Study of S-4321 in Participants With an Autoimmune or Immune-mediated Disease

NCT07455578 | Recruiting Phase 1

• 1 other identifier: S-4321-102
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 2

Brief Summary

This is a multi-center, open-label Ph 1b basket study to assess safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, biomarker response, and preliminary efficacy of multiple doses of S-4321 in adults with autoimmune or immune-mediated disease including rheumatoid arthritis (RA), psoriatic arthritis (PsA), psoriasis (PsO), cutaneous lupus erythematosus (CLE) with or without systemic manifestations, or atopic dermatitis (AD).

Conditions

Autoimmune Diseases; Psoriasis (PsO); Atopic Dermatitis (AD); Rheumatoid Arthritis (RA); Psoriatic Arthritis (PsA); Cutaneous Lupus Erythematosus (CLE)

Keywords

Autoimmune; Immune-mediated; S-4321; Seismic Therapeutic; Rheumatoid Arthritis; Atopic Dermatitis (AD); Psoriasis (PsO); Psoriatic Arthritis (PsA); Cutaneous Lupus Erythematosus (CLE); Cutaneous Lupus

Outcome Measures

Primary Outcomes (2)

• Incidence of treatment-emergent adverse events (TEAEs)

  Through Week 31

• Incidence of serious adverse events (SAEs)

  Through Week 31

Secondary Outcomes (4)

• Serum concentration of S-4321

  Through Week 28

• Change from baseline in percent Receptor Occupancy (RO)

  Through Week 28

• Change from baseline of soluble PD-1 (sPD-1)

  Through Week 28

• Incidence of anti-drug antibodies (ADAs)

  Through Week 28

Study Arms (1)

S-4321

EXPERIMENTAL

SC Dose of S-4321

Drug: S-4321

Interventions

S-4321 DRUG

Multiple doses of S-4321 via subcutaneous administration

S-4321

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult males and females, 18 to 75 years of age (inclusive)
• Body mass index (BMI) ≥18.0 and \<40.0 kg/m2 with a minimum body weight of 45 kg
• Use of adequate contraception for both males and females. Female volunteers must be of nonchildbearing potential or if of childbearing potential, must have a negative pregnancy test.

You may not qualify if:

• Have received a PD-1 agonist, immune checkpoint agonist, immune checkpoint inhibitor, anti-CD19 or anti-CD20 agents, cell therapy, B cell modulating agents, alkylating agents, or any other immune cell depleting therapy.
• Have received azathioprine, cyclosporine, mycophenolate mofetil, or tacrolimus within 4 weeks
• Unable or unwilling to discontinue a prohibited medication
• Presence of clinically relevant immunosuppression
• Current infection or history of severe infection
• Any history of malignant disease, with some exceptions
• For RA:
• Confirmed diagnosis of moderate to severe active RA by the American College of Rheumatology (ACR) 2010/European League Against Rheumatism (EULAR) criteria for at least 3 months prior to the Screening 1 visit, and:
• ≥6 swollen joint count based on 66 joint count
• ≥6 tender joint count based on 68 joint count
• Seropositive for RF and/or ACPA
• Elevated hsCRP ≥1.2 times greater than the ULN
• Does not have Class IV RA according to ACR revised criteria
• Inadequate response to, or loss of response, or intolerance to:
• \>1 conventional synthetic DMARD after 3 months of therapy OR

Sponsors & Collaborators

• Seismic Therapeutic AU Pty Ltd: lead
• Avance Clinical Pty Ltd.: collaborator

Study Sites (2)

Novatrials

Charlestown, New South Wales, 2290, Australia

RECRUITING

University of the Sunshine Coast Clinical Trials, Birtinya

Birtinya, Queensland, 4575, Australia

RECRUITING

MeSH Terms

Conditions

Autoimmune Diseases; Arthritis, Rheumatoid; Arthritis, Psoriatic; Psoriasis; Lupus Erythematosus, Cutaneous; Dermatitis, Atopic

Condition Hierarchy (Ancestors)

Immune System Diseases; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Connective Tissue Diseases; Skin and Connective Tissue Diseases; Spondylarthropathies; Spondylarthritis; Spondylitis; Spinal Diseases; Bone Diseases; Skin Diseases, Papulosquamous; Skin Diseases; Skin Diseases, Genetic; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Dermatitis; Skin Diseases, Eczematous; Hypersensitivity, Immediate; Hypersensitivity

Study Officials

• Jennifer Martin, MD

  Novatrials

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Seismic Contact

CONTACT

1800 244 475; clinical@seismictx.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 13, 2026
• First Posted: March 6, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: June 1, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

AU (2)