A Phase 1 Open-label Study to Evaluate Safety in Healthy Participants and Participants With Autoimmune Diseases

May 20, 2026 updated by: Xencor, Inc.

A Phase 1, First-in-Human, Open-Label, Dose-Escalation Study to Evaluate the Safety and Tolerability, Pharmacokinetics, and Pharmacodynamics of XmAb657 in Healthy Participants and in Participants With Autoimmune Diseases

The purpose of this study is to determine the safety and tolerability of XmAb657 in healthy participants and participants with autoimmune diseases. Participants will be given XmAb657 subcutaneously (SC) by injection under the skin.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a Phase 1 study to determine the safety, tolerability, pharmacokinetic (PK), and pharmacodynamics (PD), and immunogenicity of XmAb657 in healthy adult participants and participants with autoimmune diseases.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Australia
      • Melbourne, Australia
        • Recruiting
        • Xencor Investigative Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Healthy participants - Adult participants in good health

Idiopathic inflammatory myopathy (IIM) participants - Adult participants that meet the 2017 European Alliance of Association Rheumatology (EULAR)/American College of Rheumatology (ACR) Classification Criterion for IIM

Systemic sclerosis (SSc) participants - Adult participants that meet the 2013 ACR/EULAR Classification Criteria for SSc

Sjogren's Disease participants that meet the 2016 ACR/EULAR Classification Criteria for Primary Sjogren's Syndrome

All participants - Use of highly effective methods of contraception

Exclusion Criteria:

  • Major surgery within 12 weeks prior to dosing or planned within the study
  • Recurrent infections or active clinically significant infection
  • Active or untreated latent tuberculosis
  • Cancer or history of cancer or lymphoproliferative disease within the previous 5 years
  • Uncontrolled cardiovascular, pulmonary, renal, hepatic, endocrine, or gastrointestinal disease

Note: Additional, more specific inclusion/exclusion criteria are defined in the protocol.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dose Escalation
XmAb657 administered SC
Biological: XmAb657
Biological

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Percentage of participants with treatment emergent adverse events (TEAEs) and serious adverse events (SAEs)
Time Frame: Through Week 52
Through Week 52

Secondary Outcome Measures

Outcome Measure
Time Frame
Serum concentration of XmAb657
Time Frame: Through Week 52
Through Week 52

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Xencor, Inc.

Investigators

  • Study Director: Mark Osterman, MD, MSCE, Xencor, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 24, 2026

Primary Completion (Estimated)

October 1, 2028

Study Completion (Estimated)

October 1, 2028

Study Registration Dates

First Submitted

December 3, 2025

First Submitted That Met QC Criteria

December 15, 2025

First Posted (Actual)

December 16, 2025

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

May 20, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • XmAb657-01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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