Development of WecA-targeting immune potentiators to treat carbapenem-resistant Enterobacteriaceae (CRE) infections

Inthe CDC designated carbapenem resistant EnterobacteriaceaeCREan Urgent Threatand inthe WHO designated it a Prioritycritical superbugAs few therapies remain to treat CREthe risk ofpanresistantCREuntreatable by any currently available antibioticincreasesEntirely new agents with novel mechanisms of actionMOAnot cross resistant to SOC agents languishOur proposal aims to develop an Oantigen biosynthetic inhibitory agent that potentiates serum mediated killingSMKand is efficacious in a CRE rodent model of infectionWe have shown that the O antigen biosynthesis gene wecAa nonessential gene under standard growth conditionsis essential for growth and pathogenesis in the presence of mammalian serumOur proposal outlines a plan to develop synthetic inhibitors of WecA that we previously discovered and optimized to inhibit the Gram positive WecA orthologTarOOur Aims areAimPhasePhScreeningMOA studiesand Assay DevelopmentComplete screening of the tarocin library for SMK against EcoliEcconfirm tarocins inhibit EcWecA as their MOA for eliciting SMKestablish key target engagementTEscreening assaysanddemonstrate that tarocin induced SMK extends to KpneumoniaeKpMilestoneScreenadditional tarocin analogs for SMK activityconstruct TE assays to support Phoptimizationand identify up todistinct tarocin subseries demonstrating iandgtfold ECshift in SMK by EcWecA overexpressioniiwhole cell dose dependent depletion of O aiiicausal drugR mutations mapping to EcwecAand ivSMK activity against Kp DtolC to advanceAimPhLead Identification OptimizationIdentify WecA specific tarocins with potent WT Ec and Kp SMK byempirically testing analogs for SMK against a panel of Ec and Kp permeability efflux deficient mutantsemploying recent physicochemical rules of GN entryandexploring siderophore conjugation to drive SAR effortsWe will also optimize PK and drug like propertiesMilestoneIdentify up totop analogs demonstrating iEc Kp WT activityMIC in serumMICsandltug mliiPK exposure to cover MICs forhrsiiiEc TE and PE selectivityivtarocinR mutation that maps to wecA in Kp to establish conserved MOA across bacterial species vEc Kp FOR andltxatX MICsviMICsandltug mlnclinical isolatesand viiandgtHepGand HEKcell viability atX MICsclean vs CYP ion channelsandgtuMand PanLabs ICandgtuMAimPhIn vivo efficacy demonstrationOptimize synthetic routes to efficiently prepareanalogs for formulation and dose ranging rat PK studiesidentify formulation verhicles for theanalogs to enable oral and IV PK dosing in in vivo studiesanddemonstrate in vivo efficacy for our top compound in a rodent septicemia model using Ec and Kp strainsMilestoneSynthesizemgandgtpurityof up tooptimal analogs that best satisfy Aimmilestonesidentify formulation in a safety approved vehicle that achievesX MICStarget exposureand demonstrate andgtlog reduction of Ec and Kp bacterial burden afterh treatment Narrative Carbapenem Resistant EnterobacteriaceaeCREare Gram negativeGNgut commensal bacteria which have acquired resistance tolactams carbapenemsand often to most other antimicrobials as wellThe extensive spread of CRE has prompted the CDC to designate it as an Urgent Threat pathogenThis project will develop an entirely novel therapeutic to treat life threatening bacterial infections due to multidrug resistantMDREnterobacteriaceaeincluding CRE