Free Energy Perturbation Approach for Accurate Crystalline Aqueous Solubility Predictions.

Early assessment of crystalline thermodynamic solubility continues to be elusive for drug discovery and development despite its critical importance, especially for the ever-increasing fraction of poorly soluble drug candidates. Here we present a detailed evaluation of a physics-based free energy perturbation (FEP+) approach for computing the thermodynamic aqueous solubility. The predictive power of this approach is assessed across diverse chemical spaces, spanning pharmaceutically relevant literature compounds and more complex AbbVie compounds. Our approach achieves predictive (RMSE = 0.86) and differentiating power (R2 = 0.69) and therefore provides notably improved correlations to experimental solubility compared to state-of-the-art machine learning approaches that utilize quantum mechanics-based descriptors. The importance of explicit considerations of crystalline packing in predicting solubility by the FEP+ approach is also highlighted in this study. Finally, we show how computed energetics, including hydration and sublimation free energies, can provide further insights into molecule design to feed the medicinal chemistry DMTA cycle.

Neuromotor deficits and altered physiological responses to repeated exertional heat stroke exposures in mice.

Exertional heat stroke (EHS) is a life-threatening illness that can lead to negative health outcomes. Using a "severe" preclinical mouse model of EHS, we tested the hypotheses that one EHS exposure results in altered susceptibility to a subsequent EHS and reduced neuromotor performance. Female C57BL/6 mice underwent two protocols, 2 wk apart, either an EHS trial (EHS) or a sham exercise control trial (EXC). For EHS, mice ran in a forced running wheel at 37.5°C/40% relative humidity until loss of consciousness, followed by a slow cooling protocol (2 h recovery at 37.5°C). EXC mice exercised equally but in ∼22°C. Mice were randomized into three groups: 1) EXC-EXC (two consecutive EXC, n = 6, 2) EHS-EXC (EHS followed by EXC, n = 5), and 3) EHS-EHS (repeated EHS, n = 9). Mice underwent noninvasive neuromotor and behavioral tests during recovery and isolated soleus force measurements at the end of recovery. At the first EHS, mice reached average peak core temperatures (Tc,max) of 42.4°C, (46% mortality). On the second EHS, average Tc,max was reduced by ∼0.7°C (P < 0.05; mortality 18%). After the first EHS, both EHS-EX and EHS-EHS showed significant reductions in maximum strength (24 h and 1 wk post). After the second EHS, strength, horizontal rotation, hindlimb tone, suspended hindlimb splay, trunk curl, and provoked biting continued to decline in the EHS-EHS group. In conclusion, exposure to a second EHS after 2 wk leads to increased exercise times in the heat, symptom limitation at a lower Tc,max, and greater deficits in neuromotor and behavioral function during recovery.

Inhibition of Interleukin-23-Mediated Inflammation with a Novel Small Molecule Inverse Agonist of RORγt.

Blockade of interleukin (IL)-23 or IL-17 with biologics is clinically validated as a treatment of psoriasis. However, the clinical impact of targeting other nodes within the IL-23/IL-17 pathway, especially with small molecules, is less defined. We report on a novel small molecule inverse agonist of retinoid acid-related orphan receptor (ROR) γt and its efficacy in preclinical models of psoriasis and arthritis. 1-(2,4-Dichloro-3-((1,4-dimethyl-6-(trifluoromethyl)-1H-indol-2-yl)methyl)benzoyl)piperidine-4-carboxylic acid (A-9758) was optimized from material identified from a high-throughput screening campaign. A-9758 is selective for RORγt and exhibits robust potency against IL-17A release both in vitro and in vivo. In vivo, we also show that IL-23 is sufficient to drive the accumulation of RORγt+ cells, and inhibition of RORγt significantly attenuates IL-23-driven psoriasiform dermatitis. Therapeutic treatment with A-9758 (i.e., delivered during active disease) was also effective in blocking skin and joint inflammation. Finally, A-9758 exhibited efficacy in an ex vivo human whole blood assay, suggesting small molecule inverse agonists of RORγt could be efficacious in human IL-17-related diseases. SIGNIFICANCE STATEMENT: Using a novel small molecule inverse agonist, and preclinical assays, we show that RORγt is a viable target for the inhibition of RORγt/Th17-driven diseases such as psoriasis. Preclinical models of psoriasis show that inhibition of RORγt blocks both the accumulation and effector function of IL-17-producing T cells.

Discovery of novel quinoline sulphonamide derivatives as potent, selective and orally active RORγ inverse agonists.

A high-throughput screen against Inventiva's compound library using a Gal4/RORγ-LBD luciferase reporter gene assay led to the discovery of a new series of quinoline sulphonamides as RORγ inhibitors, eventually giving rise to a lead compound having an interesting in vivo profile after oral administration. This lead was evaluated in a target engagement model in mouse, where it reduced IL-17 cytokine production after immune challenge. It also proved to be active in a multiple sclerosis model (EAE) where it reduced the disease score. The synthesis, structure activity relationship (SAR) and biological activity of these derivatives is described herein.

Prodrugs for colon-restricted delivery: Design, synthesis, and in vivo evaluation of colony stimulating factor 1 receptor (CSF1R) inhibitors.

The ability to restrict low molecular weight compounds to the gastrointestinal (GI) tract may enable an enhanced therapeutic index for molecular targets known to be associated with systemic toxicity. Using a triazolopyrazine CSF1R inhibitor scaffold, a broad range of prodrugs were synthesized and evaluated for enhanced delivery to the colon in mice. Subsequently, the preferred cyclodextrin prodrug moiety was appended to a number of CSF1R inhibitory active parent molecules, enabling GI-restricted delivery. Evaluation of a cyclodextrin prodrug in a dextran sodium sulfate (DSS)-induced mouse colitis model resulted in enhanced GI tissue levels of active parent. At a dose where no significant depletion of systemic monocytes were detected, the degree of pharmacodynamic effect-measured as reduction in macrophages in the colon-was inferior to that observed with a systemically available positive control. This suggests that a suitable therapeutic index cannot be achieved with CSF1R inhibition by using GI-restricted delivery in mice. However, these efforts provide a comprehensive frame-work in which to pursue additional gut-restricted delivery strategies for future GI targets.

Design strategies to address kinetics of drug binding and residence time.

The kinetics of drug binding and drug residence time are recognized to be important in the clinical effectiveness of drug candidates. In most cases a long residence time of the drug-target complex results in an extended duration of pharmacodynamic activity, even when systemic concentrations of drug have been notably reduced through elimination routes. Hence, if selective for target, long residence times can increase the duration of drug efficacy in vivo and can significantly diminish the potential for off-target-mediated toxicities. Furthermore, a compound with a slower dissociation rate may allow a reduced dosing schedule relative to a compound with a rapid dissociation rate. Factors contributing to long residence time that could be useful to medicinal chemists in the prospective design of compounds with long residence times will be discussed in this perspective. Particular emphasis will be on case studies highlighting how kinetics can be measured, modulated based on supporting structure kinetic relationships and whether these effects are translatable into man.

Emerging technologies for metabolite generation and structural diversification.

Multiple technologies have emerged for structural diversification and efficient production of metabolites of drug molecules. These include expanded use of enzymatic and bioorganic transformations that mimic biological systems, biomimetic catalysis and electrochemical techniques. As this field continues to mature the breadth of transformations is growing beyond simple oxidative processes due in part to parallel development of more efficient catalytic methods for functionalization of unactivated scaffolds. These technologies allow for efficient structural diversification of both aromatic and aliphatic substrates in many cases via single step reactions without the use of protecting groups.

S1P(1) receptor agonists: Assessment of selectivity and current clinical activity.

Interest in sphingosine-1-phosphate (S1P)(1) receptor agonists has increased steadily since the discovery that the mechanism of action of fingolimod (FTY-720)-induced lymphopenia is linked to the S1P GPCR family. Fingolimod is an agonist at four out of the five S1P family receptors. Adoptive cell transfer experiments and selective S1P(1) receptor agonists provided evidence that the S1P(1) receptor is the main target responsible for trapping lymphocytes in secondary lymphoid tissue. This readily accessible, translatable biomarker has been correlated with efficacy in rodent models of immune disease. Novartis AG filed for regulatory approval for fingolimod in the US and EU for the treatment of multiple sclerosis in December 2009. In addition, more selective compounds targeting S1P receptors from several companies have entered clinical trials. These compounds can be categorized into two classes of S1P(1) receptor agonists: amino alcohol prodrugs and second-generation direct agonists. This review focuses on the development of these compounds and the role of S1P receptor family selectivity.

Scalable synthesis and isolation of the four stereoisomers of methyl 1-amino-3-(4-bromophenyl)cyclopentanecarboxylate, useful intermediates for the synthesis of S1P1 receptor agonists.

The individual isomers of methyl 1-amino-3-(4-bromophenyl)cyclopentanecarboxylate are useful intermediates for the synthesis of S1P1 receptor agonists. Herein we describe a scalable synthesis and isolation of each of the four stereoisomers of this compound in gram quantities with >98% ee and de. The utility of this approach is demonstrated by the synthesis of ((1R,3R)-1-amino-3-(4-octylphenyl)cyclopentyl)methanol in 7 steps, 11% overall yield, and >98% ee and de.

Identification of a selective thieno[2,3-c]pyridine inhibitor of COT kinase and TNF-alpha production.

COT (Tpl2 in mice) is a serine/threonine MAP3 kinase that regulates production of TNF-alpha and other pro-inflammatory cytokines such as IL-1beta via the ERK/MAP kinase pathway. As TNF-alpha and IL-1beta are clinically validated targets for therapeutic intervention in rheumatoid arthritis (RA), blocking COT provides a potential avenue for amelioration of disease. Herein we describe identification of a cellular active selective small molecule inhibitor of COT kinase.

Discovery of thieno[2,3-c]pyridines as potent COT inhibitors.

Evaluation of hit chemotypes from high throughput screening identified a novel series of 2,4-disubstituted thieno[2,3-c]pyridines as COT kinase inhibitors. Structural modifications exploring SAR at the 2- and 4-positions resulting in inhibitors with improved enzyme potency and cellular activity are disclosed.

A 13C NMR approach to categorizing potential limitations of alpha,beta-unsaturated carbonyl systems in drug-like molecules.

Compounds that contain an alpha,beta-unsaturated carbonyl moiety are often flagged as potential Michael acceptors. All alpha,beta-unsaturated carbonyl moieties are not equivalent, however, and we sought to better understand this system and its potential implications in drug-like molecules. Measurement of the (13)C NMR shift of the beta-carbon and correlation to in vitro results allowed compounds in our collection to be categorized as potential Michael acceptors, potential substrates for NADPH, or as photoisomerizable.