Analogues structurally related to anaplastic lymphoma kinase (ALK) inhibitor 1 were optimized for metabolic stability. The results from this endeavor not only led to improved metabolic stability, pharmacokinetic parameters, and in vitro activity against clinically derived resistance mutations but also led to the incorporation of activity for focal adhesion kinase (FAK). FAK activation, via amplification and/or overexpression, is characteristic of multiple invasive solid tumors and metastasis. The discovery of the clinical stage, dual FAK/ALK inhibitor 27b, including details surrounding SAR, in vitro/in vivo pharmacology, and pharmacokinetics, is reported herein.

The diastereoselective synthesis and biological activity of piperidine-3,4-diol and piperidine-3-ol-derived pyrrolotriazine inhibitors of anaplastic lymphoma kinase (ALK) are described. Although piperidine-3,4-diol and piperidine-3-ol derivatives showed comparable in vitro ALK activity, the latter subset of inhibitors demonstrated improved physiochemical and pharmacokinetic properties. Furthermore, the stereochemistry of the C3 and C4 centers had a marked impact on the in vivo inhibition of ALK autophosphorylation. Thus, trans-4-aryl-piperidine-3-ols (22) were more potent than the cis diastereomers (20).

Abstract Anaplastic lymphoma kinase (ALK) is constitutively activated in a number of human cancer types due to chromosomal translocations, point mutations, and gene amplification and has emerged as an excellent molecular target for cancer therapy. Here we report the identification and preclinical characterization of CEP-28122, a highly potent and selective orally active ALK inhibitor. CEP-28122 is a potent inhibitor of recombinant ALK activity and cellular ALK tyrosine phosphorylation. It induced concentration-dependent growth inhibition/cytotoxicity of ALK-positive anaplastic large-cell lymphoma (ALCL), non-small cell lung cancer (NSCLC), and neuroblastoma cells, and displayed dose-dependent inhibition of ALK tyrosine phosphorylation in tumor xenografts in mice, with substantial target inhibition (>90%) for more than 12 hours following single oral dosing at 30 mg/kg. Dose-dependent antitumor activity was observed in ALK-positive ALCL, NSCLC, and neuroblastoma tumor xenografts in mice administered CEP-28122 orally, with complete/near complete tumor regressions observed following treatment at doses of 30 mg/kg twice daily or higher. Treatment of mice bearing Sup-M2 tumor xenografts for 4 weeks and primary human ALCL tumor grafts for 2 weeks at 55 or 100 mg/kg twice daily led to sustained tumor regression in all mice, with no tumor reemergence for more than 60 days postcessation of treatment. Conversely, CEP-28122 displayed marginal antitumor activity against ALK-negative human tumor xenografts under the same dosing regimens. Administration of CEP-28122 was well tolerated in mice and rats. In summary, CEP-28122 is a highly potent and selective orally active ALK inhibitor with a favorable pharmaceutical and pharmacokinetic profile and robust and selective pharmacologic efficacy against ALK-positive human cancer cells and tumor xenograft models in mice. Mol Cancer Ther; 11(3); 670–9. ©2011 AACR.

Chemical strategies to mitigate cytochrome P450-mediated bioactivation of novel 2,7-disubstituted pyrrolo[2,1-f][1,2,4]triazine ALK inhibitors are described along with synthesis and biological activity. Piperidine-derived analogues showing minimal microsomal reactive metabolite formation were discovered. Potent, selective, and metabolically stable ALK inhibitors from this class were identified, and an orally bioavailable compound (32) with antitumor efficacy in ALK-driven xenografts in mouse models was extensively characterized.

A series of potent anaplastic lymphoma kinase (ALK) inhibitors based on a 7-amino-6-chloro-3H-imidazo[4,5-b]pyridine scaffold were identified through rational design from a 5-chloro-2,4-diaminopyrimidine pharmacophore, maintaining key binding elements, favourable lipophilic interactions and orienting the side chains into favoured trajectories. Importantly, potency and selectivity determinants from the parent series were directly applicable to the new scaffold. This highly focused strategy led to the identification of several lead inhibitors that displayed potent activity in enzyme and cellular assays as well as pronounced oral bioavailability.

Anaplastic lymphoma kinase (ALK) is a promising therapeutic target for the treatment of cancer, supported by considerable favorable preclinical and clinical activities over the past several years and culminating in the recent FDA approval of the ALK inhibitor crizotinib. Through a series of targeted modifications on an ALK inhibitor diaminopyrimidine scaffold, our research group has driven improvements in ALK potency, kinase selectivity, and overall pharmaceutical properties. Optimization of this scaffold has led to the identification of a potent and efficacious inhibitor of ALK, 25b. A striking feature of 25b over previously described ALK inhibitors is its >600-fold selectivity over insulin receptor (IR), a closely related kinase family member. Most importantly, 25b exhibited dose proportional escalation in rat compared to compound 3 which suffered dose limiting absorption preventing further advancement. Compound 25b exhibited significant in vivo antitumor efficacy when dosed orally in an ALK-positive ALCL tumor xenograft model in SCID mice, warranting further assessment in advanced preclinical models.

A novel set of 2,4,8,22-tetraazatetracyclo[14.3.1.13,7.19,13]docosa-1(20),3(22),4,6,9(21),10,12,16,18-nonaene macrocycles were prepared as potential anaplastic lymphoma kinase (ALK) inhibitors, designed to rigidly lock an energy-minimized bioactive conformation of the diaminopyrimidine (DAP) scaffold, a well-documented kinase platform. From 13 analogues prepared, macrocycle 2m showed the most promising in vitro ALK enzymatic (IC50 = 0.5 nM) and cellular (IC50 = 10 nM) activities. In addition, macrocycle 2m exhibited a favorable kinase selectivity preference for inhibition of ALK relative to the highly homologous insulin receptor (IR) kinase (IR/ALK ratio of 173). The inclusive in vitro biological results for this set of macrocycles validate this scaffold as a viable kinase template and further corroborate recent DAP/ALK solid state studies indicating that the inverted “U” shaped conformation of the acyclic DAPs is a preferred bioactive conformation.

Anaplastic lymphoma kinase (ALK) was originally identified as the oncogenic NPM (nucleophosmin)-ALK fusion protein due to a t (2;5) chromosomal translocation in anaplastic large cell lymphomas (ALCL). Many other chromosomal rearrangements or gene mutations/amplification leading to enhanced ALK activity have subsequently been identified and characterized in a number of human cancer types. The recent reports of EML4 (echinoderm microtubule-associated protein-like 4)-ALK oncogenic proteins in non-small cell lung cancer (NSCLC) and the identification of ALK activating point mutations and gene amplification in neuroblastoma have indicated ALK as a potential major therapeutic target for human cancers. Here we report the identification and preclinical characterization of CEP-28122, a highly potent and selective orally active ALK inhibitor. CEP-28122 is a potent inhibitor of recombinant ALK activity (IC50 of 3 nM) and NPM-ALK tyrosine phosphorylation in ALCL cells (IC50 of 20-30 nM). It is selective over a broad panel of protein kinases and a panel of receptors and ion channels with greater than 300-fold selectivity for insulin receptor. CEP-28122 induced concentration-dependent growth inhibition and cytotoxicity of ALK-positive ALCL and NSCLC cells with minimal activity against ALK-negative lymphoma and leukemia cells as well as ALK-negative NSCLC cells at concentrations up to 3 μM. CEP-28122 exhibited favorable oral bioavailability (F = 37-71% across species) with adequate tissue distribution in rodents. It displayed dose-dependent inhibition of NPM-ALK tyrosine phosphorylation in human ALCL tumor xenografts in mice with complete target inhibition (> 90%) for more than 12 h following single oral dosing at 30 mg/kg. Dose-dependent anti-tumor activity was observed in NPM-ALK-positive Sup-M2 and Karpas-299 ALCL tumor xenografts and EML4-ALK-positive NCI-H2228 and NCI-H3122 tumor xenografts in mice dosed with CEP-28122, bid, po, with complete or near complete tumor regressions observed following 2 weeks of treatment with CEP-28122 at 30 mg/kg or higher. Treatment of mice bearing Sup-M2 tumor xenografts or primary human ALCL tumorgrafts with CEP-28122 at 55 or 100 mg/kg bid, po, for 4 weeks led to sustained tumor regression in all mice, with no tumor re-emergence in any mouse up to 60 days post cessation of CEP-28122 treatment. On the contrary, CEP-28122 displayed marginal anti-tumor activity against ALK-negative lymphoma and NSCLC tumor xenografts under the same dosing regimens. It was well tolerated with all dosing regimens in mice and rats with no overt toxicity and no compound-related body weight loss. CEP-28122 advanced into preclinical development based on its potency, selectivity and overall favorable pharmacological, pharmaceutical and safety profiles. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3574. doi:10.1158/1538-7445.AM2011-3574

The synthesis and biological evaluation of potent and selective anaplastic lymphoma kinase (ALK) inhibitors from a novel class of 2,4-diaminopyrimidines, incorporating 2,3,4,5-tetrahydro-benzo[d]azepine fragments, is described. An orally bioavailable analogue (18) that displayed antitumor efficacy in ALCL xenograft models in mice was identified and extensively profiled.

A novel 2,7-disubstituted-pyrrolo[2,1-f][1,2,4]triazine scaffold has been designed as a new kinase inhibitor platform mimicking the bioactive conformation of the well-known diaminopyrimidine motif. The design, synthesis, and validation of this new pyrrolo[2,1-f][1,2,4]triazine scaffold will be described for inhibitors of anaplastic lymphoma kinase (ALK). Importantly, incorporation of appropriate potency and selectivity determinants has led to the discovery of several advanced leads that were orally efficacious in animal models of anaplastic large cell lymphoma (ALCL). A lead inhibitor (30) displaying superior efficacy was identified and in depth in vitro/in vivo characterization will be presented.

The incorporation of R,R-1,2-diaminocyclohexane at C4 in a series of 2,4-diaminopyrimidines led to a number of ALK inhibitors in which optimized activity was achieved by conversion of the 2-amino group into a methanesulfonamide. Tumor growth inhibition was observed when an orally bioavailable analog was evaluated in a Karpas-299 tumor xenograft mouse model.

A series of novel 7-amino-1,3,4,5-tetrahydrobenzo[b]azepin-2-one derivatives within the diaminopyrimidine class of kinase inhibitors were identified that target anaplastic lymphoma kinase (ALK). These inhibitors are potent against ALK in an isolated enzyme assay and inhibit autophosphorylation of the oncogenic fusion protein NPM-ALK in anaplastic large cell lymphoma (ALCL) cell lines. The lead inhibitor 15, which incorporates a bicyclo[2.2.1]hept-5-ene ring system in place of an aryl moiety, activates the pro-apoptotic caspases (3 and 7) and displays selective cytotoxicity against ALK-positive ALCL cells. Furthermore, 15 provides more than 40-fold selectivity against the structurally related insulin receptor, is orally bioavailable in multiple species, and displays in vivo antitumor efficacy when dosed orally in ALK-positive ALCL tumor xenografts in Scid mice.

Abstract Anaplastic large cell lymphomas (ALCLs) are a unique subgroup of high grade non-Hodgkin lymphomas. Approximately 60% to 70% of ALCLs contain a t (2:5) (p23; q35) chromosomal rearrangement, generating the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion protein. NPM-ALK encodes a constitutively activated tyrosine kinase directly involved in the pathogenesis of ALCL. Recent studies have provided solid proof-of-concept validation that inhibition of ALK is sufficient to attenuate the growth and proliferation of ALK (+) ALCL cells. However, differential sensitivity to an ALK inhibitor among human NPM-ALK (+) ALCL cell lines has also been observed. In this study, using 2 fused pyrrolocarbazole (FP)-derived ALK inhibitors and a diaminopyrimidine (DAP)-derived ALK inhibitor as tools, the sensitivity of ALCL cells to ALK inhibition and the signaling pathway(s) that may contribute to the differential sensitivity of ALCL cells to ALK inhibition were characterized and compared. In all four NPM-ALK (+) ALCL cell lines tested, inhibition of Stat3 phosphorylation was consistent with ALK inhibitory activity. In contrast, inhibition of Akt phosphorylation by the FP- or DAP-ALK inhibitor was only observed in the more sensitive cell lines, Sup-M2 and Sudhl-1 cells while in less sensitive cell lines, Karpas-299 and SR-786 cells, Akt was constitutively activated even when ALK phosphorylation was completed abolished. Treatment with LY-294002, a PI3K inhibitor, at 30 µM completely inhibited Akt phosphorylation and led to partial growth inhibition of Karpas-299 and SR-786 cells. Co-treatment with LY-294002 and the FP- or DAP-ALK inhibitor significantly enhanced the cytotoxicity against Karpas-299 and SR-786 cells, similar to the degree observed in Sup-M2 or Sudhl-1 cells treated with the same concentration of ALK inhibitor alone, suggesting PI3K/Akt activity is a major determinant for the sensitivity of NPM-ALK (+) ALCL to ALK inhibition. Karpas-299 subcutaneous tumor xenografts displayed faster growth rate than Sup-M2 tumor xenografts in mice, and the DAP-ALK inhibitor was less efficacious against Karpas-299 tumor xenografts (about 40% TGI and 55% TGI respectively @ 30 or 55 mg/kg, bid, po) compared to that observed against Sup-M2 tumor xenografts (partial and near complete tumor regression respectively at the same dose regimes). Treatment of mice bearing Karpas-299 tumor xenografts with rapamycin, an mTOR inhibitor, @ 10 mg/kg, ip led to the inhibition of S6 and eIF4G phosphorylation in tumor xenografts. Co-administration of rapamycin (10 mg/kg, qd, ip) and the DAP-ALK inhibitor (55 mg/kg, bid, po) significantly enhanced the anti-tumor efficacy against Karpas-299 tumor xenografts and led to near complete tumor regression. These data further support that PI3K/Akt/mTOR activity is a major determinant for the sensitivity of NPM-ALK (+) ALCL to ALK inhibition. 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 2503.

A188 Tumor cells develop resistance against anti-tumor agents. Understanding the mechanism of resistance against a specific anti-tumor agent may elucidate its mechanism of action and help generate new and more effective anti-tumor agents. Bendamustine(Treanda™), currently in Phase III clinical trials in the United States for treatment of relapsed indolent non-Hodgkin’s lymphoma (NHL), has demonstrated clinical activity in patients with disease refractory to conventional cytotoxic therapy. Studies suggest that bendamustine possesses novel mechanistic features and an activity profile that differentiates itfrom other alkylating agents that may contribute to its distinct clinical efficacy profile, but the exact mechanism of its action has not been well defined. Anaplastic large cell lymphoma (ALCL) is a subset of NHL that often present with extranodal diseases and 50-60% of ALCL are associated with the expression of constitutively active oncogenic anaplastic lymphoma kinase (ALK+). ALCL cell lines resistant to bendamustine have been developed. In this study, the sensitivity of bendamustine sensitive- and resistant- ALK positive ALCL cell lines to fused-pyrrolocarbazole-derived ALK inhibitors (CEP-14083 and CEP-14513) in culture was evaluated. Bendamustine resistant cells (Sudhl-1 BRC9) remained sensitive to growth inhibition induced by ALK inhibitors, comparable to the parental cell line, Sudhl-1. In both bendamustine sensitive (Sudhl-1) and resistant-(Sudhl-1, BRC9) cell lines, NPM-ALK phosphorylation, as well as the major downstream targets of ALK, including STAT-3 and AKT, were inhibited by ALK inhibitors with similar potency (EC50 of 50-100 nM). These data indicate that NPM-ALK-mediated signaling pathways critical for cell proliferation and survival were not altered in bendamustine-resistant ALCL cells. The potential mechanisms for bendamustine resistance in Sudhl-1, BRC9 cells will be further studied and discussed.

The roles of aberrant expression of constitutively active ALK chimeric proteins in the pathogenesis of anaplastic large-cell lymphoma (ALCL) have been well defined; nevertheless, the notion that ALK is a molecular target for the therapeutic modulation of ALK+ ALCL has not been validated thus far. Select fused pyrrolocarbazole (FP)-derived small molecules with ALK inhibitory activity were used as pharmacologic tools to evaluate whether functional ALK is essential for the proliferation and survival of ALK+ ALCL cells in culture. These compounds inhibited interleukin 3 (IL-3)-independent proliferation of BaF3/NPM-ALK cells in an ALK inhibition-dependent manner and significantly blocked colony formation in agar of mouse embryonic fibroblast (MEF) cells harboring NPM-ALK. Inhibition of NPM-ALK phosphorylation in the ALK+ ALCL-derived cell lines resulted in significant inhibition of cell proliferation and induction of apoptotic-cell death, while having marginal effects on the proliferation and survival of K562, an ALK- leukemia cell line. ALK inhibition resulted in cell-cycle G1 arrest and inactivation of ERK1/2, STAT3, and AKT signaling pathways. Potent and selective ALK inhibitors may have therapeutic application for ALK+ ALCL and possibly other solid and hematologic tumors in which ALK activation is implicated in their pathogenesis.

Anaplastic large cell lymphomas (ALCLs) are a unique subgroup of high grade non-Hodgkin lymphomas. Approximately 60% to 70% of ALCLs contain a t (2:5) (p23; q35) chromosomal rearrangement, generating the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion protein. NPM-ALK encodes a constitutively activated tyrosine kinase that has been demonstrated to be directly involved in the pathogenesis of ALCLs. Currently there is no optimal therapeutic regimen for ALK positive ALCLs. Even with high dose CHOP (cyclophophamide, doxorubicin, vincristine and prednisone)-based chemotherapy, a substantial number of patients with ALK positive ALCLs have very poor outcome, either failing to enter remission or relapsing within a few months from the start of treatment. This prompted a search for small molecule ALK inhibitors as potential therapeutic agents for these patients. In this report, we describe the identification and characterization of a potent small molecule ALK inhibitor, cmpd-1. Cmpd-1 inhibited the ALK kinase activity in an in vitro enzymatic assay with an IC50 value of 4 nM. In NPM-ALK transfected BaF3 cells and ALCL-derived cell lines, cmpd-1 potently inhibited the tyrosine phosphorylation of NPM-ALK with a cellular IC50 value of 10–30 nM. Treatment with cmpd-1 inhibited IL-3 independent proliferation of BaF3 cells expressing constitutively active NPM-ALK (more than 95% inhibition at 100 nM) and the addition of IL-3 rescued the growth of these cells, while cmpd-1 had little effect on the parental BaF3 cells. Inhibition of NPM-ALK activity by cmpd-1 in ALK positive ALCL-derived cell lines, Karpas-299, Sudhl-1, Sup-M2 and Sr-786, resulted in inhibition of cell proliferation (50–90% inhibition at 100–300 nM) and induction of apoptotic cell death, while having marginal effects on the proliferation and survival of K562, an ALK negative leukemia cell line. These data suggest that the inhibition of cell proliferation and induction of apoptosis by cmpd-1 is an ALK-dependent event. Several putative downstream targets of NPM-ALK, including ERK1/2, Stat3 and Akt, were hypo- or unphosphorylated when the ALK positive cells were treated with cmpd-1. With the potent ALK inhibitory activity, cmpd-1 can be used as a molecular and pharmacological tool to study the biological roles of ALK and to dissect ALK-mediated signaling pathways in ALCLs and possibly other tumor types in which ALK is implicated in their pathogenesis.