Discovery of CX-6258. A Potent, Selective, and Orally Efficacious pan-Pim Kinases Inhibitor

Abstract

Structure-activity relationship analysis in a series of 3-(5-((2-oxoindolin-3-ylidene)methyl)furan-2-yl)amides identified compound 13, a pan-Pim kinases inhibitor with excellent biochemical potency and kinase selectivity. Compound 13 exhibited in vitro synergy with chemotherapeutics and robust in vivo efficacy in two Pim kinases driven tumor models.

Keywords: CX-6258; MV-4-11; PC3; Pim-1; Pim-2; Pim-3.

Figure 1

Proposed molecular model of analogue 5. GLU171 and ASP128 are represented in magenta and pink, respectively.

Scheme 1. Synthesis of Analogues

Conditions: Analogues 7–17; (a) Piperidine, oxindole, EtOH; (b) CDI, DMF, NHR₆R₇. Intermediate 3; Y¹ = B(OH)₂; (c) Oxalyl chloride, CH₂Cl₂ and then Et₃N, N-methylhomopiperazine; (d) 5-formylfuran-2-ylboronic acid, Na₂CO₃, PdCl₂(dppf)₂, DMF, 80 °C. Analogues 18 and 19; intermediate 2; Y¹ = Br; N,O-dimethylhydroxylamine hydrochloride, amide coupling reagents, CH₂Cl₂ and then Me- or Et-MgBr, ether; (c) 3-Methoxycarbonylphenylboronic acid, Na₂CO₃, PdCl₂(dppf)₂, DME, 80 °C; (d) 6 M NaOH, EtOH, rt. (a) Amide coupling with methyl homopiperazine; (b) Titanium tetrachloride, THF, 5-chloroxindole, diisopropylethylamine, −78 °C to rt.

Figure 2

Crystal structure of 13 as the HCl salt coordinated to a water molecule, demonstrating the exocyclic double bond is exclusively in the E configuration.

Figure 3

Effect of 13 on phosphorylation of Pim kinase substrates in MV-4-11 cells. MV-4-11 cells were treated for 2 h with various doses of 13. Cells were lysed, and the relative levels of phospho-proteins were measured using Western hybridization.

Figure 4

Antitumor efficacy of 13 in MV-4-11 xenograft models. Nude mice were administered vehicle, 50 or 100 mg/kg dose PO once daily over a period of 21 days. Also represented is the animal body weight. Error bars denote the standard error of the mean (SEM).