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Neurology and Therapy Sep 2022Lambert-Eaton myasthenic syndrome (LEMS) is characterized by autoantibodies against voltage-gated calcium channels (VGCC) at the neuromuscular junction causing proximal...
INTRODUCTION
Lambert-Eaton myasthenic syndrome (LEMS) is characterized by autoantibodies against voltage-gated calcium channels (VGCC) at the neuromuscular junction causing proximal muscle weakness, decreased tendon reflexes, and autonomic changes. The European LEMS registry aimed to collate observational safety data for 3,4-diaminopyridine phosphate (3,4-DAPP) and examine long-term outcomes for patients with LEMS.
METHODS
Thirty centers across four countries participated in the non-interventional European LEMS registry. Any patients diagnosed with LEMS by means of clinical assessment and abnormal neurophysiological testing, or clinical assessment and positive for VGCC antibodies were eligible to participate. Patients were monitored using standard assessments for LEMS-related clinical manifestations.
RESULTS
Among 96 evaluable participants, 50 (52.1%) were being treated with 3,4-DAPP, 21 (21.9%) with 3,4-diaminopyridine (3,4-DAP), and 25 (26.0%) with other treatments (e.g., pyridostigmine, corticosteroids, immunoglobulins, and azathioprine); 74 participants (77.1%) were exposed to 3,4-DAPP at any time. Quantitative myasthenia gravis scores were similar across treatment groups. Muscle strength was generally good and maintained during follow-up. Cerebellar ataxia, defined as a negative Romberg's test and at least one other positive ataxia test, was observed in 30 (56.6%) patients. Most participants had reduced reflex tone and limited functioning. Sustained or improved functioning was observed in participants administered 3,4-DAPP. Inconsistent and sporadic functional improvement and regression was observed with 3,4-DAP and other treatments. Fifty-five treatment-related adverse events (AEs) were reported by 32 (33.3%) participants. Eight (8.3%) participants reported nine treatment-related serious AEs. No new safety signals were identified.
CONCLUSION
No new safety signals were observed following long-term management of LEMS with 3,4-DAPP.
PubMed: 35511347
DOI: 10.1007/s40120-022-00354-8 -
Biomedicine & Pharmacotherapy =... May 20213,4-Diaminopyridine (3,4-DAP) and its phosphate form, 3,4-DAPP have been used efficiently in the past years to treat muscular weakness in myasthenic syndromes with...
3,4-Diaminopyridine (3,4-DAP) and its phosphate form, 3,4-DAPP have been used efficiently in the past years to treat muscular weakness in myasthenic syndromes with neuromuscular junctions (NMJs) impairment. Pompe disease (PD), an autosomal recessive metabolic disorder due to a defect of the lysosomal enzyme α-glucosidase (GAA), presents some secondary symptoms that are related to neuromuscular transmission dysfunction, resulting in endurance and strength failure. In order to evaluate whether 3,4-DAPP could have a beneficial effect on this pathology, we took advantage of a transient zebrafish PD model that we previously generated and characterized. We investigated presynaptic and postsynaptic structures, NMJs at the electron microscopy level, and zebrafish behavior, before and after treatment with 3,4-DAPP. After drug administration, we observed an increase in the number of acetylcholine receptors an increment in the percentage of NMJs with normal structure and amelioration in embryo behavior, with recovery of typical movements that were lost in the embryo PD model. Our results revealed early NMJ impairment in Pompe zebrafish model with improvement after administration of 3,4-DAPP, suggesting its potential use as symptomatic drug in patients with Pompe disease.
Topics: Amifampridine; Animals; Behavior, Animal; Embryo, Nonmammalian; Glycogen Storage Disease Type II; Motor Activity; Muscle Fibers, Skeletal; Neuromuscular Junction; Receptors, Cholinergic; Zebrafish; alpha-Glucosidases
PubMed: 33724918
DOI: 10.1016/j.biopha.2021.111357 -
JCI Insight Jan 2020Botulinum neurotoxins (BoNTs) are potent neuroparalytic toxins that cause mortality through respiratory paralysis. The approved medical countermeasure for BoNT poisoning...
Botulinum neurotoxins (BoNTs) are potent neuroparalytic toxins that cause mortality through respiratory paralysis. The approved medical countermeasure for BoNT poisoning is infusion of antitoxin immunoglobulins. However, antitoxins have poor therapeutic efficacy in symptomatic patients; thus, there is an urgent need for treatments that reduce the need for artificial ventilation. We report that the US Food and Drug Administration-approved potassium channel blocker 3,4-diaminopyridine (3,4-DAP) reverses respiratory depression and neuromuscular weakness in murine models of acute and chronic botulism. In ex vivo studies, 3,4-DAP restored end-plate potentials and twitch contractions of diaphragms isolated from mice at terminal stages of BoNT serotype A (BoNT/A) botulism. In vivo, human-equivalent doses of 3,4-DAP reversed signs of severe respiratory depression and restored mobility in BoNT/A-intoxicated mice at terminal stages of respiratory collapse. Multiple-dosing administration of 3,4-DAP improved respiration and extended survival at up to 5 LD50 BoNT/A. Finally, 3,4-DAP reduced gastrocnemius muscle paralysis and reversed respiratory depression in sublethal models of serotype A-, B-, and E-induced botulism. These findings make a compelling argument for repurposing 3,4-DAP to symptomatically treat symptoms of muscle paralysis caused by botulism, independent of serotype. Furthermore, they suggest that 3,4-DAP is effective for a range of botulism symptoms at clinically relevant time points.
Topics: Amifampridine; Animals; Antitoxins; Botulinum Toxins; Botulinum Toxins, Type A; Botulism; Disease Models, Animal; Female; Lethal Dose 50; Mice; Muscle, Skeletal; Paralysis; Potassium Channel Blockers; Serogroup; United States; United States Food and Drug Administration
PubMed: 31996484
DOI: 10.1172/jci.insight.132891 -
BMC Neurology Sep 2021Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of neuromuscular transmission. The objective was to examine the efficacy and safety of... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of neuromuscular transmission. The objective was to examine the efficacy and safety of 3,4-diaminopyridine (3,4-DAP) in patients with LEMS.
METHODS
We searched several databases to identify relevant studies, including PubMed, EMBASE, Web of Science, MEDLINE, Cochrane Neuromuscular Disease Group Specialized Register and the Cochrane Central Register of Controlled Trials(CENTRAL). The primary outcome, quantitative myasthenia gravis (QMG) score and the secondary outcome, compound muscle action potentials (CMAP) amplitude were pooled by meta-analysis.
RESULTS
Six randomised controlled trials (RCTs) involving 115 patients with LEMS were included. QMG score showed a significant decrease (improvement) of 2.76 points (95 % CI, -4.08 to -1.45, p < 0.001) after treatment with 3, 4-DAP. Moreover, the overall mean CMAP amplitude improved significantly in LEMS patients with 3, 4-DAP treatment, compared with placebo treatment (mean difference 1.34 mV, 95 % CI, 0.98 to 1.70, p < 0.001). The overall assessment of all included trials showed a low risk of bias and low heterogeneity.
CONCLUSIONS
The pooled results of RCTs demonsrated with moderate to high evidence that 3,4-DAP has a significant effect on LEMS treatment, with improvements in muscle strength score and CMAP amplitude.
Topics: 4-Aminopyridine; Adult; Amifampridine; Humans; Lambert-Eaton Myasthenic Syndrome; Myasthenia Gravis; Randomized Controlled Trials as Topic
PubMed: 34563155
DOI: 10.1186/s12883-021-02405-3 -
Scientific Reports May 20244-aminopyridine (4AP) is a potassium (K) channel blocker used clinically to improve walking in people with multiple sclerosis (MS). 4AP binds to exposed K channels in...
4-aminopyridine (4AP) is a potassium (K) channel blocker used clinically to improve walking in people with multiple sclerosis (MS). 4AP binds to exposed K channels in demyelinated axons, reducing the leakage of intracellular K and enhancing impulse conduction. Multiple derivatives of 4AP capable of blocking K channels have been reported including three radiolabeled with positron emitting isotopes for imaging demyelinated lesions using positron emission tomography (PET). However, there remains a demand for novel molecules with suitable physicochemical properties and binding affinity that can potentially be radiolabeled and used as PET radiotracers. In this study, we introduce 3-fluoro-5-methylpyridin-4-amine (5Me3F4AP) as a novel trisubstituted K channel blocker with potential application in PET. 5Me3F4AP has comparable potency to 4AP and the PET tracer 3-fluoro-4-aminopyridine (3F4AP). Compared to 3F4AP, 5Me3F4AP exhibits comparable basicity (pK = 7.46 ± 0.01 vs. 7.37 ± 0.07, P-value = 0.08), greater lipophilicity (logD = 0.664 ± 0.005 vs. 0.414 ± 0.002, P-value < 0.0001) and higher permeability to an artificial brain membrane (P = 88.1 ± 18.3 vs. 31.1 ± 2.9 nm/s, P-value = 0.03). 5Me3F4AP is also more stable towards oxidation in vitro by the cytochrome P450 enzyme CYP2E1 (IC = 36.2 ± 2.5 vs. 15.4 ± 5.1, P-value = 0.0003); the enzyme responsible for the metabolism of 4AP and 3F4AP. Taken together, 5Me3F4AP has promising properties as a candidate for PET imaging warranting additional investigation.
Topics: Potassium Channel Blockers; Humans; Positron-Emission Tomography; 4-Aminopyridine; Amifampridine
PubMed: 38750155
DOI: 10.1038/s41598-024-61465-w -
Saudi Medical Journal Jun 2024To shed some light on a potential therapeutic modality that may facilitate resolution of botulism symptoms, namely 3,4-diaminopyridine (3,4-DAP).
OBJECTIVES
To shed some light on a potential therapeutic modality that may facilitate resolution of botulism symptoms, namely 3,4-diaminopyridine (3,4-DAP).
METHODS
In Riyadh, Saudi Arabia, we recently encountered a foodborne botulism outbreak that, luckily, was discovered early. In Prince Sultan Military Medical city, we admitted, during a period of approximately 3 weeks, 15 probable cases, 2 of which were excluded due to more likely alternative diagnoses. We report in this case series 13 highly suspected cases of botulism that we encountered during the outbreak.
RESULTS
A total of 12 out of 13 patients required intensive care unit (ICU) admission, one of which required intubation. Symptoms included cranial nerve palsies, gastrointestinal symptoms, limb and respiratory muscle weakness. Patients showed clinical improvement when received botulinum antitoxin and 3,4-DAP if given early in the course of the disease.
CONCLUSION
Early admisntration of 3,4-DAP may facilitate recovery and prevent disease progression. Larger prospective trials should be carried out to confirm that.
Topics: Humans; Botulism; Disease Outbreaks; Male; Saudi Arabia; Adult; Female; Middle Aged; Amifampridine; Botulinum Antitoxin; Young Adult
PubMed: 38830658
DOI: 10.15537/smj.2024.45.6.20240419 -
The Journal of Pharmacology and... Jan 2024Botulinum neurotoxin (BoNT) is a potent protein toxin that causes muscle paralysis and death by asphyxiation. Treatments for symptomatic botulism are intubation and...
Botulinum neurotoxin (BoNT) is a potent protein toxin that causes muscle paralysis and death by asphyxiation. Treatments for symptomatic botulism are intubation and supportive care until respiratory function recovers. Aminopyridines have recently emerged as potential treatments for botulism. The clinically approved drug 3,4-diaminopyridine (3,4-DAP) rapidly reverses toxic signs of botulism and has antidotal effects when continuously administered in rodent models of lethal botulism. Although the therapeutic effects of 3,4-DAP likely result from the reversal of diaphragm paralysis, the corresponding effects on respiratory physiology are not understood. Here, we combined unrestrained whole-body plethysmography (UWBP) with arterial blood gas measurements to study the effects of 3,4-DAP, and other aminopyridines, on ventilation and respiration at terminal stages of botulism in mice. Treatment with clinically relevant doses of 3,4-DAP restored ventilation in a dose-dependent manner, producing significant improvements in ventilatory parameters within 10 minutes. Concomitant with improved ventilation, 3,4-DAP treatment reversed botulism-induced respiratory acidosis, restoring blood levels of CO, pH, and lactate to normal physiologic levels. Having established that 3,4-DAP-mediated improvements in ventilation were directly correlated with improved respiration, we used UWBP to quantitatively evaluate nine additional aminopyridines in BoNT/A-intoxicated mice. Multiple aminopyridines were identified with comparable or enhanced therapeutic efficacies compared with 3,4-DAP, including aminopyridines that selectively improved tidal volume versus respiratory rate and vice versa. In addition to contributing to a growing body of evidence supporting the use of aminopyridines to treat clinical botulism, these data lay the groundwork for the development of aminopyridine derivatives with improved pharmacological properties. SIGNIFICANCE STATEMENT: There is a critical need for fast-acting treatments to reverse respiratory paralysis in patients with botulism. This study used unrestrained, whole-body plethysmography and arterial blood gas analysis to show that aminopyridines rapidly restore ventilation and respiration and reverse respiratory acidosis when administered to mice at terminal stages of botulism. In addition to supporting the use of aminopyridines as first-line treatments for botulism symptoms, these data are expected to contribute to the development of new aminopyridine derivatives with improved pharmacological properties.
Topics: Mice; Humans; Animals; Botulism; Aminopyridines; Amifampridine; Acidosis, Respiratory; Botulinum Toxins, Type A; Paralysis; Respiration
PubMed: 37977816
DOI: 10.1124/jpet.123.001773 -
Cureus Jan 2024After a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, approximately 10-20% of patients are affected by the post-COVID syndrome (PCS). This...
After a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, approximately 10-20% of patients are affected by the post-COVID syndrome (PCS). This condition leads to a variety of functional complaints, including symptoms of fatigue. To date, there is still no adequate treatment option. Five patients are presented, including the self-observation of one of the authors, in whom the administration of amifampridine as an "off-label use" led to a normalization of the unphysiologically increased need for sleep with a simultaneous increase in the Bell score. This effect was confirmed in a double-blind discontinuation trial (the medication was discontinued on a trial basis) in two of the patients. The five patients, who were previously unable to lead a normal life due to their fatigue symptoms, were able to return to everyday life after treatment with amifampridine. This offers hope to millions of affected patients.
PubMed: 38406122
DOI: 10.7759/cureus.52935 -
Tremor and Other Hyperkinetic Movements... Oct 2020The diagnosis of a paroxysmal dyskinesia is difficult and status dystonicus is a rare life threatening movement disorder characterised by severe, frequent or continuous...
The diagnosis of a paroxysmal dyskinesia is difficult and status dystonicus is a rare life threatening movement disorder characterised by severe, frequent or continuous episodes of dystonic spasms. A 25 year old woman with chronic ataxia and paroxysmal dyskinesia presented with facial twitching, writhing of arms, oculogyric crisis and visual and auditory hallucinations. She developed respiratory failure and was ventilated. No cause was found so whole exome sequencing was performed and this revealed a novel, non-synonymous heterozygous variant in exon 11 of the gene, K457E (c 1369A>G) in the patient but not her parents. This variant has not been previously reported in gnomAD or ClinVar. The finding of a de novo variant in a potassium channel gene guided a trial of the potassium channel antagonist 3,4 diaminopyridine resulting in significant improvement, discharge from the intensive care unit and ultimately home.
Topics: Adult; Amifampridine; Ataxia; Chorea; Dystonia; Electroencephalography; Female; Hallucinations; Humans; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; Ocular Motility Disorders; Potassium Channel Blockers
PubMed: 33178487
DOI: 10.5334/tohm.549