Assessment of Gastrointestinal Blood Loss After Receiving Aspirin or Aspirin Plus Rivaroxaban, or Aspirin Plus REGN9933, or Aspirin Plus REGN7508 in Healthy Adult Participants

Phase 1

Recruiting

• Conditions: Healthy Volunteers
• Interventions: Drug: Aspirin; Drug: REGN9933; Drug: REGN7508; Drug: Rivaroxaban

• Registration Number: NCT06444178
• Lead Sponsor: Regeneron Pharmaceuticals

Brief Summary

This study is researching experimental drugs called REGN9933 and REGN7508 (called "study drugs") and comparing their effects to approved treatments of rivaroxaban and aspirin (called "standard treatments"). Aspirin will be given alone or in combination with the study drugs or the other standard treatments to look at their effects on blood loss in the intestines.

The aim of the study is to see if aspirin alone or the study drugs REGN9933 and REGN7508, when taken with aspirin, cause less minor intestinal bleeding than standard treatments rivaroxaban with aspirin.

The 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)

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-05-30
• Study First Submitted QC: 2024-05-30
• Study First Posted: 2024-06-05
• Study Start: 2024-09-30
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-01
• Last Update Posted: 2025-05-02
• Primary Completion: 2025-08-18
• Study Completion: 2025-11-26

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 224

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 electrocardiograms (ECGs) performed at screening and/or prior to administration of initial dose of study treatment
3. Normal aPTT, normal PT, and normal platelet counts at screening period and at the day 1 visit as defined by the local laboratory
4. Hemoglobin value ≥11.0 g/dL for females and ≥12.9 g/dL for males at the screening and day 1 visits
5. Negative FOBT at Baseline (visit 2) and visit 3 as defined in the protocol

Key

Exclusion Criteria

1. History of any major surgical procedure or clinically significant physical trauma in the last 6 months, 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. Hospitalized for any reason within 30 days of the screening visit
4. Estimated glomerular filtrate rate (eGFR) of <60 mL/min/1.73m2 at screening as described in the protocol.
5. Current smoker or former smoker, including e-cigarettes, who stopped smoking within 12 months prior to the screening visit
6. History of illicit drug or alcohol abuse within the last 2 years prior to the day 1 visit
7. Use of any prescription and nonprescription medications or nutritional supplements from approximately 2 weeks or 5 half-lives, as described in protocol

Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm 2: Aspirin + REGN9933	Aspirin	Randomized 1:1:1:1
Arm 1: Aspirin	Aspirin	Randomized 1:1:1:1
Arm 2: Aspirin + REGN9933	REGN9933	Randomized 1:1:1:1
Arm 3: Aspirin + REGN7508	Aspirin	Randomized 1:1:1:1
Arm 3: Aspirin + REGN7508	REGN7508	Randomized 1:1:1:1
Arm 4: Aspirin + Rivaroxaban	Aspirin	Randomized 1:1:1:1
Arm 4: Aspirin + Rivaroxaban	Rivaroxaban	Randomized 1:1:1:1

Primary Outcome Measures

Name	Time	Method
Change in fecal hemoglobin content (FHC)	Baseline and up to day 22

Secondary Outcome Measures

Name	Time	Method
Concentrations of REGN9933	Up to day 29
Concentrations of REGN7508	Up to day 29
Change in activated partial thromboplastin time (aPTT)	Baseline and up day 29
Change in prothrombin time (PT)	Baseline and up day 29
Incidence of treatment-emergent adverse events (TEAE)	Up to day 100
Severity of TEAE	Up to day 100
Incidence of major bleeding	Up to day 100
Incidence of clinically relevant non-major (CRNM) bleeding	Up to day 100
Incidence of Anti-drug antibody (ADA) to REGN9933	Up to day 29
Titer of ADA to REGN9933	Up to day 29
Incidence of ADA to REGN7508	Up to day 29
Titer of ADA to REGN7508	Up to day 29

Trial Locations

Locations (1)

Fortrea Clinical Development; 🇬🇧 Leeds, United Kingdom