A Single-center, Phase II Study on Efficacy & Safety of SCRT+CAPOX+Serplulimab+Bevacizumab for MSS Rectal Cancer

Summary

In a single-center, prospective, phase II study (ClinicalTrials registration number: \[to be filled in\]) initiated by our center to evaluate the safety and preliminary efficacy of short-course radiotherapy followed by sequential CAPOX chemotherapy combined with serplulimab and bevacizumab as total neoadjuvant therapy for MSS-type mid-low locally advanced rectal cancer, patients with mid-low MSS-type locally advanced rectal adenocarcinoma were enrolled. They received short-course radiotherapy combined with CAPEOX, serplulimab, and bevacizumab as preoperative total neoadjuvant therapy. It is anticipated that 30 subjects with locally advanced rectal cancer will be enrolled between September 2025 and September 2027.

This phase II exploratory study targets patients with locally advanced mid-low MSS/pMMR rectal cancer. It employs short-course radiotherapy combined with CAPEOX, serplulimab, and bevacizumab as preoperative total neoadjuvant therapy, aiming to clarify the efficacy and safety of this new combined radiotherapy, chemotherapy, targeted therapy, and immunotherapy approach, while also assessing the rectal/anal preservation rate and quality of life of patients. After neoadjuvant therapy, patients will undergo imaging and endoscopic evaluations to determine subsequent treatment strategies. Radical surgical resection will be performed on patients after neoadjuvant immunotherapy, followed by further analysis of the pathological complete response (pCR) rate. The primary study endpoint is the pCR rate, and secondary study endpoints include the objective response rate, organ preservation rate, 3-year disease-free survival (DFS), 3-year overall survival (OS), incidence of adverse events, and quality of life scores (EORTC QLQ-C30, EORTC QLQ-CR29, Wexner).

Conditions

• Locally Advanced Rectal Cancer (LARC)

Interventions

RADIATION

Short-course radiotherapy

Radiotherapy adopts a short-course regimen, with a dose of 5\*5 Gy, administered once daily at 5 Gy per session for a total of 5 consecutive days of irradiation. It is recommended to use three-dimensional 3D-CRT or IMRT techniques. The irradiation fields include: (1) high-risk recurrence areas of the primary tumor, such as the tumor/tumor bed, mesorectal region, and presacral region. For middle and low rectal cancers, the target area should also encompass the ischioanal fossa; (2) regional lymphatic drainage areas, including the lymphatic drainage area along the common iliac vessels within the true pelvis, mesorectal region, lymphatic drainage area along the internal iliac vessels, and obturator lymph node region.

DRUG

CAPOX chemotherapy

Chemotherapy with the CAPOX regimen: Capecitabine tablets are available in strengths of 0.5 g/tablet and 0.15 g/tablet; Oxaliplatin for injection is available in a strength of 0.1 g. The chemotherapy protocol is as follows: After a 7-day rest following radiotherapy, on Day 1 (D1), oxaliplatin is administered intravenously at a dose of 130 mg/m² over 2 hours; from Day 1 to Day 14 of each 3-week cycle, capecitabine is taken orally at a dose of 1000 mg/m² twice daily, with each cycle lasting 3 weeks.

DRUG

Targeted therapy with bevacizumab

Targeted therapy: On Day 1 (D1) of chemotherapy initiation, bevacizumab will be administered via infusion at a dose of 7.5 mg/kg, with each treatment course lasting 3 weeks, for a total of 6 courses.

DRUG

Serplulimab immunotherapy

Immunotherapy: On Day 1 (D1) of chemotherapy initiation, administer 300 mg of serplulimab, with each treatment cycle lasting 3 weeks, for a total of 6 cycles.

Sponsors & Collaborators

• First Affiliated Hospital of Wenzhou Medical University

  lead OTHER

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-12-01

Primary Completion

2027-12-01

Completion

2030-12-01

Countries

• China

Study Locations