The purpose of the study is to evaluate the safety, tolerability, and pharmacokinetics of escalating single-dose of UB-921 in healthy male volunteers.

This is an open-label, two-part, dose-escalation and comparative pharmacokinetics study of UB-921 in healthy male volunteers. There will be two parts: dose escalation study (Main Study) and comparative pharmacokinetics study (Sub-study).

Inclusion Criteria:

• Total body weight ≧50 kg (110 lbs)
• No clinically relevant abnormalities
• To agree on using birth control barrier (eg. male condom) during the entire study period.
• Signing the written informed consent form

Exclusion Criteria:

• Previous exposure to chimeric, humanized or human monoclonal antibody, whether licensed or investigational
• A history of drug abuse or heavy drinking.
• Blood donation over 250 mL within 90 days prior to the screening
• Not in the condition to participate in this study considered by investigator(s)