NCT05855200 · GlaxoSmithKline
Study of Perioperative Dostarlimab in Participants With Untreated T4N0 or Stage III dMMR/MSI-H Resectable Colon Cancer
What this study is about
The primary purpose of this study is to evaluate the effectiveness of perioperative dostarlimab compared with the usual treatment (SOC) in participants with untreated T4N0 or Stage III (resectable), defective mismatch repair/ microsatellite instability high (dMMR/MSI-H) colon cancer.
View original scientific description
The primary purpose of this study is to evaluate the efficacy of perioperative dostarlimab compared with standard of care (SOC) in participants with untreated T4N0 or Stage III (resectable), defective mismatch repair/ microsatellite instability high (dMMR/MSI-H) colon cancer.
Interventions
BIOLOGICAL
Dostarlimab
Dostarlimab will be administered.
DRUG
CAPEOX
CAPEOX will be administered.
DRUG
FOLFOX
FOLFOX will be administered.
Primary outcome measures
Event-free Survival (EFS) Assessed by Blinded Independent Central Review (BICR)
Time frame: Up to approximately 5 years
EFS is defined as the time from randomization to either disease recurrence or death due to any cause or treatment related toxicity that results in the participant not being suitable for surgery
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
- Has untreated pathologically confirmed colon adenocarcinoma
- Has resectable colon adenocarcinoma defined as clinically T4N0 or Stage III
- Has radiologically evaluable disease
- Has a tumor demonstrating the presence of either dMMR status or MSI-H
Exclusion criteria
- Has distant metastatic disease.
- Has received prior medical therapy (chemotherapy, immunotherapy, biologic, or targeted therapy), radiation therapy or surgery for management of the current diagnosis of colon cancer
- Has a tumor that, in the investigator's judgment is causing symptomatic bowel obstruction or otherwise requires urgent/emergent surgery at the time of screening. Participants with a history of colonic obstruction are eligible after obstruction is relieved by a diverting stoma (defunctioning ileostomy or colostomy). Patients with a history of colonic obstruction in the context of current colon cancer diagnosis and treated with colonic stents are not eligible.
- Has undergone any maj
Where
- Tucson, Arizona
- Los Angeles, California
- New Haven, Connecticut
- Washington D.C., District of Columbia
- Deerfield Beach, Florida
- Fort Lauderdale, Florida
- Marietta, Georgia
- Chicago, Illinois
- Naperville, Illinois
- Westwood, Kansas
- Lexington, Kentucky
- Louisville, Kentucky
And 22 more locations — see the full list below.
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 Jan 23, 2026 · Source of record for eligibility and locations