| 1. |
- Bentzen, B. H., et al.
(författare)
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Mechanisms of Action of the KCa2-Negative Modulator AP30663, a Novel Compound in Development for Treatment of Atrial Fibrillation in Man
- 2020
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Ingår i: Frontiers in Pharmacology. - : Frontiers Media SA. - 1663-9812. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Aims Small conductance Ca2+-activated K+ channels (SK channels, K(Ca)2) are a new target for treatment of atrial fibrillation (AF). AP30663 is a small molecule inhibitor of K(Ca)2 channels that is currently in clinical development for treatment of AF. The aim of this study is to present the electrophysiological profile and mechanism of action of AP30663 and its efficacy in prolonging atrial refractoriness in rodents, and by bioinformatic analysis investigate if genetic variants in KCNN2 or KCNN3 influence the expression level of these in human heart tissue. Methods and Results Whole-cell and inside-out patch-clamp recordings of heterologously expressed K(Ca)2 channels revealed that AP30663 inhibits K(Ca)2 channels with minor effects on other relevant cardiac ion channels. AP30663 modulates the K(Ca)2.3 channel by right-shifting the Ca2+-activation curve. In isolated guinea pig hearts AP30663 significantly prolonged the atrial effective refractory period (AERP) with minor effects on the QT-interval corrected for heart rate. Similarly, in anaesthetized rats 5 and 10 mg/kg of AP30663 changed the AERP to 130.7 +/- 5.4% and 189.9 +/- 18.6 of baseline values. The expression quantitative trait loci analyses revealed that the genome wide association studies for AF SNP rs13376333 in KCNN3 is associated with increased mRNA expression of KCNN3 in human atrial appendage tissue. Conclusions AP30663 is a novel negative allosteric modulator of K(Ca)2 channels that concentration-dependently prolonged rodent atrial refractoriness with minor effects on the QT-interval. Moreover, AF associated SNPs in KCNN3 influence KCNN3 mRNA expression in human atrial tissue. These properties support continued development of AP30663 for treatment of AF in man.
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| 2. |
- Citerini, Charlotta, et al.
(författare)
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Inhibition of KCa2 and Kv11.1 Channels in Pigs With Left Ventricular Dysfunction.
- 2020
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Ingår i: Frontiers in pharmacology. - : Frontiers Media SA. - 1663-9812. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of KCa2 channels, conducting IKCa, can convert atrial fibrillation (AF) to sinus rhythm and protect against its induction. IKCa inhibition has been shown to possess functional atrial selectivity with minor effects on ventricles. Under pathophysiological conditions with ventricular remodeling, however, inhibiting IKCa can exhibit both proarrhythmic and antiarrhythmic ventricular effects. The aim of this study was to evaluate the effects of the IKCa inhibitor AP14145, when given before or after the IKr blocker dofetilide, on cardiac function and ventricular proarrhythmia markers in pigs with or without left ventricular dysfunction (LVD).Landrace pigs were randomized into an AF group (n = 6) and two control groups: SHAM1 (n = 8) and SHAM2 (n = 4). AF pigs were atrially tachypaced (A-TP) for 43 ± 4 days until sustained AF and LVD developed. A-TP and SHAM1 pigs received 20 mg/kg AP14145 followed by 100 µg/kg dofetilide whereas SHAM2 pigs received the same drugs in the opposite order. Proarrhythmic markers such as short-term variability of QT (STVQT) and RR (STVRR) intervals, and the number of premature ventricular complexes (PVCs) were measured at baseline and after administration of drugs. The influence on cardiac function was assessed by measuring cardiac output, stroke volume, and relevant echocardiographic parameters.IKCa inhibition by AP14145 did not increase STVQT or STVRR in any of the pigs. IKr inhibition by dofetilide markedly increased STVQT in the A-TP pigs, but not in SHAM operated pigs. Upon infusion of AP14145 the number of PVCs decreased or remained unchanged both when AP14145 was infused after baseline and after dofetilide. Conversely, the number of PVCs increased or remained unchanged upon dofetilide infusion. Neither AP14145 nor dofetilide affected relevant echocardiographic parameters, cardiac output, or stroke volume in any of the groups.IKCa inhibition with AP14145 was not proarrhythmic in healthy pigs, or in the presence of LVD resulting from A-TP. In pigs already challenged with 100 µg/kg dofetilide there were no signs of proarrhythmia when 20 mg/kg AP14145 were infused. KCa2 channel inhibition did not affect cardiac function, implying that KCa2 inhibitors can be administered safely also in the presence of LV dysfunction.
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| 3. |
- Citerni, Carlotta, et al.
(författare)
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Characterization of Atrial and Ventricular Structural Remodeling in a Porcine Model of Atrial Fibrillation Induced by Atrial Tachypacing.
- 2020
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Ingår i: Frontiers in veterinary science. - : Frontiers Media SA. - 2297-1769. ; 7:April
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Tidskriftsartikel (refereegranskat)abstract
- Background: Atrial fibrillation (AF) is characterized by electrical and structural remodeling. Irregular and/or fast atrio-ventricular (AV) conduction during AF can result in AV dyssynchrony, tachymyopathy, pressure and volume overload with subsequent dilatation, valve regurgitation, and ventricular dysfunction with progression to heart failure. Objective: To gain further insight into the myocardial pathophysiological changes induced by right atrial tachypacing (A-TP) in a large animal model. Methods: A total of 28 Landrace pigs were randomized as 14 into AF-induced A-TP group and 14 pigs to control group. AF pigs were tachypaced for 43 ± 4 days until in sustained AF. Functional remodeling was investigated by echocardiography (after cardioversion to sinus rhythm). Structural remodeling was quantified by histological preparations with picrosirius red and immunohistochemical stainings. Results: A-TP resulted in decreased left ventricular ejection fraction (LVEF) accompanied by increased end-diastolic and end-systolic left atrium (LA) volume and area. In addition, A-TP was associated with mitral valve (MV) regurgitation, diastolic dysfunction and increased atrial and ventricular fibrotic extracellular matrix (ECM). Conclusions: A-TP induced AF with concomitant LV systolic and diastolic dysfunction, increased LA volume and area, and atrial and ventricular fibrosis.
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| 4. |
- Diness, J. G., et al.
(författare)
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Inhibition of K(Ca)2 Channels Decreased the Risk of Ventricular Arrhythmia in the Guinea Pig Heart During Induced Hypokalemia
- 2020
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Ingår i: Frontiers in Pharmacology. - : Frontiers Media SA. - 1663-9812. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background Hypokalemia reduces the cardiac repolarization reserve. This prolongs the QT-interval and increases the risk of ventricular arrhythmia; a risk that is exacerbated by administration of classical class 3 anti-arrhythmic agents. Small conductance Ca2+-activated K+-channels (K(Ca)2) are a promising new atrial selective target for treatment of atrial fibrillation. Under physiological conditions K(Ca)2 plays a minor role in ventricular repolarization. However, this might change under hypokalemia because of concomitant increases in ventriculay -60r intracellur Ca2+. Purpose To study the effects of pharmacological K(Ca)2 channel inhibition by the compounds AP14145, ICA, or AP30663 under hypokalemic conditions as compared to dofetilide and hypokalemia alone time-matched controls (TMC). Methods The current at +10 mV was compared in HEK293 cells stably expressing K(Ca)2.3 perfused first with normo- and then hypokalemic solutions (4 mM K+ and 2.5 mM K+, respectively). Guinea pig hearts were isolated and perfused with normokalemic (4 mM K+) Krebs-Henseleit solution, followed by perfusion with drug or vehicle control. The perfusion was then changed to hypokalemic solution (2.5 mM K+) in presence of drug. 30 animals were randomly assigned to 5 groups: ICA, AP14145, AP30663, dofetilide, or TMC. QT-interval, the interval from the peak to the end of the T wave (Tp-Te), ventricular effective refractory period (VERP), arrhythmia score, and ventricular fibrillation (VF) incidence were recorded. Results Hypokalemia slightly increased K(Ca)2.3 current compared to normokalemia. Application of K(Ca)2 channel inhibitors and dofetilide prolonged the QT interval corrected for heart rate. Dofetilide, but none of the K(Ca)2 channel inhibitors increased Tp-Te during hypokalemia. During hypokalemia 4/6 hearts in the TMC group developed VF (two spontaneously, two by S1S2 stimulation) whereas 5/6 hearts developed VF in the dofetilide group (two spontaneously, three by S1S2 stimulation). In comparison, 0/6, 1/6, and 1/6 hearts developed VF when treated with the K(Ca)2 channel inhibitors AP30663, ICA, or AP14145, respectively. Conclusion Hypokalemia was associated with an increased incidence of VF, an effect that also seen in the presence of dofetilide. In comparison, the structurally and functionally different K(Ca)2 channel inhibitors, ICA, AP14145, and AP30663 protected the heart from hypokalemia induced VF. These results support that K(Ca)2 inhibition may be associated with a better safety and tolerability profile than dofetilide.
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| 5. |
- Diness, J. G., et al.
(författare)
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The KCa2 Channel Inhibitor AP30663 Selectively Increases Atrial Refractoriness, Converts Vernakalant-Resistant Atrial Fibrillation and Prevents Its Reinduction in Conscious Pigs
- 2020
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Ingår i: Frontiers in Pharmacology. - : Frontiers Media SA. - 1663-9812. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To describe the effects of the KCa2 channel inhibitor AP30663 in pigs regarding tolerability, cardiac electrophysiology, pharmacokinetics, atrial functional selectivity, effectiveness in cardioversion of tachy-pacing induced vernakalant-resistant atrial fibrillation (AF), and prevention of reinduction of AF. Methods and Results: Six healthy pigs with implanted pacemakers and equipped with a Holter monitor were used to compare the effects of increasing doses (0, 5, 10, 15, 20, and 25 mg/kg) of AP30663 on the right atrial effective refractory period (AERP) and on various ECG parameters, including the QT interval. Ten pigs with implanted neurostimulators were long-term atrially tachypaced (A-TP) until sustained vernakalant-resistant AF was present. 20 mg/kg AP30663 was tested to discover if it could successfully convert vernakalant-resistant AF to sinus rhythm (SR) and protect against reinduction of AF. Seven anesthetized pigs were used for pharmacokinetic experiments. Two pigs received an infusion of 20 mg/kg AP30663 over 60 min while five pigs received 5 mg/kg AP30663 over 30 min. Blood samples were collected before, during, and after infusion on AP30663. AP30663 was well-tolerated and prominently increased the AERP in pigs with little effect on ventricular repolarization. Furthermore, it converted A-TP induced AF that had become unresponsive to vernakalant, and it prevented reinduction of AF in pigs. Both a >30 ms increase of the AERP and conversion of AF occurred in different pigs at a free plasma concentration level of around 1.0–1.4 µM of AP30663, which was achieved at a dose level of 5 mg/kg. Conclusion: AP30663 has shown properties in animals that would be of clinical interest in man. © Copyright © 2020 Diness, Kirchhoff, Speerschneider, Abildgaard, Edvardsson, Sørensen, Grunnet and Bentzen.
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| 6. |
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| 7. |
- Gal, P., et al.
(författare)
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First Clinical Study with AP30663-a K(Ca)2 Channel Inhibitor in Development for Conversion of Atrial Fibrillation
- 2020
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Ingår i: Cts-Clinical and Translational Science. - : Wiley. - 1752-8054 .- 1752-8062. ; 13:6, s. 1336-1344
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Tidskriftsartikel (refereegranskat)abstract
- Pharmacological cardioversion of atrial fibrillation (AF) is frequently inefficacious. AP30663, a small conductance Ca(2+)activated K+(K(Ca)2) channel blocker, prolonged the atrial effective refractory period in preclinical studies and subsequently converted AF into normal sinus rhythm. This first-in-human study evaluated the safety and tolerability, and pharmacokinetic (PK) and pharmacodynamic (PD) effects were explored. Forty-seven healthy male volunteers (23.7 +/- 3.0 years) received AP30663 intravenously in ascending doses. Due to infusion site reactions, changes to the formulation and administration were implemented in the latter 24 volunteers. Extractions from a 24-hour continuous electrocardiogram were used to evaluate the PD effect of AP30663. Data were analyzed with a repeated measure analysis of covariance, noncompartmental analysis, and concentration-effect analysis. In total, 33 of 34 adverse events considered related to AP30663 exposure were related to the infusion site, mild in severity, and temporary in nature, although full recovery took up to 110 days. After formulation and administration changes, the local infusion site reaction remained, but the median duration was shorter despite higher dose levels. AP30663 displayed a less than dose proportional increase in peak plasma concentration (C-max) and a terminal half-life of around 5 hours. In healthy volunteers, no effect of AP30663 was observed on electrocardiographic parameters, other than a concentration-dependent effect on the corrected QT Fridericia's formula interval (+18.8 +/- 4.3 ms for the highest dose level compared with time matched placebo). In conclusion, administration of AP30663, a novel K(Ca)2 channel inhibitor, was safe and well-tolerated systemically in humans, supporting further development in patients with AF undergoing cardioversion.
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| 8. |
- Holst, Anders G., et al.
(författare)
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Inhibition of the KCa2 potassium channel in atrial fibrillation: a randomized phase 2 trial
- 2023
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Ingår i: Nature Medicine. - 1078-8956 .- 1546-170X.
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Tidskriftsartikel (refereegranskat)abstract
- Existing antiarrhythmic drugs to treat atrial fibrillation (AF) have incomplete efficacy, contraindications and adverse effects, including proarrhythmia. AP30663, an inhibitor of the KCa2 channel, has demonstrated AF efficacy in animals; however, its efficacy in humans with AF is unknown. Here we conducted a phase 2 trial in which patients with a current episode of AF lasting for 7 days or less were randomized to receive an intravenous infusion of 3 or 5 mg kg−1 AP30663 or placebo. The trial was prematurely discontinued because of slow enrollment during the coronavirus disease 2019 pandemic. The primary endpoint of the trial was cardioversion from AF to sinus rhythm within 90 min from the start of the infusion, analyzed with Bayesian statistics. Among 59 patients randomized and included in the efficacy analyses, the primary endpoint occurred in 42% (5 of 12), 55% (12 of 22) and 0% (0 of 25) of patients treated with 3 mg kg−1 AP30663, 5 mg kg−1 AP30663 or placebo, respectively. Both doses demonstrated more than 99.9% probability of superiority over placebo, surpassing the prespecified 95% threshold. The mean time to cardioversion, a secondary endpoint, was 47 (s.d. = 23) and 41 (s.d. = 24) minutes for 3 mg kg−1 and 5 mg kg−1 AP30663, respectively. AP30663 caused a transient increase in the QTcF interval, with a maximum mean effect of 37.7 ms for the 5 mg kg−1 dose. For both dose groups, no ventricular arrhythmias occurred and adverse event rates were comparable to the placebo group. AP30663 demonstrated AF cardioversion efficacy in patients with recent-onset AF episodes. KCa2 channel inhibition may be an attractive mechanism for rhythm control of AF that should be studied further in randomized trials. ClinicalTrials.gov registration: NCT04571385 .
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| 9. |
- Sztaniszlav, Aron, 1979-, et al.
(författare)
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All-cause mortality trends in patients hospitalized for atrial fibrillation in Sweden: Role of age, stroke risk, and education
- 2022
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Ingår i: Ijc Heart & Vasculature. - : Elsevier BV. - 2352-9067. ; 43
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Tidskriftsartikel (refereegranskat)abstract
- Background: The incidence of atrial fibrillation (AF) has long been increasing, and AF is associated with increased mortality. Over time, mortality trends may differ between subgroups depending on their underlying risk patterns and treatments. Aim: To explore all-cause-mortality trends over time in patients hospitalized for incident AF, and the effects of age, stroke risk, and education level. Methods and results: Patients hospitalized for incident AF between January 1995 and December 2003 were selected from Swedish national registries. Based on date of index admission, patients were divided into four cohorts and followed for five years. Age- and sex-matched controls were selected. Kaplan-Meier estimates and Cox regressions with trend analysis were used for statistical evaluation. There were 64,489 patients (mean age 72 +/- 10.1 years) and 116,893 controls. There was a significantly decreasing trend in the relative risk of all-cause mortality in AF patients over time, with a trend hazard ratio of 0.94 (95 % confidence interval [CI] 0.92-0.96, p < 0.001) in women and 0.91 (95 % CI 0.89-0.93, p < 0.001) in men. The mortality trends did not differ significantly between AF patients and controls. The mortality risk remained unchanged in women aged 18-64 years, in patients with low stroke risk, and in patients with post-secondary education. Conclusion: The all-cause mortality risk decreased over time in both patients and controls, but subgroup analysis revealed an unchanged mortality trend in women aged 18-64 years, in patients with low stroke risk, and in patients with post-secondary education.
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| 10. |
- Yfanti, Christina, et al.
(författare)
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A phase 1 trial of AP30663, a KCa2 channel inhibitor in development for conversion of atrial fibrillation
- 2024
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Ingår i: BRITISH JOURNAL OF CLINICAL PHARMACOLOGY. - 0306-5251 .- 1365-2125. ; 90:4, s. 1027-1035
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Tidskriftsartikel (refereegranskat)abstract
- Aims: AP30663 is a novel compound under development for pharmacological conversion of atrial fibrillation by targeting the small conductance Ca2+ activated K+ (K(Ca)2) channel. The aim of this extension phase 1 study was to test AP30663 at higher single doses compared to the first-in-human trial.Methods: Sixteen healthy male volunteers were randomized into 2 cohorts: 6- and 8-mg/kg intravenous single-dose administration of AP30663 vs. placebo. Safety, pharmacokinetic and pharmacodynamic data were collected.Results: AP30663 was associated with mild and transient infusion site reactions with no clustering of other adverse events but with an estimated maximum mean QTcF interval prolongation of 45.2 ms (95% confidence interval 31.5-58.9) in the 6 mg/kg dose level and 50.4 ms (95% confidence interval 36.7-64.0) with 8 mg/kg. Pharmacokinetics was dose proportional with terminal half-life of around 3 h.Conclusion: AP30663 in doses up to 8 mg/kg was associated with mild and transient infusion site reactions and an increase of the QTcF interval. Supporting Information support that the QTc effect may be explained by an off-target inhibition of the I-Kr channel.
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