Abstract 447TiP
Background
Neoadjuvant radiotherapy plus immune checkpoint inhibitors have achieved pCR rates of 23%∼48.1% in locally advanced rectal cancers (LARC). But currently existing reports are all phase II, single-cohort trials. We aims to clarify the efficacy and safety of neoadjuvant long-course chemoradiation plus Tislelizumab (anti-PD1) in LARC with this randomized, controlled trial.
Trial design
This phase II, multi-center, open-label, 3-arm, randomized trial aims to recruit patients aged 18-75 years, diagnosed histologically as rectal adenocarcinoma, without metastasis (by CT), staged II/III (by MRI, T4b excluded), with distal margin within 10cm to anal verge (MRI). All patients should have no history of immune diseases, nor history of immunotherapy or radiotherapy. Sample size was thoroughly calculated to be 120. Eligible participants will be randomly assigned to Experiment Arm 1 (50.4Gy radiation, capecitabine, and anti-PD1 starting at Day 8 of radiation), Experiment Arm 2 (50.4Gy radiation, capecitabine, and anti-PD1 starting 2 weeks after completion of radiation), and Control Arm (50.4Gy radiation, capecitabine) in a 1:1:1 ratio. Randomization is stratified by different centers, with a block size of 6. For both experiment arms, Tislelizumab (anti-PD1) is scheduled to be administered at 200mg each time for 3 consecutive times, with 3-week intervals. And for all 3 arms, the interval from completion of radiotherapy to surgery is 10∼12 weeks. The primary endpoint is pCR rate, and secondary endpoints include sphincter-preserving rate, adverse event rates, and DFS and OS rate at 2, 3 and 5 years post-operation. Data will be analyzed with an intention-to-treat approach. This study started on Apr 1, 2022. As of Apr 26, 2022, 7 patients have been included and ramdomized. Inclusion is scheduled to be completed by the end of Year 2022.
Clinical trial identification
NCT05245474.
Editorial acknowledgement
Legal entity responsible for the study
Zhongtao Zhang.
Funding
Ministry of Science and Technology of the People's Republic of China, and BeiGene, Ltd.
Disclosure
All authors have declared no conflicts of interest.