Phase 1, Safety and Tolerability Study of XmAb541 in Advanced Solid Tumors

March 13, 2026 updated by: Xencor, Inc.

A Phase 1, First-in-Human, Dose Escalation and Expansion Study to Evaluate the Safety and Tolerability of XmAb541 in Advanced Solid Tumors

The primary purpose of this study is to determine whether the investigational drug XmAb541 is safe and well tolerated, and to determine an optimal and safe dose(s) for further study. The study will also evaluate the effect of XmAb541 on tumor outcomes.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

282

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 Locations

  • United States
    • California
      • Duarte, California, United States, 91010
        • Not yet recruiting
        • City of Hope
      • Palo Alto, California, United States, 94304
        • Not yet recruiting
        • Stanford
      • San Francisco, California, United States, 94158
        • Recruiting
        • University of California
    • Florida
      • Tampa, Florida, United States, 33612
        • Recruiting
        • Moffitt Cancer Center
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Recruiting
        • Winship Cancer Institute, Emory University
    • Illinois
      • Chicago, Illinois, United States, 60637
        • Recruiting
        • University of Chicago Medical Center
    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Recruiting
        • Indian University Melvin and Bren Simon Comprehensive Cancer Center
    • Michigan
      • Detroit, Michigan, United States, 48201
        • Recruiting
        • Karmanos Cancer Institute
    • New Jersey
      • Hackensack, New Jersey, United States, 07601
        • Recruiting
        • The John Theruer Cancer Center at Hackensack University Medical Center
    • New York
      • New York, New York, United States, 10029
        • Recruiting
        • Icahn School of Medicine at Mount Sinai
      • The Bronx, New York, United States, 10461
        • Recruiting
        • Montefiore Einstein Comprehensive Cancer Center
    • Ohio
      • Columbus, Ohio, United States, 43210
        • Recruiting
        • The Ohio State University
    • Oklahoma
      • Oklahoma City, Oklahoma, United States, 73104
        • Recruiting
        • OU Health Stephenson Cancer Center
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15232
        • Recruiting
        • UPMC Hillman Cancer Center
    • Tennessee
      • Nashville, Tennessee, United States, 37203
        • Recruiting
        • SCRI Oncology Partners
    • Virginia
      • Charlottesville, Virginia, United States, 22903
        • Recruiting
        • University of Virginia

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Age ≥ 18 years. For subjects with GCTs, age ≥15 years
  • CLDN6+ tumor
  • Histological or cytological documentation of locally advanced, recurrent, or metastatic ovarian, fallopian tube, or peritoneal cancer, adenocarcinoma of the endometrium (endometrial cancer, uterine cancer, or carcinoma of the uterine corpus), GCT resistant to previous treatment
  • Adequate Eastern Cooperative Oncology Group performance status
  • Life expectancy ≥ 3 months
  • Adequate liver, kidney, and bone marrow function

Key Exclusion Criteria:

  • Patients with treated brain metastases may participate, provided they are radiologically stable.
  • Active known or suspected autoimmune disease
  • Have any condition requiring systemic treatment with corticosteroids, prednisone equivalents, or other immunosuppressive medications within 14 days prior to first dose of study drug
  • Clinically significant cardiovascular, pulmonary or gastrointestinal disease
  • Active hepatitis B or hepatitis C

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: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dose escalation and Dose Expansion of XmAb541
Intravenous or Subcutaneous administration
Biological: XmAb541
Monoclonal bispecific antibody

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of dose-limiting toxicities (DLTs)
Time Frame: Day 1 to Day 28
Day 1 to Day 28
Incidence of cytokine release syndrome (CRS)
Time Frame: Day 1 to Day 28
Day 1 to Day 28
Incidence of adverse events
Time Frame: Day 1 to 2 years
Day 1 to 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Measurement of Cmax
Time Frame: Day 1 to 2 years
Peak plasma concentration
Day 1 to 2 years
Measurement of area under curve (AUC)
Time Frame: Day 1 to 1.4 years
Area under the plasma concentration versus time curve
Day 1 to 1.4 years
Measurement of Ctrough
Time Frame: Day 1 to 2 years
Plasma concentration before next dose
Day 1 to 2 years
Objective Response Rate
Time Frame: Day 1 to 2 years
Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging
Day 1 to 2 years
Duration of Response
Time Frame: Day 1 to 2 years
Duration of Response Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging
Day 1 to 2 years
Changes in Circulating Tumor DNA (ctDNA)
Time Frame: Day 1 to 4 months
Maximum variant frequency or mean/median variant frequency
Day 1 to 4 months

Collaborators and Investigators

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

Sponsor

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)

April 4, 2024

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

February 16, 2024

First Submitted That Met QC Criteria

February 16, 2024

First Posted (Actual)

February 26, 2024

Study Record Updates

Last Update Posted (Actual)

March 17, 2026

Last Update Submitted That Met QC Criteria

March 13, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • XmAb541-01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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