NCT06557733 · National Cancer Institute (NCI)
An Investigational Drug (TPST-1495) in Patients With Familial Adenomatous Polyposis
What this study is about
This where both patients and doctors know the treatment given phase II trial tests how well TPST-1495 works in reducing the number of polyps in the small bowel and colon in patients with familial adenomatous polyposis (FAP). FAP is an inherited condition in which numerous polyps (growths that protrude from mucous membranes) form on the inside walls of the colon and rectum.
View original scientific description
This open-label phase II trial tests how well TPST-1495 works in reducing the number of polyps in the small bowel and colon in patients with familial adenomatous polyposis (FAP). FAP is an inherited condition in which numerous polyps (growths that protrude from mucous membranes) form on the inside walls of the colon and rectum. It increases the risk for colon cancer. TPST-1495 binds to specific prostaglandin receptors.
Interventions
PROCEDURE
Biopsy Procedure
Undergo biopsy
PROCEDURE
Biospecimen Collection
Undergo blood sample collection
DRUG
EP2/EP4 Antagonist TPST-1495
Given PO
PROCEDURE
Esophagogastroduodenoscopy
Undergo EGD
PROCEDURE
Gastrointestinal Endoscopy
Undergo GI endoscopy
OTHER
Questionnaire Administration
Ancillary studies
Primary outcome measures
Percent change in duodenal polyp burden
Time frame: Baseline to 6 months
Will be determined based on the sum of diameters from all polyps. Will be assessed by comparing upper gastrointestinal (GI) endoscopies respectively. Will be described using a two-sided 95% confidence interval and examined for difference from zero with a one-side paired t-test.
Incidence of adverse events
Time frame: Up to 7 months
Will examine the proportion of patients with grade 2 or 3 adverse events according to the Common Terminology Criteria for Adverse Events version 6.0. Will be summarized as a proportion with a 1-sided 90% confidence interval.
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
- Diagnosis of familial adenomatous polyposis (FAP), defined as at least one of the following:
- Genetic diagnosis with confirmed APC mutation (clinical CLIA \[clinical laboratory improvement amendments\] certified lab or research testing)
- Obligate carrier
- Clinical diagnosis of classic FAP with ≥ 100 colorectal adenomas status post colectomy and a family history of FAP
- Clinical diagnosis of FAP, based on personal and family history. Note: This criterion requires documented review and agreement from either the study chair or the MW consortium lead investigator
- Previously underwent prophylactic colectomy with IRA (ileo-rectal anastomosis) or IPAA at least 12 months before pre-registration evaluation and without ongoing surgical complication
- Willing to discontinue taking non-steroidal anti-inflammatory drugs (NSAIDs) 5 days prior to initiation of study treatment and limit frequency of NSAID dosing during study treatment
- Age ≥ 18. Because no dosing
Where
- Phoenix, Arizona
- Rochester, Minnesota
- Salt Lake City, Utah
- Madison, Wisconsin
Related conditions & keywords
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 Jul 8, 2026 · Source of record for eligibility and locations