Discovery of a JAK1/3 Inhibitor and Use of a Prodrug To Demonstrate Efficacy in a Model of Rheumatoid Arthritis

Abstract

The four members of the Janus family of nonreceptor tyrosine kinases play a significant role in immune function. The JAK family kinase inhibitor, tofacitinib 1, has been approved in the United States for use in rheumatoid arthritis (RA) patients. A number of JAK inhibitors with a variety of JAK family selectivity profiles are currently in clinical trials. Our goal was to identify inhibitors that were functionally selective for JAK1 and JAK3. Compound 22 was prepared with the desired functional selectivity profile, but it suffered from poor absorption related to physical properties. Use of the phosphate prodrug 32 enabled progression to a murine collagen induced arthritis (CIA) model. The demonstration of a robust efficacy in the CIA model suggests that use of phosphate prodrugs may resolve issues with progressing this chemotype for the treatment of autoimmune diseases such as RA.

Discovery and Biological Evaluation of N-Methyl-pyrrolo[2,3-b]pyridine-5-carboxamide Derivatives as JAK1-Selective Inhibitors

“…STATs are the phosphorylated downstream of JAKs, and these activated STAT dimers induce proinflammatory gene transcription inside the nucleus . As JAK/STAT signaling is generally involved in inflammation and autoimmune responses, researchers have actively developed JAK inhibitors for the treatment of inflammation and autoimmune-related diseases such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and atopic dermatitis . Recent studies have indicated the potential of JAK inhibitors in the treatment of hepatic fibrosis. , The connective tissue growth factor (CTGF) is constantly expressed in activated hepatic stellate cells (HSCs) and modulates extracellular matrix production downstream of TGF-β in the fibrotic liver .…”

“…NMR (400 MHz, methanol-d 4 ) δ 8.17 (s, 1H), 7.43−7.27 (m, 5H), 7.09 (d, J = 3.7 Hz, 1H),6.62 (d, J = 3 7. Hz, 1H), 4.45−4.37 (m, 1H), 3.81 (s, 2H), 2.97−2.87 (m, 2H), 2.87 (s, 3H), 2.88−2.78 (m, 2H), 2.27−2.14 (m, 2H), 1.94−1.84 (m, 2H), 1.80 (dd, J = 11.1, 7.4 Hz, 2H); 13 C NMR (100 MHz, methanol-d 4 ) δ 163.2, 141.3, 141.1, 135.6, 121.3, 121.0, 120.7, 120.1, 119.4, 118.6, 113.4, 97.2, 95.5, 93.8, 53.9, 46.9, 44.0, 41.9, 26.3, 25.3, 17.2, 14.6; HRMS (ESI, m/z) calcd for C 22 H 28 N 5 O [M + H] + 378.2288, found 378.2292.…”

“…Methoxybenzyl)azepan-4-yl)amino)-N-methyl-1Hpyrrolo[2,3-b]pyridine-5-carboxamide (30e). 30e was synthesized in 74% yield according to the same procedure as 20d using 26 and 4methoxybenzaldehyde;1 H NMR (400 MHz, chloroform-d) δ 9.38 (d, J = 7.9 Hz, 1H), 8.28 (s, 1H), 7.34 (d, J = 8.5 Hz, 2H),6.93 (d, J = 3.3 Hz, 1H), 6.91−6.85 (m, 2H), 6.46 (d, J = 3.0 Hz, 1H), 4.30 (s, 1H), 3.81 (s, 3H), 3.74 (s, 2H), 3.00 (d, J = 4.7 Hz, 3H), 2.98−2.80 (m, 2H), 2.74 (dd, J = 8.9, 4.4 Hz, 1H), 2.31−2.15 (m, 1H), 1.98− 1.75 (m, 4H);13 C NMR (100 MHz, methanol-d 4 ) δ 170.6, 159.3, 149.6, 149.4, 148.5, 142.8, 131.0, 121.4, 113.9, 105.3, 103.5, 102.4, 61.5, 55.1, 55.0, 51.9, 34.4, 32.9, 26.4, 26.2, 22.6; HRMS (ESI, m/z) calcd for C 23 H 30 N 5 O 2 [M + H] + 408.2394, found 408.2390. 4-((1-(4-Cyanobenzyl)aze5pan-4-yl)amino)-N-methyl-1Hpyrrolo[2,3-b]pyridine-5-carboxamide (30f).…”

Copper‐Mediated Oxidative [3+2]‐Annulation of Nitroalkenes and Ylides of 1,2‐Diazines: Assembly of Functionalized Pyrrolo[1,2‐b]pyridazines

“…There are promising inhibitors of various kinase enzymes (e. g., JAK, IRAK) which may be useful for treatment of diseases such as rheumatoid arthritis (Figure 1). [5] Moreover, these heterocycles were explored as blue light emitting fluorophores with highly promising properties. [6] Therefore, development of new synthetic routes to pyrrolo [1,2-b]pyridazines is an important task.…”

Optimization of Pyrimidine Compounds as Potent JAK1 Inhibitors and the Discovery of R507 as a Clinical Candidate

“…It has been well established that certain cytokines, for example, IL-2, can activate JAK1 or JAK3 kinase, which upon phosphorylation, binds STAT5 proteins and initiates the signaling pathways that regulate immune response and cell proliferation. To characterize JAK1/3 inhibitors functionally, we used cell-based assays that measure the inhibition of STAT5 phosphorylation and the cell proliferation of human primary T-cells when induced by IL-2. , Since the inhibition of JAK2 kinase is associated with anemia, thrombocytopenia, hyperlipidemia, and neutropenia, it is desirable to develop JAK1/3 inhibitors with selectivity over JAK2. It is also known that JAK2 kinase is involved in survival of erythroid precursor cells, which give rise to mature red blood cells, upon activation by erythropoietin (EPO); thus, a cell-based assay measuring survival of cultured human erythroid precursor cells (CHEP) was used to evaluate the activity for JAK2 inhibition. , …”