A randomized controlled trial of CAPEOX vs observation in patients with early-stage colorectal cancer with positive MRD after curative surgery (CAREME).

Abstract

TPS225 Background: Most patients (pts) with early-stage colorectal cancer (CRC) have a good prognosis, but some still relapse shortly after surgery. Effective methods to assess the risk of recurrence in these pts and guide adjuvant chemotherapy (ACT) decision-making are lacking. Increasing studies have shown that circulating tumor DNA (ctDNA) can detect minimal residual disease (MRD) and identify pts with a high risk of recurrence. ACT could improve survival of MRD-positive pts with stage Ⅱ CRC suggested by recent studies, whether it is appropriate for those with stage Ⅰ or clinically low-risk stage Ⅱ CRC remains unknown. Methods: CAREME is a multicenter randomized controlled clinical trial aimed at investigating the benefit of chemotherapy for MRD-positive pts with early-stage CRC. Pts with resected stage Ⅰ or Ⅱ CRC will be evaluated by oncologists. Those who did not receive neoadjuvant therapy and are deemed suitable for active surveillance (i.e., ACT is not needed) will undergo a postoperative ctDNA test using MinerVa MRD assay (a tumor-informed assay covering 769 cancer-related genes). Pts with mismatch repair-deficient tumors will be excluded and stage Ⅱ pts should have no traditional high-risk features according to clinical practice guidelines. Pts with positive ctDNA (N = 38) will be equally randomized into two groups: treatment group (Arm A) or surveillance group (Arm B). Arm A will receive 8 cycles of CAPEOX therapy while pts in Arm B will not receive any ACT; both groups will undergo ctDNA tests at 6 months after randomization and be followed up every 3 months. The primary endpoint is 18-month recurrence-free survival, and a key secondary endpoint is ctDNA clearance at 6 months after randomization. Tumor samples from the pts will be collected for MRD assay and exploratory research. Accrual started in February 2023. Support: Genecast Biotechnology Company. Clinical trial information: NCT05699746 .