Development of ProTx-II Analogues as Highly Selective Peptide Blockers of Na1.7 for the Treatment of Pain.

Inhibitor cystine knot peptides, derived from venom, have evolved to block ion channel function but are often toxic when dosed at pharmacologically relevant levels . The article describes the design of analogues of ProTx-II that safely display systemic blocking of Na1.7, resulting in a latency of response to thermal stimuli in rodents.

A Series of Novel, Highly Potent, and Orally Bioavailable Next-Generation Tricyclic Peptide PCSK9 Inhibitors.

Proprotein convertase subtilisin-like/kexin type 9 (PCSK9) is a key regulator of plasma LDL-cholesterol (LDL-C) and a clinically validated target for the treatment of hypercholesterolemia and coronary artery disease. Starting from second-generation lead structures such as , we were able to refine these structures to obtain extremely potent bi- and tricyclic PCSK9 inhibitor peptides. Optimized molecules such as demonstrated sufficient oral bioavailability to maintain therapeutic levels in rats and cynomolgus monkeys after dosing with an enabled formulation.

Series of Novel and Highly Potent Cyclic Peptide PCSK9 Inhibitors Derived from an mRNA Display Screen and Optimized via Structure-Based Design.

Proprotein convertase subtilisin-like/kexin type 9 (PCSK9) is a key regulator of plasma LDL-cholesterol (LDL-C) and a clinically validated target for the treatment of hypercholesterolemia and coronary artery disease. In this paper, we describe a series of novel cyclic peptides derived from an mRNA display screen which inhibit the protein-protein interaction between PCSK9 and LDLR. Using a structure-based drug design approach, we were able to modify our original screening lead to optimize the potency and metabolic stability and minimize the molecular weight to provide novel bicyclic next-generation PCSK9 inhibitor peptides such as .

Discovery of a potent and selective ROMK inhibitor with improved pharmacokinetic properties based on an octahydropyrazino[2,1-c][1,4]oxazine scaffold.

Following the discovery of small molecule acyl piperazine ROMK inhibitors, the acyl octahydropyrazino[2,1-c][1,4]oxazine series was identified. This series displays improved ROMK/hERG selectivity, and as a consequence, the resulting ROMK inhibitors do not evoke QTc prolongation in an in vivo cardiovascular dog model. Further efforts in this series led to the discovery of analogs with improved pharmacokinetic profiles.

Discovery of MK-7145, an Oral Small Molecule ROMK Inhibitor for the Treatment of Hypertension and Heart Failure.

ROMK, the renal outer medullary potassium channel, is involved in potassium recycling at the thick ascending loop of Henle and potassium secretion at the cortical collecting duct in the kidney nephron. Because of this dual site of action, selective inhibitors of ROMK are expected to represent a new class of diuretics/natriuretics with superior efficacy and reduced urinary loss of potassium compared to standard-of-care loop and thiazide diuretics. Following our earlier work, this communication will detail subsequent medicinal chemistry endeavors to further improve lead selectivity against the hERG channel and preclinical pharmacokinetic properties.

Differentiation of ROMK potency from hERG potency in the phenacetyl piperazine series through heterocycle incorporation.

Following the discovery of small molecule acyl piperazine ROMK inhibitors and their initial preclinical validation as a novel diuretic agent, our group set out to discover new ROMK inhibitors with reduced risk for QT effects, suitable for further pharmacological experiments in additional species. Several strategies for decreasing hERG affinity while maintaining ROMK inhibition were investigated and are described herein. The most promising candidate, derived from the newly discovered 4-N-heteroaryl acetyl series, improved functional hERG/ROMK ratio by >10× over the previous lead.

Discovery of a Potent and Selective ROMK Inhibitor with Pharmacokinetic Properties Suitable for Preclinical Evaluation.

A new subseries of ROMK inhibitors exemplified by 28 has been developed from the initial screening hit 1. The excellent selectivity for ROMK inhibition over related ion channels and pharmacokinetic properties across preclinical species support further preclinical evaluation of 28 as a new mechanism diuretic. Robust pharmacodynamic effects in both SD rats and dogs have been demonstrated.

Discovery of potent selective bioavailable phosphodiesterase 2 (PDE2) inhibitors active in an osteoarthritis pain model. Part II: optimization studies and demonstration of in vivo efficacy.

Selective phosphodiesterase 2 (PDE2) inhibitors are shown to have efficacy in a rat model of osteoarthritis (OA) pain. We identified potent, selective PDE2 inhibitors by optimizing residual PDE2 activity in a series of phosphodiesterase 4 (PDE4) inhibitors, while minimizing PDE4 inhibitory activity. These newly designed PDE2 inhibitors bind to the PDE2 enzyme in a cGMP-like binding mode orthogonal to the cAMP-like binding mode found in PDE4.

Discovery of potent, selective, bioavailable phosphodiesterase 2 (PDE2) inhibitors active in an osteoarthritis pain model, part I: transformation of selective pyrazolodiazepinone phosphodiesterase 4 (PDE4) inhibitors into selective PDE2 inhibitors.

We identified potent, selective PDE2 inhibitors by optimizing residual PDE2 activity in a series of PDE4 inhibitors, while simultaneously minimizing PDE4 activity. These newly designed PDE2 inhibitors bind to the PDE2 enzyme in a cGMP-like mode in contrast to the cAMP-like binding mode found in PDE4. Structure activity relationship studies coupled with an inhibitor bound crystal structure in the active site of the catalytic domain of PDE2 identified structural features required to minimize PDE4 inhibition while simultaneously maximizing PDE2 inhibition.

Discovery of Selective Small Molecule ROMK Inhibitors as Potential New Mechanism Diuretics.

The renal outer medullary potassium channel (ROMK or Kir1.1) is a putative drug target for a novel class of diuretics that could be used for the treatment of hypertension and edematous states such as heart failure. An internal high-throughput screening campaign identified 1,4-bis(4-nitrophenethyl)piperazine (5) as a potent ROMK inhibitor.

4-anilino-5-carboxamido-2-pyridone derivatives as noncompetitive inhibitors of mitogen-activated protein kinase kinase.

A new series of MEK1 inhibitors, the 4-anilino-5-carboxamido-2-pyridones, were designed and synthesized using a combination of medicinal chemistry, computational chemistry, and structural elucidation. The effect of variation in the carboxamide side chain, substitution on the pyridone nitrogen, and replacement of the 4'-iodide were all investigated. This study afforded several compounds which were either equipotent or more potent than the clinical candidate CI-1040 (1) in an isolated enzyme assay, as well as murine colon carcinoma (C26) cells, as measured by suppression of phosphorylated ERK substrate.

Structure-based design of nonpeptide inhibitors of interleukin-1beta converting enzyme (ICE, caspase-1).

A novel class of reversible inhibitors of Interleukin-1beta-converting enzyme (ICE, caspase-1) were discovered by iterative structure-based design. Guided by the X-ray crystal structure of analogues 1, 7 and 10 bound to ICE, we have designed a nonpeptide series of small molecule inhibitors. These compounds incorporate an arylsulfonamide moiety which replaces Val-His unit (P3-P2 residues) amino acids of the native substrate.