Primary Objective: Determine blood concentrations of two formulations of REGN1033.

Secondary Objective: Assess safety and tolerability of REGN1033.

Key Inclusion Criteria:

1. Healthy males and females (not of childbearing potential) between the ages of 18 and 65 years
2. Body weight between 50.0 kg and 95.0 kg
3. Willing and able to comply with clinic visits and study-related procedures
4. Provide signed informed consent

Key Exclusion Criteria:

1. Donation or loss of approximately 400 mL or more of blood within 8 weeks prior to dosing, or plasma up to 14 days prior to dosing
2. Hemoglobin not within normal limits
3. Positive drug and alcohol screen test results at screening visits 1 and 2
4. Low or elevated blood pressure and/or heart rate after 3 minutes resting in the seated position:
5. Recent use (within 3 months prior to screening) of androgenic steroids
6. Participation in any clinical research study that evaluated 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
7. Previous exposure to any biological therapeutic agent, except vaccines
8. Known sensitivity to tamoxifen, doxycycline, or similar compounds (ie, tetracyclines)
9. Pregnant or breastfeeding women, and women of childbearing potential
10. Sexually active men who are unwilling to practice adequate contraception during the study