RESUMO
Novel cardiac troponin activators were identified using a high throughput cardiac myofibril ATPase assay and confirmed using a series of biochemical and biophysical assays. HTS hit 2 increased rat cardiomyocyte fractional shortening without increasing intracellular calcium concentrations, and the biological target of 1 and 2 was determined to be the cardiac thin filament. Subsequent optimization to increase solubility and remove PDE-3 inhibition led to the discovery of CK-963 and enabled pharmacological evaluation of cardiac troponin activation without the competing effects of PDE-3 inhibition. Rat echocardiography studies using CK-963 demonstrated concentration-dependent increases in cardiac fractional shortening up to 95%. Isothermal calorimetry studies confirmed a direct interaction between CK-963 and a cardiac troponin chimera with a dissociation constant of 11.5 ± 3.2 µM. These results provide evidence that direct activation of cardiac troponin without the confounding effects of PDE-3 inhibition may provide benefit for patients with cardiovascular conditions where contractility is reduced.
Assuntos
Contração Miocárdica , Troponina , Animais , Masculino , Ratos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Troponina/metabolismoRESUMO
Cardiac myosin activation has been shown to be a viable approach for the treatment of heart failure with reduced ejection fraction. Here, we report the discovery of nelutroctiv (CK-136), a selective cardiac troponin activator intended for patients with cardiovascular conditions where cardiac contractility is reduced. Discovery of nelutroctiv began with a high-throughput screen that identified compound 1R, a muscle selective cardiac sarcomere activator devoid of phosphodiesterase-3 activity. Optimization of druglike properties for 1R led to the replacement of the sulfonamide and aniline substituents which resulted in improved pharmacokinetic (PK) profiles and a reduced potential for human drug-drug interactions. In vivo echocardiography assessment of the optimized leads showed concentration dependent increases in fractional shortening and an improved pharmacodynamic window compared to myosin activator CK-138. Overall, nelutroctiv was found to possess the desired selectivity, a favorable pharmacodynamic window relative to myosin activators, and a preclinical PK profile to support clinical development.
Assuntos
Contração Miocárdica , Humanos , Animais , Contração Miocárdica/efeitos dos fármacos , Doenças Cardiovasculares/tratamento farmacológico , Ratos , Relação Estrutura-Atividade , Masculino , Descoberta de Drogas , Troponina/metabolismo , Camundongos , Ratos Sprague-Dawley , Sulfonamidas/farmacologia , Sulfonamidas/farmacocinética , Sulfonamidas/química , Sulfonamidas/uso terapêutico , Sulfonamidas/síntese químicaRESUMO
Hypercontractility of the cardiac sarcomere may be essential for the underlying pathological hypertrophy and fibrosis in genetic hypertrophic cardiomyopathies. Aficamten (CK-274) is a novel cardiac myosin inhibitor that was discovered from the optimization of indoline compound 1. The important advancement of the optimization was discovery of an Indane analogue (12) with a less restrictive structure-activity relationship that allowed for the rapid improvement of drug-like properties. Aficamten was designed to provide a predicted human half-life (t1/2) appropriate for once a day (qd) dosing, to reach steady state within two weeks, to have no substantial cytochrome P450 induction or inhibition, and to have a wide therapeutic window in vivo with a clear pharmacokinetic/pharmacodynamic relationship. In a phase I clinical trial, aficamten demonstrated a human t1/2 similar to predictions and was able to reach steady state concentration within the desired two-week window.
Assuntos
Miosinas Cardíacas/efeitos dos fármacos , Cardiomiopatia Hipertrófica/tratamento farmacológico , Descoberta de Drogas , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The discovery of reldesemtiv, a second-generation fast skeletal muscle troponin activator (FSTA) that increases force production at submaximal stimulation frequencies, is reported. Property-based optimization of high throughput screening hit 1 led to compounds with improved free exposure and in vivo muscle activation potency compared to the first-generation FSTA, tirasemtiv. Reldesemtiv demonstrated increased muscle force generation in a phase 1 clinical trial and is currently being evaluated in clinical trials for the treatment of amyotrophic lateral sclerosis.
Assuntos
Descoberta de Drogas , Músculo Esquelético/efeitos dos fármacos , Troponina/metabolismo , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Relação Estrutura-AtividadeRESUMO
The identification and optimization of the first activators of fast skeletal muscle are reported. Compound 1 was identified from high-throughput screening (HTS) and subsequently found to improve muscle function via interaction with the troponin complex. Optimization of 1 for potency, metabolic stability, and physical properties led to the discovery of tirasemtiv (25), which has been extensively characterized in clinical trials for the treatment of amyotrophic lateral sclerosis.
RESUMO
Limited neural input results in muscle weakness in neuromuscular disease because of a reduction in the density of muscle innervation, the rate of neuromuscular junction activation or the efficiency of synaptic transmission. We developed a small-molecule fast-skeletal-troponin activator, CK-2017357, as a means to increase muscle strength by amplifying the response of muscle when neural input is otherwise diminished secondary to neuromuscular disease. Binding selectively to the fast-skeletal-troponin complex, CK-2017357 slows the rate of calcium release from troponin C and sensitizes muscle to calcium. As a consequence, the force-calcium relationship of muscle fibers shifts leftwards, as does the force-frequency relationship of a nerve-muscle pair, so that CK-2017357 increases the production of muscle force in situ at sub-maximal nerve stimulation rates. Notably, we show that sensitization of the fast-skeletal-troponin complex to calcium improves muscle force and grip strength immediately after administration of single doses of CK-2017357 in a model of the neuromuscular disease myasthenia gravis. Troponin activation may provide a new therapeutic approach to improve physical activity in diseases where neuromuscular function is compromised.
Assuntos
Cálcio/metabolismo , Músculo Esquelético/metabolismo , Doenças Neuromusculares/metabolismo , Troponina C/agonistas , Troponina C/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Bovinos , Humanos , Imidazóis/química , Imidazóis/uso terapêutico , Terapia de Alvo Molecular , Contração Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/patologia , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/metabolismo , Miastenia Gravis/patologia , Miosinas/isolamento & purificação , Miosinas/metabolismo , Doenças Neuromusculares/tratamento farmacológico , Doenças Neuromusculares/patologia , Pirazinas/química , Pirazinas/uso terapêutico , Coelhos , Ratos , Troponina/metabolismo , Troponina/fisiologiaRESUMO
We report the design, synthesis, and optimization of the first, selective activators of cardiac myosin. Starting with a poorly soluble, nitro-aromatic hit compound (1), potent, selective, and soluble myosin activators were designed culminating in the discovery of omecamtiv mecarbil (24). Compound 24 is currently in clinical trials for the treatment of systolic heart failure.
RESUMO
We have been actively involved in the development of parallel approaches for the discovery of phosphine ligands. Our approach has been based on the incorporation of phosphine-containing amino acids into peptide sequences that are designed to have stable secondary structures. We have examined helical and turn secondary structures and have reported that alkylation of cyclopentenyl acetate with dimethylmalonate can be catalyzed in high enantiomeric excess (ee) with a beta-turn-based ligand. The importance of the peptide secondary structure was demonstrated through the synthesis of a series of peptide ligands where the nature of the turn-forming residues was probed. Additionally, other turn-forming units and a variety of different phosphine-containing amino acids have been examined for their ability to control the selectivity of the allylation reaction. This paper reports the results obtained through the examination of different turn motifs as well as different phosphine substitutions on the "best" turn sequence, Pps-Pro-d-Xxx-Pps.