Study of Perioperative Dostarlimab in Participants With Untreated T4N0 or Stage III dMMR/MSI-H Resectable Colon Cancer

Phase 3

Recruiting

• Conditions: Neoplasms, Colon; Colonic Neoplasms
• Interventions: Drug: CAPEOX; Biological: Dostarlimab; Drug: FOLFOX

• Registration Number: NCT05855200
• Lead Sponsor: GlaxoSmithKline

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-05-03
• Study First Submitted QC: 2023-05-03
• Study First Posted: 2023-05-11
• Study Start: 2023-08-01
• Status Verified: 2025-08
• Last Update Submitted: 2025-08-07
• Last Update Posted: 2025-08-08
• Primary Completion: 2029-03-19
• Study Completion: 2031-03-27

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 811

Inclusion Criteria

• Has untreated pathologically confirmed colon adenocarcinoma
• Has resectable colon adenocarcinoma defined as clinically T4N0 or Stage III
• Has radiologically evaluable disease
• Has a tumor demonstrating the presence of either dMMR status or MSI-H

Exclusion Criteria

• Has distant metastatic disease.
• Has received prior medical therapy (chemotherapy, immunotherapy, biologic, or targeted therapy), radiation therapy or surgery for management of the current diagnosis of colon cancer
• Has a tumor that, in the investigator's judgment is causing symptomatic bowel obstruction or otherwise requires urgent/emergent surgery at the time of screening. Participants with a history of colonic obstruction are eligible after obstruction is relieved by a diverting stoma (defunctioning ileostomy or colostomy). Patients with a history of colonic obstruction in the context of current colon cancer diagnosis and treated with colonic stents are not eligible.
• Has undergone any major surgical procedure, open biopsy, or experienced significant traumatic injury within 28 days prior to randomization
• Has any history of interstitial lung disease or pneumonitis and/or history of radiation induced enteritis.
• Has cirrhosis or current unstable liver or biliary disease per investigator assessment defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminemia, esophageal/gastric varices, or persistent jaundice
• Has a history of allogenic stem cell transplantation or organ transplantation
• Is receiving any other anticancer or experimental therapy. No other experimental therapies (including but not limited to chemotherapy, radiation, hormonal treatment, antibody therapy, immunotherapy, gene therapy, vaccine therapy, or other experimental drugs) of any kind are permitted while the participant is receiving study intervention
• Is pregnant, breastfeeding, or expecting to conceive children within the projected duration of the study
• 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 FOLFOX or CAPEOX

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Standard of Care (SOC)	CAPEOX	Participants will receive SOC (FOLFOX/CAPEOX) or undergo expectant observation post surgery.
Standard of Care (SOC)	FOLFOX	Participants will receive SOC (FOLFOX/CAPEOX) or undergo expectant observation post surgery.
Dostarlimab	Dostarlimab	Participants will receive Dostarlimab pre and post surgery

Primary Outcome Measures

Name	Time	Method
Event-free Survival (EFS) Assessed by Blinded Independent Central Review (BICR)	Up to approximately 5 years	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

Secondary Outcome Measures

Name	Time	Method
Number of Participants with Pathological Response	Up to approximately 5 years	Pathological response will be categorized as a complete pathologic response, major pathologic response, partial pathologic response, or negligible pathologic response.
Number of Participants with Anti-Drug Antibodies against Dostarlimab	Up to approximately 5 years
Overall Survival (OS)	Up to approximately 5 years	OS is defined as time from randomization to death from any cause
Event-free Survival (EFS) assessed by local assessment	Up to approximately 5 years	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
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	Up to approximately 5 years
Number of Participants with AEs and SAEs by Severity	Up to approximately 5 years
Serum Concentration of Dostarlimab	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)	End of Infusion (EoI) of Cycle 1 to Cycle 10 (each cycle is of 21 days)
Serum Predose trough concentration (Ctrough) of Dostarlimab	Predose of Cycle 1 to Cycle 10 (each cycle is of 21 days)

Trial Locations

Locations (1)

GSK Investigational Site; 🇬🇧 Sutton, United Kingdom