Kevin Koch

Biological Characterization of ARRY-142886 (AZD6244), a Potent, Highly Selective Mitogen-Activated Protein Kinase Kinase 1/2 Inhibitor

Purpose: The Ras-Raf-mitogen-activated protein kinase kinase (MEK) pathway is overactive in many human cancers and is thus a target for novel therapeutics. We have developed a highly potent and selective inhibitor of MEK1/2. The purpose of these studies has been to show the biological efficacy of ARRY-142886 (AZD6244) in enzymatic, cellular, and animal models. Experimental Design: The ability of ARRY-142886 to inhibit purified MEK1 as well as other kinases was evaluated. Its effects on extracellular signal-regulated kinase (ERK) phosphorylation and proliferation in several cell lines were also determined. Finally, the inhibitor was tested in HT-29 (colorectal) and BxPC3 (pancreatic) xenograft tumor models. Results: The IC50 of ARRY-142886 was determined to be 14 nmol/L against purified MEK1. This activity is not competitive with ATP, which is consistent with the high specificity of compound for MEK1/2. Basal and epidermal growth factor–induced ERK1/2 phosphorylation was inhibited in several cell lines as well as 12-O-tetradecanoylphorbol-13-acetate–induced ERK1/2 phosphorylation in isolated peripheral blood mononuclear cells. Treatment with ARRY-142886 resulted in the growth inhibition of several cell lines containing B-Raf and Ras mutations but had no effect on a normal fibroblast cell line. When dosed orally, ARRY-142886 was capable of inhibiting both ERK1/2 phosphorylation and growth of HT-29 xenograft tumors in nude mice. Tumor regressions were also seen in a BxPC3 xenograft model. In addition, tumors remained responsive to growth inhibition after a 7-day dosing holiday. Conclusions: ARRY-142886 is a potent and selective MEK1/2 inhibitor that is highly active in both in vitro and in vivo tumor models. This compound is currently being investigated in clinical studies.

UK-78,282, a novel piperidine compound that potently blocks the Kv1.3 voltage-gated potassium channel and inhibits human T cell activation

UK‐78,282, a novel piperidine blocker of the T lymphocyte voltage‐gated K+ channel, Kv1.3, was discovered by screening a large compound file using a high‐throughput 86Rb efflux assay. This compound blocks Kv1.3 with a IC50 of ∼200 nM and 1 : 1 stoichiometry. A closely related compound, CP‐190,325, containing a benzyl moiety in place of the benzhydryl in UK‐78,282, is significantly less potent. Three lines of evidence indicate that UK‐78,282 inhibits Kv1.3 in a use‐dependent manner by preferentially blocking and binding to the C‐type inactivated state of the channel. Increasing the fraction of inactivated channels by holding the membrane potential at −50 mV enhances the channels sensitivity to UK‐78,282. Decreasing the number of inactivated channels by exposure to ∼160 mM external K+ decreases the sensitivity to UK‐78,282. Mutations that alter the rate of C‐type inactivation also change the channels sensitivity to UK‐78,282 and there is a direct correlation between τh and IC50 values. Competition experiments suggest that UK‐78,282 binds to residues at the inner surface of the channel overlapping the site of action of verapamil. Internal tetraethylammonium and external charybdotoxin do not compete UK‐78,282s action on the channel. UK‐78,282 displays marked selectivity for Kv1.3 over several other closely related K+ channels, the only exception being the rapidly inactivating voltage‐gated K+ channel, Kv1.4. UK‐78,282 effectively suppresses human T‐lymphocyte activation.

Ring closing metathesis in organic synthesis: Evolution of a high speed, solid phase method for the preparation of β-turn mimetics

Abstract Complimentary solid phase syntheses of the Freidinger lactam class of β-turn mimetics have been developed using ring closing metathesis as both the key carbon-carbon bond forming step and the cyclative cleavage mechanism. Solid phase variants of the Fukuyama-Mitsunobu process were utilized as part of a rapid three-step sequence to construct immobilized lactam precursors. An alternative solid phase process is offered which utilizes an Ugi/ring closing metathesis reaction tandem to deliver the desired compounds in two synthetic operations.

Solid phase heterocyclic synthesis via ring closing metathesis: Traceless linking and cyclative cleavage through a carbon-carbon double bond

Abstract Ring closing metathesis was utilized to affect cyclative cleavage of resin-bound α,ω dienes in the solid phase synthesis of dihydropyarans, pipecolinic acid derivatives and Freidinger lactams.

A Phase I and Pharmacokinetic Study of Lapatinib in Combination with Letrozole in Patients with Advanced Cancer

Purpose: The main objectives of this phase I and pharmacokinetic, open-label study were to determine the optimally tolerated regimen (OTR), safety, pharmacokinetics, and clinical activity of lapatinib in combination with letrozole in patients with advanced solid malignancies. Experimental Design: Patients with advanced breast cancer with immunohistochemically detectable estrogen or progesterone receptors or other cancers were eligible. Doses of lapatinib were escalated in cohorts of three subjects from 1,250 to a maximum of 1,500 mg/d based on dose-limiting toxicities in the first treatment cycle. The letrozole dose was fixed at 2.5 mg/d. Additional patients were enrolled at the OTR dose level to further evaluate safety and for pharmacokinetic analyses. Results: Thirty-nine patients were enrolled in the study: 12 in the dose-escalation group, 7 in the OTR safety group, and 20 in the pharmacokinetic group. The OTR dose level was identified as 1,500 mg/d lapatinib and 2.5 mg/d letrozole. The most common (>25% of patients) drug-related adverse events were diarrhea (77%), rash (62%), nausea (46%), and fatigue (26%). No significant differences were observed in the pharmacokinetic variables (Cmax and AUC) of lapatinib and letrozole when coadministered compared with single-agent administration. One patient with endometrial cancer had a confirmed partial response. Conclusions: Clinically relevant doses of lapatinib in combination with letrozole were well tolerated and did not result in a pharmacokinetic interaction, and clinical antitumor activity was observed.

Effects of ketoconazole and carbamazepine on lapatinib pharmacokinetics in healthy subjects.

AIMS To characterize the impact of potent CYP3A4 inhibition and induction on lapatinib pharmacokinetics. METHODS Two studies were conducted in healthy subjects. One study examined the effect of ketoconazole 200 mg b.i.d. for 7 days on a single 100-mg dose of lapatinib in 22 healthy subjects. The other study examined the effect of carbamazepine titrated up to 200 mg b.i.d. over 20 days on a single 250-mg dose of lapatinib in 24 healthy subjects. RESULTS Ketoconazole altered lapatinib AUC, C(max) and half-life, with geometric mean [95% confidence interval (CI)] increases of 3.57-fold (3.07, 4.15), 2.14-fold (1.74, 2.64) and 1.66-fold (1.50, 1.84), respectively, but had no effect on absorption rate. Carbamazepine altered lapatinib AUC, C(max) and absorption rate, with geometric mean (95% CI) decreases of 72% (68, 77), 59% (49, 66) and 28% (4, 46), respectively, but had no effect on half-life. CONCLUSIONS Systemic exposure to lapatinib was significantly altered by potent inhibition and induction of CYP3A4. Dose adjustments may be required when lapatinib is administered with orally administered drugs that potently alter the activity of this enzyme.

A second generation solid phase approach to Freidinger lactams: Application of Fukuyama's amine synthesis and cyclative release via ring closing metathesis

Abstract A high-speed solid phase synthesis of Freidinger lactams was accomplished using a novel variant of Fukuyamas amine synthesis and ring closing metathesis-promoted cyclative cleavage as key steps.

Abstract 2515: Preclinical Development of ARRY-162, A Potent and Selective MEK 1/2 Inhibitor

Activation of the Ras/Raf/MEK/MAP kinase pathway is implicated in uncontrolled cell proliferation and tumor growth. Inappropriate activation of the RAS pathway can occur through several distinct mechanisms, including activating mutations in Ras and B-raf, or activated growth factor-signaling, cytokines and stress responses. Mutated, oncogenic forms of Ras are found in 50% of colon, 90% of pancreatic, and 30% of lung cancers. Also, B-Raf mutations have been identified in more than 60% of malignant melanomas and from 40-70% of papillary thyroid cancers. MEK, a dual specific kinase, is a key player in this pathway; it is downstream of both Ras and Raf and activates ERK1/2 through phosphorylation of key tyrosine and threonine residues. These data suggest that targeting MEK can inhibit cancer cell signaling mediated by a wide variety of signals, making MEK an attractive target for the treatment of cancer. We have discovered ARRY-162, a novel ATP-uncompetitive inhibitor of MEK 1/2, which is un-competitive with respect to ATP. ARRY-162 has nanomolar activity against purified MEK enzyme (IC50 = 12 nM) and is highly selective. It has been evaluated against 220 serine/threonine and tyrosine kinases with no inhibitory activity observed up to 20 μM. ARRY-162 inhibits both basal and induced levels of ERK phosphorylation in numerous cancer cell lines with IC50s as low as 5 nM. ARRY-162 is especially potent at inhibiting the cell proliferation of mutant B-Raf and Ras cell lines such as HT29, Malme-3M, SK-MEL-2, COLO 205, SK-MEL-28 and A375 (IC50s from 30-250 nM). In vivo, ARRY-162 has demonstrated efficacy in several xenograft tumor models in mice, including HT29, BxPC3, MIA PaCa2, A549, LoVo, Calu6, DU145 and COLO 205. In the HT29 and in the COLO 205 colon carcinoma models, dose-dependent inhibition of tumor growth (up to 75% TGI) was observed at doses ranging from 3 to 30 mg/kg, QD, PO for 21 days. In the Colo-205 colon carcinoma model, significant tumor regressions were observed with 50% partial responses and 13% complete responses at 30 mg/kg, PO, QD. In the BxPC3 pancreatic carcinoma model (which does not harbor either Ras or Raf mutations), tumor growth inhibition (∼70% TGI) and 13% partial responses were seen at doses of 30 mg/kg, QD, PO for 21 days. Consistent with ARRY-1629s mechanism of action, tumor growth inhibition correlates with decreased phospho-ERK levels in tumor xenografts. In addition to its potency against MEK, this compound demonstrates other desirable attributes for development including good physical chemical characteristics, low clearance, medium-to-high Caco-2 permeability and minimal predicted drug-drug interactions. With preclinical efficacy and safety studies on ARRY-162 completed, this compound has entered clinical development for treatment of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2515.

Abstract 852: ARRY-380, a potent, small molecule inhibitor of ErbB2, increases survival in intracranial ErbB2+ xenograft models in mice

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL ARRY-380 is an orally active, potent small molecule targeting ErbB2 inhibitor currently in clinical development in patients with ErbB2+ metastatic breast cancer (MBC). This compound has shown excellent activity in numerous SC mouse tumor models including breast (BT-474, MDA-MB-453), ovarian (SK-OV-3) and gastric (N87) carcinoma models. In breast cancer patients, brain metastases are a serious unmet medical need. Patients with ErbB2+ breast cancer have a significantly increased incidence of brain metastases following trastuzumab therapy. Here we demonstrate significant single agent activity of ARRY-380 in two ErbB2+ intracranial mouse xenograft models. For these studies, female nude mice received intracranial implantations of tumor cells (either NCI-N87 or BT-474) by direct injection into the brain parenchyma (via the sagittal suture). In pilot studies, we demonstrated that the blood brain barrier was not disrupted by mechanical injections and that increasing tumor burden correlates negatively with neurologic outcome, body weight and survival. In the N87 studies, animals received treatments beginning on Day 2 post-implantation and continuing for up to 6 weeks. Dose groups (n=12/group) were vehicle, ARRY-380 at MTD (75 mg/kg, PO, BID) or lapatinib at MTD (50 mg/kg, PO, BID). All animals in the vehicle- or lapatinib-treated groups did not survive beyond Day 22. In the ARRY-380-treated-group, 75% of the animals were alive on Day 43. Brain PK/PD was also evaluated in the N87 model. ARRY-380 and its active metabolite caused a significant reduction in brain pErbB2 (80%). In the BT-474 model, animals received treatments beginning on Day 2 post-implantation and continuing for up to 8 weeks. Dose groups (n=13/group) were vehicle, ARRY-380 at MTD (75 mg/kg, PO, BID), lapatinib at MTD (50 mg/kg, PO, BID) or neratinib at MTD (40 mg/kg, PO, QD). On Day 56, survival in the ARRY-380 group was 69% while survival rates in the vehicle, lapatinib or neratinib-treated groups were 23%, 8% and 23%, respectively. Thus ARRY-380 treatment significantly enhances survival in two ErbB2 driven intracranial tumor xenograft models, with superior activity compared to other ErbB2 agents in these studies. Additionally, ARRY-380 has demonstrated durable clinical activity in heavily pre-treated patients with ErbB2+ MBC. These preclinical and clinical data suggest that ARRY-380 may provide benefit to patients with ErbB2+ MBC with brain metastases. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 852. doi:1538-7445.AM2012-852

Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis: Anti-inflammatory patent highlights: January-July 1994

An extensive review of the anti-inflammatory patent and primary literature published during the first half of 1994 is presented. Agents with defined molecular, mechanistic-based targets are emphasised and the latest significant biological results are included wherever possible. The topics of this review are divided into the following sections: leukotriene biosynthesis inhibitors and antagonists, platelet activating factor antagonists, phospholipase inhibitors, cyclooxy-genase inhibitors with combined CO/LO inhibitors, phosphodi-esterase inhibitors, neurogenic inflammation antagonists (including tachykinins), cytokine antagonists/synthesis inhibitors, tissue destructive proteinase inhibitors, protein kinase inhibitors, immunosup-pressive agents, and inhibitors of cellular adhesion and migration.