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Completed

NCT Number: NCT05585034

Phase 1, First-in-human, Dose-finding and Expansion Study to Evaluate XmAb®808 in Combination With Pembrolizumab in Advanced Solid Tumors

The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics of intravenous (IV) administration of XmAb808 in combination with pembrolizumab in subjects with selected advanced solid tumors and to identify the minimum safe and biologically effective/recommended dose (RD) and schedule for XmAb808.

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Key information

Conditions

Head and Neck Squamous Cell Carcinoma Adenocarcinoma Adnexal Diseases Breast Diseases Breast Neoplasms Bronchial Neoplasms Carcinoma Carcinoma, Bronchogenic Carcinoma, Non-Small-Cell Lung Carcinoma, Ovarian Epithelial Carcinoma, Renal Cell Carcinoma, Squamous Cell Carcinoma, Transitional Cell Castration-resistant Prostate Cancer Colonic Diseases Colorectal Cancer Colorectal Neoplasms Digestive System Diseases Digestive System Neoplasms Endocrine Gland Neoplasms Endocrine System Diseases Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Gastrointestinal Diseases Gastrointestinal Neoplasms Genital Diseases Genital Diseases, Female Genital Neoplasms, Female Gonadal Disorders Head and Neck Neoplasms Intestinal Diseases Intestinal Neoplasms Kidney Diseases Kidney Neoplasms Lung Diseases Lung Neoplasms Male Urogenital Diseases Melanoma Excluding Uveal Melanoma Neoplasms Neoplasms by Histologic Type Neoplasms by Site Neoplasms, Glandular and Epithelial Non-small Cell Lung Cancer, Squamous or Non-squamous Ovarian Cancer, Epithelial Ovarian Diseases Ovarian Neoplasms Rectal Diseases Renal Cell Carcinoma, Clear Cell Respiratory Tract Diseases Respiratory Tract Neoplasms Skin Diseases Skin and Connective Tissue Diseases Squamous Cell Carcinoma of Head and Neck TNBC - Triple-Negative Breast Cancer Thoracic Neoplasms Triple Negative Breast Neoplasms Urogenital Diseases Urogenital Neoplasms Urologic Diseases Urologic Neoplasms Urothelial Carcinoma

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

UCLA Hematology/Oncology, Los Angeles, California, United States

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About this study

This is a Phase 1, open-label, first-in-human (FIH), multiple-dose, dose escalation study with cohort expansion at the RD, designed to evaluate the safety and tolerability of XmAb808 in combination with pembrolizumab. This study will be conducted in 2 parts: Part A (dose escalation) and Part B (cohort expansion).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Part A: Histologically confirmed advanced/metastatic castration-resistant prostate adenocarcinoma, epithelial ovarian cancer, head and neck squamous cell carcinoma, non-small cell lung cancer, urothelial carcinoma, melanoma, renal cell carcinoma, triple-negative breast cancer, or colorectal cancer that has progressed on standard therapies
  • Part B: Histologically confirmed advanced/metastatic castration-resistant prostate cancer that is PD1-naïve; head and neck squamous cell carcinoma that is PD1-naïve or has progressed on prior PD1 therapy; or melanoma that is PD1-naïve or has progressed on prior PD1 therapy
  • Measurable disease by RECIST 1.1; subjects with prostate cancer who have evaluable disease according to PCWG3 criteria may enroll
  • Life expectancy > 3 months
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

Key Exclusion Criteria:

  • Subjects currently receiving other anticancer therapies
  • Any prior treatment with an investigational agent targeting CD28
  • History of a life-threatening adverse event related to prior immunotherapy
  • Known active central nervous system involvement by malignant disease. Subjects with previously treated brain metastases may participate provided they are radiologically and clinically stable

Treatment and study plan

XmAb®808

Biological

Monoclonal bispecific antibody

KEYTRUDA® (pembrolizumab)

Biological

Monoclonal antibody

Primary outcomes

  1. Incidence of treatment-emergent adverse events (TEAEs)

    Time frame: Up to 5 years

    Safety and tolerability as assessed by incidence of TEAEs, including clinically significant changes in safety laboratory tests and clinical findings

  2. Incidence of dose-limiting toxicities (DLTs)

    Time frame: 49 days

    Safety and tolerability as assessed by incidence of DLTs and all available data which will be used to determine the optimal dose regimen

Secondary outcomes

  1. Measurement of Cmax

    Time frame: Through study completion, Up to 5 years

    Peak plasma concentration (Cmax)

  2. Measurement of AUCtau

    Time frame: Through study completion, Up to 5 years

    Area under the plasma concentration versus time curve (AUCtau)

  3. Objective Response Rate

    Time frame: Through study completion, Up to 5 years

    Objective response rate by RECIST 1.1 assessment of CT/MRI imaging, as modified by PCWG3 for participants with prostate cancer

  4. Progression-free Survival

    Time frame: Through study completion, Up to 5 years

    Progression-free survival by RECIST 1.1 assessment of CT/MRI imaging, as modified by PCWG3 for participants with prostate cancer

  5. Duration of Response

    Time frame: Through study completion, Up to 5 years

    Duration of Response by RECIST 1.1 assessment of CT/MRI imaging, as modified by PCWG3 for participants with prostate cancer

Sponsors and collaborators

Lead sponsor

Xencor, Inc.

Industry

Registry information

Official study title

A Phase 1, First-in-Human, Dose-Finding and Expansion Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Activity of XmAb®808 in Combination With Pembrolizumab in Selected Advanced Solid Tumors

Important dates

Study start
2022
Primary completion
2025
Study completion
2025
First posted
Oct 18, 2022
Registry last updated
Aug 7, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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