Discovery of the Irreversible Covalent FGFR Inhibitor 8‑(3-(4-Acryloyl­piperazin-1-yl)propyl)-6-(2,6-dichloro-3,5-dimethoxyphenyl)-2-(methylamino)­pyrido[2,3‑<i>d</i>]­pyrimidin-7(8<i>H</i>)‑one (PRN1371) for the Treatment of Solid Tumors

Aberrant signaling of the FGF/FGFR pathway occurs frequently in cancers and is an oncogenic driver in many solid tumors. Clinical validation of FGFR as a therapeutic target has been demonstrated in bladder, liver, lung, breast, and gastric cancers. Our goal was to develop an irreversible covalent inhibitor of FGFR1–4 for use in oncology indications. An irreversible covalent binding mechanism imparts many desirable pharmacological benefits including high potency, selectivity, and prolonged target inhibition. Herein we report the structure-based design, medicinal chemistry optimization, and unique ADME assays of our irreversible covalent drug discovery program which culminated in the discovery of compound <b>34</b> (PRN1371), a highly selective and potent FGFR1–4 inhibitor

Discovery of the Irreversible Covalent FGFR Inhibitor 8‑(3-(4-Acryloyl­piperazin-1-yl)propyl)-6-(2,6-dichloro-3,5-dimethoxyphenyl)-2-(methylamino)­pyrido[2,3‑<i>d</i>]­pyrimidin-7(8<i>H</i>)‑one (PRN1371) for the Treatment of Solid Tumors

Aberrant signaling of the FGF/FGFR pathway occurs frequently in cancers and is an oncogenic driver in many solid tumors. Clinical validation of FGFR as a therapeutic target has been demonstrated in bladder, liver, lung, breast, and gastric cancers. Our goal was to develop an irreversible covalent inhibitor of FGFR1–4 for use in oncology indications. An irreversible covalent binding mechanism imparts many desirable pharmacological benefits including high potency, selectivity, and prolonged target inhibition. Herein we report the structure-based design, medicinal chemistry optimization, and unique ADME assays of our irreversible covalent drug discovery program which culminated in the discovery of compound <b>34</b> (PRN1371), a highly selective and potent FGFR1–4 inhibitor

Discovery of <i>Tirasemtiv</i>, the First Direct Fast Skeletal Muscle Troponin Activator

The identification and optimization of the first activators of fast skeletal muscle are reported. Compound <b>1</b> was identified from high-throughput screening (HTS) and subsequently found to improve muscle function via interaction with the troponin complex. Optimization of <b>1</b> for potency, metabolic stability, and physical properties led to the discovery of tirasemtiv (<b>25</b>), which has been extensively characterized in clinical trials for the treatment of amyotrophic lateral sclerosis

Potent Nonimmunosuppressive Cyclophilin Inhibitors With Improved Pharmaceutical Properties and Decreased Transporter Inhibition

Nonimmunosuppressive cyclophilin inhibitors have demonstrated efficacy for the treatment of hepatitis C infection (HCV). However, alisporivir, cyclosporin A, and most other cyclosporins are potent inhibitors of OATP1B1, MRP2, MDR1, and other important drug transporters. Reduction of the side chain hydrophobicity of the P4 residue preserves cyclophilin binding and antiviral potency while decreasing transporter inhibition. Representative inhibitor <b>33</b> (NIM258) is a less potent transporter inhibitor relative to previously described cyclosporins, retains anti-HCV activity in cell culture, and has an acceptable pharmacokinetic profile in rats and dogs. An X-ray structure of <b>33</b> bound to rat cyclophilin D is reported