This study is being conducted to assess the safety and tolerability of a single ascending intravenous (IV) dose of REGN846 in healthy volunteers.

Inclusion Criteria:

• Healthy men and women between the ages of 18 and 65; women must be postmenopausal or surgically sterile
• Body Mass Index (BMI) between 18.0 and 30.0 kg/m2, inclusive
• Normal vital signs after resting in a sitting position for 5 minutes:
• Normal standard 12-lead ECG
• Willing and able to comply with clinic visits and study-related procedures
• Provide signed informed consent
• Able to understand and complete study-related questionnaires

Exclusion Criteria:

• Current or prior history of smoking
• Any illness or condition that would adversely affect the subject's participation in this study
• Hospitalization within 60 days of the screening visit
• Any clinically significant abnormalities observed during the screening visit
• History of or positive human immunodeficiency virus (HIV) screen result at the screening visit
• History of positive blood test for hepatitis B/hepatitis C or positive hepatitis screen result at the screening visit
• History of positive drug screen result for drug or alcohol abuse within a year prior to the screening visit
• Known sensitivity to any of the components of the Investigational Product formulation
• Participation in any clinical research study evaluating another investigational drug or therapy within 30 days or at least 5 half-lives (whichever is longer), of the investigational drug prior to the screening visit
• Any condition that would place the subject at risk, interfere with participation in the study
• History of a parasitic infection or recent (within the previous 6 months) travel to a parasitic endemic area
• Live/attenuated vaccinations within 12 weeks of screening or during the study
• Any subjects with planned elective surgery
• Sexually active men who are unwilling to utilize adequate contraception