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Study of XELOX chemotherapy with or without dostarlimab after chemoradiation in patients with locally advanced rectal cancer

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What is this trial about?

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

This study focuses on patients with Locally Advanced Rectal Cancer (LARC) who have specific genetic characteristics described as pMMR/MSS or MSI-Low. The study compares two different treatment approaches after patients have completed standard chemoradiation therapy. Both treatment groups will receive XELOX, which is a combination of chemotherapy medications, but one group will also receive an additional medication called dostarlimab (also known as JEMPERLI).

The purpose of this research is to determine how well patients respond to treatment by examining whether there are any remaining cancer cells after the therapy is completed. Dostarlimab is given through an intravenous infusion, which means it is delivered directly into the bloodstream through a vein. The medication belongs to a group of drugs that help the body's immune system fight cancer cells.

During the study, patients will receive treatment for up to 60 months. The treatment includes regular medical check-ups to monitor the patient's health and response to therapy. Doctors will use various imaging techniques to check how well the treatment is working and to ensure the safety of the participants. The effectiveness of the treatment will be evaluated both through physical examinations and imaging tests.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment phase

    You will receive standard chemoradiation therapy as the first phase of treatment

    After completing chemoradiation, you will be randomly assigned to one of two treatment groups

  2. Step 2

    Consolidation treatment - Group assignment

    Group A: You will receive XELOX plus dostarlimab treatment

    Group B: You will receive XELOX alone treatment

    The treatment you receive will be determined randomly

  3. Step 3

    Response evaluation at 12 months

    Your response to treatment will be evaluated 12 months after completing consolidation therapy

    The evaluation includes digital and endoscopic examination of the rectum

    An MRI scan will be performed to check for any remaining disease

  4. Step 4

    Long-term monitoring

    Your condition will be monitored at 24 and 36 months

    Regular examinations will continue to check for any signs of disease

    Quality of life assessments will be conducted using questionnaires

    Blood samples will be collected to monitor treatment effectiveness

  5. Step 5

    Safety monitoring

    Throughout the study, you will be monitored for any side effects

    Regular laboratory tests will be performed to ensure your safety

    Any adverse events will be recorded and evaluated

Who can join the trial?

17 criteria

  • Must have confirmed rectal cancer (adenocarcinoma) located less than 16 cm from the anal opening
  • Must be at least 18 years old
  • Must provide written informed consent to participate
  • Must have cancer that has not spread beyond local lymph nodes (specific staging criteria apply)
  • Must have a specific type of tumor known as pMMR/MSS or MSI-Low (relates to how the tumor cells repair DNA damage)
  • Must be able to perform daily activities independently or with minimal assistance (ECOG Performance Status 0-1)
  • Must not have received any previous chemotherapy or radiation therapy
  • Must not have received any previous immunotherapy treatments (except cancer vaccines)
  • Must have adequate blood test results, including:
    • White blood cells above 1,500/mL
    • Platelets above 100,000/mL
    • Hemoglobin above 9.0 g/dL
    • Liver and kidney function within specified limits
    • Must have acceptable blood clotting test results. Patients taking blood thinners (warfarin) must have stable dosing
    • For women who can become pregnant:
      • Must not be pregnant or breastfeeding
      • Must use highly effective birth control
      • Must have a negative pregnancy test before starting the study
      • Must agree not to donate eggs during the study and for 120 days after

Who cannot join the trial?

12 criteria

  • Known hypersensitivity (severe allergic reactions) to any of the study medications
  • Active or untreated brain metastases (cancer that has spread to the brain)
  • Previous treatment with immune checkpoint inhibitors
  • Active autoimmune disease (condition where immune system attacks healthy cells) requiring systemic treatment
  • Uncontrolled or significant heart disease
  • Active infection requiring treatment, including hepatitis B, hepatitis C, or HIV
  • Other malignancies (cancers) within the past 3 years, except for adequately treated non-melanoma skin cancer or carcinoma in situ
  • Pregnant or breastfeeding women
  • Immunodeficiency (weakened immune system) or using immunosuppressive medications
  • Psychiatric or substance abuse disorders that could interfere with study participation
  • Any condition that, in the investigator's opinion, makes the patient unsuitable for the study
  • Unable to understand or provide informed consent
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Investigated drugs

Dostarlimab is a type of immunotherapy medication that helps your immune system fight cancer cells. It works by blocking a protein that cancer cells use to hide from the immune system, allowing your body's natural defenses to better recognize and attack the cancer. XELOX is a combination chemotherapy treatment that consists of two medications: capecitabine (taken as pills) and oxaliplatin (given through an IV). This combination works together to kill cancer cells and prevent them from growing and spreading. Note: The trial compares these treatments in patients with locally advanced rectal cancer, using them after standard chemoradiation therapy. One group receives both XELOX and dostarlimab, while the other group receives only XELOX.

What is already known about the treatment

  • Dostarlimab

    A monoclonal antibody medication administered through intravenous infusion that works by blocking PD-1 (programmed cell death protein 1) receptors on immune cells, helping the immune system recognize and attack cancer cells. It is currently being investigated in clinical trials for locally advanced rectal cancer (LARC), particularly in patients with specific molecular characteristics (pMMR/MSS or MSI-Low). This immunotherapy agent belongs to the class of immune checkpoint inhibitors and represents a novel approach in combination with standard chemotherapy for treating colorectal cancers.

  • XELOX

    A chemotherapy combination regimen consisting of capecitabine (Xeloda) taken orally and oxaliplatin administered intravenously, commonly used in the treatment of colorectal cancers. This combination works by interfering with cancer cell DNA replication and division, with capecitabine converting to 5-fluorouracil in the body while oxaliplatin forms platinum-DNA adducts. The regimen belongs to the class of antineoplastic combinations and is well-established in clinical practice for treating various stages of colorectal cancer, including locally advanced rectal cancer.

Investigated diseases

Locally Advanced Rectal Cancer (LARC) - A form of rectal cancer where the tumor has grown through the wall of the rectum and may have spread to nearby tissues or lymph nodes, but has not spread to distant parts of the body. The disease develops in the last part of the large intestine, specifically in the rectum. It typically progresses from early-stage cancer confined to the rectum wall to a more advanced state where it extends beyond the rectal wall. This condition can affect the normal functioning of the bowel and may cause changes in bowel habits. The cancer can be characterized by different molecular features, including MMR (mismatch repair) and MSI (microsatellite instability) status, which influence its biological behavior.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519798-20-00Protocol codeGOIRC-02-2024Estimated enrolment270 patientsSponsorGOIRC Gruppo Oncologico Italiano Di Ricerca Clinica

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).