A Phase 1/2a study of AR-301, Aridis Pharmaceuticals Inc’s fully human monoclonal antibody against Staphylococcus aureus alpha-toxin, has achieved its primary safety endpoint, according to the company.

The antibody is being evaluated as an adjunctive therapy in combination with standard of care antibiotics for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Aridis will move forward with plans for late-stage clinical studies of AR-301 in 2017.

“These clinical results for AR-301 are very encouraging,” stated Paul-Andre de Lame, MD, Aridis’ Chief Medical Officer.  “As anticipated, our antibody was safe and well tolerated by HAP and VAP patients at all dose levels. Exploratory analyses of efficacy are currently ongoing.”

AR-301 (or Salvecin) is a fully human monoclonal IgG1 antibody that specifically targets S. aureus alpha-toxin and protects host cells from destruction.  It was discovered by applying Aridis’ MabIgX technology to screen human B-cells of convalescent pneumonia patients.

S. aureus is a gram-positive bacterium and is among the leading causative agents of bacterial pneumonia in intensive care units (ICU) and other hospital-acquired infections. S. aureus is also a common pathogen in other infections including the skin and soft tissues infection, post-surgery infection, endocarditis, bacteremia, sepsis, and toxic shock syndrome.

AR-301’s mode of action is independent of the antibiotic resistance profile of S. aureus, hence it is active against drug-resistant strains, including MRSA (methicillin-resistant S. aureus).  In animal studies, AR-301 reduced bacterial load and significantly improved survival following localized and systemic S. aureus infections.

Vu Truong, PhD, Chief Executive Officer of Aridis, further added, “We look forward to discussing the full results with the FDA in the coming months and to advancing AR-301 toward late-stage clinical studies.”