A Phase 3 interventional study of Dostarlimab and CAPEOX in Colonic Neoplasms and Neoplasms, Colon, sponsored by GlaxoSmithKline. Recruiting at 266 sites in 28 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-23.
Sponsored by GlaxoSmithKline · Phase 3, Interventional, and Treatment
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.
Exclusion Criteria:
Participants will receive Dostarlimab pre and post surgery
Biological: Dostarlimab
Participants will receive SOC (FOLFOX/CAPEOX) or undergo expectant observation post surgery.
Drug: CAPEOX · Drug: FOLFOX
Dostarlimab will be administered.
CAPEOX will be administered.
FOLFOX will be administered.
Event-free Survival (EFS) Assessed by Blinded Independent Central Review (BICR)
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
Time frame: Up to approximately 5 years
Overall Survival (OS)
OS is defined as time from randomization to death from any cause
Time frame: Up to approximately 5 years
Number of Participants with Pathological Response
Pathological response will be categorized as a complete pathologic response, major pathologic response, partial pathologic response, or negligible pathologic response.
Time frame: Up to approximately 5 years
Event-free Survival (EFS) assessed by local assessment
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
Time frame: Up to approximately 5 years
Number of Participants with treatment emergent adverse events (AEs), serious adverse events (SAEs), Immune-mediated Adverse Event (imAEs), AEs leading to death and AEs leading to discontinuation of study treatment
Time frame: Up to approximately 5 years
Number of Participants with AEs and SAEs by Severity
Time frame: Up to approximately 5 years
Serum Concentration of Dostarlimab
Time frame: Predose and End of Infusion (EoI) of Cycle 1 and EoI of Cycle 2 to Cycle 10 (each cycle is of 21 days)
Serum Concentration of Dostarlimab at End of Infusion (C-EoI)
Time frame: End of Infusion (EoI) of Cycle 1 to Cycle 10 (each cycle is of 21 days)
Serum Predose trough concentration (Ctrough) of Dostarlimab
Time frame: Predose of Cycle 1 to Cycle 10 (each cycle is of 21 days)
Number of Participants with Anti-Drug Antibodies against Dostarlimab
Time frame: Up to approximately 5 years
Showing the first 100 of 266 sites across 28 countries.
Plan to share: Yes — Qualified researchers may request access to anonymized individual patient-level data (IPD) and related study documents of the eligible studies via the Data Sharing Portal. Details on GSK's data sharing criteria can be found at: https://www.gsk.com/en-gb/innovation/trials/data-transparency/
Supporting information: Study protocol, Sap, Icf, Csr
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