The study was terminated due to an unexpected preliminary result obtained from the study with CR8020.

The purpose of the study is to assess the safety, pharmacokinetics (what the body does to the drug) and immunogenicity (ability of a particular substance to provoke an immune response in the human body) of CR8020 in japanese healthy participants

This study is a randomized (study medication is assigned by chance), double-blind (neither physician nor participant knows the treatment that the participant receives), placebo-controlled (placebo comparator is compared with the study medication to evaluate safety profile of the study medication in clinical study), single-dose study in Japanese healthy adult male participants. The study will include screening phase (28 to 2 days prior to the study medication administration), treatment phase (Study medication will be administered on Day 1), and follow-up phase (up to 99 days). Twelve participants will be randomly assigned to CR8020 50 mg/kg or placebo groups in a 2:1 ratio and receive an assigned treatment on Day 1. Safety will be assessed by evaluating adverse events, clinical laboratory tests, 12-lead Electrocardiogram, vital signs, and physical examination. Total maximum duration of participation of an individual participant will be 127 days.

Inclusion Criteria:

• Have signed an informed consent document
• Body mass index between 18 and 30 kg/m2, with body weight greater than or equal to 50 kg at screening
• Must agree to use an adequate contraception method (eg, vasectomy, double-barrier, partner using effective contraception) and to not donate sperm from the study drug administration until Day 99
• Blood pressure between 90 and 140 mmHg systolic, inclusive, and no higher than 90 mmHg diastolic at screening
• Non-smoker or participant who smokes no more than 10 cigarettes, or 2 cigars, or 2 pipes of tobacco per day for at least 6 months before the study drug administration

Exclusion Criteria:

• History of or current clinically significant medical illness determined by the investigators including (but not limited to) cardiac arrhythmias or other cardiac disease, hematologic disease, and coagulation disorders
• Clinically significant abnormal values for hematology, clinical chemistry or urinalysis
• Clinically significant abnormal physical examination, vital signs or 12-lead electrocardiogram
• A diagnosis of influenza infection or any constellation of clinical symptoms consistent with influenza infection within 14 days before the study drug administration is scheduled
• Participants with a fever of over 37.5°C on Day -1 or at predose