Andreas Wållberg

T-type calcium channels inhibitors: a patent review

Importance of the field: T-type calcium channels are transmembrane proteins that regulate calcium entry in the cell in a voltage-dependent manner. Intracellular calcium levels are the key to many physiological processes, ranging from neuron firing to cardiac pacemaking. Inhibition of T-type calcium channels is heralded as a potential treatment to peripheral and CNS disorders, including hypertension, heart failure, sleep, epilepsy, drug addiction and neuropathic pain. Areas covered in this review: A comprehensive summary of patent literature disclosing T-type calcium channels inhibitors is provided. What the reader will gain: In all, 46 patent applications including 15 chemical structure classes are reviewed. Available in vitro, in vivo and clinical results are also discussed. Take home message: Several selective T-type calcium channels inhibitors with demonstrated in vitro and in vivo effects, including one Phase I clinical candidate, are now available. While future clinical results will be paramount to assess target validity in patients, these novel inhibitors represent excellent tools to further investigate the role of T-type channels in pathophysiological conditions.

Discovery of 4-morpholino-pyrimidin-6-one and 4-morpholino-pyrimidin-2-one-containing Phosphoinositide 3-kinase (PI3K) p110β isoform inhibitors through structure-based fragment optimisation.

The discovery of 4-morpholino-pyrimidin-6-one and 4-morpholino-pyrimidin-2-one-containing inhibitors of Phosphoinositide 3-kinases (PI3K) p110β isoform is reported. Structure-based optimisation of the original fragment hit resulted in lead compounds with improvements in ligand efficiency, lipophilicity efficiency, p110β potency and selectivity over p110α.

Discovery of phosphoinositide 3-kinases (PI3K) p110β isoform inhibitor 4-[2-hydroxyethyl(1-naphthylmethyl)amino]-6-[(2S)-2-methylmorpholin-4-yl]-1H-pyrimidin-2-one, an effective antithrombotic agent without associated bleeding and insulin resistance.

Structure-based evolution of the original fragment leads resulted in the identification of 4-[2-hydroxyethyl(1-naphthylmethyl)amino]-6-[(2S)-2-methylmorpholin-4-yl]-1H-pyrimidin-2-one, (S)-21, a potent, selective phosphoinositide 3-kinases (PI3K) p110β isoform inhibitor with favourable in vivo antiplatelet effect. Despite its antiplatelet action, (S)-21 did not significantly increase bleeding time in dogs. Additionally, due to its enhanced selectivity over p110α, (S)-21 did not induce any insulin resistance in rats.

Discovery of N-[[1-[2-(tert-butylcarbamoylamino)ethyl]-4-(hydroxymethyl)-4-piperidyl]methyl]-3,5-dichloro-benzamide as a selective T-type calcium channel (Cav3.2) inhibitor.

The T-type calcium channel inhibitor Mibefradil was reported to protect the heart from atrial remodeling, a key process involved in the development of atrial fibrillation and arrhythmias. Mibefradil is not a selective T-type calcium channel inhibitor and also affects the function of different ion channels. Our aim was to develop a selective T-type calcium channel inhibitor to validate the importance of T-type-related pharmacology in atrial fibrillation. Structural optimisation of a previously disclosed hit series focussed on minimising exposure to the central nervous system and improving pharmacokinetic properties, while maintain adequate potency and selectivity. This resulted in the design of N-[[1-[2-(tert-butylcarbamoylamino)ethyl]-4-(hydroxymethyl)-4-piperidyl]methyl]-3,5-dichloro-benzamide, a novel, selective, peripherally restricted chemical probe to verify the role of T-type calcium channel inhibition on atrial fibrillation protection.