A Phase 2 interventional study of Short-course radiotherapy and Capecitabine in Rectal Cancer, Radiotherapy and Immunotherapy, sponsored by Tao Zhang. Not yet recruiting at 1 site in China. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Tao Zhang · Phase 2, Interventional, and Treatment
This is a prospective, single-arm, biomarker-stratified, multicenter phase 2 clinical trial. All enrolled patients first receive short-course radiotherapy (SCRT), followed by measurement of serum β-hydroxybutyrate (β-HB) levels to calculate the post-radiotherapy elevation rate. Patients are stratified into an β-HB-positive stratum (elevation ≥10%) and an β-HB-negative stratum (elevation \<10%), then randomized 1:1 within each stratum to receive either perioperative chemotherapy plus PD-1 inhibitor or perioperative chemotherapy alone.
The primary endpoint is the complete response (CR) rate, defined as the composite of pathological complete response (pCR) and clinical complete response (cCR). The study aims to evaluate the efficacy and safety of adding PD-1 inhibitor to perioperative chemotherapy in LARC, and to validate post-radiotherapy β-HB elevation as a predictive biomarker for immunotherapy benefit.
Exclusion Criteria:
β-HB-Positive (β-HB Elevation ≥10%) * Radiation: Short-course radiotherapy (SCRT): 25 Gy delivered in 5 fractions over 1 week. * Chemotherapy: 6 cycles of CAPEOX (Capecitabine 1000 mg/m² PO BID D1-14 + Oxaliplatin 130 mg/m² IV D1, q3w) at investigator's discretion. * PD-1 Inhibitor: Approved anti-PD-1 monoclonal antibody, administered on Day 1 of each chemotherapy cycle for 6 cycles. Dose may be delayed for immune-related adverse events (irAEs) (max delay ≤6 weeks). * Procedure: Restaging after 6 cycles; TME surgery or Watch \& Wait strategy per multidisciplinary evaluation.
Radiation: Short-course radiotherapy · Drug: Capecitabine · Drug: Oxaliplatin · Procedure: TME surgery · Drug: PD -1/PD-L1 monoclonal antibody · Other: Watch & Wait strategy
β-HB-Positive (β-HB Elevation ≥10%) * Radiation: Short-course radiotherapy (SCRT): 25 Gy delivered in 5 fractions over 1 week. * Chemotherapy: 6 cycles of CAPEOX (Capecitabine 1000 mg/m² PO BID D1-14 + Oxaliplatin 130 mg/m² IV D1, q3w) at investigator's discretion. * Procedure: Restaging after 6 cycles; TME surgery or Watch \& Wait strategy per multidisciplinary evaluation.
Radiation: Short-course radiotherapy · Drug: Capecitabine · Drug: Oxaliplatin · Procedure: TME surgery · Other: Watch & Wait strategy
β-HB-Negative (β-HB Elevation \<10%) * Radiation: Short-course radiotherapy (SCRT): 25 Gy delivered in 5 fractions over 1 week. * Chemotherapy: 6 cycles of CAPEOX (Capecitabine 1000 mg/m² PO BID D1-14 + Oxaliplatin 130 mg/m² IV D1, q3w) at investigator's discretion. * PD-1 Inhibitor: Approved anti-PD-1 monoclonal antibody, administered on Day 1 of each chemotherapy cycle for 6 cycles. Dose may be delayed for immune-related adverse events (irAEs) (max delay ≤6 weeks). * Procedure: Restaging after 6 cycles; TME surgery or Watch \& Wait strategy per multidisciplinary evaluation.
Radiation: Short-course radiotherapy · Drug: Capecitabine · Drug: Oxaliplatin · Procedure: TME surgery · Drug: PD -1/PD-L1 monoclonal antibody · Other: Watch & Wait strategy
β-HB-Negative (β-HB Elevation \<10%) * Radiation: Short-course radiotherapy (SCRT): 25 Gy delivered in 5 fractions over 1 week. * Chemotherapy: 6 cycles of CAPEOX (Capecitabine 1000 mg/m² PO BID D1-14 + Oxaliplatin 130 mg/m² IV D1, q3w) at investigator's discretion. * Procedure: Restaging after 6 cycles; TME surgery or Watch \& Wait strategy per multidisciplinary evaluation.
Radiation: Short-course radiotherapy · Drug: Capecitabine · Drug: Oxaliplatin · Procedure: TME surgery · Other: Watch & Wait strategy
Eligible subjects will receive short-course radiotherapy (SCRT). One week after the end of treatment, subjects continued to receive neoadjuvant chemotherapy.
1000mg/m2, bid, po, d1-14,q3w
130mg/m2, ivgtt, d1,q3w
The surgery was performed 1 week after the end of neoadjuvant therapy.
200 mg via intravenous infusion every 3 weeks (q3w) for 6 cycles, initiated 1 week after radiotherapy completion.
The Watch \& Wait (W\&W) strategy is an organ-preserving clinical management approach for patients with locally advanced rectal cancer who achieve a clinical complete response (cCR) after neoadjuvant therapy. In this strategy, definitive surgical resection (total mesorectal excision, TME) is withheld, and patients are instead managed with a standardized, intensive surveillance regimen to monitor for disease regrowth.
complete response (CR) rate
Defined as pathological complete response (pCR) + Clinical complete response (cCR)
Time frame: an expected average of 12 months
3-year disease-Free Survival
The time from the first day of disease free (operation date) to local or distant recurrence, or the death event caused by any reason, whichever occurs first
Time frame: an expected average of 3 years
Overall Survival
The time from the date of randomization to the death caused by any cause
Time frame: an expected average of 5 years
Adverse events (AEs) were graded according to the NCI CTCAE version 5·0
Adverse events and surgical safety
Time frame: an expected average of 1.5 years
Plan to share: Undecided
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Tao Zhang