Nicole Blaquiere

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.

Four‐Component Synthesis of Fully Substituted 1,2,4‐Triazoles

The generation of a-aza-biaryl linkages continues to challenge synthetic chemists and is the focus of much research effort. Classic transition-metal-catalyzed C C cross-coupling remains the most prevalent route for biaryl synthesis; however, issues with the unavailability and instability of organometallic reactants for a-heteroatom biaryl coupling still limit the success of this approach. Importantly, recent improvements have been made in the mild generation, increased benchtop stability, controlled release, and mild coupling of these previously unreliable reaction partners. Direct C H arylation avoids the preparation of stoichiometric organometallic reagents altogether and has proven to be a powerful method for the synthesis of biaryls. However, limitations still exist and reaction optimization for specific coupling partners is commonplace. As many azole and azine heterocycles can be generated by the cyclodehydration of appropriate carbonyl precursors, an alternative approach to a-aza-biaryl coupling stems from the transition-metal-catalyzed carbonylative coupling of acyclic reagents that can undergo in situ cyclodehydration (Figure 1). Importantly, a

Heteroarylation of Azine N-Oxides

Azine N-oxides undergo highly regioselective metalation with TMPZnCl·LiCl under mild conditions. A palladium-catalyzed Negishi cross-coupling reaction of the resulting organozinc species with heteroaromatic bromides provides heterobiaryls specifically oxidized at one nitrogen position in up to 95% yield.

Rapid Synthesis of 1,3,5-Substituted 1,2,4-Triazoles from Carboxylic Acids, Amidines, and Hydrazines

A general method for the synthesis of 1,3,5-trisubstituted 1,2,4-triazoles has been developed from reaction of carboxylic acids, primary amidines, and monosubstituted hydrazines. This highly regioselective and one-pot process provides rapid access to highly diverse triazoles.

Discovery of thiazolobenzoxepin PI3-kinase inhibitors that spare the PI3-kinase β isoform.

A series of suitable five-membered heterocyclic alternatives to thiophenes within a thienobenzoxepin class of PI3-kinase (PI3K) inhibitors was discovered. Specific thiazolobenzoxepin 8-substitution was identified that increased selectivity over PI3Kβ. PI3Kβ-sparing compound 27 (PI3Kβ Ki,app/PI3Kα Ki,app=57) demonstrated dose-dependent knockdown of pAKT, pPRAS40 and pS6RP in vivo as well as differential effects in an in vitro proliferation cell line screen compared to pan PI3K inhibitor GDC-0941. A new structure-based hypothesis for reducing inhibition of the PI3K β isoform while maintaining activity against α, δ and γ isoforms is presented.

Structure-Based Design of Tricyclic NF-κB Inducing Kinase (NIK) Inhibitors That Have High Selectivity over Phosphoinositide-3-kinase (PI3K)

We report here structure-guided optimization of a novel series of NF-κB inducing kinase (NIK) inhibitors. Starting from a modestly potent, low molecular weight lead, activity was improved by designing a type 11/2 binding mode that accessed a back pocket past the methionine-471 gatekeeper. Divergent binding modes in NIK and PI3K were exploited to dampen PI3K inhibition while maintaining NIK inhibition within these series. Potent compounds were discovered that selectively inhibit the nuclear translocation of NF-κB2 (p52/REL-B) but not canonical NF-κB1 (REL-A/p50).

Development of a tripartite solvent blend for sustainable chromatography

A three-component solvent system (isopropyl acetate, methanol, and heptane) was designed to empower routine chromatographic separation of a wide range of compounds, from polar to nonpolar molecules, without the need for undesired chlorinated solvent. This system was evaluated with a pharmaceutically-relevant set of compounds via practical silica gel chromatographic purification, making the solvent blend an attractive sustainable chromatography solution for drug discovery efforts.

Abstract DDT02-01: Discovery of GDC-0032: A beta-sparing PI3K inhibitor active against PIK3CA mutant tumors.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Modifications of the phosphoinositide-3 kinase (PI3K)/Akt signaling pathway are frequent in cancer due to multiple mechanisms, including activating mutations of the alpha isoform of PI3K. The dysregulation of this pathway has been implicated in many processes involved in oncogenesis. Thus, PI3K is a promising therapeutic target for cancer. Previously we have disclosed GDC-0941, a class 1 selective PI3K inhibitor and our class 1 PI3K/mTOR kinase inhibitor, GDC-0980. In this presentation we describe the design and discovery of a new class of PI3K inhibitors, which selectively inhibit the activated PI3Kα isoform relative to the PI3Kβ isoform. A lead was identified from a high throughput screen (HTS) that resulted in a novel chemical series of kinase inhibitors. Through a structure-based approach, this lead was optimized to provide very potent inhibitors of PI3K. In addition, this chemical series allowed for designing molecules that have different selectivity patterns with respect to the class 1 PI3K isoforms. In particular, a series of inhibitors were designed that could preferentially inhibit PI3Kα relative to PI3Kβ (“beta-sparing”). Further modification of the physicochemical properties led to the discovery of GDC-0032. GDC-0032 is a potent inhibitor of PI3Kα (PIK3CA) isoform with a Ki =0.2 nM, and with reduced inhibitory activity against PI3Kβ. This selectivity profile allowed for greater efficacy in vivo at the maximum tolerated dose relative to a pan inhibitor in representative PI3Kα (PIK3CA) mutant xenografts. It is notable that GDC-0032 preferentially inhibited PI3Kα (PIK3CA) mutant cells relative to cells with wild-type PI3K. Taken together, GDC-0032 is a potent and effective beta-sparing PI3K inhibitor, which currently is in clinical trials. Citation Format: Alan G. Olivero, Timothy P. Heffron, Matthew Baumgardner, Marcia Belvin, Leanne Berry Ross, Nicole Blaquiere, Erin Bradley, Georgette Castanedo, Mika Derynck, Steven Do, Jennafer Dotson, Danette Dudley, Kyle Edgar, Adrian Folkes, Ross Francis, Tony Gianetti, Richard Goldsmith, Paul Goldsmith, Jane Guan, Trevor Harrison, Robert Heald, Jerry Hsu, Phillip Jackson, Graham Jones, Amy Kim, Aleks Kolesnikov, Mark Lackner, Leslie Lee, John Lesnick, Cristina Lewis, Michael Mamounas, Neville McLean, Jeremy Murray, Chudi Ndubaku, Jim Nonomiya, Jodie Pang, Neil Pegg, Wei Wei Prior, Laurent Salphati, Deepack Sampath, Stephen Sideris, Michael Siu, Steven Staben, Daniel Sutherlin, Mark Ultsch, Jeff Wallin, Lan Wang, Christian Wiesmann, Xiaolin Zhang, Lori S. Friedman. Discovery of GDC-0032: A beta-sparing PI3K inhibitor active against PIK3CA mutant tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr DDT02-01. doi:10.1158/1538-7445.AM2013-DDT02-01

Scaffold-Hopping Approach To Discover Potent, Selective, and Efficacious Inhibitors of NF-κB Inducing Kinase

NF-κB-inducing kinase (NIK) is a protein kinase central to the noncanonical NF-κB pathway downstream from multiple TNF receptor family members, including BAFF, which has been associated with B cell survival and maturation, dendritic cell activation, secondary lymphoid organ development, and bone metabolism. We report herein the discovery of lead chemical series of NIK inhibitors that were identified through a scaffold-hopping strategy using structure-based design. Electronic and steric properties of lead compounds were modified to address glutathione conjugation and amide hydrolysis. These highly potent compounds exhibited selective inhibition of LTβR-dependent p52 translocation and transcription of NF-κB2 related genes. Compound 4f is shown to have a favorable pharmacokinetic profile across species and to inhibit BAFF-induced B cell survival in vitro and reduce splenic marginal zone B cells in vivo.