Home › Trials › NCT06567782

Testing a new treatment for colon cancer using dostarlimab and chemotherapy

A Phase 2, Open Label, Randomized Study of Neoadjuvant Dostarlimab Plus CAPEOX Versus CAPEOX in Participants With Previously Untreated T4N0 or Stage III MMRp/ MSS Colon Cancer

Phase 2 Interventional GlaxoSmithKline · NCT06567782

This study is testing if combining a new drug called dostarlimab with chemotherapy can help people with certain types of colon cancer do better before surgery.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment120 (estimated)
Ages18 Years and up
SexAll
SponsorGlaxoSmithKline Industry-sponsored
Drugs / interventionsdostarlimab, chemotherapy, immunotherapy, radiation
Locations33 sites (Aalst and 32 other locations)
Trial IDNCT06567782 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate the effectiveness of combining dostarlimab with the chemotherapy regimen CAPEOX (capecitabine and oxaliplatin) as a neoadjuvant treatment for patients with untreated T4N0 or Stage III mismatch repair proficient/microsatellite stable (MMRp/MSS) colon cancer. Participants will receive this combination therapy before any surgical intervention, with the goal of determining if it leads to better outcomes compared to CAPEOX alone. The study will also assess specific biomarkers in blood and tumor samples to predict treatment response and enhance understanding of dostarlimab's role in the therapeutic process.

Who should consider this trial

Good fit: Ideal candidates include individuals with untreated, resectable colon adenocarcinoma classified as T4N0 or Stage III with MMRp/MSS status.

Not a fit: Patients with non-resectable colon cancer or those with mismatch repair deficient (dMMR) tumors may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could improve outcomes for patients with a specific type of colon cancer by enhancing the effectiveness of chemotherapy.

How similar studies have performed: While the combination of immunotherapy and chemotherapy is being explored in various cancers, this specific approach for MMRp/MSS colon cancer is relatively novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Has untreated pathologically confirmed colon adenocarcinoma
* Has resectable colon adenocarcinoma defined as clinically T4N0 or Stage III
* Has a tumor demonstrating the presence of either-

  1. MMR status: MMR status must be assessed by Immunohistochemistry (IHC) for MMR protein expression (MLH1, MSH2, MSH6, PMS2) where all proteins are present indicates MMRp; MMR status may be determined local laboratory; or
  2. MSS or Microsatellite Instability-L (MSI-L) phenotype as determined by polymerase chain reaction (PCR) or by tissue next generation sequencing (NGS), determined by local laboratory
* Provides fresh tumor tissue obtained during either the pre-screening or screening period via colonoscopy performed per procedure manual. Tissue biopsy is required
* Is willing to use adequate contraception male and/or female participants
* Has an Eastern Cooperative Oncology Group - Performance status (ECOG-PS) of 0 or 1
* Has adequate organ function

Exclusion Criteria:

* Has distant metastatic disease
* Has received prior medical therapy (chemotherapy, immunotherapy, biologic, or targeted therapy), radiation therapy or surgery for management of colon cancer
* Has, in the investigator's opinion, a tumor that is not amenable to surgery or has any other contraindication to surgery
* Has experienced any of the following with prior immunotherapy: any imAE ≥ Grade 3, immune-mediated severe neurologic events of any-grade (e.g., myasthenic syndrome/myasthenia gravis, encephalitis, Guillain Barré Syndrome, or transverse myelitis), exfoliative dermatitis of any grade \[Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), or Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome\], or myocarditis of any grade. Non-clinically significant laboratory abnormalities are not exclusionary
* Has any history of interstitial lung disease or immune-related pneumonitis
* Has a history or current evidence of any medical condition, therapy, or laboratory abnormality that might confound the study results, interfere with their participation for the full duration of the study intervention, or indicate it is not in the best interest of the participant to participate, in the opinion of the investigator
* Is considered, in investigator's opinion, a poor medical risk due to a serious, uncontrolled medical disorder, non-malignant systemic disease, or active infection requiring systemic therapy
* Has received treatment with an investigational agent within \[4 weeks\] of the first dose of study intervention
* Is pregnant or breastfeeding
* Has a history of severe allergic and/or anaphylactic reactions to chimeric, human, or humanized antibodies, fusion proteins, or known allergies to dostarlimab, or its excipients, or any components of CAPEOX

Where this trial is running

Aalst and 32 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Neoplasms, ColonColon cancerMMRpMSSDostarlimabCAPEOXNeoadjuvantGSK4057190A
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.