Preclinical trial of a MAP4K4 inhibitor to reduce infarct size in the pig: does cardioprotection in human stem cell-derived myocytes predict success in large mammals?

Reducing infarct size (IS) by interfering with mechanisms for cardiomyocyte death remains an elusive goal. DMX-5804, a selective inhibitor of the stress-activated kinase MAP4K4, suppresses cell death in mouse myocardial infarction (MI), human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), and 3D human engineered heart tissue, whose fidelity to human biology is hoped to strengthen the route to clinical success. Here, DMX-10001, a soluble, rapidly cleaved pro-drug of DMX-5804, was developed for i.v. testing in large-mammal MI. Following pharmacodynamic studies, a randomized, blinded efficacy study was performed in swine subjected to LAD balloon occlusion (60 min) and reperfusion (24 h). Thirty-six animals were enrolled; 12 were excluded by pre-defined criteria, death before infusion, or technical issues. DMX-10001 was begun 20 min before reperfusion (30 min, 60 mg/kg/h; 23.5 h, 17 mg/kg/h). At all times tested, beginning 30 min after the start of infusion, DMX-5804 concentrations exceeded > fivefold the levels that rescued hPSC-CMs and reduced IS in mice after oral dosing with DMX-5804 itself. No significant reduction occurred in IS or no-reflow corrected for the area at ischemic risk, even though DMX-10001 reduced IS, expressed in grams or % of LV mass, by 27%. In summary, a rapidly cleaved pro-drug of DMX-5804 failed to reduce IS in large-mammal MI, despite exceeding the concentrations for proven success in both mice and hPSC-CMs.

Discovery of (2,4-dihydroxy-5-isopropylphenyl)-[5-(4-methylpiperazin-1-ylmethyl)-1,3-dihydroisoindol-2-yl]methanone (AT13387), a novel inhibitor of the molecular chaperone Hsp90 by fragment based drug design

Inhibitors of the molecular chaperone heat shock protein 90 (Hsp90) are currently generating significant interest in clinical development as potential treatments for cancer. In a preceding publication (DOI: 10.1021/jm100059d ) we describe Astex's approach to screening fragments against Hsp90 and the subsequent optimization of two hits into leads with inhibitory activities in the low nanomolar range. This paper describes the structure guided optimization of the 2,4-dihydroxybenzamide lead molecule 1 and details some of the drug discovery strategies employed in the identification of AT13387 (35), which has progressed through preclinical development and is currently being tested in man.

Total synthesis of (+)-sarain A

This article describes the details of our synthetic studies toward the complex marine alkaloid sarain A. Various strategies were conceived, setbacks encountered, and solutions developed, ultimately leading to a successful enantioselective total synthesis. Our route to (+)-sarain A features a number of key steps, including an asymmetric Michael addition to install the C4'-C3'-C7' stereotriad, an enoxysilane-N-sulfonyliminium ion cyclization to set the C3 quaternary carbon stereocenter, and assemble the diazatricycloundecane core, a ring-closing metathesis to construct the 13-membered ring, an intramolecular Stille coupling to fashion the unsaturated 14-membered macrocycle, and a late-stage installation of the tertiary amine-aldehyde proximity interaction.

Identification of inhibitors of protein kinase B using fragment-based lead discovery

Using fragment-based screening techniques, 5-methyl-4-phenyl-1H-pyrazole (IC50 80 microM) was identified as a novel, low molecular weight inhibitor of protein kinase B (PKB). Herein we describe the rapid elaboration of highly potent and ligand efficient analogues using a fragment growing approach. Iterative structure-based design was supported by protein-ligand structure determinations using a PKA-PKB "chimera" and a final protein-ligand structure of a lead compound in PKBbeta itself.

Structure-activity studies on prolactin-releasing peptide (PrRP). Analogues of PrRP-(19-31)-peptide

An investigation of a series of single replacement analogues of PrRP-(19-31)-peptide has shown that good functional activity was retained when Phe31 was replaced with His(Bzl), Phe(4Cl), Nle, Trp, Cys(Bzl) or Glu(OBzl); when Val28 or Ile25 was replaced with Phg; when Gly24 was replaced with D-Ala, L-Ala, Pro or Sar; when Ser22 was replaced with Gly and when Ala21 was replaced with Thr or MeAla. The results confirm that the functionally important residues are located within the carboxyl terminal segment, -Ile-Arg-Pro-Val-Gly-Arg-Phe-NH2.