A Study of CLSP-1025 in Adult Patients With Solid Tumors That Harbor the p53 R175H Mutation

NCT06778863 | Recruiting Phase 1 FDA Drug

• 1 other identifier: CLSP-1025-101
• Study Type: interventional
• Target: 90
• Locations: 1 country
• Sites: 21

Brief Summary

Phase 1 dose escalation and expansion study of CLSP-1025, a first-in-class HLA-A\*02:01 specific T cell engager (TCE) targeting solid tumors that harbor the p53 R175H mutation.

Conditions

Advanced Solid Tumor; Unresectable Solid Tumor; Metastatic Solid Tumor; Colorectal Adenocarcinoma; Pancreatic Adenocarcinoma; Lung Cancer; Ovarian Cancer; Breast Cancer; Head and Neck Squamous Cell Carcinoma; Prostate Cancer; Bladder Cancer

Keywords

CLSP-1025; T Cell Engager; TCE; TP53

Outcome Measures

Primary Outcomes (2)

• Part A: Determine the maximum tolerated dose (MTD) and/or the recommended dose(s) for expansion (RDE[s])

  Rate of dose-limiting toxicities (DLTs) after infusion of CLSP-1025

  28 days after infusion

• Part B: Evaluate the Objective response rate (ORR) of CLSP-1025 as a monotherapy in HLA-selected patients with advanced solid tumors that express the p53 R175H mutation

  Objective response rate (ORR) per RECIST V1.1 determined by Investigator assessment

  Up to 24 months after infusion

Secondary Outcomes (15)

• Number of patients with treatment-emergent adverse events, as assessed by CTCAE, v5.0

  Up to 24 months after infusion

• Number of patients with treatment-related adverse events, as assessed by CTCAE, v5.0

  Up to 24 months after infusion

• Number of patients with clinically significant changes in QTcF Interval

  Up to 24 months after infusion

• Maximum plasma concentration (Cmax) of CLSP-1025

  Pre-dose and up to 168 hours post-dose

• Minimum plasma concentration (Cmin) of CLSP-1025

  Pre-dose and up to 168 hours post-dose

Study Arms (2)

Part A: Monotherapy Dose Escalation of CLSP-1025

EXPERIMENTAL

Dose escalation of CLSP-1025 in HLA-A\*02:01-positive adult patients with advanced solid tumors that harbor the p53 R175H mutation

Drug: CLSP-1025

Part B: Monotherapy Dose Expansion of CLSP-1025

EXPERIMENTAL

Dose expansion of CLSP-1025 in HLA-A\*02:01-positive adult patients with advanced solid tumors that harbor the p53 R175H mutation

Drug: CLSP-1025

Interventions

CLSP-1025 DRUG

CLSP-1025 will be administered by IV infusion

Part A: Monotherapy Dose Escalation of CLSP-1025; Part B: Monotherapy Dose Expansion of CLSP-1025

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients must be at least 18 years of age at the time of signing the informed consent.
• Patients must be willing and able to provide written informed consent
• Patients must have locally advanced or metastatic solid tumors that have progressed after standard of care therapy or for which no standard therapy exists
• Tumors must harbor a TP53 R175H variant mutation confirmed by an accredited laboratory-based test
• Patients must be HLA-A\*02:01 positive by central assay
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at the time of enrollment
• Adequate hematological, renal and hepatic function
• Per Investigator judgement, patient is willing and able to complete study visits and/or procedures per the protocol and comply with study requirements for study participation

You may not qualify if:

• Patients with Li-Fraumeni syndrome or other known germline p53 R175H mutation
• Patients who have received other p53 R175H-directed therapies
• Patients who have not fully recovered from adverse events due to previous anticancer therapies
• Patients with active infection requiring systemic antimicrobial therapy
• Any other primary malignancy within the 2 years prior to enrollment (except for non- melanoma skin cancer, carcinoma in situ (eg, cervix, bladder, breast) or prostate cancer in remission.
• Known active central nervous system metastases and/or carcinomatous meningitis

Sponsors & Collaborators

• Clasp Therapeutics, Inc.: lead

Study Sites (21)

HonorHealth Research Institute

Scottsdale, Arizona, 85258, United States

RECRUITING

The University of Arizona Cancer Center

Tucson, Arizona, 85719, United States

RECRUITING

USC - Norris Comprehensive Cancer Center

Los Angeles, California, 90033, United States

RECRUITING

University of California Davis Comprehensive Cancer Center

Sacramento, California, 95817, United States

RECRUITING

University of California San Francisco

San Francisco, California, 94143, United States

RECRUITING

University of Miami - Sylvester Comprehensive Cancer Center

Miami, Florida, 33136, United States

RECRUITING

The University of Chicago Comprehensive Cancer Center

Chicago, Illinois, 60637, United States

RECRUITING

University of Kentucky Markey Cancer Center

Lexington, Kentucky, 40536, United States

RECRUITING

Johns Hopkins - Sidney Kimmel Comprehensive Cancer Center

Baltimore, Maryland, 21287, United States

RECRUITING

Hackensack University Medical Center

Hackensack, New Jersey, 07601, United States

RECRUITING

NYU Langone Health

New York, New York, 10016, United States

RECRUITING

Memorial Sloan Kettering Cancer Center

New York, New York, 10065, United States

RECRUITING

Duke Cancer Institute

Durham, North Carolina, 27701, United States

RECRUITING

Thomas Jefferson University, Sidney Kimmel Cancer Center

Philadelphia, Pennsylvania, 19107, United States

RECRUITING

Fox Chase Cancer Center

Philadelphia, Pennsylvania, 19111, United States

RECRUITING

Sarah Cannon Research Institute (SCRI) Oncology Partners

Nashville, Tennessee, 37203, United States

RECRUITING

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

RECRUITING

Mary Crowley Cancer Research

Dallas, Texas, 75230, United States

RECRUITING

Baylor University Medical Center

Dallas, Texas, 75246, United States

RECRUITING

MD Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

Fred Hutchinson Cancer Center

Seattle, Washington, 98109, United States

RECRUITING

MeSH Terms

Conditions

Neoplasm Metastasis; Lung Neoplasms; Ovarian Neoplasms; Breast Neoplasms; Squamous Cell Carcinoma of Head and Neck; Prostatic Neoplasms; Urinary Bladder Neoplasms

Condition Hierarchy (Ancestors)

Neoplastic Processes; Neoplasms; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Respiratory Tract Neoplasms; Thoracic Neoplasms; Neoplasms by Site; Lung Diseases; Respiratory Tract Diseases; Endocrine Gland Neoplasms; Ovarian Diseases; Adnexal Diseases; Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Neoplasms, Female; Urogenital Neoplasms; Genital Diseases; Endocrine System Diseases; Gonadal Disorders; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases; Carcinoma, Squamous Cell; Carcinoma; Neoplasms, Glandular and Epithelial; Neoplasms by Histologic Type; Head and Neck Neoplasms; Genital Neoplasms, Male; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Urologic Neoplasms; Urinary Bladder Diseases; Urologic Diseases

Central Study Contacts

Lauren Harshman, MD

CONTACT

+1-617-812-1431; LHarshman@clasptx.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 8, 2025
• First Posted: January 16, 2025
• Study Start: February 28, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): June 1, 2028
• Last Updated: February 13, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (21)