Neoadjuvant dostarlimab before surgery for resectable stage III pMMR/MSS colon cancer

Early Phase II Exploratory, Open-Label, Non-Randomized Study of Neoadjuvant Dostarlimab Monotherapy in Participants With Untreated T3-4N0-2 or Stage III pMMR/MSS Resectable Colon Cancer

Phase 2 Interventional Universitaire Ziekenhuizen KU Leuven · NCT06830239

This will test whether two pre-surgery infusions of the PD-1 drug dostarlimab help people with resectable stage III pMMR/MSS colon cancer.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment10 (estimated)
Ages18 Years and up
SexAll
SponsorUniversitaire Ziekenhuizen KU Leuven Academic / other
Drugs / interventionsimmunotherapy, Dostarlimab
Locations1 site (Leuven)
Trial IDNCT06830239 on ClinicalTrials.gov

What this trial studies

Adults with primary resectable cT3-4 or stage III pMMR/MSS colon adenocarcinoma will receive two 500 mg IV doses of dostarlimab given three weeks apart before planned surgery. Tumor and blood samples will be collected to study molecular changes induced by the immunotherapy. Dostarlimab is approved in Belgium for other indications but not for colon cancer, and its ability to change surgical or long-term outcomes in pMMR/MSS colon cancer is unproven. Standard surgical resection is performed after the neoadjuvant dosing per the treating team.

Who should consider this trial

Good fit: Adults with resectable primary colon adenocarcinoma staged cT3-4, cN0-2 or stage III that are MMR-proficient/MSS, who have not received prior cancer therapy and are fit for immunotherapy and surgery.

Not a fit: Patients with metastatic or non-resectable disease, prior cancer treatment, or who have a dMMR/MSI-high tumor profile are not eligible for this approach and are unlikely to benefit from this specific regimen.

Why it matters

Potential benefit: If successful, the treatment could shrink tumors before surgery and improve surgical outcomes or long-term control for some patients.

How similar studies have performed: Checkpoint inhibitors have shown clear benefit in dMMR/MSI-high colorectal cancers, but responses in pMMR/MSS colon cancer have been rare, so this approach is largely exploratory for this population.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* at least 18 years of age and capable of giving informed consent
* primary adenocarcinoma colon cancer than can be removed surgically, staged cT3-4, cN0-2, cM0 or stage III
* tumour expresses an MMR proficient/microsatellite stable called MSS
* tissue samples from tumour and colon mucosa available for molecular analyses
* capable of receiving immunotherapy
* adequate general health status and organ function (blood tests)

Exclusion Criteria:

* no prior cancer treatment
* not pregnant and using effective contraception if applicable

Where this trial is running

Leuven

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.
Conditions Colon Cancer Stage IIIColon CancerNeoadjuvantpMMR/MSSResectable
Last reviewed 2026-06-09 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.