This clinical study will evaluate the study drug, REGN22044, in healthy participants. REGN22044 has not previously been studied in humans.

The purpose of this study is to learn:

• What side effects may happen when REGN22044 is taken
• How much of REGN22044 is in the blood at different times
• Whether the body makes antibodies against REGN22044 (which could make the drug less effective or could lead to side effects)

Key Inclusion Criteria:

1. Is judged by the investigator to be in good health as described in the protocol

Key Exclusion Criteria:

1. History of clinically significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, psychiatric, or neurological disease, as assessed by the investigator
2. Use of any prescription or non-prescription medications or nutritional supplements from approximately 14 days or 5 half-lives, whichever is longer, prior to administration of study intervention or any planned use through the end of the study, except the permitted medications as listed in the protocol
3. Participants with fever (>38°C) associated with infection, or chronic, persistent, or recurring infection(s) requiring active treatment with antibiotics, antivirals or antifungals within 8 weeks prior to the screening visit or the randomization visit, or other frequent recurrent infections deemed unacceptable as per investigator judgment
4. Evidence of active or latent tuberculosis (TB) as documented by medical history and examination

Note: Other protocol defined Inclusion/ Exclusion criteria apply.

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf