3 research outputs found
Acyl Guanidine Inhibitors of β‑Secretase (BACE-1): Optimization of a Micromolar Hit to a Nanomolar Lead via Iterative Solid- and Solution-Phase Library Synthesis
This report describes the discovery and optimization
of a BACE-1
inhibitor series containing an unusual acyl guanidine chemotype that
was originally synthesized as part of a 6041-membered solid-phase
library. The synthesis of multiple follow-up solid- and solution-phase
libraries facilitated the optimization of the original micromolar
hit into a single-digit nanomolar BACE-1 inhibitor in both radioligand
binding and cell-based functional assay formats. The X-ray structure
of representative inhibitors bound to BACE-1 revealed a number of
key ligand:protein interactions, including a hydrogen bond between
the side chain amide of flap residue Gln73 and the acyl guanidine
carbonyl group, and a cation−π interaction between Arg235
and the isothiazole 4-methoxyphenyl substituent. Following subcutaneous
administration in rats, an acyl guanidine inhibitor with single-digit
nanomolar activity in cells afforded good plasma exposures and a dose-dependent
reduction in plasma Aβ levels, but poor brain exposure was observed
(likely due to Pgp-mediated efflux), and significant reductions in
brain Aβ levels were not obtained
Discovery of Clinical Candidate 2‑((2<i>S</i>,6<i>S</i>)‑2-Phenyl-6-hydroxyadamantan-2-yl)-1-(3′-hydroxyazetidin-1-yl)ethanone [BMS-816336], an Orally Active Novel Selective 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor
BMS-816336
(<b>6n-2</b>), a hydroxy-substituted adamantyl
acetamide, has been identified as a novel, potent inhibitor against
human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)
enzyme (IC<sub>50</sub> 3.0 nM) with >10000-fold selectivity over
human 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). <b>6n-2</b> exhibits a robust acute pharmacodynamic effect in cynomolgus
monkeys (ED<sub>50</sub> 0.12 mg/kg) and in DIO mice. It is orally
bioavailable (%<i>F</i> ranges from 20 to 72% in preclinical
species) and has a predicted pharmacokinetic profile of a high peak
to trough ratio and short half-life in humans. This ADME profile met
our selection criteria for once daily administration, targeting robust
inhibition of 11β-HSD1 enzyme for the first 12 h period after
dosing followed by an “inhibition holiday” so that the
potential for hypothalamic–pituitary–adrenal (HPA) axis
activation might be mitigated. <b>6n-2</b> was found to be well-tolerated
in phase 1 clinical studies and represents a potential new treatment
for type 2 diabetes, metabolic syndrome, and other human diseases
modulated by glucocorticoid control
Discovery and Preclinical Characterization of the Cyclopropylindolobenzazepine BMS-791325, A Potent Allosteric Inhibitor of the Hepatitis C Virus NS5B Polymerase
Described herein are structure–activity
relationship studies
that resulted in the optimization of the activity of members of a
class of cyclopropyl-fused indolobenzazepine HCV NS5B polymerase inhibitors.
Subsequent iterations of analogue design and syntheses successfully
addressed off-target activities, most notably human pregnane X receptor
(hPXR) transactivation, and led to significant improvements in the
physicochemical properties of lead compounds. Those analogues exhibiting
improved solubility and membrane permeability were shown to have notably
enhanced pharmacokinetic profiles. Additionally, a series of alkyl
bridged piperazine carboxamides was identified as being of particular
interest, and from which the compound BMS-791325 (<b>2</b>)
was found to have distinguishing antiviral, safety, and pharmacokinetic
properties that resulted in its selection for clinical evaluation