Mark A. Hilfiker

GSK1562590, a slowly dissociating urotensin‐II receptor antagonist, exhibits prolonged pharmacodynamic activity ex vivo

BACKGROUND AND PURPOSE Recently identified antagonists of the urotensin–II (U‐II) receptor (UT) are of limited utility for investigating the (patho)physiological role of U‐II due to poor potency and limited selectivity and/or intrinsic activity.

Discovery of novel aminothiadiazole amides as selective EP3 receptor antagonists

This Letter discloses a series of 2-aminothiadiazole amides as selective EP(3) receptor antagonists. SAR optimization resulted in compounds with excellent functional activity in vitro. In addition, efforts to optimize DMPK properties in the rat are discussed. These efforts have resulted in the identification of potent, selective EP(3) receptor antagonists with excellent DMPK properties suitable for in vivo studies.

Optimization of a Novel Series of TRPV4 Antagonists with In Vivo Activity in a Model of Pulmonary Edema.

High-throughput screening and subsequent hit optimization identified 1-piperidinylbenzimidazoles, exemplified by compound 1, as TRPV4 inhibitors. Lead optimization identified potent TRPV4 blocker 19, which has good target activity and pharmacokinetic properties. Inhibitor 19 was then profiled in an in vivo rat model, demonstrating its ability to inhibit TRPV4-mediated pulmonary edema.

Aminomethylpiperazines as selective urotensin antagonists.

Aminomethylpiperazines, reported previously as being kappa-opioid receptor agonists, were identified as lead compounds in the development of selective urotensin receptor antagonists. Optimized substitution of the piperazine moiety has provided high affinity urotensin receptor antagonists with greater than 100-fold selectivity over the kappa-opioid receptor. Select compounds were found to inhibit urotensin-induced vasoconstriction in isolated rat aortic rings consistent with the hypothesis that an urotensin antagonist may be useful for the treatment of hypertension.

Novel 3-Oxazolidinedione-6-aryl-pyridinones as Potent, Selective, and Orally Active EP3 Receptor Antagonists.

High-throughput screening and subsequent optimization led to the discovery of novel 3-oxazolidinedione-6-aryl-pyridinones exemplified by compound 2 as potent and selective EP3 antagonists with excellent pharmacokinetic properties. Compound 2 was orally active and showed robust in vivo activities in overactive bladder models. To address potential bioactivation liabilities of compound 2, further optimization resulted in compounds 9 and 10, which maintained excellent potency, selectivity, and pharmacokinetic properties and showed no bioactivation liability in glutathione trapping studies. These highly potent, selective, and orally active EP3 antagonists are excellent tool compounds for investigating and validating potential therapeutic benefits from selectively inhibiting the EP3 receptor.

Development of potent and selective small-molecule human Urotensin-II antagonists.

This work describes the development of potent and selective human Urotensin-II receptor antagonists starting from lead compound 1, (3,4-dichlorophenyl)methyl{2-oxo-2-[3-phenyl-2-(1-pyrrolidinylmethyl)-1-piperidinyl]ethyl}amine. Several problems relating to oral bioavailability, cytochrome P450 inhibition, and off-target activity at the kappa opioid receptor and cardiac sodium channel were addressed during lead development. hUT binding affinity relative to compound 1 was improved by more than 40-fold in some analogs, and a structural modification was identified which significantly attenuated both off-target activities.

Potent and selective small-molecule human urotensin-II antagonists with improved pharmacokinetic profiles.

Lead compound 1 was successfully redesigned to provide compounds with improved pharmacokinetic profiles for this series of human urotensin-II antagonists. Replacement of the 2-pyrrolidinylmethyl-3-phenyl-piperidine core of 1 with a substituted N-methyl-2-(1-pyrrolidinyl)ethanamine core as in compound 7 resulted in compounds with improved oral bioavailability in rats. The relationship between stereochemistry and selectivity for hUT over the kappa-opioid receptor was also explored.

Structure-activity relationship studies of novel 3-oxazolidinedione-6-naphthyl-2-pyridinones as potent and orally bioavailable EP3 receptor antagonists.

Multiple regions of the 3-oxazolidinedione-6-naphthyl-pyridinone series identified via high throughput screening were explored. SAR studies of these regions including the left-hand side oxazolidinedione moiety, α-substituent on the oxazolidinedione ring, central pyridinone core, and substituents on the central pyridinone core led to the discovery of potent EP(3) receptor antagonists such as compound 29 which possesses outstanding rat pharmacokinetic properties. Synthesis and SAR of these novel compounds and DMPK properties of representative compounds are discussed.

Reverse Hydroxamate Inhibitors of Bone Morphogenetic Protein 1

Bone Morphogenetic Protein 1 (BMP1) inhibition is a potential method for treating fibrosis because BMP1, a member of the zinc metalloprotease family, is required to convert pro-collagen to collagen. A novel class of reverse hydroxamate BMP1 inhibitors was discovered, and cocrystal structures with BMP1 were obtained. The observed binding mode is unique in that the small molecule occupies the nonprime side of the metalloprotease pocket providing an opportunity to build in metalloprotease selectivity. Structure-guided modification of the initial hit led to the identification of an oral in vivo tool compound with selectivity over other metalloproteases. Due to irreversible inhibition of cytochrome P450 3A4 for this chemical class, the risk of potential drug-drug interactions was managed by optimizing the series for subcutaneous injection.