Short-Course Radiotherapy Combined with Intracavitary Brachytherapy Followed by Pucotenlimab, Bevacizumab, Oxaliplatin, and Trifluridine/Tipiracil (TAS-102) for Total Neoadjuvant Therapy of Microsatellite Stable (MSS) Locally Advanced Low Rectal Cancer

Sponsor
Sir Run Run Shaw Hospital
Study ID
NCT06872606
Phase
PHASE2
Status
Not Yet Recruiting

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Conditions

  • Rectal Adenocarcinoma

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • Pucotenlimab — DRUG
    Pucotenlimab (200 mg IV, q3w)
  • Bevacizumab — DRUG
    Bevacizumab (7.5 mg/kg IV, q3w)
  • Oxaliplatin — DRUG
    Oxaliplatin (130 mg/m² IV, q3w)
  • Trifluridine/Tipiracil Hydrochloride — DRUG
    TAS-102 (25 mg/m² orally, days 1-5 and 8-12).
  • Short-course radiotherapy — RADIATION
    (25 Gy/5 fractions)
  • intracavitary brachytherapy — RADIATION
    brachytherapy (3 Gy/3 fractions).

Study Details

A Prospective Single-Arm Study of Short-Course Radiotherapy Followed by PD-1 Monoclonal Antibody, Bevacizumab, Oxaliplatin, and Trifluridine/Tipiracil for Total Neoadjuvant Therapy in MSS Locally Advanced Low Rectal Cancer. This is a Non-Randomized, Single Group Assignment, Open Label, Phase: Phase II study. The Primary Objective is to assess the organ preservation rate (clinical complete response, cCR) after total neoadjuvant therapy. Secondary Objectives are Tumor regression grade (TRG), 3-year overall survival (OS) and disease-free survival (DFS), and Safety and quality of life (QoL). In this study, the investigators will perform the multi-dimensional omics study to explore the tumors microenvironments, explore the characteristics of the treatment benefit population, and try to construct an efficacy prediction model to screen the treatment benefit population early and implement precise treatment.

Key Dates

First listed
Mar 12, 2025
Start date
Apr 1, 2025
Status verified
Mar 2025
Primary completion
Apr 1, 2026
Completion
Apr 1, 2028

Study Design

Enrollment
33 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT

Arms

  • Experimental: POBTAS Trial Arm
    Intervention: 1.Radiotherapy: 1. Phase 1 (Short-Course External Radiotherapy): Intensity-modulated radiotherapy (IMRT) at 5 Gy X 5F, completed within 1 week. 2. Phase 2 (Intracavitary Brachytherapy): Administered during weeks 5-6, targeting residual lesions with 3Gy X 3F, completed within 1 week. 2.Systemic Therapy Post-Initial Radiotherapy: 1. Cycles 1-2: PD-1 antibody immunotherapy (pucotenlimab) combined with bevacizumab, oxaliplatin, and trifluridine/tipiracil (TAS-102). 2. Cycles 3-4: Sequential PD-1 immunotherapy + oxaliplatin + TAS-102 (bevacizumab omitted in Cycle 4). 3.Post-Cycle 4 Evaluation: If ypT0 (local pathological complete response): Enter follow-up observation. If non-CR: Proceed to Step 4. 4.Extended Systemic Therapy for Non-CR Patients: Cycles 5-8: Repeat PD-1 immunotherapy + bevacizumab + oxaliplatin + TAS-102 (bevacizumab omitted in Cycle 8). 5.Post-Cycle 8 Evaluation: If ypT0: Enter follow-up observation. If non-ypT0: Proceed to TME surgery.

Primary Outcome Measure

Organ preservation rate [ Time Frame: Up to 2 weeks (once evaluation or biopsy is done) ]

Central Contacts

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