NCT06778863 · Clasp Therapeutics, Inc.
A Study of CLSP-1025 in Adult Patients With Solid Tumors That Harbor the p53 R175H Mutation
(GUARDIAN-101)
What this study is about
Phase 1 gradually increasing doses 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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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
Where
- Scottsdale, Arizona
- Tucson, Arizona
- Los Angeles, California
- Sacramento, California
- San Francisco, California
- Miami, Florida
- Chicago, Illinois
- Lexington, Kentucky
- Baltimore, Maryland
- Hackensack, New Jersey
- New York, New York
- Durham, North Carolina
And 5 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 13, 2026 · Source of record for eligibility and locations