Background: Regorafenib or trifluridine/tipiracil as third-line treatment have limited efficacy in metastatic colorectal cancer (mCRC). Methods: This Phase 2 trial evaluated the efficacy and safety of irinotecan plus cetuximab rechallenge as third-line treatment in KRAS wild-type mCRC patients who achieved clinical benefit with first-line cetuximab-containing therapy. The primary endpoint was 3-month progression-free survival (PFS) rate. A sample size was calculated; 30 patients with a 3-month PFS rate of 45% deemed promising and 15% unacceptable. Patients with greater and less than the cut-off value of cetuximab-free intervals (CFIs) were classified into the long and short CFI groups, respectively, in subgroup analyses. Results: Among 34 eligible patients who received treatment at least once, 3-month PFS rate was 44.1% (95% confidence interval, 27.4–60.8%). The median PFS and overall survival (OS) were 2.4 and 8.2 months, respectively. The response and disease control rates were 2.9 and 55.9%, respectively. PFS and OS were significantly longer in the long- than in the short CFI group. Conclusions: Irinotecan plus cetuximab rechallenge as third-line treatment for KRAS wild-type mCRC was safe and had promising activity, especially in those with a long CFI, warranting further investigation in a Phase 3 randomised trial. Clinical trial registration: UMIN000010638

DESTINY-CRC01 (NCT03384940) was a multicentre, open-label, phase 2 study that investigated the safety and efficacy of trastuzumab deruxtecan (T-DXd) in patients with human epidermal growth factor receptor 2 (HER2)-expressing metastatic colorectal cancer (CRC). The present exploratory biomarker analysis aims to investigate relationships between biomarkers and clinical outcomes in patients with HER2-positive (immunohistochemistry [IHC] 3+ or IHC 2+ and in situ hybridization [ISH] positive) Cohort A (N = 53) of DESTINY-CRC01. Higher levels of HER2 biomarkers in baseline tissue and liquid biopsies, including HER2 status (IHC/ISH), HER2/CEP17 ratio, HER2 ISH signals, HER2 H-score, plasma HER2 (ERBB2) amplification status, HER2 adjusted plasma copy number, and HER2 extracellular domain correlate with antitumor activity (indicated by objective response rate, progression-free survival, and overall survival) of T-DXd. Baseline circulating tumor DNA (ctDNA) analysis suggests antitumor activity of T-DXd in patients who had baseline activating RAS, PIK3CA, or HER2 mutations detected in ctDNA.

Purpose: Rapid decision-making is essential in precision medicine for initiating molecular targeted therapy for patients with cancer. This study aimed to extract pathomorphologic features that enable the accurate prediction of genetic abnormalities in cancer from hematoxylin and eosin images using deep learning (DL). Experimental Design: A total of 1,657 images (one representative image per patient) of thin formalin-fixed, paraffin-embedded tissue sections from either primary or metastatic tumors with next-generation sequencing–confirmed genetic abnormalities—including BRAFV600E and KRAS mutations, and microsatellite instability high (MSI-H)—that are directly relevant to therapeutic strategies for advanced colorectal cancer were obtained from the nationwide SCRUM-Japan GI-SCREEN project. The images were divided into three groups of 986, 248, and 423 images to create one training and two validation cohorts, respectively. Pathomorphologic feature-prediction DL models were first developed on the basis of pathomorphologic features. Subsequently, gene-prediction DL models were constructed for all possible combinations of pathomorphologic features that enabled the prediction of gene abnormalities based on images filtered by the combination of pathomorphologic feature-prediction models. Results: High accuracies were achieved, with AUCs > 0.90 and 0.80 for 12 and 27, respectively, of 33 analyzed pathomorphologic features, with high AUCs being yielded for both BRAFV600E (0.851 and 0.859) and MSI-H (0.923 and 0.862). Conclusions: These findings show that novel next-generation pathology methods can predict genetic abnormalities without the need for standard-of-care gene tests, and this novel next-generation pathology method can be applied for colorectal cancer treatment planning in the near future.

Background: This open-label, multicentre, phase II/III trial assessed the noninferiority of trifluridine/tipiracil (FTD/TPI) plus bevacizumab vs. fluoropyrimidine and irinotecan plus bevacizumab (control) as second-line treatment for metastatic colorectal cancer (mCRC). Methods: Patients were randomised (1:1) to receive FTD/TPI (35 mg/m² twice daily, days 1–5 and days 8–12, 28-day cycle) plus bevacizumab (5 mg/kg, days 1 and 15) or control. The primary endpoint was overall survival (OS). The noninferiority margin of the hazard ratio (HR) was set to 1.33. Results: Overall, 397 patients were enrolled. Baseline characteristics were similar between the groups. Median OS was 14.8 vs. 18.1 months (FTD/TPI plus bevacizumab vs. control; HR 1.38; 95% confidence interval [CI] 0.99–1.93; P_{noninferiority} = 0.5920). In patients with a baseline sum of the diameter of target lesions of <60 mm (n = 216, post hoc analyses), the adjusted median OS was similar between groups (FTD/TPI plus bevacizumab vs. control, 21.4 vs. 20.7 months; HR 0.92; 95% CI 0.55–1.55). Grade ≥3 adverse events (FTD/TPI plus bevacizumab vs. control) included neutropenia (65.8% vs. 41.6%) and diarrhoea (1.5% vs. 7.1%). Conclusions: FTD/TPI plus bevacizumab did not demonstrate noninferiority to fluoropyrimidine and irinotecan plus bevacizumab as second-line treatment for mCRC. Clinical trial registration: JapicCTI-173618, jRCTs031180122.

There is no standard first-line chemotherapy for advanced gastric cancer with severe peritoneal metastasis. Although fluoropyrimidine is often used, its efficacy is limited, and it remains unclear whether combination therapy with platinum improves clinical outcomes. This retrospective study involved patients at six Japanese academic hospitals between 2010 and 2016. Patients with advanced gastric cancer and severe peritoneal metastasis were included if they had massive ascites and/or inadequate oral intake requiring intravenous nutritional support. We then compared the efficacy and safety of fluoropyrimidine monotherapy with those of fluoropyrimidine/platinum combination therapy. Compared with the combination therapy group (n = 64), the monotherapy group (n = 65) had worse general health (more patients with elderly age, performance status > 2, and having both massive ascites and inadequate oral intake). Both overall survival (9.0 vs 5.0 months, p < 0.01) and progression-free survival (4.3 vs 2.3 months, p < 0.01) were significantly longer in the combination group, and the significance remained after adjusting for prognostic variables (hazard ratios of 0.47 and 0.41, respectively; p < 0.01). Improvements in ascites and oral intake were also greater in the combination group. Although neutropenia (grade ≥ 3) occurred more frequently with combination therapy, both treatments in this study were tolerable. Combination therapy with fluoropyrimidine and platinum might be more effective than monotherapy with fluoropyrimidine and was tolerable for patients with advanced gastric cancer and severe peritoneal metastasis.