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Low-Dose Radiotherapy to Sensitize Pucotenlimab Plus CAPEOX for pMMR Locally Advanced Rectal Cancer

NCT07448142 · Status: RECRUITING · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 50

Last updated 2026-05-07

No results posted yet for this study

Summary

This is a prospective, open-label, randomized, parallel-group phase II trial evaluating the efficacy and safety of a low-dose radiotherapy sensitization strategy combined with a PD-1 antibody (pucotenlimab) and CAPEOX as neoadjuvant therapy in patients with pMMR/MSS locally advanced rectal adenocarcinoma. Participants will be randomized 1:1 to receive either 2 Gy or 5 Gy low-dose radiotherapy. Low-dose radiotherapy is delivered as a single fraction of 2 Gy (Arm A) or 5 Gy (Arm B). On the day after radiotherapy, participants will start pucotenlimab 200 mg IV Q3W (administered on Day 2 of each 21-day cycle) plus CAPEOX chemotherapy. Early response will be assessed after 2 cycles using endoscopy and pelvic MRI to guide subsequent treatment: participants with partial response may discontinue radiotherapy and continue neoadjuvant systemic therapy; participants with stable disease may switch to standard chemoradiotherapy; participants with progressive disease will receive multidisciplinary-team-guided salvage therapy. After 4 cycles, participants with clinical complete response may adopt a watch-and-wait strategy; otherwise, they will undergo radical surgery 2-4 weeks after completion of neoadjuvant therapy. Long-term follow-up will include recurrence and survival outcomes and quality of life.

Conditions

  • Colorectal Cancer (CRC)

Interventions

RADIATION

Low-dose radiotherapy

Low-dose radiotherapy delivered by linear accelerator to the primary rectal tumor and regional lymphatic drainage areas using IMRT or 3D-CRT techniques. Participants receive either 2 Gy or 5 Gy according to randomized assignment, administered prior to initiation of systemic neoadjuvant therapy.

DRUG

Pucotenlimab

Pucotenlimab is a programmed cell death protein 1 (PD-1) monoclonal antibody. It is administered at a fixed dose of 200 mg by intravenous infusion on Day 2 of each 21-day cycle, every 3 weeks (Q3W), during the neoadjuvant treatment phase.

DRUG

CAPEOX/XELOX

CAPEOX chemotherapy consists of oxaliplatin 130 mg/m² administered intravenously on Day 1 and capecitabine 1000-1250 mg/m² administered orally twice daily on Days 1-14 of each 21-day cycle during neoadjuvant therapy.

Sponsors & Collaborators

  • Sun Yat-sen University

    lead OTHER

Principal Investigators

  • Pei-Rong Ding · Sun Yat-Sen University Cancer Center

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
75 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2026-03-15
Primary Completion
2027-09-01
Completion
2032-09-01

Countries

  • China

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07448142 on ClinicalTrials.gov