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