NBI-921352, a first-in-class, NaV1.6 selective, sodium channel inhibitor that prevents seizures in Scn8a gain-of-function mice, and wild-type mice and rats

NBI-921352 (formerly XEN901) is a novel sodium channel inhibitor designed to specifically target Na_V1.6 channels. Such a molecule provides a precision-medicine approach to target SCN8A-related epilepsy syndromes (SCN8A-RES), where gain-of-function (GoF) mutations lead to excess Na_V1.6 sodium current, or other indications where Na_V1.6 mediated hyper-excitability contributes to disease (Gardella and Møller, 2019; Johannesen et al., 2019; Veeramah et al., 2012). NBI-921352 is a potent inhibitor of Na_V1.6 (IC₅₀0.051 µM), with exquisite selectivity over other sodium channel isoforms (selectivity ratios of 756 X for Na_V1.1, 134 X for Na_V1.2, 276 X for Na_V1.7, and >583 Xfor Na_V1.3, Na_V1.4, and Na_V1.5). NBI-921352is a state-dependent inhibitor, preferentially inhibiting inactivatedchannels. The state dependence leads to potent stabilization of inactivation, inhibiting Na_V1.6 currents, including resurgent and persistent Na_V1.6 currents, while sparing the closed/rested channels. The isoform-selective profile of NBI-921352 led to a robust inhibition of action-potential firing in glutamatergic excitatory pyramidal neurons, while sparing fast-spiking inhibitory interneurons, where Na_V1.1 predominates. Oral administration of NBI-921352 prevented electrically induced seizures in a Scn8a GoF mouse,as well as in wild-type mouse and ratseizure models. NBI-921352 was effective in preventing seizures at lower brain and plasma concentrations than commonly prescribed sodium channel inhibitor anti-seizure medicines (ASMs) carbamazepine, phenytoin, and lacosamide. NBI-921352 waswell tolerated at higher multiples of the effective plasma and brain concentrations than those ASMs. NBI-921352 is entering phase II proof-of-concept trials for the treatment of SCN8A-developmental epileptic encephalopathy (SCN8A-DEE) and adult focal-onset seizures.

Discovery of Aryl Sulfonamides as Isoform-Selective Inhibitors of NaV1.7 with Efficacy in Rodent Pain Models

We report on a novel series of aryl sulfonamides that act as nanomolar potent, isoform-selective inhibitors of the human sodium channel hNaV1.7. The optimization of these inhibitors is described. We aimed to improve potency against hNaV1.7 while minimizing off-target safety concerns and generated compound 3. This agent displayed significant analgesic effects in rodent models of acute and inflammatory pain and demonstrated that binding to the voltage sensor domain 4 site of NaV1.7 leads to an analgesic effect in vivo. Our findings corroborate the importance of hNaV1.7 as a drug target for the treatment of pain.

Design of substituted imidazolidinylpiperidinylbenzoic acids as chemokine receptor 5 antagonists: potent inhibitors of R5 HIV-1 replication

The redesign of the previously reported thiophene-3-yl-methyl urea series, as a result of potential cardiotoxicity, was successfully accomplished, resulting in the identification of a novel potent series of CCR5 antagonists containing the imidazolidinylpiperidinyl scaffold. The main redesign criteria were to reduce the number of rotatable bonds and to maintain an acceptable lipophilicity to mitigate hERG inhibition. The structure-activity relationship (SAR) that was developed was used to identify compounds with the best pharmacological profile to inhibit HIV-1. As a result, five advanced compounds, 6d, 6e, 6i, 6h, and 6k, were further evaluated for receptor selectivity, antiviral activity against CCR5 using (R5) HIV-1 clinical isolates, and in vitro and in vivo safety. On the basis of these results, 6d and 6h were selected for further development.

HIV-1 entry inhibition by small-molecule CCR5 antagonists: a combined molecular modeling and mutant study using a high-throughput assay

Based on the attrition rate of CCR5 small molecule antagonists in the clinic the discovery and development of next generation antagonists with an improved pharmacology and safety profile is necessary. Herein, we describe a combined molecular modeling, CCR5-mediated cell fusion, and receptor site-directed mutagenesis approach to study the molecular interactions of six structurally diverse compounds (aplaviroc, maraviroc, vicriviroc, TAK-779, SCH-C and a benzyloxycarbonyl-aminopiperidin-1-yl-butane derivative) with CCR5, a coreceptor for CCR5-tropic HIV-1 strains. This is the first study using an antifusogenic assay, a model of the interaction of the gp120 envelope protein with CCR5. This assay avoids the use of radioactivity and HIV infection assays, and can be used in a high throughput mode. The assay was validated by comparison with other established CCR5 assays. Given the hydrophobic nature of the binding pocket several binding models are suggested which could prove useful in the rational drug design of new lead compounds.

Design and synthesis of pyridin-2-yloxymethylpiperidin-1-ylbutyl amide CCR5 antagonists that are potent inhibitors of M-tropic (R5) HIV-1 replication

A novel series of CCR5 antagonists were identified based on the redesign of Schering C. An SAR was established based on inhibition of CCR5 (RANTES) binding and these compounds exhibited potent inhibition of R5 HIV-1 replication in peripheral blood mononuclear cells.

Unsymmetrical dienophiles and their reactions with ortho-quinodimethanes

Three unsymmetrical chiral dienophiles have been synthesized and their reactivities with α-hydroxy-ortho-quinodimethanes have been assessed. Thus, the methyl (S)-lactyl esters of trans-4-bromocrotonate and trans-4-acetoxycrotonate (1 and 2) and mono (methyl (S)-lactyl) fumarate 3 were synthesized. Each was reacted with α-hydroxy-o-quinodimethane and α-hydroxy-α-phenyl-o-quinodimethane. While reaction with α-hydroxy-o-quinodimethane gave synthetically useful yields of cycloadducts with high regioselectivity and diastereoselectivity, the corresponding reactions with α-hydroxy-α-phenyl-o-quinodimethane were less successful. The reaction of 3 with α-hydroxy-α′-phenyl-o-quinodimethane also gave a mixture of cycloadducts. Keywords: ortho-quinodimethanes, lignans, Diels–Alder, asymmetric, lactate.

Testing the monocyte-macrophage system in human cancer

The participation of the monocyte-macrophages cells in the host immune defence mechanisms against cancer has been recognized since a few years. Testing this component of host homeostasis appears as an additional tool necessary for evaluation of immune deficiency in cancer patient. We review here the most current tests used in the frame of such an evaluation, and also the most interesting results.