Substituted Indazoles as Na_v1.7 Blockers for the Treatment of Pain

The genetic validation for the role of the Na_v1.7 voltage-gated ion channel in pain signaling pathways makes it an appealing target for the potential development of new pain drugs. The utility of nonselective Na_v blockers is often limited due to adverse cardiovascular and CNS side effects. We sought more selective Na_v1.7 blockers with oral activity, improved selectivity, and good druglike properties. The work described herein focused on a series of 3- and 4-substituted indazoles. SAR studies of 3-substituted indazoles yielded analog <b>7</b> which demonstrated good in vitro and in vivo activity but poor rat pharmacokinetics. Optimization of 4-substituted indazoles yielded two compounds, <b>27</b> and <b>48</b>, that exhibited good in vitro and in vivo activity with improved rat pharmacokinetic profiles. Both <b>27</b> and <b>48</b> demonstrated robust activity in the acute rat monoiodoacetate-induced osteoarthritis model of pain, and subchronic dosing of <b>48</b> showed a shift to a lower EC₅₀ over 7 days

Substituted Indazoles as Na_v1.7 Blockers for the Treatment of Pain

The genetic validation for the role of the Na_v1.7 voltage-gated ion channel in pain signaling pathways makes it an appealing target for the potential development of new pain drugs. The utility of nonselective Na_v blockers is often limited due to adverse cardiovascular and CNS side effects. We sought more selective Na_v1.7 blockers with oral activity, improved selectivity, and good druglike properties. The work described herein focused on a series of 3- and 4-substituted indazoles. SAR studies of 3-substituted indazoles yielded analog <b>7</b> which demonstrated good in vitro and in vivo activity but poor rat pharmacokinetics. Optimization of 4-substituted indazoles yielded two compounds, <b>27</b> and <b>48</b>, that exhibited good in vitro and in vivo activity with improved rat pharmacokinetic profiles. Both <b>27</b> and <b>48</b> demonstrated robust activity in the acute rat monoiodoacetate-induced osteoarthritis model of pain, and subchronic dosing of <b>48</b> showed a shift to a lower EC₅₀ over 7 days

Discovery of ABT-267, a Pan-Genotypic Inhibitor of HCV NS5A

We describe here <i>N</i>-phenylpyrrolidine-based inhibitors of HCV NS5A with excellent potency, metabolic stability, and pharmacokinetics. Compounds with 2<i>S</i>,5<i>S</i> stereochemistry at the pyrrolidine ring provided improved genotype 1 (GT1) potency compared to the 2<i>R</i>,5<i>R</i> analogues. Furthermore, the attachment of substituents at the 4-position of the central <i>N</i>-phenyl group resulted in compounds with improved potency. Substitution with <i>tert</i>-butyl, as in compound <b>38</b> (ABT-267), provided compounds with low-picomolar EC₅₀ values and superior pharmacokinetics. It was discovered that compound <b>38</b> was a pan-genotypic HCV inhibitor, with an EC₅₀ range of 1.7–19.3 pM against GT1a, -1b, -2a, -2b, -3a, -4a, and -5a and 366 pM against GT6a. Compound <b>38</b> decreased HCV RNA up to 3.10 log₁₀ IU/mL during 3-day monotherapy in treatment-naive HCV GT1-infected subjects and is currently in phase 3 clinical trials in combination with an NS3 protease inhibitor with ritonavir (r) (ABT-450/r) and an NS5B non-nucleoside polymerase inhibitor (ABT-333), with and without ribavirin