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

A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single-Center Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Ascending Doses of REGN7508, a Monoclonal Antibody Against Factor XI, in Healthy Adult Subjects

This study is researching an experimental drug called REGN7508 (called "study drug"). The aim of this study is to see how safe and tolerable the study drug is in healthy participants.

This study is looking at several other research questions, including:

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

Study Overview

• Status: Completed
• Conditions: Healthy Volunteer
• Intervention / Treatment: Drug: REGN7508 (IV); Drug: Matching Placebo (IV); Drug: REGN7508 (SC); Drug: Matching Placebo (SC)

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Phase 1

Contacts and Locations

Study Locations

• United Kingdom
  • Leeds, United Kingdom, LS2 9LH
    • Labcorp Clinical Research Unit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Key Inclusion Criteria:

1. Body mass index between 18.0 and 32.5 kg/m2 (inclusive) at the screening visit
2. Judged 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 drug
3. Participant is in good health based on laboratory safety testing obtained at the screening visit and/or prior to administration of initial dose of study drug
4. Normal 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 laboratory
5. Hemoglobin value ≥11.0 g/dL for females and ≥12.9 g/dL for males at the screening and day 1 visits

Key Exclusion Criteria:

1. 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 participation
2. Whole blood donation within the previous 56 days or plasma donation within the previous 7 days prior to the screening visit
3. History 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 protocol
4. Estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73m2 at screening
5. Current smoker or former smoker, including e-cigarettes, who stopped smoking within 12 months prior to the screening visit
6. Confirmed 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 visit
7. History of alcohol abuse within the last 2 years prior to the day 1 visit
8. Any 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 visit
9. History of significant multiple and/or severe allergies (eg, latex gloves) or has had an anaphylactic reaction to prescription or nonprescription drugs or food

NOTE: Other Protocol Defined Inclusion / Exclusion Criteria Apply

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Quadruple

Number of Arms

10

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort 1 Lowest IV Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose
Experimental: Cohort 2 Low IV Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose
Experimental: Cohort 3 Mid IV Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose
Experimental: Cohort 4 High IV Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose
Experimental: Cohort 5 Higher IV Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose
Experimental: Optional: Cohort 8 Highest IV or SC Dose; Randomized 3:1	Drug: REGN7508 (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: Matching Placebo (IV); Administered sequential, ascending single intravenous (IV) dose; Drug: REGN7508 (SC); Administered sequential, ascending single subcutaneous (SC) dose; Drug: Matching Placebo (SC); Administered sequential, ascending single subcutaneous (SC) dose
Experimental: Cohort 6 High SC Dose; Randomized 3:1	Drug: REGN7508 (SC); Administered sequential, ascending single subcutaneous (SC) dose; Drug: Matching Placebo (SC); Administered sequential, ascending single subcutaneous (SC) dose
Experimental: Cohort 7 Higher SC Dose; Randomized 3:1	Drug: REGN7508 (SC); Administered sequential, ascending single subcutaneous (SC) dose; Drug: Matching Placebo (SC); Administered sequential, ascending single subcutaneous (SC) dose
Experimental: Cohort 9 High SC Dose; Randomized 3:1	Drug: REGN7508 (SC); Administered sequential, ascending single subcutaneous (SC) dose; Drug: Matching Placebo (SC); Administered sequential, ascending single subcutaneous (SC) dose
Experimental: Optional: Cohort 10 Highest SC Dose; Randomized 3:1	Drug: REGN7508 (SC); Administered sequential, ascending single subcutaneous (SC) dose; Drug: Matching Placebo (SC); Administered sequential, ascending single subcutaneous (SC) dose

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidences of treatment-emergent adverse events (TEAE)	Treatment-emergent adverse events are defined as those that are not present at baseline or represent the exacerbation of a pre-existing condition during the on-treatment period.	Up to 36 days
Severity of TEAE	Treatment-emergent adverse events are defined as those that are not present at baseline or represent the exacerbation of a pre-existing condition during the on-treatment period.	Up to 36 days

Secondary Outcome Measures

Outcome Measure	Time Frame
Change from baseline in activated partial thromboplastin time (aPTT)	Up to 36 days
Change from baseline in prothrombin time (PT)	Up to 36 days
Concentrations of total REGN7508 in serum	Up to 36 days
Concentrations of functional REGN7508 in plasma	Up to 36 days
Absolute concentration and change from baseline in total Factor XI (FXI) concentrations	Up to 36 days
Absolute concentration and change from baseline in free FXI concentrations	Up to 36 days
Incidence of antidrug antibodies (ADAs) to REGN7508 over time	Up to 36 days

Collaborators and Investigators

• Sponsor: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Actual): January 12, 2023
• Primary Completion (Actual): September 17, 2024
• Study Completion (Actual): September 17, 2024

Study Registration Dates

• First Submitted: October 27, 2022
• First Submitted That Met QC Criteria: October 27, 2022
• First Posted (Actual): November 2, 2022

Study Record Updates

• Last Update Posted (Actual): October 1, 2024
• Last Update Submitted That Met QC Criteria: September 27, 2024
• Last Verified: September 1, 2024

More Information

Terms related to this study

• Keywords: Thrombotic disorders
• Other Study ID Numbers: R7508-HV-21102; 2022-002001-20 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
• IPD Sharing Time Frame: 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, has made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry), has the legal authority to share the data, and has ensured the ability to protect participant privacy.
• IPD Sharing Access Criteria: 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
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes