NCT07068763

Node-Sparing Short-Course Radiation Combined With Capecitabine and PD-1/CTLA-4 for MSS Early Rectal Cancer

Node-Sparing Short-Course Radiation Combined With Capecitabine and PD-1/CTLA-4 for MSS Early Middle and Low Rectal Cancer (mRCAT-E): An Open-label, Single-arm, Prospective Multicenter Clinical Trial

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 52 (estimated)
• Sponsor: Sir Run Run Shaw Hospital · Academic / Other
• Sex: All
• Age: 18 Years – 80 Years
• Healthy volunteers: Not accepted

Summary

This is a single-arm, prospective, multicenter study evaluating a novel neoadjuvant treatment strategy for patients with early, mid-low rectal adenocarcinoma that is microsatellite stable (MSS). Instead of irradiating regional lymph nodes, we deliver short-course radiotherapy (25 Gy in 5 fractions) exclusively to the primary tumor ("lymph-node-sparing" approach), immediately followed by four 3-week cycles of capecitabine plus combined PD-1/CTLA-4 immune checkpoint inhibitors. Two weeks after completing chemo-immunotherapy, tumor response is assessed. Patients who achieve a clinical complete response may enter a "watch-and-wait" program; others will undergo local excision or total mesorectal excision (TME) as appropriate. The primary endpoint is the rate of complete response (clinical and pathological). Secondary endpoints include organ-preservation rate, 3-year local recurrence, 3-year disease-free and overall survival, toxicity, and quality-of-life measures. Results from a pilot study suggest that this regimen may substantially improve complete response rates while reducing radiation-related toxicity, potentially allowing more patients to avoid radical surgery and permanent stoma.

Conditions

• Rectal Cancer

Interventions

Type	Name	Description
RADIATION	Lymph-node-sparing short-course radiotherapy	Three-dimensional conformal or intensity-modulated radiotherapy targeting only the primary tumor bed (no regional lymph nodes), delivering a total dose of 25 Gy in 5 Gy fractions over five consecutive days.
DRUG	Capecitabine	Oral capecitabine 1,000 mg/m² administered twice daily on Days 1-14 of each 21-day cycle, for a total of four cycles.
DRUG	PD-1/CTLA-4 inhibitor (Aiparolitoworixureli injection)	Intravenous PD-1/CTLA-4 bispecific monoclonal antibody at 5 mg/kg every 3 weeks for four cycles, starting on Day 8 after completion of radiotherapy.

Timeline

• Start date: 2025-10-09
• Primary completion: 2026-12-31
• Completion: 2029-12-31
• First posted: 2025-07-16
• Last updated: 2026-01-06

Locations

1 site across 1 country: China