SIB-RT Combined With CAPOX and PD-1 for High-Risk Rectal Cancer

NCT07297030 | Not Yet Recruiting Phase 2 DMC

• 1 other identifier: GIHSYSU-38
• Study Type: interventional
• Target: 37
• Locations: 1 country
• Sites: 1

Brief Summary

The biological effective dose of short-course radiotherapy is relatively lower compared to long-course radiotherapy, which may lead to an increased local recurrence rate in patients with mid to low rectal cancer who are at high risk of locally advanced disease due to insufficient radiation dose. Combining short-course radiotherapy with simultaneous integrated boost (SIB) and immunotherapy-chemo regimens could potentially further enhance tumor regression and improve local control, providing a promising treatment option for high-risk locally advanced rectal cancer patients. Therefore, this clinical trial aims to explore the safety and effectiveness of a short-course SIB radiotherapy regimen combined with immunotherapy and chemotherapy as neoadjuvant treatment for locally advanced rectal cancer, based on short-course radiotherapy combined with chemotherapy and immunotherapy.

Conditions

Rectal Cancer

Keywords

SIB; PD-1; neoadjuvant chemoradiotherapy

Outcome Measures

Primary Outcomes (1)

• The Complete Response (CR) rate

  The Complete Response (CR) rate refers to the sum of the pathological Complete Response (pCR) rate, defined as the absence of residual cancer cells in the surgical resection specimen observed microscopically, and the probability of patients achieving clinical Complete Response (cCR) who then undergo a watchful waiting (W\&W) approach. The primary endpoint of my study is the CR rate.

  3 months

Secondary Outcomes (6)

• Rate of ≥Grade 3 toxicities

  3 months

• 3-Year Disease-Free Survival Rate (3yDFS%)

  3 years

• 3-Year Locoregional Recurrence-Free Survival Rate (3yLRFS%)

  3 years

• 3-Year Overall Survival Rate (3yOS%)

  3 years

• Surgical Complications

  6 months

Study Arms (1)

SIB-SCRT+CAPOX+PD-1

EXPERIMENTAL

Patients received neoadjuvant treatment consisting of SIB-SCRT ( PTV-GTV 31Gy/5F/6.2Gy) followed by sintilimab (3mg/kg intravenous drip on day 1; every 3-week cycle for two cycles) combined with CAPOX (oxaliplatin 130 mg/m2 intravenous infusion over 2 h on day 1, capecitabine 1000 mg/m2 orally twice daily from day 1-14, in every 3-week cycle for two cycles) 1 week later.

Radiation: SIB-SCRT; Drug: CAPOX; Drug: Immunotherapy

Interventions

SIB-SCRT RADIATION

The pelvic lymphatic drainage regions receive 25 Gy in 5 fractions (5 Gy per fraction). A ssequential boost to a total dose of 30 Gy in 6 fractions is delivered to the primary tumour and any radiologically suspicious lymph nodes.

SIB-SCRT+CAPOX+PD-1

CAPOX DRUG

* Oxaliplatin 130 mg/m² intravenously on day 1. * Capecitabine 1,000 mg/m² orally twice daily on days 1-14.

SIB-SCRT+CAPOX+PD-1

Immunotherapy DRUG

\- Tislelizumab 200 mg intravenously on day 1.

SIB-SCRT+CAPOX+PD-1

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Participants must voluntarily agree to join this study and sign an informed consent form.
• Age at the time of signing the informed consent form must be between 18 and 75 years.
• Histologically confirmed diagnosis of rectal adenocarcinoma.
• The inferior margin of the tumor must be ≤10 cm from the anal verge.
• No prior anti-cancer treatment for rectal cancer (including local-regional and systemic therapy).
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) score of 0-1.
• At least one measurable lesion according to RECIST v1.1 criteria.
• Normal function of major organs without severe abnormalities in hematological, cardiovascular, pulmonary, hepatic, renal, or bone marrow function; laboratory tests must meet the following requirements:
• Hemoglobin (Hb) ≥ 70 g/L; White blood cell count (WBC) ≥ 3.0 × 10\^9/L; Neutrophil count (NEUT) ≥ 1.5 × 10\^9/L; Platelet count (PLT) ≥ 100 × 10\^9/L; Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels ≤ 2.5 times the upper limit of normal (ULN); Total bilirubin (TBIL) ≤ 1.5 times the upper limit of normal (ULN); Renal function (serum creatinine, sCr) level ≤ 1.5 times the upper limit of normal (ULN).

You may not qualify if:

• Evidence of distant metastasis.
• Recurrent rectal cancer.
• Documented allergy to the investigational drug and/or its excipients.
• Contraindications to radiotherapy and/or chemotherapy.
• Women who are pregnant or breastfeeding.
• A history of other malignancies.
• Patients who have participated in other clinical trials involving investigational drugs within the last 6 months.

Sponsors & Collaborators

• Sun Yat-sen University: lead

Study Sites (1)

Department of colorectal surgery, the Sixth Affiliated Hospital, Sun Yat-Sen University

Guangzhou, Guangdong, 510000, China

Location

MeSH Terms

Conditions

Rectal Neoplasms

Interventions

Immunotherapy

Condition Hierarchy (Ancestors)

Colorectal Neoplasms; Intestinal Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Diseases; Rectal Diseases

Intervention Hierarchy (Ancestors)

Immunomodulation; Biological Therapy; Therapeutics

Central Study Contacts

Liang Huang, MD. and Phd.

CONTACT

020-38455369; huangl75@mail.sysu.edu.cn

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: M.D.

Study Record Dates

• First Submitted: July 13, 2025
• First Posted: December 22, 2025
• Study Start: December 20, 2025
• Primary Completion: May 31, 2026
• Study Completion (Estimated): May 1, 2029
• Last Updated: December 22, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)