Toll-like receptor (TLR) 4 pathways are major contributors to pathological inflammatory responses induced by tissue damage. NI-0101 is the first monoclonal antibody blocking TLR4 signaling. This activity is independent of the ligand type and concentration, therefore blocking potentially any TLR4 ligands. A Phase 1 single ascending dose study was conducted in 73 healthy volunteers (HV) to evaluate NI-0101 tolerability, preliminary safety, pharmacokinetics and pharmacodynamics, in absence and in presence of a systemic challenge with lipopolysaccharide (LPS), a TLR4 ligand. NI-0101 was well tolerated without safety concern. The pharmacokinetic profile was characterized by a half-life of approximately 10 days at high concentrations and by a rapid elimination at low concentrations due to expected target mediated drug disposition. NI-0101 prevented cytokine release following ex vivo and in vivo LPS administration and also prevented the CRP increase and the occurrence of flu-like symptoms expected following the in vivo administration of LPS. This article is protected by copyright. All rights reserved.