The study will consist of 3 phases: Screening, Inpatient, and Outpatient Follow-up. Enrollment criteria will be determined during the 21-day Screening Phase (Visit 1), following by a 3 night inpatient phase where eligible subjects will receive a single dose of IV ETI-204 or matching placebo as described above and undergo routine safety monitoring, dermatologic assessments, and blood draws at pre-specified time points. Subjects will be discharged from the center after collection of the 48-hour PK sample. During the subsequent 70-day outpatient follow-up phase, subjects will return to the center on Days 8, 15, 29, 43 and 71 for clinical laboratory testing (hematology and clinical chemistry), physical examinations and vital signs measurements, and routine safety monitoring. Blood samples for PK and anti-drug antibodies (ADA)will also be collected. The 70 day post-dosing follow-up in this study was selected to allow characterization for the PK profile of ETI-204 and the potential development of ADA.