Recruiting

Phase 1

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

Sponsor:

Clasp Therapeutics, Inc.

Code:

NCT06778863

Conditions

Advanced Solid Tumor

Unresectable Solid Tumor

Metastatic Solid Tumor

Colorectal Adenocarcinoma

Pancreatic Adenocarcinoma

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

CLSP-1025

Study Details

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

Study ID

NCT06778863

Start date

Feb 28, 2025

Status verified date

Feb, 2026

Completion date

Jun, 2028

Anticipated

Primary completion date

Dec, 2027

Anticipated

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Key Inclusion Criteria:

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

Key Exclusion Criteria:

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

Study Design

Enrollment

90 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Part A: Monotherapy Dose Escalation of CLSP-1025

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

experimental: Part B: Monotherapy Dose Expansion of CLSP-1025

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

Interventions

CLSP-1025

CLSP-1025 will be administered by IV infusion

Primary outcome measure

Part A: Determine the maximum tolerated dose (MTD) and/or the recommended dose(s) for expansion (RDE[s]) [ Time Frame: 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 [ Time Frame: Up to 24 months after infusion ]

Central Contacts and Locations

Central contacts

Lauren Harshman, MD

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

Locations

HonorHealth Research Institute

Recruiting

Scottsdale, Arizona, United States, 85258

Contacts

833-354-6667

The University of Arizona Cancer Center

Recruiting

Tucson, Arizona, United States, 85719

Contacts

UACC-ClinicalTrialsInfo@arizona.edu

USC - Norris Comprehensive Cancer Center

Recruiting

Los Angeles, California, United States, 90033

Contacts

323-865-0451 clinical.trials@med.usc.edu

University of California Davis Comprehensive Cancer Center

Recruiting

Sacramento, California, United States, 95817

Contacts

916-703-5558

University of California San Francisco

Recruiting

San Francisco, California, United States, 94143

Contacts

hdfccc.cip@ucsf.edu

University of Miami - Sylvester Comprehensive Cancer Center

Recruiting

Miami, Florida, United States, 33136

Contacts

407-765-9589

The University of Chicago Comprehensive Cancer Center

Recruiting

Chicago, Illinois, United States, 60637

Contacts

855-403-0533

University of Kentucky Markey Cancer Center

Recruiting

Lexington, Kentucky, United States, 40536

Contacts

859-257-4488

Johns Hopkins - Sidney Kimmel Comprehensive Cancer Center

Recruiting

Baltimore, Maryland, United States, 21287

Contacts

410-955-8964

Hackensack University Medical Center

Recruiting

Hackensack, New Jersey, United States, 07601

Contacts

Oncology Clinical Research Referral Office

551-996-1777 OncologyResearchReferral@hmhn.org

NYU Langone Health

Recruiting

New York, New York, United States, 10016

Contacts

212-263-4432

Memorial Sloan Kettering Cancer Center

Recruiting

New York, New York, United States, 10065

Contacts

646-608-4042

Duke Cancer Institute

Recruiting

Durham, North Carolina, United States, 27701

Contacts

866-385-3123

Thomas Jefferson University, Sidney Kimmel Cancer Center

Recruiting

Philadelphia, Pennsylvania, United States, 19107

Contacts

Aliya Rogers

axr028@jefferson.edu

Fox Chase Cancer Center

Recruiting

Philadelphia, Pennsylvania, United States, 19111

Contacts

215-214-1515

Sarah Cannon Research Institute (SCRI) Oncology Partners

Recruiting

Nashville, Tennessee, United States, 37203

Contacts

615-329-7640

Vanderbilt University Medical Center

Recruiting

Nashville, Tennessee, United States, 37232

Contacts

615-936-8422

Mary Crowley Cancer Research

Recruiting

Dallas, Texas, United States, 75230

Contacts

972-566-3000

Baylor University Medical Center

Recruiting

Dallas, Texas, United States, 75246

Contacts

888-507-3732

MD Anderson Cancer Center

Recruiting

Houston, Texas, United States, 77030

Contacts

888-989-5374

Fred Hutchinson Cancer Center

Recruiting

Seattle, Washington, United States, 98109

Contacts

855-557-0555

More Information

Sponsor

Clasp Therapeutics, Inc.

Last update posted

Feb 13, 2026

Last verified

Feb, 2026

Keywords

CLSP-1025
T Cell Engager
TCE
TP53

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Clasp Therapeutics, Inc. on 2026-02-13.