The interim analysis of the CIRCULATE-Japan GALAXY observational study demonstrated the association of circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) detection with recurrence risk and benefit from adjuvant chemotherapy (ACT) in resectable colorectal cancer (CRC). This updated analysis with a 23-month median follow-up, including 2,240 patients with stage II-III colon cancer or stage IV CRC, reinforces the prognostic value of ctDNA positivity during the MRD window with significantly inferior disease-free survival (DFS; hazard ratio (HR): 11.99, P < 0.0001) and overall survival (OS; HR: 9.68, P < 0.0001). In patients who experienced recurrence, ctDNA positivity correlated with shorter OS (HR: 2.71, P < 0.0001). The significantly shorter DFS in MRD-positive patients was consistent across actionable biomarker subsets. Sustained ctDNA clearance in response to ACT was an indicator of favorable DFS and OS compared to transient clearance (24-month DFS: 89.0% versus 3.3%; 24-month OS: 100.0% versus 82.3%). True spontaneous clearance rate with no clinical recurrence was 1.9% (2/105). Overall, our findings provide evidence for the utility of ctDNA monitoring for post-resection recurrence and mortality risk stratification that could be used for guiding adjuvant therapy.

Background Clinicopathological and molecular features of responders to nivolumab for advanced gastric cancer (AGC) are not well understood. Methods Patients (pts) with AGC who were treated with nivolumab after two or more chemotherapy regimens in a single institution from September 2017 to May 2018 were enrolled in this study. PD-L1 expression in tumor cells (TC) and mismatch repair (MMR) were analyzed by immunohistochemistry. Epstein-Barr virus (EBV) was detected by in situ hybridization. Cancer genome alterations were evaluated by a next-generation sequencing-based panel. High tumor mutation burden (TMB) was defined as more than 10 mutations/megabase. Results A total of 80 pts were analyzed in this study. Tumor response was evaluated in 72 pts with measurable lesions and 14 pts (19%) had an objective response. Overall response rate (ORR) was significantly higher in pts with ECOGPS 0 in those with PS 1 or 2, MMR-deficient (MMR-D) in those with MMR-proficient (MMR-P), PD-L1+ in TC in those with PD-L1- in TC and PIK3CA mutation in those with PIK3CA wild-type. ORR was 31% in pts with at least one of the following factors; MMR-D, high TMB, EBV+ and PD-L1+ in TC vs. 0% in those without these factors. Progression-free survival was significantly longer in pts with PS 0 than in those with PS 1 or 2, MMR-D than in those with MMR-P, and PD-L1+ in TC than in those with PD-L1- in TC. Conclusions Some features were associated with favorable response to nivolumab for AGC. Combining these features might be useful to predict efficacy.

PURPOSE: To evaluate the efficacy and safety of tucatinib and trastuzumab in patients with previously treated human epidermal growth factor receptor 2–positive (HER2+) metastatic biliary tract cancer (mBTC). METHODS: SGNTUC-019 (ClinicalTrials.gov identifier: NCT04579380 ) is an open-label phase II basket study evaluating the efficacy and safety of tucatinib and trastuzumab in patients with HER2-altered solid tumors. In the biliary tract cancer cohort, patients had previously treated HER2 overexpressing or amplified (HER2+) tumors (identified with local testing) with no prior HER2-directed therapy. The primary end point was confirmed objective response rate (cORR) per investigator assessment. Patients were treated on a 21-day cycle with tucatinib (300 mg orally twice daily) and trastuzumab (8 mg/kg intravenously followed by 6 mg/kg every 3 weeks). RESULTS: Thirty patients were enrolled. As of data cutoff (January 30, 2023), the median duration of follow-up was 10.8 months. The cORR was 46.7% (90% CI, 30.8 to 63.0), with a disease control rate of 76.7% (90% CI, 60.6 to 88.5). The median duration of response and progression-free survival were 6.0 months (90% CI, 5.5 to 6.9) and 5.5 months (90% CI, 3.9 to 8.1), respectively. At data cutoff, 15 patients (50.0%) had died, and the estimated 12-month overall survival rate was 53.6% (90% CI, 36.8 to 67.8). The two most common treatment-emergent adverse events (TEAEs) were pyrexia (43.3%) and diarrhea (40.0%). Grade ≥3 TEAEs were reported in 18 patients (60.0%), with the most common being cholangitis, decreased appetite, and nausea (all 10.0%), which were generally not treatment related. TEAEs led to treatment regimen discontinuation in one patient, and there were no deaths due to TEAEs. CONCLUSION: Tucatinib combined with trastuzumab had clinically significant antitumor activity and was well tolerated in patients with previously treated HER2+ mBTC.

PURPOSE: Earlier detection of cancer recurrence using circulating tumor DNA (ctDNA) to detect molecular residual disease (MRD) has the potential to dramatically affect cancer management. We review evidence supporting the use of ctDNA as a biomarker for detection of MRD and highlight the potential impact that ctDNA testing could have on the conduct of clinical trials. METHODS: We searched the literature using MEDLINE (via PubMed) for articles from January 1, 2000, focusing on studies that assessed ctDNA as a predictor of cancer recurrence. Broadly focused searches on ctDNA and cancer were also performed to provide additional background information. www.clinialtrials.gov was searched to identify trials that incorporate ctDNA testing. RESULTS: Numerous studies across different cancer types indicate that ctDNA-based MRD detection predicts recurrence with high sensitivity and specificity, and with lead times that precede standard imaging by up to 12 months. Recently, ctDNA testing has started being used to enroll MRD-positive patients at high risk of recurrence into trials, promising gains in statistical power that allow clinical utility to be demonstrated with smaller cohorts. Trials where ctDNA testing based-MRD detection is used to stratify patients into low or high-risk categories for treatment assignment are also ongoing. In addition, there is increasing evidence supporting the use of ctDNA dynamics or clearance as a surrogate end point, which could significantly reduce trial duration. CONCLUSION: ctDNA-based trial enrichment across many cancers seems likely to become increasingly common for cost- and time-reduction benefits. Trial efficiency could also benefit from using ctDNA as a surrogate end point, leading to accelerated approval of new therapeutics. A clear demonstration of efficacy from trials that use ctDNA-based MRD detection to assign treatment could transform clinical practice.