Identification of Reversible Small Molecule Inhibitors of Endothelial Lipase (EL) That Demonstrate HDL-C Increase In Vivo.

Endothelial lipase (EL) hydrolyzes phospholipids in high-density lipoprotein (HDL) resulting in reduction in plasma HDL levels. Studies with murine transgenic, KO, or loss-of-function variants strongly suggest that inhibition of EL will lead to sustained plasma high-density lipoprotein cholesterol (HDL-C) increase and, potentially, a reduced cardiovascular disease (CVD) risk. Herein, we describe the discovery of a series of oxadiazole ketones, which upon optimization, led to the identification of compound 12. Compound 12 was evaluated in a mouse pharmacodynamics (PD) model and demonstrated a 56% increase in plasma HDL-C. In a mouse reverse cholesterol transport study, compound 12 stimulated cholesterol efflux by 53% demonstrating HDL-C functionality.

Discovery of a Lead Triphenylethanamine Cholesterol Ester Transfer Protein (CETP) Inhibitor.

Lead optimization of the diphenylpyridylethanamine (DPPE) and triphenylethanamine (TPE) series of CETP inhibitors to improve their pharmaceutical profile is described. Polar groups at the N-terminus position in the DPPE series resulted in further improvement in potency and pharmaceutical properties concomitant with retaining the safety, efficacy, and pharmacokinetic (PK) profile. A structure-activity relationship observed in the DPPE series was extended to the corresponding analogs in the more potent TPE series, and further optimization resulted in the identification of 2-amino-N-((R)-1-(3-cyclopropoxy-4-fluorophenyl)-1-(3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl)-2-phenylethyl)-4,4,4-trifluoro-3-hydroxy-3-(trifluoromethyl)butanamide (13). Compound 13 demonstrated no significant changes in either mean arterial blood pressure or heart rate in telemetry rats, had an excellent PK profile, and demonstrated robust efficacy in human CETP/apo-B-100 dual transgenic mice and in hamsters.

PK/PD Disconnect Observed with a Reversible Endothelial Lipase Inhibitor.

Screening of a small set of nonselective lipase inhibitors against endothelial lipase (EL) identified a potent and reversible inhibitor, N-(3-(3,4-dichlorophenyl)propyl)-3-hydroxy-1-methyl-2-oxo-1,2-dihydropyridine-4-carboxamide (5; EL IC50 = 61 nM, ELHDL IC50 = 454 nM). Deck mining identified a related hit, N-(3-(3,4-dichlorophenyl)propyl)-4-hydroxy-1-methyl-5-oxo-2,5-dihydro-1H-pyrrole-3-carboxamide (6a; EL IC50 = 41 nM, ELHDL IC50 = 1760 nM). Both compounds were selective against lipoprotein lipase (LPL) but nonselective versus hepatic lipase (HL). Optimization of compound 6a for EL inhibition using HDL as substrate led to N-(4-(3,4-dichlorophenyl)butan-2-yl)-1-ethyl-4-hydroxy-5-oxo-2,5-dihydro-1H-pyrrole-3-carboxamide (7c; EL IC50 = 148 nM, ELHDL IC50 = 218 nM) having improved PK over compound 6a, providing a tool molecule to test for the ability to increase HDL-cholesterol (HDL-C) levels in vivo using a reversible EL inhibitor. Compound 7c did not increase HDL-C in vivo despite achieving plasma exposures targeted on the basis of enzyme activity and protein binding demonstrating the need to develop more physiologically relevant in vitro assays to guide compound progression for in vivo evaluation.

Discovery of hydroxyl 1,2-diphenylethanamine analogs as potent cholesterol ester transfer protein inhibitors.

Hydroxyl 1,2-diphenylethanamine analogs were identified as potent inhibitors of cholesterol ester transfer protein (CETP), a therapeutic target to raise HDL cholesterol. In an effort to improve the pharmaceutical properties in the previously disclosed DiPhenylPyridineEthanamine (DPPE) series, polar groups were introduced to the N-linked quaternary center. Optimization of analogues for potency, in vitro liability profile and efficacy led to identification of lead compound 16 which demonstrated robust pharmacodynamic effects in human CETP/apo-B100 dual transgenic mice.

Triphenylethanamine Derivatives as Cholesteryl Ester Transfer Protein Inhibitors: Discovery of N-[(1R)-1-(3-Cyclopropoxy-4-fluorophenyl)-1-[3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-phenylethyl]-4-fluoro-3-(trifluoromethyl)benzamide (BMS-795311).

Cholesteryl ester transfer protein (CETP) inhibitors raise HDL-C in animals and humans and may be antiatherosclerotic by enhancing reverse cholesterol transport (RCT). In this article, we describe the lead optimization efforts resulting in the discovery of a series of triphenylethanamine (TPE) ureas and amides as potent and orally available CETP inhibitors. Compound 10g is a potent CETP inhibitor that maximally inhibited cholesteryl ester (CE) transfer activity at an oral dose of 1 mg/kg in human CETP/apoB-100 dual transgenic mice and increased HDL cholesterol content and size comparable to torcetrapib (1) in moderately-fat fed hamsters. In contrast to the off-target liabilities with 1, no blood pressure increase was observed with 10g in rat telemetry studies and no increase of aldosterone synthase (CYP11B2) was detected in H295R cells. On the basis of its preclinical profile, compound 10g was advanced into preclinical safety studies.

Diphenylpyridylethanamine (DPPE)-based aminoheterocycles as cholesteryl ester transfer protein inhibitors.

A series of diphenylpyridylethanamine-based inhibitors of cholesteryl ester transfer protein with aminoheterocycles appended onto the N-terminus of the chemotype were explored as urea mimetics. Potent compounds were discovered and were further optimized to improve metabolic stability and PXR transactivation profile.

Identification of a potent and metabolically stable series of fluorinated diphenylpyridylethanamine-based cholesteryl ester transfer protein inhibitors.

A novel series of diphenylpyridylethanamine-based inhibitors of cholesteryl ester transfer protein is described. Optimization of the urea moiety, particularly by incorporation of fluorine, is explored to balance in vitro metabolic stability with CETP potency in the whole plasma assay.

Diphenylpyridylethanamine (DPPE) derivatives as cholesteryl ester transfer protein (CETP) inhibitors.

A series of diphenylpyridylethanamine (DPPE) derivatives was identified exhibiting potent CETP inhibition. Replacing the labile ester functionality in the initial lead 7 generated a series of amides and ureas. Further optimization of the DPPE series for potency resulted in the discovery of cyclopentylurea 15d, which demonstrated a reduction in cholesterol ester transfer activity (48% of predose level) in hCETP/apoB-100 dual transgenic mice. The PK profile of 15d was suboptimal, and further optimization of the N-terminus resulted in the discovery of amide 20 with an improved PK profile and robust efficacy in transgenic hCETP/apoB-100 mice and in hamsters. Compound 20 demonstrated no significant changes in either mean arterial blood pressure or heart rate in telemeterized rats despite sustained high exposures.

2-Arylbenzoxazoles as novel cholesteryl ester transfer protein inhibitors: optimization via array synthesis.

2-Arylbenzoxazole 5 was identified as a hit from a fluorescence-based high-throughput screen for CETP inhibitors. The synthesis and SAR investigation employing array synthesis of the A- and B-rings are described.