Study to Assess the Safety and Tolerability of Multiple Ascending Doses of REGN1500

Inclusion Criteria:

- Provide signed informed consent

- Otherwise healthy men and women ages 18 to 65 years, inclusive

- Body mass index of 18.0 kg/m2to 38.0 kg/m2, inclusive

- Normal standard 12-lead ECG

- Willing to refrain from the consumption of alcohol for 24 hours prior to each study
visit

- Willing to consistently maintain his/her usual diet for the duration of the study

- Willing to refrain from strenuous exercise for the duration of the trial

- Willing and able to comply with clinic visits and study-related procedures

- For sexually active men and women of childbearing potential, willingness to utilize
adequate contraception and not become pregnant (or have their partner[s] become
pregnant) during the full duration of the study.

Exclusion Criteria:

- Any clinically significant abnormalities observed during the screening visit

- History of drug or alcohol abuse within 1 year of screening

- Receipt of 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.

- Significant concomitant illness or history of significant illness such as cardiac,
renal, neurological, endocrinological, metabolic or lymphatic disease, or any other
illness or condition that may adversely affect the subjects participation in this
study

- Known history of human immunodeficiency virus (HIV) antibody; and/or positive
hepatitis B surface antigen (HBsAg), and/or positive hepatitis C antibody (HCV) at
the screening visit

- Hospitalization for any reason within 60 days of screening

- History or presence of malignancy within 5 years prior to the screening visit (other
than successfully treated non-metastatic cutaneous squamous cell or basal cell
carcinoma, and/or localized carcinoma in situ of the cervix

- Any medical or psychiatric condition which, in the opinion of the investigator, would
place the subject at risk, interfere with participation in the study or interfere
with the interpretation of the study results

- Any subject who is the investigator or any sub-investigator, research assistant,
pharmacist, study coordinator, or other staff directly involved in the conduct of the
protocol, or family member of staff involved in the conduct of the protocol

- Pregnant or breast-feeding women

Note: The information listed above is not intended to contain all considerations relevant
to a patient's potential participation in this clinical trial and not all inclusion/
exclusion criteria are listed.