To promote objective safety and tolerance assessments during this trial, study subjects, and site personnel administering the study drug and performing the clinical assessments on the subjects, will be blinded to individual subjects' treatments assignments (active NVR 3-778 or placebo doses), for all treatment cohorts in the study. Study advancement to subsequent patient cohorts will require satisfactory interim reviews of available cumulative safety data by the Safety Review Committees (SRC), using the safety criteria and review procedures described in the protocol. Also, there will be one interim review of safety data by an independent Safety Monitoring Board (SMB), as described in the protocol.