Phase 1, Safety and Tolerability Study of XmAb541 and XmAb808 in Advanced Solid Tumors

A Phase 1 Trial, Evaluating the Safety and Tolerability of XmAb541 in Combination With XmAb808 in Advanced Solid Tumors

Status

Recruiting

Phases

Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07593092

Enrollment

Registered

2026-05-18

Start date

2026-06-30

Completion date

2028-12-01

Last updated

2026-08-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Ovarian Cancer

Keywords

Phase 1, Ovarian Cancer, HGSOC, B7H3, CLDN6, T-cell Engager

Brief summary

The primary purpose of this study is to determine whether the combination of the investigational drug XmAb541 in combination with the investigational drug XmAb808 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 in combination with XmAb808 on participants' tumor outcomes.

Interventions

BIOLOGICALXmAb541

Monoclonal Bispecific Antibody

BIOLOGICALXmAb808

Monoclonal Bispecific Antibody

Study design

Allocation

Intervention model

SEQUENTIAL

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

FEMALE

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Age ≥ 18 years. * CLDN6+ tumor * Histological or cytological documentation of locally advanced, recurrent, or metastatic high grade serous ovarian carcinoma (HGSOC) including fallopian tube or primary peritoneal origin * Adequate Eastern Cooperative Oncology Group performance status * Life expectancy ≥ 3 months * Adequate organ function

Exclusion criteria

* Prior exposure to a CLDN6 targeting immune cell engager * 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 viral hepatitis B or hepatitis C

Design outcomes

Primary

Measure	Time frame
Incidence of Adverse Events	Day 1 to 2 years
Incidence of dose-limiting toxicities	Day 1 to Day 43

Secondary

Measure	Time frame	Description
Measurement of Cmax	Day 1 - 2 years	Peak Plasma Concentration
Measurement of area under curve (AUC)	Day 1 to 2 years	Area under the plasma concentration versus time curve
Measurement of Ctrough	Day 1 to 2 years	Plasma concentration before next dose
Objective Response Rate	Day 1 to 2 years	Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging
Duration of Response	Day 1 to 2 years	Duration of Objective Response Rate by RECIST 1.1 assessment of CT/MRI imaging

Countries

United States

Contacts

CONTACT541-02 Study Information

info541-02@xencor.com

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 14, 2026