Christophe Meyer

Abstract 4747: Design and synthesis of a series highly potent and bioavailable FASN KR domain inhibitors for cancer

Fatty Acid Synthase (FASN) is a multi-domain protein that carries out de novo fatty acid (palmitate) synthesis from acetate and malonate in mammalian cells. FASN is up-regulated in cancer cells, providing fatty acid building blocks for rapid cell growth and cell division. Increased FASN expression is correlated with disease progression and poor prognosis in many cancers including prostate, breast, ovary, colon, and lung. FASN has been demonstrated to play an important role in carcinogenesis by protecting cells from apoptosis. Herein we report a new series of potent, selective and orally bioavailable FASN inhibitors. Recent publications disclose several FASN inhibitor chemotypes that share a common pharmacophore, wherein an aromatic group and an acylated cyclic amine are attached to a central scaffold. We postulated that a spirocyclic imidazolinone core would be an acceptable and drug-like scaffold, inspired by the precedent of irbesartan, an approved antihypertensive drug in which a spirocyclopentyl-imidazolinone core replaces the substituted imidazole ring of losartan, an older approved agent from the same drug class. This hypothesis led to a new spirocyclic imidazolinone based FASN inhibitors. Extensive SAR efforts resulted in FASN inhibitors with potent enzyme and cell activity, selectivity, and oral bioavailability exemplified by JNJ-54302833. JNJ-54302833 is a potent inhibitor of human FASN (IC50 = 28 nM) and also potently inhibits proliferation of A2780 ovarian cells (IC50 = 13 nM) in lipid-reduced medium. This cellular activity can be rescued by addition of palmitate, demonstrating on-target effects. JNJ-54302833 is also potent in many other cells, including PC3M (IC50 = 25 nM) and LnCaP-Vancouver prostate cells (IC50 = 66 nM), and is highly bioavailable (F 61%) with good exposures. In a pharmacodynamics study in H460 lung xenograft-bearing mice, oral treatment with JNJ-54302833 resulted in elevated tumor levels of malonyl-CoA and decreased tumor levels of palmitate. This novel series potently inhibits the FASN KR domain (IC50 = 54 nM for JNJ-54302833); specific binding to KR was confirmed by crystal structures.In summary, we have designed and discovered a new series of FASN inhibitors that are potent both in enzyme and in cell proliferation assays, are highly bioavailable, and bind to KR domain. Additionally, palmitate rescue of lipid-reduced cellular activity suggests selectivity and pharmacodynamics studies confirm target engagement. Citation Format: Tianbao Lu, Richard Alexander, Gilles Bignan, James Bischoff, Peter Connolly, Max Cummings, Sabine De Breucker, Norbert Esser, Erwin Fraiponts, Ron Gilissen, Bruce Grasberger, Boudewijn Janssens, Donald Ludovici, Lieven Meerpoel, Christophe Meyer, Michael Parker, Danielle Peeters, Carsten Schubert, Karine Smans, Luc Van Nuffel, Peter Vermeulen. Design and synthesis of a series highly potent and bioavailable FASN KR domain inhibitors for cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4747. doi:10.1158/1538-7445.AM2014-4747

Design and synthesis of a series of bioavailable fatty acid synthase (FASN) KR domain inhibitors for cancer therapy

We designed and synthesized a new series of fatty acid synthase (FASN) inhibitors with potential utility for the treatment of cancer. Extensive SAR studies led to highly active FASN inhibitors with good cellular activity and oral bioavailability, exemplified by compound 34. Compound 34 is a potent inhibitor of human FASN (IC50 = 28 nM) that effectively inhibits proliferation of A2780 ovarian cells (IC50 = 13 nM) in lipid-reduced serum (LRS). This cellular activity can be rescued by addition of palmitate, consistent with an on-target effect. Compound 34 is also active in many other cell types, including PC3M (IC50 = 25 nM) and LnCaP-Vancouver prostate cells (IC50 = 66 nM), and is highly bioavailable (F 61%) with good exposure after oral administration. In a pharmacodynamics study in H460 lung xenograft-bearing mice, oral treatment with compound 34 results in elevated tumor levels of malonyl-CoA and decreased tumor levels of palmitate, fully consistent with the desired target engagement.

Abstract 2535: Structure-activity relationships of novel N-benzoyl arylpiperidine and arylazetidine FASN inhibitors

De novo synthesis of fatty acids in mammalian cells is catalyzed by Fatty Acid Synthase (FASN), a complex dimeric protein with seven catalytic domains that processes acetyl-CoA and malonyl-CoA into palmitic acid. Palmitate and other fatty acids are essential for normal physiological processes like energy storage and production and are key intermediates in the biosynthesis of hormones and other essential biomolecules. The role of FASN in cancer has been well documented over the past decade. While FASN is expressed at low levels in most normal tissue (except liver and adipose tissue), it is highly expressed in many tumors including prostate, breast, and colon. FASN overexpression and activity is correlated with poor prognosis and disease progression. Numerous publications describing anti-cancer effects of small molecule FASN inhibitors have appeared in the scientific and patent literature. Recently, several groups reported anticancer and antiviral activities of N-benzoyl arylpiperidine FASN inhibitors. In this work we describe the discovery of novel N-benzoyl arylpiperidine and arylazetidine compounds that potently inhibit FASN enzymatic activity in vitro and antiproliferative activity in FASN-sensitive cell lines. We conducted focused structure-activity (SAR) studies exploring the benzoyl group and the aryl substituent on the piperidine or azetidine heterocycle to optimize potency, improve properties and oral bioavailability, and achieve in vivo FASN-driven pharmacodynamic (PD) activity. X-ray crystal structures of these molecules confirm a unique binding mode within the KR subdomain of FASN. Using structural information and molecular modeling, we were able to rationalize SAR trends and design FASN inhibitors with excellent in vitro potency and cellular activity. These efforts resulted in the discovery of compounds exemplified by JNJ-54380482, a potent FASN inhibitor (IC50 = 26 nM) that inhibits proliferation of A2780 ovarian cells in lipid-reduced medium (LRM, IC50 = 8.9 nM). Engagement of FASN in cellular assays is confirmed by rescue of proliferation upon addition of palmitate. JNJ-54380482 is orally bioavailable in mice (F% = 51) and exhibits excellent plasma exposure when dosed at 10 mg/kg (Cmax = 2.6 µM, T1/2 = 5 h). In a PD study using H460 lung xenograft-bearing mice, oral treatment with 30 mg/kg of JNJ-54380482 results in 36-fold higher tumor levels of malonyl-CoA vs vehicle. In summary, we synthesized several hundred compounds having the N-benzoyl arylpiperidine and arylazetidine chemotypes. Utilizing structural information from X-ray co-crystals to understand SAR and guide the design of more potent molecules, we identified >100 analogs with highly potent FASN enzymatic (IC50 ≤ 50 nM) and antiproliferative activities in A2780 cells in LRM (IC50 ≤ 100 nM). Key examples from these series have good in vitro properties, are orally bioavailable, and demonstrate FASN target engagement in a mouse PD model. Citation Format: Peter J. Connolly, Gilles Bignan, James Bischoff, Sabine De Breucker, Norbert Esser, Erwin Fraiponts, Ron Gilissen, Bruce Grasberger, Boudewijn Janssens, Tianbao Lu, Donald Ludovici, Lieven Meerpoel, Christophe Meyer, Michael Parker, Danielle Peeters, Carsten Schubert, Karine Smans, Luc Van Nuffel, Peter Vermeulen. Structure-activity relationships of novel N-benzoyl arylpiperidine and arylazetidine FASN inhibitors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2535. doi:10.1158/1538-7445.AM2014-2535

Abstract 2926: Selective PERK kinase inhibition triggers a biphasic concentration-dependent induction of ER stress in multiple myeloma and B-cell lymphoma.

Plasma cell malignancies, such as multiple myeloma, are characterized by an extensively developed endoplasmic reticulum (ER) to accommodate the high secretion rate of immunoglobulins. An adaptive stress response mechanism, termed the unfolded protein response (UPR), is markedly elevated in multiple myeloma cells to ensure a homeostatic balance between ER burden and ER capacity. One branch of the UPR consists of the activation of PERK under chronic ER stress: PERK phosphorylates and impairs the function of the translation initiation factor, eIF2α, thereby downregulating global protein synthesis, and reducing the secretory burden on the ER. To test the therapeutic potential of PERK inhibitors in multiple myeloma, we identified two chemically diverse PERK inhibitors: both are sub-nM inhibitors of PERK, and have a >100-fold window against other kinases (including other eIF2α kinases). These compounds inhibit phosphorylation of eIF2α at 10-20nM (IC 50 ) in HEK293 cells, incubated with the ER stressor tunicamycin. Both PERK inhibitors were selectively anti-proliferative in an ER-stressed epithelial cancer model (A549 cells with tunicamycin) at nM concentrations, but not in the absence of ER stress. Furthermore, in the absence of an exogenous ER stressor, both PERK inhibitors induced ER stress (eg, as evidenced by induction of the pro-apoptotic CHOP gene) selectively in multiple myeloma cell lines (and certain B-cell lymphoma lines) at low nM concentrations but not in normal or malignant epithelial cells (induction of CHOP at 10 μM). The magnitude of this induction was comparable to well-established ER stressors, such as bortezomib or tunicamycin, and correlated closely with reduced proliferation in malignant B-cell lines. The potent induction of CHOP occurred both in vitro and upon oral dosing of mice, with a xenografted multiple myeloma tumour (JIM-1); however, in both instances, the induction of ER stress was maximal at a dose corresponding to approximately 50-75% inhibition of PERK, whereas, remarkably, at dose levels corresponding to more complete PERK inhibition (as evidenced by inhibition of P-eIF2α), CHOP induction (and ER-stress induction in general as determined by a genome-wide expression profile) was reduced, eventually down to baseline levels. Consistently, both PERK inhibitors resulted in a biphasic concentration-dependent reduction of proliferation of certain myeloma and B-cell lymphoma lines. Hence, PERK inhibition triggers a biphasic induction of ER stress and inhibition of cell proliferation, selectively in B-cell malignancies. The possible underlying mechanism as well as the therapeutic implications of these findings will be discussed. Citation Format: Matthias Versele, Tamara Geerts, Jeroen Van De Ven, Ilse Van den Wyngaert, Peter Vermeulen, Inge Beerden, Danielle Peeters, Johnny Liebregts, Kurt Van Baelen, Cedric Simillion, Boudewijn Janssen, Tinne Verhulst, Norbert Esser, Christophe Meyer, Ian Stansfield, James Bischoff. Selective PERK kinase inhibition triggers a biphasic concentration-dependent induction of ER stress in multiple myeloma and B-cell lymphoma. [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 2926. doi:10.1158/1538-7445.AM2013-2926