Leveraging Structure-Based Drug Design to Identify Next-Generation MAT2A Inhibitors, Including Brain-Penetrant and Peripherally Efficacious Leads.

Inhibition of the -adenosyl methionine (SAM)-producing metabolic enzyme, methionine adenosyltransferase 2A (MAT2A), has received significant interest in the field of medicinal chemistry due to its implication as a synthetic lethal target in cancers with the deletion of the methylthioadenosine phosphorylase (MTAP) gene. Here, we report the identification of novel MAT2A inhibitors with distinct properties that may enhance their utility in treating patients. Following a high-throughput screening, we successfully applied the structure-based design lessons from our first-in-class MAT2A inhibitor, , to rapidly redesign and optimize our initial hit into two new lead compounds: a brain-penetrant compound, , and a potent, but limited brain-penetrant compound, .

Preclinical Drug Metabolism, Pharmacokinetic, and Pharmacodynamic Profiles of Ivosidenib, an Inhibitor of Mutant Isocitrate Dehydrogenase 1 for Treatment of Isocitrate Dehydrogenase 1-Mutant Malignancies.

Point mutations in isocitrate dehydrogenase 1 () result in conversion of -ketoglutarate to the oncometabolite, d-2-hydroxyglutarate (2-HG). Ivosidenib is a once daily (QD), orally available, potent, mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor approved for the treatment of patients with relapsed or refractory acute myeloid leukemia (AML) and intensive chemotherapy-ineligible newly diagnosed AML, with a susceptible mutation. We characterized the protein binding, metabolism, metabolites, cell permeability, and drug-drug interaction potential of ivosidenib in humans, monkeys, dogs, rats, and/or mice in in vitro experiments.

Selective Vulnerability to Pyrimidine Starvation in Hematologic Malignancies Revealed by AG-636, a Novel Clinical-Stage Inhibitor of Dihydroorotate Dehydrogenase.

Agents targeting metabolic pathways form the backbone of standard oncology treatments, though a better understanding of differential metabolic dependencies could instruct more rationale-based therapeutic approaches. We performed a chemical biology screen that revealed a strong enrichment in sensitivity to a novel dihydroorotate dehydrogenase (DHODH) inhibitor, AG-636, in cancer cell lines of hematologic versus solid tumor origin. Differential AG-636 activity translated to the setting, with complete tumor regression observed in a lymphoma model.

A chemical biology screen identifies a vulnerability of neuroendocrine cancer cells to SQLE inhibition.

Aberrant metabolism of cancer cells is well appreciated, but the identification of cancer subsets with specific metabolic vulnerabilities remains challenging. We conducted a chemical biology screen and identified a subset of neuroendocrine tumors displaying a striking pattern of sensitivity to inhibition of the cholesterol biosynthetic pathway enzyme squalene epoxidase (SQLE). Using a variety of orthogonal approaches, we demonstrate that sensitivity to SQLE inhibition results not from cholesterol biosynthesis pathway inhibition, but rather surprisingly from the specific and toxic accumulation of the SQLE substrate, squalene.

Structure and inhibition mechanism of the catalytic domain of human squalene epoxidase.

Squalene epoxidase (SQLE), also known as squalene monooxygenase, catalyzes the stereospecific conversion of squalene to 2,3(S)-oxidosqualene, a key step in cholesterol biosynthesis. SQLE inhibition is targeted for the treatment of hypercholesteremia, cancer, and fungal infections. However, lack of structure-function understanding has hindered further progression of its inhibitors.

Selective CB2 receptor agonists. Part 3: the optimization of a piperidine-based series that demonstrated efficacy in an in vivo neuropathic pain model.

A novel class of potent cannabinoid receptor 2 (CB2) agonists based on a (S)-piperidine scaffold was identified using ligand-based pharmacophore models. Optimization of solubility and metabolic stability led to the identification of several potent CB2 agonists (e.g.

Selective CB2 receptor agonists. Part 2: Structure-activity relationship studies and optimization of proline-based compounds.

Through a ligand-based pharmacophore model (S)-proline based compounds were identified as potent cannabinoid receptor 2 (CB2) agonists with high selectivity over the cannabinoid receptor 1 (CB1). Structure-activity relationship investigations for this compound class lead to oxo-proline compounds 21 and 22 which combine an impressive CB1 selectivity profile with good pharmacokinetic properties. In a streptozotocin induced diabetic neuropathy model, 22 demonstrated a dose-dependent reversal of mechanical hyperalgesia.

SAR studies of non-zinc-chelating MMP-13 inhibitors: improving selectivity and metabolic stability.

SAR studies to improve the selectivity and metabolic stability of a class of recently discovered MMP-13 inhibitors are reported. Improved selectivity was achieved by modifying interactions with the S1' pocket. Metabolic stability was improved through reduction of inhibitor lipophilicity.

Evaluation of microdosing to assess pharmacokinetic linearity in rats using liquid chromatography-tandem mass spectrometry.

The microdosing strategy allows for early assessment of human pharmacokinetics of new chemical entities using more limited safety assessment requirements than those requisite for a conventional phase I program. The current choice for evaluating microdosing is accelerator mass spectrometry (AMS) due to its ultrasensitivity for detecting radiotracers. However, the AMS technique is still expensive to be used routinely and requires the preparation of radiolabeled compounds.

Population pharmacokinetics of eniporide and its metabolite in healthy subjects and patients with acute myocardial infarction.

Eniporide (EMD 96 875) is a novel and selective inhibitor of the Na+-H+ exchange (NHE-1) inhibitor. The study objectives were to identify a structural model for population pharmacokinetic analysis of eniporide and its metabolite (EMD 112 843) using nonlinear mixed-effects modeling after short-term infusion (dose: 2.5-400 mg) in healthy subjects and patients undergoing myocardial reperfusion therapy.

Efficacy of dichloroacetate as a lactate-lowering drug.

Dichloroacetate (DCA) decreases blood, cerebral spinal fluid, and intracellular lactate concentrations by activating the mitochondrial pyruvate dehydrogenase enzyme complex. The authors reviewed the efficacy of this investigational drug in the treatment of acquired or congenital forms of lactic acidosis from data in 40 English-language publications. The hypolactatemic effect of DCA occurs over a broad range of pretreatment lactate concentrations and is directly related to the baseline lactate level.

Population kinetics, efficacy, and safety of dichloroacetate for lactic acidosis due to severe malaria in children.

The authors conducted a randomized, double-blind, placebo-controlled trial of intravenous dichloroacetate (DCA) for the purpose of treating lactic acidosis in 124 West African children with severe Plasmodium falciparum malaria. Lactic acidosis independently predicts mortality in severe malaria, and DCA stimulates the oxidative removal of lactate in vivo. A single infusion of 50 mg/kg DCA was well tolerated.

Pharmacokinetic/pharmacodynamic modeling of luteinizing hormone (LH) suppression and LH surge delay by cetrorelix after single and multiple doses in healthy premenopausal women.

Cetrorelix (CET) is a potent luteinizing hormone-releasing hormone (LH-RH) antagonist and is used to prevent premature ovulation in IVF (in vitro fertilization) procedures. The objective of the present study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model for the LH suppression and LH surge delay after single doses (SD) and multiple doses (MD) of CET in healthy premenopausal women without ovarian stimulation. CET was given by subcutaneous route (SD, 0.

Microdialysis of triamcinolone acetonide in rat muscle.

The objective of this study was to compare plasma and muscle concentrations of triamcinolone acetonide (TA) in the rat by microdialysis. Microdialysis experiments were carried out at steady state in rats after an initial I.V.

Population pharmacokinetics of digoxin in Egyptian pediatric patients: impact of one data point utilization.

A population pharmacokinetic (PK) study was designed to estimate the PK parameters of digoxin among a selected group of Egyptian pediatric patients (n = 30) with mean age +/- SD and body weight +/- SD of 8.88 +/- 3.01 years and 23.