A novel eNAMPT-neutralizing mAb to reduce antimicrobial resistance following hospital- and ventilator-associated bacterial pneumonia - ABSTRACT Hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP) contrib- ute to antimicrobial resistance (AMR), a major global public health threat. Furthermore, greater than one third of ICU patients on mechanical ventilation, or with the acute respiratory distress syndrome (ARDS), acquire bac- terial superinfection and develop VABP with attributable mortality due to irreversible lung tissue injury. This A1 RO1 application tests the hypothesis that the targeting of eNAMPT (extracellular nicotinamide phosphoribosyl transferase), a novel DAMP (damage-associated molecular pattern protein) and Toll-like receptor-4 (TLR4) lig- and, may mitigate the risk of developing bacterial superinfection in subjects with HABP and VABP. We speculate that the ALT-100 mAb will serve as an immunomodulatory approach to reduce the severity of lung tissue injury, preserve lung function, and eliminate locus minoris resistentiae to limit bacterial tissue persistence, a risk factor for emergence of AMR. We have shown that eNAMPT is a potent amplifier of innate immunity inflammation and directly contributes to the severity of human/preclinical pneumonia, ARDS, ventilator-induced lung injury (VILI) and sepsis. The ALT-100 mAb proved highly effective in preclinical models of ARDS/VILI/sepsis and recent preliminary interim analysis in a Phase 2A ARDS/VILI clinical trial indicates mAb efficacy. Three Specific Aims will define the value of targeting the eNAMPT/TLR4 signaling cascade in reducing AMR utilizing preclinical mod- els of pneumonia (HABP) and VABP caused by two highly clinically-challenging Gram-negative pathogens, P. aeruginosa (PA) and A. baumanii (AB). SA #1 will expose wild type C57BL/6J mice (+/- ALT-100 mAb), genet- ically-engineered Nampt+/- heterozygous mice, and cNamptec/ec mice (conditional NAMPT KO restricted to endo- thelium) to PA- and AB-induced HABP and VABP. SA #2 will examine the effect of ALT-100 mAb on antibiotic bacterial killing (meropenem, meropenem/tobramycin combination) and explore potential synergistic reductions in lung injury in Swiss Webster (SW) mice exposed to PA- and AB-induced HABP. SA #3 will directly define the microbiological and therapeutic effects of ALT-100 mAb in VABP- exposed SW mice (PA, AB) treated with mero- penem or meropenem/tobramycin. Phenotyping studies will assess antibiotic concentrations, bacterial growth, bacterial killing, resistance emergence, and lung tissue AB/PA protein toxin levels with integration via transla- tional mathematical modeling. We will perform high quality analyses of renal/lung histology, bronchoalveolar lavage (BAL) cell and proteins, blood and lung tissue inflammatory markers and single cell RNA sequencing of lung tissues. These studies, conducted by an team of accomplished investigators with extensive, synergistic expertise (pulmonary medicine, lung pathobiology, antimicrobial pharmacology, translational modeling), will sup- port a novel strategy (in synchrony with the ATS/IDSA guidelines) that addresses the interplay between persis- tent inflammation, immune perturbation and development of antimicrobial resistance (AMR). We endeavor to address the serious societal and medical unmet need to limit the emergence of drug-resistant pathogens.
