Sintilimab Combined With LCCRT Followed by Capeox Chemotherapy in pMMR/MSS/MSI-L Locally Advanced Rectal Cancer

October 30, 2026 updated by: Innovent Biologics (Suzhou) Co. Ltd.

Sintilimab Combined With Long-Course Concurrent Chemoradiotherapy Followed by Capeox Consolidation Chemotherapy vs. Long-Course Concurrent Chemoradiotherapy Followed by Capeox Consolidation Chemotherapy for Total Neoadjuvant Therapy in Patients With Mismatch Repair-Proficient (pMMR) or Microsatellite Stable/Low Microsatellite Instability (MSS/MSI-L) Locally Advanced Rectal Cancer: A Multicenter, Randomized, Double-Blind, Controlled Phase III Study

This is a randomized, double-blind, controlled, Phase III clinical study to evaluate the efficacy and safety of sintilimab combined with long-course concurrent chemoradiotherapy followed by Capeox consolidation chemotherapy, which is planned to enroll 500 subjects with locally advanced rectal cancer.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

500

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

    • Guangdong
      • Guangzhou, Guangdong, China, 510060
        • Sun Yat sen University Cancer Center
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria

  1. Has signed the written Informed Consent Form and is capable of complying with the visit schedules and relevant procedures specified in the protocol.
  2. Histopathologically confirmed locally advanced rectal adenocarcinoma, with clinical stage cT3-4NanyM0 or cT1-2N1-2M0 as defined by the AJCC 8th edition, and assessed as amenable to R0 resection after neoadjuvant therapy. MRI demonstrates that the lower edge of the tumor is within 10 cm from the anal verge.
  3. Tumor pathological tissue testing confirms pMMR, i.e., immunohistochemical staining shows positive expression of all four proteins MLH1, MSH2, MSH6, and PMS2, or tumor tissue-based genetic testing indicates MSI-L or MSS.
  4. No signs of intestinal obstruction; or intestinal obstruction that has been relieved after proximal colostomy.
  5. No prior rectal surgery; no prior systemic anti-cancer therapy, or other investigational drug therapy.
  6. Age ≥18 years, both sexes eligible.
  7. Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1.
  8. Expected survival of ≥2 years.
  9. Adequate bone marrow and organ function. Exclusion Criteria

1. Currently participating in another interventional clinical study, except for observational (non-interventional) clinical studies or those in the survival follow-up phase of an interventional study.

2. Plans to receive other anti-tumor therapy during the treatment period of this study.

3. Receipt of any live vaccine within 4 weeks before the first dose of study drug, or plans to receive any live vaccine during the study period.

4. Presence of toxicity from prior therapy that has not recovered to Grade 0 or 1 per NCI CTCAE V6.0 before the first dose of study drug (excluding alopecia, fatigue, pigmentation, and other conditions judged by the investigator to pose no safety risk).

5. Major surgery 6. Receipt of immunosuppressive therapy within 4 weeks before the first dose of study drug, excluding topical corticosteroids administered intranasally, by inhalation, or by other local routes, or physiological doses of systemic corticosteroids , or corticosteroids used to prevent contrast agent allergy.

7. Recurrent rectal cancer; multiple primary colorectal cancers. 8. History of pelvic or abdominal radiotherapy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo

Placebo combined with long-course concurrent chemoradiotherapy followed by Capeox consolidation chemotherapy

130 mg/m²,IV,Q3W

20 ml D1 IV Q3W

PTV1 50 Gy/25 times, PTV2 45 Gy/25 times, 5 days a week, for a total of 5 weeks (D1-D35)

825 mg/m ² PO BID ,Days 1-5 QW;1000mg/m ² PO BID ,Days 1-14 Q3W;

Radical resection of rectal cancer

Experimental: Sintilimab

sintilimab combined with long-course concurrent chemoradiotherapy followed by Capeox consolidation chemotherapy

130 mg/m²,IV,Q3W

PTV1 50 Gy/25 times, PTV2 45 Gy/25 times, 5 days a week, for a total of 5 weeks (D1-D35)

825 mg/m ² PO BID ,Days 1-5 QW;1000mg/m ² PO BID ,Days 1-14 Q3W;

Radical resection of rectal cancer

200 mg D1 IV Q3W

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
EFS
Time Frame: throutg treatment completion an average of 5 years

EFS refers to the time from randomization to the first occurrence of any of the following events: disease progression precluding surgical treatment, local or distant recurrence, death from any cause, etc.

throutg treatment completion an average of 5 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
OS
Time Frame: throutg treatment completion an average of 5 years

OS is defined as the time from the date of randomization until the date of death from any cause.

throutg treatment completion an average of 5 years
CCR
Time Frame: up to 5 years after enrollment

CCR defined as the proportion of participants achieving pathological complete response (pCR) or clinical complete response (cCR)

up to 5 years after enrollment
R0 resection rate
Time Frame: up to 5 years after enrollment

R0 resection rate: Descriptive summary of R0 resection rate

up to 5 years after enrollment
EFS3
Time Frame: 3yaers

EFS3 defined as the proportion of participants who remain free from any of the following events for 3 years after randomization: disease progression precluding surgery, local or distant recurrence, or death from any cause

3yaers
TRG
Time Frame: up to 5 years after enrollment

Pathological assessment of tumor regression grading (TRG) after neoadjuvant therapy

up to 5 years after enrollment
neoadjuvant therapy completion rate
Time Frame: up to 5 years after enrollment

Neoadjuvant therapy completion rate: Descriptive summary of Neoadjuvant therapy completion rate

up to 5 years after enrollment
OPR
Time Frame: up to 5 years after enrollment

The definition of organ preservation is: no radical total mesorectal excision (TME) performed, and no local regrowth, unless such regrowth can be salvaged by local excision achieving a limited, radical (R0) resection, with no permanent stoma (including a protective stoma that has never been reversed, or a stoma resulting from adverse events and/or poor functional outcome, or a permanent stoma).

up to 5 years after enrollment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

November 25, 2026

Primary Completion (Estimated)

March 25, 2030

Study Completion (Estimated)

November 24, 2031

Study Registration Dates

First Submitted

October 19, 2026

First Submitted That Met QC Criteria

October 30, 2026

First Posted (Actual)

November 4, 2026

Study Record Updates

Last Update Posted (Actual)

November 4, 2026

Last Update Submitted That Met QC Criteria

October 30, 2026

Last Verified

October 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • CIBI308H301

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.