Cyclin-dependent kinase 12 is a drug target for visceral leishmaniasis

Visceral leishmaniasis causes considerable mortality and morbidity in many parts of the world. There is an urgent need for the development of new, effective treatments for this disease. Here we describe the development of an anti-leishmanial drug-like chemical series based on a pyrazolopyrimidine scaffold. The leading compound from this series (7, DDD853651/GSK3186899) is efficacious in a mouse model of visceral leishmaniasis, has suitable physicochemical, pharmacokinetic and toxicological properties for further development, and has been declared a preclinical candidate. Detailed mode-of-action studies indicate that compounds from this series act principally by inhibiting the parasite cdc-2-related kinase 12 (CRK12), thus defining a druggable target for visceral leishmaniasis

Identification of GSK3186899/DDD853651 as a Preclinical Development Candidate for the Treatment of Visceral Leishmaniasis

The leishmaniases are diseases that affect millions of people across the world, in particular visceral leishmaniasis (VL) which is fatal unless treated. Current standard of care for VL suffers from multiple issues and there is a limited pipeline of new candidate drugs. As such, there is a clear unmet medical need to identify new treatments. This paper describes the optimization of a phenotypic hit against Leishmania donovani, the major causative organism of VL. The key challenges were to balance solubility and metabolic stability while maintaining potency. Herein, strategies to address these shortcomings and enhance efficacy are discussed, culminating in the discovery of preclinical development candidate GSK3186899/DDD853651 (<b>1</b>) for VL

Identification and Characterization of Hundreds of Potent and Selective Inhibitors of Trypanosoma brucei Growth from a Kinase-Targeted Library Screening Campaign

© 2014 Diaz et al. In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2) cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053). This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs.Peer Reviewe

Identification and Characterization of Hundreds of Potent and Selective Inhibitors of <i>Trypanosoma brucei</i> Growth from a Kinase-Targeted Library Screening Campaign

<div><p>In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in <i>Trypanosomal brucei,</i> a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2) cells. In this way, we have identified 797 sub-micromolar inhibitors of <i>T. brucei</i> growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of <i>in silico</i> and <i>in vitro</i> physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of <i>T. brucei rhodesiense</i> with one of these compounds (NEU-1053). This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for <i>T. brucei,</i> and new HAT therapeutics discovery programs.</p></div

Scatter plot showing the average pEC₅₀ at the 18 hour time point for the 242 compounds tested in the cidality assay.

<p>Compounds are colored on the basis of reversibility behavior (cidal = red; static = green).</p

Compound composite scoring schema.

a<p>“Fast” is defined as pEC₅₀≥6 at 18 h.</p>b<p>“Cidal” is defined as pEC₉₉≥6 in the reversibility experiments. Only compounds that were rapidly acting and/or had an MPO score ≥4 were tested in the cidality assay; compounds not tested in the cidal assay are assigned a score of 0.</p><p>Compound composite scoring schema.</p

(A) Peripheral blood levels of NEU-1200 (blue), NEU-1207 (red) and NEU-1053 (green) after intraperitoneal administration of 5 mg/kg single dose to NMRI mice (n = 3).

<p>The average and standard deviation of the mean for each time point are represented in the plot. Blood levels of NEU-1053 after IP administration was observed till 24h post-dose. Y-axis is represented in log scale. (B) Animal survival plot showing the effects of dosing of NEU-1053 (ip 20/mg/kg/day; orange) versus DMSO control (black line) in <i>T. b. brucei</i> or (C) <i>T. b. rhodesiense</i> infection. Parasitemia was checked on days indicated by circles.</p

Histogram distributions of cLogP, MW and TPSA for (a) the whole HTS set (42,444 compounds, red), and (b) the 797 potent and specific compounds (pEC₅₀>6 and 100-fold specificity, blue).

<p>Histogram distributions of cLogP, MW and TPSA for (a) the whole HTS set (42,444 compounds, red), and (b) the 797 potent and specific compounds (pEC₅₀>6 and 100-fold specificity, blue).</p