A Trial to Learn if Single Ascending Intravenous (IV) Doses of REGN7508 Are Safe and Well Tolerated, and How it Works in the Body of Healthy Adult Participants

The primary objective of the study is to evaluate the safety and tolerability of single doses of REGN7508 in healthy adult participantsThe secondary objectives of the study are to:Evaluate the effects of single doses of REGN7508 on intrinsic/common pathway coagulationEvaluate the effects of single doses of REGN7508 on extrinsic/common pathway coagulationCharacterize the drug concentration profiles and pharmacokinetics (PK) following single escalating doses of REGN7508Characterize the concentration profiles of total Factor XI (FXI) following single escalating doses of REGN7508Assess the immunogenicity of single doses of REGN7508

Key Inclusion Criteria:Body mass index between 18.0 and 32.5 kg/m2 (inclusive) at the screening visitJudged by the investigator to be in good health based on medical history, physical examination, vital sign measurements, and echocardiograms (ECGs) performed at screening and/or prior to administration of initial dose of study drugParticipant is in good health based on laboratory safety testing obtained at the screening visit and/or prior to administration of initial dose of study drugNormal activated partial thromboplastin time (aPTT), normal prothrombin time (PT), and normal platelet counts at screening period and at the day -1 visit as defined by the local laboratoryHemoglobin value ≥11.0 g/dL for females and ≥12.9 g/dL for males at the screening and day 1 visitsKey Exclusion Criteria:History of any major surgical procedure or clinically significant physical trauma, in the opinion of the investigator, that may pose a risk to the participant by study participationWhole blood donation within the previous 56 days or plasma donation within the previous 7 days prior to the screening visitHistory of clinically significant cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, psychiatric, neurological, or dermatologic disease, as assessed by the investigator, that may confound the results of the study or poses an additional risk to the participant by study participation, as defined in the protocolEstimated glomerular filtration rate (eGFR) of <60 mL/min/1.73m2 at screeningCurrent smoker or former smoker, including e-cigarettes, who stopped smoking within 12 months prior to the screening visitConfirmed positive drug test result at the screening visit and/or prior to randomization or a history of drug abuse within a year prior to the screening visitHistory of alcohol abuse within the last 2 years prior to the day 1 visitAny malignancy, except for nonmelanoma skin cancer or cervical/anus in situ, that have been resected with no evidence of metastatic disease for 3 years prior to the screening visitHistory of significant multiple and/or severe allergies (eg, latex gloves) or has had an anaphylactic reaction to prescription or nonprescription drugs or foodNOTE: Other Protocol Defined Inclusion / Exclusion Criteria Apply