Thirty-two healthy male subjects (8 per cohort) were randomized 6:2 to active:placebo. LSVT-1701, an antistaphylococcal lysin, was administered intravenously as a 6-mg/kg single dose and as 1.5, 3, and 4.5 mg/kg twice daily for 4 days. LSVT-1701 exposure increased in a greater than dose proportional manner and did not accumulate. Treatment-emergent adverse events (TEAEs) were predominantly of mild intensity. The most common TEAEs were chills, pyrexia, headache, infusion site events, cough, rhinorrhea, and increases in C-reactive protein. (This study has been registered at ClinicalTrials.gov under identifier NCT03446053.).