RIP1 regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including immune-mediated inflammatory diseases. Small-molecule inhibitors of RIP1 kinase that are suitable for advancement into the clinic have yet to be described. Herein, we report our lead optimization of a benzoxazepinone hit from a DNA-encoded library and the discovery and profile of clinical candidate GSK2982772 (compound 5), currently in phase 2a clinical studies for psoriasis, rheumatoid arthritis, and ulcerative colitis. Compound 5 potently binds to RIP1 with exquisite kinase specificity and has excellent activity in blocking many TNF-dependent cellular responses. Highlighting its potential as a novel anti-inflammatory agent, the inhibitor was also able to reduce spontaneous production of cytokines from human ulcerative colitis explants. The highly favorable physicochemical and ADMET properties of 5, combined with high potency, led to a predicted low oral dose in humans.
The recent discovery of the role of receptor interacting protein 1 (RIP1) kinase in tumor necrosis factor (TNF)-mediated inflammation has led to its emergence as a highly promising target for the treatment of multiple inflammatory diseases. We screened RIP1 against GSK's DNA-encoded small-molecule libraries and identified a novel highly potent benzoxazepinone inhibitor series. We demonstrate that this template possesses complete monokinase selectivity for RIP1 plus unique species selectivity for primate versus nonprimate RIP1. We elucidate the conformation of RIP1 bound to this benzoxazepinone inhibitor driving its high kinase selectivity and design specific mutations in murine RIP1 to restore potency to levels similar to primate RIP1. This series differentiates itself from known RIP1 inhibitors in combining high potency and kinase selectivity with good pharmacokinetic profiles in rodents. The favorable developability profile of this benzoxazepinone template, as exemplified by compound 14 (GSK'481), makes it an excellent starting point for further optimization into a RIP1 clinical candidate.
RIP1 kinase regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including inflammatory and neurological diseases. Currently, RIP1 kinase inhibitors have advanced into early clinical trials for evaluation in inflammatory diseases such as psoriasis, rheumatoid arthritis, and ulcerative colitis and neurological diseases such as amyotrophic lateral sclerosis and Alzheimer's disease. In this paper, we report on the design of potent and highly selective dihydropyrazole (DHP) RIP1 kinase inhibitors starting from a high-throughput screen and the leadoptimization of this series from a lead with minimal rat oral exposure to the identification of dihydropyrazole 77 with good pharmacokinetic profiles in multiple species. Additionally, we identified a potent murine RIP1 kinase inhibitor 76 as a valuable in vivo tool molecule suitable for evaluating the role of RIP1 kinase in chronic models of disease. DHP 76 showed efficacy in mouse models of both multiple sclerosis and human retinitis pigmentosa.
RIP1
regulates cell death and inflammation and is believed to play an important
role in contributing to a variety of human pathologies, including
immune-mediated inflammatory diseases and cancer. While small-molecule
inhibitors of RIP1 kinase have been advanced to the clinic for inflammatory
diseases and CNS indications, RIP1 inhibitors for oncology indications
have yet to be described. Herein we report on the discovery and profile
of GSK3145095 (compound
6
). Compound
6
potently
binds to RIP1 with exquisite kinase specificity and has excellent
activity in blocking RIP1 kinase-dependent cellular responses. Highlighting
its potential as a novel cancer therapy, the inhibitor was also able
to promote a tumor suppressive T cell phenotype in pancreatic adenocarcinoma
organ cultures. Compound
6
is currently in phase 1 clinical
studies for pancreatic adenocarcinoma and other selected solid tumors.
Transformation of alcohol 4 to α-azidoketone 6, a hexacyclic steroid bearing the requisite functionality
and spiroketal stereochemistry of the symchiral South portion of cephalostatin 7 (10) is described. Reaction of
a 1:1 mixture of α-azidoketones 5 and 6 with sodium hydrogen telluride is followed by cleavage of the protecting
groups cephalostatin 12 (9), cephalostatin 7 (10), and ritterazine K (11).
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