Low-Dose Radiotherapy to Sensitize Pucotenlimab Plus CAPEOX for pMMR Locally Advanced Rectal Cancer (NCT07448142) | Clinical Trial Compass
RecruitingPhase 2
Low-Dose Radiotherapy to Sensitize Pucotenlimab Plus CAPEOX for pMMR Locally Advanced Rectal Cancer
China50 participantsStarted 2026-03-15
Plain-language 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.
Who can participate
Age range
18 Years – 75 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria
* Written informed consent provided prior to any study-specific procedures.
* Age 18 to 75 years at the time of enrollment.
* Histologically confirmed rectal adenocarcinoma.
* Tumor located within 10 cm from the anal verge, as assessed by endoscopy or imaging.
* Locally advanced disease, defined as clinical stage T2N+ or T3-T4a (any N) based on pelvic magnetic resonance imaging (MRI).
* Proficient mismatch repair (pMMR) or microsatellite-stable (MSS) tumor status confirmed by immunohistochemistry or molecular testing.
* No evidence of distant metastasis on preoperative imaging, including chest, abdominal, and pelvic computed tomography (CT).
* Circumferential resection margin (CRM) ≥2 mm and no involvement of the mesorectal fascia on baseline MRI.
* Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
* Adequate organ function as defined by:
* Absolute neutrophil count ≥1.5 × 10⁹/L
* Platelet count ≥100 × 10⁹/L
* Hemoglobin ≥90 g/L
* Total bilirubin ≤1.5 × upper limit of normal (ULN)
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × ULN
* Creatinine clearance ≥50 mL/min
* Thyroid-stimulating hormone (TSH) within normal limits
* Women of childbearing potential must have a negative pregnancy test and agree to use effective contraception during the study and for a protocol-defined period after the last dose.
* Men with partners of childbearing potential must agree to use effective contraception during the study and for …
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Complete Response Rate (CR)
Timeframe: From the start of neoadjuvant therapy until the completion of pre-operative assessment (approximately 12 weeks) and the time of surgery (approximately 14-16 weeks).