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Study Comparing Dostarlimab with CAPEOX and CAPEOX Alone for Patients with Untreated Stage III Colon Cancer

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a type of colon cancer known as Stage III MMRp/MSS colon cancer. The study is investigating the effectiveness and safety of a treatment that combines two medications: dostarlimab and CAPEOX. Dostarlimab is a medication that helps the immune system fight cancer, and it is also known by the code names WBP-285 and TSR-042. CAPEOX is a combination of two chemotherapy drugs, capecitabine and oxaliplatin, which are used to kill cancer cells. The purpose of the study is to compare the effects of using dostarlimab with CAPEOX against using CAPEOX alone in patients who have not received any previous treatment for their cancer.

Participants in the study will be randomly assigned to receive either the combination of dostarlimab and CAPEOX or CAPEOX alone. The study will last for a period of up to 12 months, during which participants will receive their assigned treatment. The treatments will be administered either orally, in the form of tablets, or intravenously, which means through a vein. Throughout the study, participants will be closely monitored to assess how well the treatment is working and to check for any side effects. Some participants may receive a placebo, which is a substance with no active medication, to help compare the effects of the actual treatment.

The study aims to provide valuable information on whether adding dostarlimab to the standard CAPEOX treatment can improve outcomes for patients with Stage III MMRp/MSS colon cancer. By participating in this study, researchers hope to find more effective ways to treat this type of cancer and improve the quality of life for those affected. The results of this study could lead to new treatment options for patients in the future.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes reviewing medical history and performing necessary tests to ensure the presence of colon cancer that is suitable for the study.

  2. Step 2

    Treatment group assignment

    Participants are randomly assigned to one of two treatment groups. One group receives a combination of dostarlimab and CAPEOX, while the other group receives only CAPEOX. CAPEOX is a combination of capecitabine and oxaliplatin.

  3. Step 3

    Medication administration

    For those receiving dostarlimab, it is administered as an intravenous infusion. Capecitabine is taken orally in the form of film-coated tablets. Oxaliplatin is also administered intravenously as a solution for infusion.

  4. Step 4

    Treatment schedule

    The treatment is administered over a specified period, with regular intervals for medication intake. The exact dosage and frequency are determined by the study protocol and the medical team overseeing the trial.

  5. Step 5

    Monitoring and follow-up

    Throughout the trial, participants undergo regular monitoring to assess the effectiveness and safety of the treatment. This includes routine check-ups, imaging tests, and laboratory assessments.

  6. Step 6

    Completion of treatment

    Upon completion of the treatment phase, a final assessment is conducted to evaluate the response to the therapy. This includes determining the extent of any pathological response and any side effects experienced during the trial.

Who can join the trial?

10 criteria

  • The participant must be at least 18 years old or the legal age of consent in the area where the study is conducted.
  • The participant must have a type of colon cancer called **adenocarcinoma** that has not been treated yet. Adenocarcinoma is a common type of cancer that starts in glandular cells.
  • The cancer must be **resectable**, meaning it can be removed by surgery, and classified as **clinically T4N0** or **Stage III**. These terms describe the size and spread of the cancer.
  • The tumor must show specific characteristics:
    • **MMR status**: This involves checking for certain proteins (MLH1, MSH2, MSH6, PMS2) in the tumor. If all are present, it indicates **MMRp**. This is done using a test called **IHC** (immunohistochemistry).
    • Alternatively, the tumor can have an **MSS** or **MSI-L** phenotype, determined by tests like **PCR** (polymerase chain reaction) or **NGS** (next-generation sequencing).
    • The participant must provide a fresh sample of the tumor tissue, obtained during a procedure called a **colonoscopy**.
    • The participant must agree to use effective birth control methods if they are of childbearing potential, to prevent pregnancy during the study and for a specified time after.
    • The participant must be able to give informed consent, meaning they understand the study and agree to participate.
    • The participant must have an **ECOG-PS** of 0 or 1. This is a scale that measures how well a person can perform daily activities, with 0 being fully active and 1 being restricted in physically strenuous activity but able to carry out light work.
    • The participant must have adequate organ function, as defined in the study protocol.

Who cannot join the trial?

4 criteria

  • Patients with a different type of colon cancer than the one being studied cannot participate.
  • Patients who are not in the specific stages of colon cancer being studied (T4N0 or Stage III) cannot participate.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who are part of a vulnerable population, which means they might need special protection, cannot participate.
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Investigated drugs

  • Dostarlimab

    is a medication used in this trial to help the body's immune system fight cancer cells. It is being tested to see if it can improve the treatment outcomes for patients with certain types of colon cancer when used before surgery.

  • CAPEOX

    is a combination of two chemotherapy drugs, capecitabine and oxaliplatin. This combination is used to treat colon cancer by killing cancer cells and stopping them from growing and spreading. In this trial, CAPEOX is used both alone and in combination with dostarlimab to compare their effectiveness.

What is already known about the treatment

Dostarlimab – Dostarlimab is administered intravenously and is currently being studied in clinical trials for its effectiveness in treating certain types of colon cancer, specifically MMRp/MSS colon cancer. It is an investigational medication, meaning it is not yet approved for general medical use but is being evaluated for its potential benefits and safety. The main therapeutic indication for dostarlimab in this trial is as a neoadjuvant treatment, which means it is given before the main treatment to shrink a tumor. At the molecular level, dostarlimab works by blocking a protein called PD-1, which helps the immune system recognize and attack cancer cells. It is classified as an immune checkpoint inhibitor, a type of drug that helps the body's immune system fight cancer.

Investigated diseases

Colon Cancer – Colon cancer is a type of cancer that begins in the large intestine, which is part of the digestive system. It often starts as small, noncancerous clumps of cells called polyps that form on the inside of the colon. Over time, some of these polyps can become cancerous. The disease can progress through various stages, starting from localized growths to spreading to nearby lymph nodes and other organs. Symptoms may include changes in bowel habits, blood in the stool, and abdominal discomfort. Early stages may not present noticeable symptoms, making regular screenings important for detection.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-513441-36-00Protocol code222892Estimated enrolment187 patientsSponsorGlaxosmithkline Research & Development Limited

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