Aleksandr Kolesnikov

Discovery of 2-{3-[2-(1-Isopropyl-3-methyl-1H-1,2–4-triazol-5-yl)-5,6-dihydrobenzo[f]imidazo[1,2-d][1,4]oxazepin-9-yl]-1H-pyrazol-1-yl}-2-methylpropanamide (GDC-0032): A β-Sparing Phosphoinositide 3-Kinase Inhibitor with High Unbound Exposure and Robust in Vivo Antitumor Activity

Dysfunctional signaling through the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway leads to uncontrolled tumor proliferation. In the course of the discovery of novel benzoxepin PI3K inhibitors, we observed a strong dependency of in vivo antitumor activity on the free-drug exposure. By lowering the intrinsic clearance, we derived a set of imidazobenzoxazepin compounds that showed improved unbound drug exposure and effectively suppressed growth of tumors in a mouse xenograft model at low drug dose levels. One of these compounds, GDC-0032 (11l), was progressed to clinical trials and is currently under phase I evaluation as a potential treatment for human malignancies.

Optimization of a screening lead for factor VIIa/TF

The structure-based design and progression of a screening lead to a 3nM factor VIIa/TF inhibitor with improved selectivity versus related enzymes is described.

Development of potent and selective factor Xa inhibitors

The development of potent and selective small molecule inhibitors of factor Xa is described.

Discovery of 5-Azaindazole (GNE-955) as a Potent Pan-Pim Inhibitor with Optimized Bioavailability

Pim kinases have been identified as promising therapeutic targets for hematologic-oncology indications, including multiple myeloma and certain leukemia. Here, we describe our continued efforts in optimizing a lead series by improving bioavailability while maintaining high inhibitory potency against all three Pim kinase isoforms. The discovery of extensive intestinal metabolism and major metabolites helped refine our design strategy, and we observed that optimizing the pharmacokinetic properties first and potency second was a more successful approach than the reverse. In the resulting work, novel analogs such as 20 (GNE-955) were discovered bearing 5-azaindazole core with noncanonical hydrogen bonding to the hinge.

Discovery of a Potent (4R,5S)-4-Fluoro-5-methylproline Sulfonamide Transient Receptor Potential Ankyrin 1 Antagonist and Its Methylene Phosphate Prodrug Guided by Molecular Modeling

Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation channel expressed in sensory neurons where it functions as an irritant sensor for a plethora of electrophilic compounds and is implicated in pain, itch, and respiratory disease. To study its function in various disease contexts, we sought to identify novel, potent, and selective small-molecule TRPA1 antagonists. Herein we describe the evolution of an N-isopropylglycine sulfonamide lead (1) to a novel and potent (4 R,5 S)-4-fluoro-5-methylproline sulfonamide series of inhibitors. Molecular modeling was utilized to derive low-energy three-dimensional conformations to guide ligand design. This effort led to compound 20, which possessed a balanced combination of potency and metabolic stability but poor solubility that ultimately limited in vivo exposure. To improve solubility and in vivo exposure, we developed methylene phosphate prodrug 22, which demonstrated superior oral exposure and robust in vivo target engagement in a rat model of AITC-induced pain.