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

ClinicalTrials.gov ID

NCT06778863

Lead Sponsor

Clasp Therapeutics, Inc.INDUSTRY

Overall Status

Recruiting

Study Type

Interventional

Phase

Phase 1

Enrollment

90Estimated

Last Update Posted

Feb 13, 2026Actual

Start Date

Feb 28, 2025Actual

Primary Completion Date

Dec 2027Estimated

Completion Date

Jun 2028Estimated

Official Title

GUARDIAN-101: A Phase 1 Dose Escalation and Expansion Study of CLSP-1025 in Adult Patients With Solid Tumors That Harbor the p53 R175H Mutation

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.

Detailed Description

This Phase 1, open-label, multicenter study is designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary clinical activity of CLSP-1025 when administered to HLA-A*02:01-positive adult patients with advanced solid tumors that harbor the p53 R175H mutation. The study will be conducted in 2 parts: Part A Monotherapy Dose Escalation to determine the recommended dose(s) for expansion (RDE[s]) and Part B Monotherapy Expansion to explore the preliminary antitumor activity as well as further characterize the safety, tolerability, PK, and PD of CLSP-1025 at the RDE(s).

• 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

• CLSP-1025

Ages Eligible for Study

Adult (18-64)Older Adult (65+)

Sexes Eligible for Study

All

Accepts Healthy Volunteers

No

Eligibility Criteria

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

Primary Purpose

Treatment

Allocation

Non-Randomized

Interventional Model

Sequential Assignment

Masking

None (Open Label)

Lead Sponsor

Clasp Therapeutics, Inc.INDUSTRY

212-263-4432

888-989-5374

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