Targeting eNAMPT-TLR4 signaling with the novel ALT-100 mAb to slow IPF progression

ABSTRACT: There is a major unmet need to identify novel therapies for idiopathic pulmonary fibrosis (IPF), a rapidly pro- gressing fibrotic lung disease often resulting in fatal respiratory failure. Current IPF drugs only moderately slow the progression of the disease and fail to halt or reverse fibrosis development. Many IPF patients are ineligible for lung transplantation, the only IPF treatment option, and often expire prior to transplantation. Consistent with recognition of innate immunity-driven inflammatory responses as key contributors to IPF development and sub- sequent progression, we identified eNAMPT (extracellular nicotinamide phosphoribosyltransferase) as a novel damage-associated molecular pattern protein (DAMP) and therapeutic IPF target that binds and activates Toll- Like Receptor 4 (TLR4) to evoke innate immunity-mediated inflammatory and fibrotic pathways. Expression of eNAMPT in plasma, lung tissues and PBMCs is strongly linked to the severity of human IPF, including 3 year survival. Importantly, we have manufactured a humanized eNAMPT-neutralizing mAb (6 gms/L expression) that attenuates lung fibrosis progression in two models of preclinical models of lung fibrosis (radiation, bleomycin). In this R-41 application, we will optimize the dose of subcutaneously-delivered ALT-100 mAb (1 mg/kg, 2 mg/kg, 4 kg/kg, 6 mg/kg) that most effectively ameliorates established lung fibrotic injury in preclinical models of radia- tion-induced lung fibrosis (Specific Aim #1A) and intratracheal bleomycin-induced lung fibrosis (Specific Aim #1B) utilizing C57Bl6 mice. Specific Aim #2 will utilize the bleomycin IPF model to assess responses of the optimized dose of ALT-100 mAb in combination with the FDA-approved IPF drugs: i) pirfenidone, and ii) nintedanib. Murine phenotyping will include histologic lung fibrosis scores, physiologic lung stiffening (re- sistance/elastance), expression of key fibrosis-related proteins (TGFb, SMAD, thrombospondin), and single-cell RNA sequencing of SA #1/SA #2-derived murine lung tissues to identify the primary target cells and signaling pathways rectified by ALT-100 mAb therapy. Supporting ALT-100 mAb feasibility as an IPF therapy, we have completed Phase 1A ALT-100 mAb safety studies in healthy human volunteers (zero serious adverse events) and initiated a Phase 2A clinical trial of ALT-100 mAb for ARDS (NCT05938036). IV ALT-100 mAb exhibits a T1/2 half-life of 16-27 days and recently completed IND-enabling chronic pharmacokinetic and 6 month toxicity studies with subQ ALT-100 mAb showed a T1/2 half-life of 10-14 days in rats and no discernable toxicity in rats or pigs. These studies leverage the strong academic-private biotech partnership between the University of Flor- ida and Aqualung Therapeutics and will yield valuable histologic/biochemical/genomic evidence that validates eNAMPT/TLR4 as a druggable IPF target and ALT-100 as a novel strategy to directly address the unmet need for therapeutics that reduce IPF severity. Successful completion of these Phase I Specific Aims will allow us to proceed to receive IND approval from the FDA to conduct safety studies in healthy volunteers and clinical trials to evaluate ALT-100 mAb as a novel therapeutic approach for subjects with IPF.