A novel series of N-(azetidin-3-yl)-2-(heteroarylamino)acetamide CCR2 antagonists.

The inflammatory response associated with the activation of C-C chemokine receptor CCR2 via it's interaction with the monocyte chemoattractant protein-1 (MCP-1, CCL2) has been implicated in many disease states, including rheumatoid arthritis, multiple sclerosis, atherosclerosis, asthma and neuropathic pain. Small molecule antagonists of CCR2 have been efficacious in animal models of inflammatory disease, and have been advanced into clinical development. The necessity to attenuate hERG binding appears to be a common theme for many of the CCR2 antagonist scaffolds appearing in the literature, presumably due the basic hydrophobic motif present in all of these molecules. Following the discovery of a novel cyclohexyl azetidinylamide CCR2 antagonist scaffold, replacement of the amide bond with heterocyclic rings was explored as a strategy for reducing hERG binding and improving pharmacokinetic properties.

Enhancement of kinase selectivity in a potent class of arylamide FMS inhibitors.

Structure-activity relationship (SAR) studies on a highly potent series of arylamide FMS inhibitors were carried out with the aim of improving FMS kinase selectivity, particularly over KIT. Potent compound 17r (FMS IC50 0.7 nM, FMS cell IC50 6.1 nM) was discovered that had good PK properties and a greater than fivefold improvement in selectivity for FMS over KIT kinase in a cellular assay relative to the previously reported clinical candidate 4. This improved selectivity was manifested in vivo by no observed decrease in circulating reticulocytes, a measure of bone safety, at the highest studied dose. Compound 17r was highly active in a mouse pharmacodynamic model and demonstrated disease-modifying effects in a dose-dependent manner in a strep cell wall-induced arthritis model of rheumatoid arthritis in rats.

Design and synthesis of polyethylene glycol-modified biphenylsulfonyl-thiophene-carboxamidine inhibitors of the complement component C1s.

Complement C1s protease inhibitors have potential utility in the treatment of diseases associated with activation of the classical complement pathway such as humorally mediated graft rejection, ischemia-reperfusion injury (IRI), vascular leak syndrome, and acute respiratory distress syndrome (ARDS). The utility of biphenylsulfonyl-thiophene-carboxamidine small-molecule C1s inhibitors are limited by their poor in vivo pharmacokinetic properties. Pegylation of a potent analog has provided compounds with good potency and good in vivo pharmacokinetic properties.

Design, synthesis and SAR of indazole and benzoisoxazole containing 4-azetidinyl-1-aryl-cyclohexanes as CCR2 antagonists.

A novel series of 4-azetidinyl-1-aryl-cyclohexanes containing indazole or benzoisoxazole moiety have been identified as potent CCR2 antagonists with high selectivity versus hERG.

The discovery of novel cyclohexylamide CCR2 antagonists.

As a result of further SAR studies on a piperidinyl piperidine scaffold, we report the discovery of compound 44, a potent, orally bioavailable CCR2 antagonist. While having some in vitro hERG activity, this molecule was clean in an in vivo model of QT prolongation. In addition, it showed excellent efficacy when dosed orally in a transgenic murine model of acute inflammation.

Overcoming hERG activity in the discovery of a series of 4-azetidinyl-1-aryl-cyclohexanes as CCR2 antagonists.

A series of 4-azetidinyl-1-aryl-cyclohexanes as potent CCR2 antagonists with high selectivity over activity for the hERG potassium channel is discovered through divergent SARs of CCR2 and hERG.

Reducing ion channel activity in a series of 4-heterocyclic arylamide FMS inhibitors.

During efforts to improve the bioavailability of FMS kinase inhibitors 1 and 2, a series of saturated and aromatic 4-heterocycles of reduced basicity were prepared and evaluated in an attempt to also improve the cardiovascular safety profile over lead arylamide 1, which possessed ion channel activity. The resultant compounds retained excellent potency and exhibited diminished ion channel activity.

7-fluoroindazoles as potent and selective inhibitors of factor Xa.

We have developed a novel series of potent and selective factor Xa inhibitors that employ a key 7-fluoroindazolyl moiety. The 7-fluoro group on the indazole scaffold replaces the carbonyl group of an amide that is found in previously reported factor Xa inhibitors. The structure of a factor Xa cocrystal containing 7-fluoroindazole 51a showed the 7-fluoro atom hydrogen-bonding with the N-H of Gly216 (2.9 A) in the peptide backbone. Thus, the 7-fluoroindazolyl moiety not only occupied the same space as the carbonyl group of an amide found in prior factor Xa inhibitors but also maintained a hydrogen bond interaction with the protein's beta-sheet domain. The structure-activity relationship for this series was consistent with this finding, as the factor Xa inhibitory potencies were about 60-fold greater (DeltaDelta G approximately 2.4 kcal/mol) for the 7-fluoroindazoles 25a and 25c versus the corresponding indazoles 25b and 25d. Highly convergent synthesis of these factor Xa inhibitors is also described.

Carboxylic acid bioisosteres acylsulfonamides, acylsulfamides, and sulfonylureas as novel antagonists of the CXCR2 receptor.

A series of novel acylsulfonamide, acylsulfamide, and sulfonylurea bioisosteres of carboxylic acids were prepared as CXCR2 antagonists. Structure-activity relationships are reported for these series. One potent orally bioavailable inhibitor had excellent PK properties and was active in a lung injury model in hyperoxia-exposed newborn rats.

Orally efficacious thrombin inhibitors with cyanofluorophenylacetamide as the P2 motif.

2-Cyano-6-fluorophenylacetamide was explored as a novel P2 scaffold in the design of thrombin inhibitors. Optimization around this structural motif culminated in 14, which is a potent thrombin inhibitor (K(i)=1.2nM) that exhibits robust efficacy in canine anticoagulation and thrombosis models upon oral administration.

Structure-based optimization of a potent class of arylamide FMS inhibitors.

An anti-inflammatory 1,2,4-phenylenetriamine-containing series of FMS inhibitors with a potential to form reactive metabolites was transformed into a series with equivalent potency by incorporation of carbon-based replacement groups. Structure-based modeling provided the framework to efficiently effect this transformation and restore potencies to previous levels. This optimization removed a risk factor for potential idiosyncratic drug reactions.

Biphenylsulfonyl-thiophene-carboxamidine inhibitors of the complement component C1s.

Complement activation has been implicated in disease states such as hereditary angioedema, ischemia-reperfusion injury, acute respiratory distress syndrome, and acute transplant rejection. Even though the complement cascade provides several protein targets for potential therapeutic intervention only two complement inhibitors have been approved so far for clinical use including anti-C5 antibodies for the treatment of paroxysmal nocturnal hemoglobinuria and purified C1-esterase inhibitor replacement therapy for the control of hereditary angioedema flares. In the present study, optimization of potency and physicochemical properties of a series of thiophene amidine-based C1s inhibitors with potential utility as intravenous agents for the inhibition of the classical pathway of complement is described.

Discovery of novel FMS kinase inhibitors as anti-inflammatory agents.

The optimization of the arylamide lead 2 resulted in identification of a highly potent series of 2,4-disubstituted arylamides. Compound 8 (FMS kinase IC(50)=0.0008 microM) served as a proof-of-concept candidate in a collagen-induced model of arthritis in mice.

Synthesis and evaluation of novel 3,4,6-substituted 2-quinolones as FMS kinase inhibitors.

A series of 3,4,6-substituted 2-quinolones has been synthesized and evaluated as inhibitors of the kinase domain of macrophage colony-stimulating factor-1 receptor (FMS). The fully optimized compound, 4-(4-ethyl-phenyl)-3-(2-methyl-3H-imidazol-4-yl)-2-quinolone-6-carbonitrile 21b, has an IC(50) of 2.5 nM in an in vitro assay and 5.0 nM in a bone marrow-derived macrophage cellular assay. Inhibition of FMS signaling in vivo was also demonstrated in a mouse pharmacodynamic model.

Novel potent and selective alphavbeta3/alphavbeta5 integrin dual antagonists with reduced binding affinity for human serum albumin.

The binding of lead compounds and drugs to human serum albumin (HSA) is a ubiquitous problem in drug discovery since it modulates the availability of the leads and drugs to their intended target, which is linked to biological efficacy. In our continuing efforts to identify small molecule alpha(V)beta(3) and alpha(V)beta(5) dual antagonists, we recently reported indoles 2-4 as potent and selective alpha(V)beta(3)/alpha(V)beta(5) antagonists with good oral bioavailability profile. In spite of subnanomolar binding affinity of these compounds to human alpha(V)beta(3) and alpha(V)beta(5) integrins, high HSA binding (96.5-97.3%) emerged as a limiting feature for these leads. Structure-activity HSA binding data of organic acids reported in the literature have demonstrated that the incorporation of polar groups into a given molecule can dramatically decrease the affinity toward HSA. We sought to apply this strategy by examining the effects of such modifications in both the central core constrain and the substituent beta to the carboxylate. Most of these derivatives were prepared in good yields through a cesium fluoride-catalyzed coupling reaction. This reaction was successful with a variety of nitrogen-containing scaffolds (20, 33, and 43) and selected acetylenic derivatives (16, 19, and 34). Among the compounds synthesized, the 3-[5-[2-(5,6,7,8-tetrahydro [1,8]naphthyridin-2-yl)ethoxy]indol-1-yl]-3-[5-(N,N-dimethylaminomethyl)-3-pyridyl]propionic acid (25) was found to be the most promising derivative within this novel series with a subnanomolar affinity for both alpha(v)beta(3) and alpha(v)beta(5) (IC(50) = 0.29 and 0.16 nM, respectively), similar to our initial lead receptor antagonists 2-4, and exhibiting a low HSA protein binding (40% bound, K(d) = 1.1+/-0.4 x 10(3) microM) and an improved in vitro stability profile toward human and mouse microsomes (99.9% and 98.7% remaining after 10 min). Moreover, the selectivity of 25 toward alpha(5)beta(1) and IIbIIIa integrins was perfectly maintained when compared to the parent leads 2-4. Thus, compound 25 was selected as a new lead with improved drug-like properties for further evaluations in the field of oncology and osteoporosis.

Design, synthesis, and biological evaluation of novel potent and selective alphavbeta3/alphavbeta5 integrin dual inhibitors with improved bioavailability. Selection of the molecular core.

A novel series of potent and selective alpha(v)beta(3)/alpha(v)beta(5) dual( )()inhibitors was designed, synthesized, and evaluated against several integrins. These compounds were synthesized through a Mitsunobu reaction between the guanidinium mimetics and the corresponding central templates. Guanidinium mimetics with enhaced rigidity (i.e., (2-pyridylamino)propoxy versus the 2-(6-methylamino-2-pyridyl)ethoxy) led to improved activity toward alpha(v)beta(3). Exemplary oral bioavailability in mice was achieved using the indole central scaffold. Although, oral bioavailability was maintained when the indole molecular core was replace with the bioisosteric benzofuran or benzothiophene ring systems, it was found to not significantly impact the integrin activity or selectivity. However, the indole series displayed the best in vivo pharmacokinetic properties. Thus, the indole series was selected for further structure-activity relationships to obtain more potent alpha(v)beta(3)/alpha(v)beta(5) dual antagonist with improved oral bioavailability.

Optimization of a potent class of arylamide colony-stimulating factor-1 receptor inhibitors leading to anti-inflammatory clinical candidate 4-cyano-N-[2-(1-cyclohexen-1-yl)-4-[1-[(dimethylamino)acetyl]-4-piperidinyl]phenyl]-1H-imidazole-2-carboxamide (JNJ-28312141).

A class of potent inhibitors of colony-stimulating factor-1 receptor (CSF-1R or FMS), as exemplified by 8 and 21, was optimized to improve pharmacokinetic and pharmacodynamic properties and potential toxicological liabilities. Early stage absorption, distribution, metabolism, and excretion assays were employed to ensure the incorporation of druglike properties resulting in the selection of several compounds with good activity in a pharmacodynamic screening assay in mice. Further investigation, utilizing the type II collagen-induced arthritis model in mice, culminated in the selection of anti-inflammatory development candidate JNJ-28312141 (23, FMS IC(50) = 0.69 nM, cell assay IC(50) = 2.6 nM). Compound 23 also demonstrated efficacy in rat adjuvant and streptococcal cell wall-induced models of arthritis and has entered phase I clinical trials.

Potency variation of small-molecule chymase inhibitors across species.

Chymases (EC 3.4.21.39) are mast cell serine proteinases that are variably expressed in different species and, in most cases, display either chymotryptic or elastolytic substrate specificity. Given that chymase inhibitors have emerged as potential therapeutic agents for treating various inflammatory, allergic, and cardiovascular disorders, it is important to understand interspecies differences of the enzymes as well as the behavior of inhibitors with them. We have expressed chymases from humans, macaques, dogs, sheep (MCP2 and MCP3), guinea pigs, and hamsters (HAM1 and HAM2) in baculovirus-infected insect cells. The enzymes were purified and characterized with kinetic constants by using chromogenic substrates. We evaluated in vitro the potency of five nonpeptide inhibitors, originally targeted against human chymase. The inhibitors exhibited remarkable cross-species variation of sensitivity, with the greatest potency observed against human and macaque chymases, with K(i) values ranging from approximately 0.4 to 72nM. Compounds were 10-300-fold less potent, and in some instances ineffective, against chymases from the other species. The X-ray structure of one of the potent phosphinate inhibitors, JNJ-18054478, complexed with human chymase was solved at 1.8A resolution to further understand the binding mode. Subtle variations in the residues in the active site that are already known to influence chymase substrate specificity can also strongly affect the compound potency. The results are discussed in the context of selecting a suitable animal model to study compounds ultimately targeted for human chymase.

Discovery and clinical evaluation of 1-{N-[2-(amidinoaminooxy)ethyl]amino}carbonylmethyl-6-methyl-3-[2,2-difluoro-2-phenylethylamino]pyrazinone (RWJ-671818), a thrombin inhibitor with an oxyguanidine P1 motif.

We have identified RWJ-671818 (8) as a novel, low molecular weight, orally active inhibitor of human alpha-thrombin (K(i) = 1.3 nM) that is potentially useful for the acute and chronic treatment of venous and arterial thrombosis. In a rat deep venous thrombosis model used to assess antithrombotic efficacy, oral administration of 8 at 30 and 50 mg/kg reduced thrombus weight by 87 and 94%, respectively. In an anesthetized rat antithrombotic model, where electrical stimulation of the carotid artery created a thrombus, 8 prolonged occlusion time 2- and 3-fold at 0.1 and 1.0 mg/kg, i.v., respectively, and more than doubled activated clotting time and activated partial thromboplastin time at the higher dose. This compound had excellent oral bioavailability of 100% in dogs with an estimated half-life of approximately 3 h. On the basis of its noteworthy preclinical data, 8 was advanced into human clinical trials and successfully progressed through phase 1 studies.

Pyrido[2,3-d]pyrimidin-5-ones: a novel class of antiinflammatory macrophage colony-stimulating factor-1 receptor inhibitors.

A series of pyrido[2,3-d]pyrimidin-5-ones has been synthesized and evaluated as inhibitors of the kinase domain of macrophage colony-stimulating factor-1 receptor (FMS). FMS inhibitors may be useful in treating rheumatoid arthritis and other chronic inflammatory diseases. Structure-based optimization of the lead amide analogue 10 led to hydroxamate analogue 37, which possessed excellent potency and an improved pharmacokinetic profile. During the chronic phase of streptococcal cell wall-induced arthritis in rats, compound 37 (10, 3, and 1 mg/kg) was highly effective at reversing established joint swelling. In an adjuvant-induced arthritis model in rats, 37 prevented joint swelling partially at 10 mg/kg. In this model, osteoclastogenesis and bone erosion were prevented by low doses (1 or 0.33 mg/kg) that had minimal impact on inflammation. These data underscore the potential of FMS inhibitors to prevent erosions and reduce symptoms in rheumatoid arthritis.