Anthony B. Reed

Discovery of highly selective and potent p38 inhibitors based on a phthalazine scaffold.

Investigations into the structure-activity relationships (SAR) of a series of phthalazine-based inhibitors of p38 are described. These efforts originated from quinazoline 1 and through rational design led to the development of a series of orally bioavailable, potent, and selective inhibitors. Kinase selectivity was achieved by exploiting a collection of interactions with p38alpha including close contact to Ala157, occupation of the hydrophobic gatekeeper pocket, and a residue flip with Gly110. Substitutions on the phthalazine influenced the pharmacokinetic properties, of which compound 16 displayed the most desirable profile. Oral dosing (0.03 mg/kg) of 16 in rats 1 h prior to LPS challenge gave a >50% decrease in TNFalpha production.

Structure-based design of a novel series of potent, selective inhibitors of the class I phosphatidylinositol 3-kinases.

A highly selective series of inhibitors of the class I phosphatidylinositol 3-kinases (PI3Ks) has been designed and synthesized. Starting from the dual PI3K/mTOR inhibitor 5, a structure-based approach was used to improve potency and selectivity, resulting in the identification of 54 as a potent inhibitor of the class I PI3Ks with excellent selectivity over mTOR, related phosphatidylinositol kinases, and a broad panel of protein kinases. Compound 54 demonstrated a robust PD-PK relationship inhibiting the PI3K/Akt pathway in vivo in a mouse model, and it potently inhibited tumor growth in a U-87 MG xenograft model with an activated PI3K/Akt pathway.

Selective Class I Phosphoinositide 3-Kinase Inhibitors: Optimization of a Series of Pyridyltriazines Leading to the Identification of a Clinical Candidate, AMG 511

The phosphoinositide 3-kinase family catalyzes the phosphorylation of phosphatidylinositol-4,5-diphosphate to phosphatidylinositol-3,4,5-triphosphate, a secondary messenger which plays a critical role in important cellular functions such as metabolism, cell growth, and cell survival. Our efforts to identify potent, efficacious, and orally available phosphatidylinositol 3-kinase (PI3K) inhibitors as potential cancer therapeutics have resulted in the discovery of 4-(2-((6-methoxypyridin-3-yl)amino)-5-((4-(methylsulfonyl)piperazin-1-yl)methyl)pyridin-3-yl)-6-methyl-1,3,5-triazin-2-amine (1). In this paper, we describe the optimization of compound 1, which led to the design and synthesis of pyridyltriazine 31, a potent pan inhibitor of class I PI3Ks with a superior pharmacokinetic profile. Compound 31 was shown to potently block the targeted PI3K pathway in a mouse liver pharmacodynamic model and inhibit tumor growth in a U87 malignant glioma glioblastoma xenograft model. On the basis of its excellent in vivo efficacy and pharmacokinetic profile, compound 31 was selected for further evaluation as a clinical candidate and was designated AMG 511.

Discovery of 5-(1H-indol-5-yl)-1,3,4-thiadiazol-2-amines as potent PIM inhibitors.

PIM kinases are a family of Ser/Thr kinases that are implicated in tumorigenesis. The discovery of a new class of PIM inhibitors, 5-(1H-indol-5-yl)-1,3,4-thiadiazol-2-amines, is discussed with optimized compounds showing excellent potency against all three PIM isoforms.

4-Methoxy-N-[2-(trifluoromethyl)biphenyl-4-ylcarbamoyl]nicotinamide: A Potent and Selective Agonist of S1P1

The sphingosine-1-phosphate-1 receptor (S1P1) and its endogenous ligand sphingosine-1-phosphate (S1P) cooperatively regulate lymphocyte trafficking from the lymphatic system. Herein, we disclose 4-methoxy-N-[2-(trifluoromethyl)biphenyl-4-ylcarbamoyl]nicotinamide (8), an uncommon example of a synthetic S1P1 agonist lacking a polar headgroup, which is shown to effect dramatic reduction of circulating lymphocytes (POC = -78%) in rat 24 h after a single oral dose (1 mg/kg). The excellent potency that 8 exhibits toward S1P1 (EC50 = 0.035 μM, 96% efficacy) and the >100-fold selectivity that it displays against receptor subtypes S1P2-5 suggest that it may serve as a valuable tool to understand the clinical relevance of selective S1P1 agonism.

The discovery and optimization of aminooxadiazoles as potent Pim kinase inhibitors.

High levels of Pim expression have been implicated in several hematopoietic and solid tumor cancers. These findings suggest that inhibition of Pim signaling by a small molecule Pim-1,2 inhibitor could provide patients with therapeutic benefit. Herein, we describe our progress towards this goal starting from the highly Pim-selective indole-thiadiazole compound (1), which was derived from a nonselective hit identified in a high throughput screening campaign. Optimization of this compounds potency and its pharmacokinetic properties resulted in the discovery of compound 29. Cyclopropane 29 was found to exhibit excellent enzymatic potency on the Pim-1 and Pim-2 isoforms (Ki values of 0.55nM and 0.28nM, respectively), and found to inhibit the phosphorylation of BAD in the Pim-overexpressing KMS-12 cell line (IC50=150nM). This compound had moderate clearance and bioavailability in rat (CL=2.42L/kg/h; %F=24) and exhibited a dose-dependent inhibition of p-BAD in KMS-12 tumor pharmacodynamic (PD) model with an EC50 value of 6.74μM (18μg/mL) when dosed at 10, 30, 100 and 200mg/kg po in mice.

The discovery of novel 3-(pyrazin-2-yl)-1H-indazoles as potent pan-Pim kinase inhibitors.

The three Pim kinases are a small family of serine/threonine kinases regulating several signaling pathways that are fundamental to tumorigenesis. As such, the Pim kinases are a very attractive target for pharmacological inhibition in cancer therapy. Herein, we describe our efforts toward the development of a potent, pan-Pim inhibitor. The synthesis and hit-to-lead SAR development from a 3-(pyrazin-2-yl)-1H-indazole derived hit 2 to the identification of a series of potent, pan-Pim inhibitors such as 13o are described.

Optimization of a Potent, Orally Active S1P1 Agonist Containing a Quinolinone Core

The optimization of a series of S1P1 agonists with limited activity against S1P3 is reported. A polar headgroup was used to improve the physicochemical and pharmacokinetic parameters of lead quinolinone 6. When dosed orally at 1 and 3 mg/kg, the azahydroxymethyl analogue 22 achieved statistically significant lowering of circulating blood lymphocytes 24 h postdose. In rats, a dose-proportional increase in exposure was measured when 22 was dosed orally at 2 and 100 mg/kg.

Discovery and Optimization of Quinazolinone-pyrrolopyrrolones as Potent and Orally Bioavailable Pan-Pim Kinase Inhibitors

The high expression of proviral insertion site of Moloney murine leukemia virus kinases (Pim-1, -2, and -3) in cancers, particularly the hematopoietic malignancies, is believed to play a role in promoting cell survival and proliferation while suppressing apoptosis. The three isoforms of Pim protein appear largely redundant in their oncogenic functions. Thus, a pan-Pim kinase inhibitor is highly desirable. However, cell active pan-Pim inhibitors have proven difficult to develop because Pim-2 has a low Km for ATP and therefore requires a very potent inhibitor to effectively block the kinase activity at cellular ATP concentrations. Herein, we report a series of quinazolinone-pyrrolopyrrolones as potent and selective pan-Pim inhibitors. In particular, compound 17 is orally efficacious in a mouse xenograft model (KMS-12 BM) of multiple myeloma, with 93% tumor growth inhibition at 50 mg/kg QD upon oral dosing.

Quinolinone-based agonists of S1P1: Use of a N-scan SAR strategy to optimize in vitro and in vivo activity

We reveal how a N-scan SAR strategy (systematic substitution of each CH group with a N atom) was employed for quinolinone-based S1P(1) agonist 5 to modulate physicochemical properties and optimize in vitro and in vivo activity. The diaza-analog 17 displays improved potency (hS1P(1) RI; 17: EC(50)=0.020 μM, 120% efficacy; 5: EC(50)=0.070 μM, 110% efficacy) and selectivity (hS1P(3) Ca(2+) flux; 17: EC(50) >25 μM; 5: EC(50)=1.5 μM, 92% efficacy), as well as enhanced pharmacokinetics (17: CL=0.15 L/h/kg, V(dss)=5.1L/kg, T(1/2)=24h, %F=110; 5: CL=0.93L/h/kg, V(dss)=11L/kg, T(1/2)=15 h, %F=60) and pharmacodynamics (17: 1.0mg/kg po, 24h PLC POC=-67%; 5: 3mg/kg po, 24h PLC POC=-51%) in rat.