Radical Concurrent Chemoradiotherapy With DDP/5-FU and PD-1 Antibody for Non-metastatic Rectal Squamous Cell Carcinoma

Radical Concurrent Chemoradiotherapy With DDP/5-FU and PD-1 Antibody for Newly Diagnosed Non-metastatic Rectal Squamous Cell Carcinoma: A Multicenter, Prospective, Single Arm, Phase II Study(RICH).

The goal of this clinical trial is to learn if PD-1 monoclonal antibody combined with radical chemoradiotherapy works to treat rectal squamous cell carcinoma (rSCC). lt will also learn about the safety of the regime. The main questions it aims to answer are:

Does PD-1 monoclonal antibody combined with radical chemoradiotherapy improve survival prognosis? What is the complete response rate (CCR) of the regime？ Researchers will compare PD-1 monoclonal antibody combined with radical chemoradiotherapy to previous study to see if this regime works to treat rSCCs.

Participants will receive chemotherapy with DDP and 5-FU, immunotherapy with PD-1 monoclonal antibody and radiotherapy with a total dose of 50-54GY.

Study Overview

• Status: Recruiting
• Conditions: Rectal Squamous Cell Carcinoma
• Intervention / Treatment: Combination product: PD-1 and CRT

Detailed Description

Rectal squamous cell cancer (rSCC) is a rare malignancy, and its incidence is increasing year by year. Due to the rarity of rSCC, there is no consensus on its epidemiology, pathogenesis, prognosis and treatment management. Due to the limitation of clinical data, there is an urgent need for further clinical exploration and research.

In recent years, the combination of CRT and immunotherapy has attracted more and more attention, as they may have more advantages over CRT alone.A number of prospective clinical trials of PD-1 monoclonal antibody combined with CRT for the first-line treatment of advanced aSCC are also underway (NCT03233711, NCT04230759, NCT05661188, NCT05374252, etc.). Similarly, the efficacy and safety of PD-1 monoclonal antibody in rSCC patients are also worthy of further discussion, in order to further improve the survival prognosis of rSCC patients. Our previous study data showed that the 3-year OS and DFS of radical CRT were 88.9% and 66.7%, respectively, for non-metastatic rSCC, and 100% and DFS for radical CRT combined with immunotherapy, respectively, and CRT combined with immunotherapy significantly improved survival compared with radical CRT (P=0.02).

The goal of this clinical trial is to learn if PD-1 monoclonal antibody combined with radical chemoradiotherapy works to treat rectal squamous cell carcinoma (rSCC). lt will also learn about the safety of the regime. Therefore, we plan to conduct a multicenter, prospective, single-arm, phase II study to provide evidence-based medical evidence for the treatment of locally advanced rectal squamous cell carcinoma.

The primary outcome is 1-year tumor-free survival (DFS), and the secondary outcomes are including 1-year overall survival (OS), 1-year relapse-free survival (RFS), 1-year metastasis free survival (DMFS), 1-year stoma-free survival, incidence of chemotherapy and immunotherapy-related adverse reactions and complete response rate (CRR).

Participants will receive interventions below:

Chemotherapy (/4W): a)DDP 75 mg/m2, d1, intravenous infusion; b)5-FU 1000 mg/m2, d1-4, continuous pumping intravenously; Immunotherapy (/4W): PD-1 monoclonal antibody(sintlimab) 200mg, d1, intravenous infusion; Radiotherapy (at 2rd week after firstime of chemotherapy):Daily single dose of 2Gy, with a total dose of 50-54Gy(clinical I-II stage)/54-59Gy(clinical III stage).

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Jun Huang, MD; Phone Number: +86-13926451242; Email: huangj97@mail.sysu.edu.cn
• Study Contact Backup: Name: Fang He, MD; Phone Number: +86-18826059789; Email: hefang23@mail.sysu.edu.cn

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Recruiting
      • Sixth Affiliated Hospital, Sun Yat-sen University
      • Contact: Jun Huang, MD; Phone Number: +86-13926451242; Email: huangj97@mail.sysu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Voluntarily sign the informed consent;
2. 18-75 years old;
3. Patients with pathologically confirmed rectal squamous cell carcinoma;
4. imaging to rule out distant metastases;

5. Peripheral blood and liver and kidney function before treatment within the following allowable limits (tested within 14 days before the start of treatment)

   1. White blood cell (WBC) ≥ 3.0×109/L or neutrophil (ANC) ≥1.5×109/L;
   2. Hemoglobin (HGB) ≥80 g/L;
   3. Platelets (PLT) ≥ 100×109/L;
   4. Hepatic transaminases (AST/ALT) < 3.0 times the upper limit of the normal range;
   5. Total bilirubin (TBIL) < 1.5 times the upper limit of the normal range;
   6. Creatinine (CREAT) < 1.5 times the upper limit of the normal range.
6. ECOG performance status score of 0-2;
7. No history of other malignant tumors in the past.

Exclusion Criteria:

1. Non-treatment-naïve patients who have previously received chemotherapy, radiotherapy or complete surgical resection of rectal squamous cell carcinoma;
2. Distant metastases (M1) confirmed by whole-body CT, MR, or PET-CT (including at least the chest, abdomen, and pelvis);
3. Previous or concurrent presence of other active malignancies (except for malignant tumors that have received curative therapy and have been disease-free for more than 3 years or carcinoma in situ that can be cured by adequate treatment);
4. Major surgery such as laparotomy, thoracotomy, resection of organs by laparoscopic surgery or severe trauma within the past 4 weeks (the surgical incision should be completely healed before randomization);
5. Active coronary artery disease, severe/unstable angina pectoris or newly diagnosed angina pectoris or myocardial infarction within 12 months prior to enrollment in the study;
6. Thrombotic or embolic events such as cerebrovascular accident (including transient ischemic attack), pulmonary embolism, deep vein thrombosis within the past 6 months;
7. New York Heart Association (NYHA) Class II or above congestive heart failure;
8. Prior receipt of any investigational drug;
9. Pregnant or lactating women;
10. Any medical condition that is unstable or would affect patient safety and their compliance with the study;
11. Patients judged by the investigator to be unsuitable to participate in this clinical trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: PD-1 + CRT; Patients from experimental group are underwent treatment together with PD-1 monoclonal antibody and radical CRT

Combination product: PD-1 and CRT; Chemotherapy (/4W): a)DDP 75 mg/m2, d1, intravenous infusion; b)5-FU 1000 mg/m2, d1-4, continuous pumping intravenously; Immunotherapy (/4W): PD-1 monoclonal antibody(sintlimab) 200mg, d1, intravenous infusion; Radiotherapy (at 2rd week after firstime of chemotherapy):Daily single dose of 2Gy, with a total dose of 50-54Gy(clinical I-II stage)/54-59Gy(clinical III stage).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
3-year tumor-free survival(DFS)	The proportion of patients who do not have any of the following events from the beginning of randomization to the end of the first year	3 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
1-year overall survival (OS)	Time interval from the date of randomization to death	1 year
1-year relapse-free survival (RFS)	Time interval from the date of randomization to the onset of recurrence	1 year
1-year metastasis free survival (DMFS)	Time interval from the date of randomization to the occurrence of distant metastases	1 year
Incidence of chemotherapy and immunotherapy-related adverse reactions	The occurrence of chemotherapy and immune-related side effects during treatment	through study completion, an average of 6 months
Complete response rate (CRR)	The proportion of the total number of patients with complete response after treatment to the total number of evaluable cases in solid tumor treatment studies	through study completion, an average of 6 months
1-year stoma-free survival	The occurrence of stoma	1 year

Collaborators and Investigators

• Sponsor: Sixth Affiliated Hospital, Sun Yat-sen University
• Investigators: Principal Investigator: Jun Huang, MD, Sixth Affiliated Hospital, Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): April 12, 2024
• Primary Completion (Estimated): April 20, 2026
• Study Completion (Estimated): February 28, 2027

Study Registration Dates

• First Submitted: April 2, 2024
• First Submitted That Met QC Criteria: April 12, 2024
• First Posted (Actual): April 15, 2024

Study Record Updates

• Last Update Posted (Actual): November 24, 2025
• Last Update Submitted That Met QC Criteria: November 18, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: PD-1; Chemoradiotherapy
• Additional Relevant MeSH Terms: Digestive System Diseases; Neoplasms by Histologic Type; Neoplasms; Neoplasms by Site; Neoplasms, Glandular and Epithelial; Gastrointestinal Neoplasms; Digestive System Neoplasms; Gastrointestinal Diseases; Intestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colorectal Neoplasms; Neoplasms, Squamous Cell; Carcinoma; Rectal Neoplasms; Carcinoma, Squamous Cell
• Other Study ID Numbers: E2024074

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No