Phase IIa Clinical Study of N-Rephasin® SAL200

Subjects: Patients with persistent Staphylococcus aureus bacteremia for more than 48 hours from the beginning of antibiotics treatment to which Staphylococcus aureus is susceptible. Study Method: 1. Selection of patients with persistent S.aureus bacteremia for more than 48 hours even after application of the standard treatment for S. aureus bacteremia 2. Randomization according to the trial institutions 3. The control group receives a single intravenous dose of the placebo in addition to the standard treatment for persistent Staphylococcus aureus bacteremia 4. The study group receives a single intravenous dose of the N-Rephasin® SAL200 (3 mg/kg) in addition to the standard treatment for persistent Staphylococcus aureus bacteremia 5. A blood culture is performed 18 hours (±6 hours) after the administration of N-Rephasin® SAL200 6. Blood cultures continue to be performed every 24 hours (±6 hours) or 48 hours (±6 hours) after the previous blood culture, until two consecutive results of 'no growth (negative conversion)' are obtained 7. Adverse events are monitored at the time of the first blood culture following the administration of N-Rephasin® SAL200 or placebo, and at the subsequent intervals of 24 hours or 48 hours Statistical Analysis: 1. Primary endpoints * Safety analysis is conducted in the Safety group. A distribution table of patients who experience at least one adverse event (incidence), and distribution tables of the relationship of the reported adverse events with the investigational product (distribution tables for severity and the relationship with the drug) are presented with respect to the groups (study group, control group), to determine safety of the investigational product. * The results of the laboratory tests, anaphylaxis test, inflammatory cytokine test and vital signs at baseline and the last visit are summarized as mean values and standard deviations, to determine the change before and after the treatment within each group. * Categorical data are divided into normal and abnormal, and summarized as the frequency and percentage to determine the difference before and after treatment within each group. 2. Secondary endpoints * Proportion of patients who are negative for bacterial growth in the first blood culture after administration of the investigational drug. The descriptive statistics for the proportion of patients who are negative for bacterial growth in the first blood culture (the rate of no growth) after the first treatment are presented by treatment group. Whether the rate of no growth is superior in the study group compared to the control group, is evaluated by a descriptive statistical method. * Proportion of patients who die due to S. aureus bacteremia by Day14 after the incidence of bacteremia. The descriptive statistics for the proportion of patients who die due to S. aureus bacteremia by Day14 are presented by treatment group and evaluated. * Proportion of treatment failure for S. aureus bacteremia by Day 14 (if two consecutive results of 'no growth' are not achieved in the blood cultures which are performed until Day 14. The descriptive statistics for the proportion of treatment failure for S. aureus bacteremia by Day 14 are presented and evaluated.