Not Yet RecruitingPhase 1

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

24 participantsStarted 2026-02

Plain-language 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 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).

Who can participate

Age range18 Years – 75 Years

SexALL

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Inclusion criteria

✓. 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.

Exclusion criteria

✕. 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
✕. 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

What they're measuring

Incidence of treatment-emergent adverse events (TEAEs)

Timeframe: Through Week 16

Incidence of serious adverse events (SAEs)

Timeframe: Through Week 16

Trial details

NCT IDNCT07455578

SponsorSeismic Therapeutic AU Pty Ltd

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2027-06

Contact for this trial

Seismic Contact

1800 244 475 clinical@seismictx.com

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