A Phase 1 Study of S-4321

Phase 1

Recruiting

• Conditions: Healthy Volunteer
• Interventions: Drug: S-4321; Other: Placebo

• Registration Number: NCT06877611
• Lead Sponsor: Seismic Therapeutic AU Pty Ltd

Brief Summary

This is the first-in-human study of S-4321 designed to provide safety, tolerability, pharmacokinetic, and pharmacodynamic data in healthy volunteers.

Detailed Description

This is a randomized, placebo-controlled, double-blind, study to assess the safety, tolerability, pharmacokinetics, pharmacodynamics of S-4321 administered to healthy adult participants. This study will be conducted in two parts, Part 1 (single ascending dose, SAD) and Part 2 (multiple ascending doses, MAD).

Study Timeline

• Status Verified: 2025-03
• Study First Submitted: 2025-03-10
• Study First Submitted QC: 2025-03-10
• Study First Posted: 2025-03-14
• Study Start: 2025-04-03
• Last Update Submitted: 2025-04-10
• Last Update Posted: 2025-04-15
• Primary Completion: 2026-04
• Study Completion: 2026-04

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 96

Inclusion Criteria

1. Is available for the entire duration of the study and follow up.
2. Is willing and able to comply with all study assessments and adhere to the protocol schedule and restrictions.
3. Voluntarily consents to participation in the trial as documented by signing the study informed consent form (ICF).
4. Has a body mass index (BMI) within 18 to 32 kg/m2, inclusive, and weighs ≥45 kg.
5. Is in good physical and mental health in the opinion of the Investigator or delegate.

Major

Exclusion Criteria

1. Has a history of severe allergic or anaphylactic reaction as determined by the Investigator or delegate.
2. Is pregnant, nursing, or is planning to become pregnant or breastfeed during the trial.
3. Has a known immunodeficiency disorder.
4. Has a history of malignancy or confirmed cervical dysplasia.
5. Has a history of human immunodeficiency virus (HIV) or positive serology for HIV at Screening.
6. Has positive laboratory evidence for active hepatitis at screening.
7. Has any other condition or prior therapy that, in the opinion of the Investigator or delegate, may potentially compromise the safety or compliance of the participant, or may preclude the participant from successfully completing the study.

Other inclusion/exclusion eligibility criteria apply.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
S-4321 Part 1: Single ascending dose (SAD) cohorts	S-4321	-
S-4321 Part 1: Single ascending dose (SAD) cohorts	Placebo	-
S-4321 Part 2: Multiple ascending dose (MAD) cohorts	S-4321	-
S-4321 Part 2: Multiple ascending dose (MAD) cohorts	Placebo	-

Primary Outcome Measures

Name	Time	Method
Number of participants with treatment-related adverse and serious adverse events as assessed by CTCAE v5.0	2 months

Secondary Outcome Measures

Name	Time	Method
To assess the maximum serum concentration (CMAX)	2 months
To assess time to reach maximum serum concentration (tMAX)	2 months
To assess elimination half-life (t1/2)	2 months
To assess area under the serum concentration-time curve from time 0 to t hours (AUC0-t) and to infinity (AUC0-inf)	2 months
To assess clearance (CL)	2 months
To assess volume of distribution (Vz) and steady-state volume of distribution (Vss)	2 months
To assess bioavailability after SC administration (F%)	2 months
To characterize absolute change from baseline of Receptor Occupancy (RO) at multiple timepoints	2 months
Incidence and characterization of anti-drug antibody (ADA)	2 months

Trial Locations

Locations (1)

Veritus Research; 🇦🇺 Bayswater, Victoria, Australia