the effects of 5 mg 4-AP on nystagmus and postural stability.
Collapse
Affiliation(s)
- Jens Claassen
- Department of Neurology and German Center for Vertigo and Balance Disorders (IFBLMU), University Hospital Munich, Campus Großhadern, , Munich, Bavaria, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Sandhu B, Fonari MS, Sawyer K, Timofeeva TV. A series of crystalline solids composed of aminopyridines and succinic, fumaric, and sebacic acids. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.08.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
19
|
Zebrafish calls for reinterpretation for the roles of P/Q calcium channels in neuromuscular transmission. J Neurosci 2013; 33:7384-92. [PMID: 23616544 DOI: 10.1523/jneurosci.5839-12.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A long-held tenet of neuromuscular transmission is that calcium-dependent neurotransmitter release is mediated by N-type calcium channels in frog but P/Q-type channels in mammals. The N-type assignment in frog is based principally on pharmacological sensitivity to ω-conotoxin GVIA. Our studies show that zebrafish neuromuscular transmission is also sensitive to ω-conotoxin GVIA. However, positional cloning of a mutant line with compromised neuromuscular function identified a mutation in a P/Q- rather than N-type channel. Cloning and heterologous expression of this P/Q-type channel confirmed a block by ω-conotoxin GVIA raising the likelihood that all vertebrates, including frog, use the P/Q-type calcium channel for neuromuscular transmission. In addition, our P/Q defective mutant line offered a means of testing the ability of roscovitine, known to potentiate frog neuromuscular transmission, to mediate behavioral and functional rescue. Acute treatment led to rapid improvement of both, pointing to potential therapeutic benefit for myasthenic disorders involving calcium channel dysfunction.
Collapse
|
20
|
4-aminopyridine does not enhance flocculus function in tottering, a mouse model of vestibulocerebellar dysfunction and ataxia. PLoS One 2013; 8:e57895. [PMID: 23451282 PMCID: PMC3581497 DOI: 10.1371/journal.pone.0057895] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/27/2013] [Indexed: 01/06/2023] Open
Abstract
The potassium channel antagonist 4-aminopyridine (4-AP) improves a variety of motor abnormalities associated with disorders of the cerebellum. The most rigorous quantitative data relate to 4-AP's ability to improve eye movement deficits in humans referable to dysfunction of the cerebellar flocculus. Largely based on work in the ataxic mouse mutant tottering (which carries a mutation of the Cacna1a gene of the P/Q voltage-activated calcium channel), 4-AP is hypothesized to function by enhancing excitability or rhythmicity of floccular Purkinje cells. We tested this hypothesis by determining whether systemic or intrafloccular administration of 4-AP would ameliorate the eye movement deficits in tottering that are attributable to flocculus dysfunction, including the reductions in amplitude of the yaw-axis vestibulo-ocular reflex (VOR) and vision-enhanced vestibulo-ocular reflex (VVOR), and the optokinetic reflex (OKR) about yaw and roll axes. Because tottering's deficits increase with age, both young and elderly mutants were tested to detect any age-dependent 4-AP effects. 4-AP failed to improve VOR, VVOR, and OKR gains during sinusoidal stimuli, although it may have reduced the tendency of the mutants' responses to VOR and VVOR to decline over the course of a one-hour recording session. For constant-velocity optokinetic stimuli, 4-AP generated some enhancement of yaw OKR and upward-directed roll OKR, but the effects were also seen in normal C57BL/6 controls, and thus do not represent a specific reversal of the electrophysiological consequences of the tottering mutation. Data support a possible extra-floccular locus for the effects of 4-AP on habituation and roll OKR. Unilateral intrafloccular 4-AP injections did not affect ocular motility, except to generate mild eye elevations, consistent with reduced floccular output. Because 4-AP did not produce the effects expected if it normalized outputs of floccular Purkinje cells, there is a need for further studies to elucidate the drug's mechanism of action on cerebellar motor dysfunction.
Collapse
|
21
|
Vrinten C, Weinreich SS, Scholten RJPM, Verschuuren JJGM. 3,4-Diaminopyridine for myasthenia gravis. Hippokratia 2012. [DOI: 10.1002/14651858.cd009675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Charlotte Vrinten
- VU University Medical Center; Community Genetics Section, Clinical Genetics; BS7, D420 PO Box 7057 1007 MB Amsterdam Netherlands
| | - Stephanie S. Weinreich
- VU University Medical Center; Community Genetics Section, Clinical Genetics; BS7, D420 PO Box 7057 1007 MB Amsterdam Netherlands
| | - Rob JPM Scholten
- Academic Medical Center; Dutch Cochrane Centre; Room J1B - 211 P.O. Box 22700 Amsterdam Netherlands 1100 DE
| | - Jan JGM Verschuuren
- Leiden University Medical Center; Department of Neurology; PO Box 9600 Leiden Netherlands 2300 RC
| |
Collapse
|
22
|
Gilhus NE. Lambert-eaton myasthenic syndrome; pathogenesis, diagnosis, and therapy. Autoimmune Dis 2011; 2011:973808. [PMID: 21969911 PMCID: PMC3182560 DOI: 10.4061/2011/973808] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 08/04/2011] [Indexed: 11/29/2022] Open
Abstract
Lambert-Eaton Myasthenic Syndrome (LEMS) is a rare disease with a well-characterized pathogenesis. In 50% of the patients, LEMS is a paraneoplastic manifestation and caused by a small cell lung carcinoma (SCLC). Both LEMS patients with SCLC and those without this tumour have in 85% of cases pathogenetic antibodies of very high LEMS specificity against voltage-gated calcium channels (VGCCs) in the cell membrane of the presynaptic motor nerve terminal. Better understanding of LEMS pathogenesis has lead to targeted symptomatic therapy aimed at the neuromuscular junction and to semispecific immuno-suppression. For SCLC LEMS, tumour therapy is essential.
Collapse
Affiliation(s)
- Nils Erik Gilhus
- Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway
- Department of Neurology, Haukeland University Hospital, 5021 Bergen, Norway
| |
Collapse
|
23
|
Green DM, Jones AC, Brain KR. Content variability of active drug substance in compounded oral 3,4-diaminopyridine products. J Clin Pharm Ther 2011; 37:53-7. [PMID: 21501202 DOI: 10.1111/j.1365-2710.2011.01249.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE 3,4-diaminopyridine (3,4-DAP; amifampridine) is used for symptomatic treatment of Lambert-Eaton myasthenic syndrome. Until recently, it was only available as a compounded product, which raises safety concerns because of possible high variability in active drug substance content. The objective of this study was to evaluate the variability in dosage form weight, active content variability and impurity of compounded oral 3,4-DAP drug products. METHODS Ten samples each of 9 oral 3,4-DAP compounded products were weighed, extracted with water and the 3,4-DAP content determined by ultra high-performance liquid chromatography. RESULTS AND DISCUSSION Variability in dosage form weight ranged from 0·81% relative standard deviation (RSD) to 4·82% RSD. In the 90 samples tested, 3,4-DAP content ranged from 22·2% to 125·2% of declared label content. All 10 samples of one compounded product had active drug substance content well below the declared label content (35·0%, 51·7% RSD). No compounded product achieved the Good Manufacturing Practice (GMP) standard of 95-105% range limit of declared label content; one achieved 90-110%, and four others achieved 80-120% of declared content for all 10 samples. There was no evidence of a significant presence of degradation products or related substances in any compounded product. WHAT IS NEW AND CONCLUSION Compounded 3,4-DAP products are subject to considerable variability in active drug substance content. This variability seems to be principally because of heterogeneous formulated material rather than variation in dosage form weight.
Collapse
Affiliation(s)
- D M Green
- An-eX Analytical Services Ltd., Capital Business Park, Cardiff, UK.
| | | | | |
Collapse
|
24
|
Pasqualoni E, Aubart F, Brihaye B, Sacré K, Maisonobe T, Laissy JP, Lidove O, Papo T. Lambert–Eaton Myasthenic syndrome and follicular thymic hyperplasia in systemic lupus erythematosus. Lupus 2011; 20:745-8. [DOI: 10.1177/0961203310393769] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- E Pasqualoni
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - F Aubart
- Department of Neurophysiology, Pitié-Salpetrière Hospital, Paris, France
| | - B Brihaye
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - K Sacré
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - T Maisonobe
- Department of Neurophysiology, Pitié-Salpetrière Hospital, Paris, France
| | - J-P Laissy
- Department of Radiology, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - O Lidove
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - T Papo
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| |
Collapse
|
25
|
Lindquist S, Stangel M. Update on treatment options for Lambert-Eaton myasthenic syndrome: focus on use of amifampridine. Neuropsychiatr Dis Treat 2011; 7:341-9. [PMID: 21822385 PMCID: PMC3148925 DOI: 10.2147/ndt.s10464] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Indexed: 12/12/2022] Open
Abstract
In Lambert-Eaton myasthenic syndrome (LEMS), antibodies against presynaptic voltage-gated calcium channels reduce the quantal release of acetylcholine, causing muscle weakness and autonomic dysfunction. More than half of the affected patients have associated small cell lung cancer, and thorough screening for an underlying malignancy is crucial. The mainstay of treatment for LEMS is symptomatic but immunotherapy is needed in more severely affected patients. Symptomatic therapies aim at increasing the concentration of acetylcholine at the muscle endplate. While acetylcholinesterase inhibitors were the first drugs to be used for the amelioration of symptoms, 3,4-diaminopyridine (3,4-DAP, amifampridine) has been shown to be more effective. 3,4-DAP blocks presynaptic potassium channels, thereby prolonging the action potential and increasing presynaptic calcium concentrations. This then results in increased quantal release of acetylcholine. The efficacy of 3,4-DAP for increasing muscle strength and resting compound muscle action potentials has been demonstrated by four placebo-controlled trials. Side effects are usually mild, and the most frequently reported are paresthesias. The most common serious adverse events are epileptic seizures. 3,4-DAP is currently the treatment of choice in patients with Lambert-Eaton myasthenic syndrome.
Collapse
Affiliation(s)
- Sabine Lindquist
- Section Clinical Neuroimmunology and Neurochemistry, Department of Neurology, Hannover Medical School, Hannover, Germany
| | | |
Collapse
|