Bando, Hideaki

Abstract Background Synthetic control arms (SCAs) derived from historical trial data can complement randomized controlled trials (RCTs), particularly in oncology where feasibility, ethical, and cost constraints may limit conventional trial designs. However, their validity for overall survival (OS) remains uncertain. We evaluated the feasibility and limitations of constructing SCAs from the ARCAD metastatic colorectal cancer (mCRC) database across multiple treatment lines. Methods Seven landmark RCTs representing first-, second-, and third-line settings were selected. External control arms were constructed from ARCAD individual patient-level data using propensity score matching based on key clinical and biological variables from a validated ARCAD prognostic score, with adjustment for geographic region and time era when needed. A prespecified two-step benchmarking framework assessed: (1) control-arm OS reproducibility and (2) virtual trial comparisons between matched synthetic controls and original RCT experimental arms. Agreement was evaluated using hazard ratios (HRs) and Z-tests. Results A total of 28,022 patients met the inclusion criteria. ARCAD-derived SCAs were successfully constructed for all selected RCTs and closely reproduced control-arm OS. After matching, baseline characteristics were well balanced, with minimal differences between included and excluded patients. Virtual trials showed concordant treatment-effect estimates with the original RCTs, with a median absolute HR deviation of 0.05 and no significant differences by Z-tests (P>.05). Survival outcomes were consistently reproduced across treatment lines. Conclusion ARCAD-derived SCAs reliably reproduced control-arm OS and benchmark treatment-effect estimates from landmark RCTs in mCRC. Despite limitations related to residual confounding and missing data, this framework supports benchmarking, trial design, and exploratory analyses when conventional control arms are impractical.

Abstract Background Early tumor shrinkage and depth of response have emerged as potential prognostic indicators in metastatic colorectal cancer (CRC). However, their associations with overall survival, progression-free survival (PFS), and postprogression survival in patients receiving anti–epidermal growth factor receptor (EGFR) antibodies or bevacizumab remain unclear. Methods We analyzed 3219 treatment-naive patients with RAS wild-type metastatic CRC from 8 randomized studies (CRYSTAL, OPUS, PRIME, CAIRO2, CALGB80405, WJOG4407G, ATOM, PARADIGM) in the Aid and Research in Digestive Cancerology database. Early tumor shrinkage was defined as a 20% or more reduction in tumor size at 8 ± 2 weeks, whereas depth of response was assessed by maximum tumor shrinkage at nadir. Cox regression models evaluated the associations of early tumor shrinkage and depth of response with overall survival, PFS, and postprogression survival, adjusting for confounders. A 2-sided test was conducted with a significance level of .05. Results Early tumor shrinkage and depth of response substantially stratified overall survival, PFS, and postprogression survival outcomes across all treatment groups. Early tumor shrinkage positivity was associated with improved overall survival, PFS, and postprogression survival in anti-EGFR and bevacizumab-based therapies, with a trend toward better outcomes in the anti-EGFR group. The depth of response analysis revealed optimal cutoff values of 0.55 for anti-EGFR–based therapy and 0.47 for bevacizumab-based therapy to achieve a median overall survival of approximately 32 months. Conclusions Early tumor shrinkage and depth of response serve as valuable prognostic markers in RAS wild-type metastatic CRC, particularly for patients treated with anti-EGFR antibodies. These findings highlight the potential role of early tumor shrinkage and depth of response in guiding treatment strategies and improving outcomes for patients with CRC.

PURPOSE This study aimed to investigate the clinicomolecular profiles and the efficacy of human epidermal growth factor receptor 2 (HER2)-targeted therapy in HER2 -amplified biliary tract cancer (BTC). METHODS This study was an international collaboration that used combined data from the prospective SCRUM-Japan GOZILA and MONSTAR-SCREEN in Japan and retrospective reviews in the United States; patients with advanced BTC who had received systemic therapy were included. The clinicomolecular profiles were evaluated in an exploratory cohort, whereas the efficacy of HER2-targeted therapy was assessed in a biomarker-selected cohort. RESULTS Of the 439 patients in the exploratory cohort, 43 (10%) had HER2 amplification. The frequencies of coalterations were higher in patients with HER2 amplification versus patients without HER2 amplification including HER2 mutations (26% v 5%, P < .001), TP53 mutations (84% v 61%, P = .003), and BRAF amplification (9% v 2%, P = .030). There were no KRAS mutations identified in patients with HER2- amplified BTC. No significant difference in overall survival (OS) was observed between patients with and without HER2 amplification (median, 17.7 v 16.9 months; hazard ratio [HR], 0.95 [95% CI, 0.65 to 1.40]). Of the 60 patients with HER2 -amplified BTC in the biomarker-selected cohort (43 from Japan and 17 from the United States), the OS was significantly longer in 29 patients who received HER2-targeted therapy than in those who did not receive HER2-targeted therapy (median, 24.3 v 12.1 months; HR, 0.39 [95% CI, 0.23 to 0.82]). Multivariate analysis identified HER2-targeted therapy as an independent prognostic factor for OS (HR, 0.29 [95% CI, 0.14 to 0.58]; P < .001). CONCLUSION HER2 amplification was found in 10% of advanced BTC and was not identified as an independent prognostic factor for OS. Patients with HER2 -amplified BTC derive significant benefit from HER2-targeted therapy.