Published papers

PURPOSE: Non-V600 mutations comprise approximately 35% of all BRAF mutations in cancer. Many of these mutations have been identified as oncogenic drivers and can be classified into three classes according to molecular characteristics. Consensus treatment strategies for class 2 and 3 BRAF mutations have not yet been established. METHODS: We performed a systematic review and meta-analysis with published reports of individual patients with cancer harboring class 2 or 3 BRAF mutations from 2010 to 2021, to assess treatment outcomes with US Food and Drug Administration-approved mitogen-activated protein kinase (MAPK) pathway targeted therapy (MAPK TT) according to BRAF class, cancer type, and MAPK TT type. Coprimary outcomes were response rate and progression-free survival. RESULTS: A total of 18,167 studies were screened, identifying 80 studies with 238 patients who met inclusion criteria. This included 167 patients with class 2 and 71 patients with class 3 BRAF mutations. Overall, 77 patients achieved a treatment response. In both univariate and multivariable analyses, response rate and progression-free survival were higher among patients with class 2 compared with class 3 mutations, findings that remain when analyses are restricted to patients with melanoma or lung primary cancers. MEK ± BRAF inhibitors demonstrated greater clinical activity in class 2 compared with class 3 BRAF-mutant tumors than BRAF or EGFR inhibitors. CONCLUSION: This meta-analysis suggests that MAPK TTs have clinical activity in some class 2 and 3 BRAF-mutant cancers. BRAF class may dictate responsiveness to current and emerging treatment strategies, particularly in melanoma and lung cancers. Together, this analysis provides clinical validation of predictions made on the basis of a mutation classification system established in the preclinical literature. Further evaluation with prospective clinical trials is needed for this population.

Fibroblast growth factor receptor 2b (FGFR2b) is a novel protein biomarker expressed in gastric and gastroesophageal junction tumors (GC/GEJC). Phase III trials are evaluating the efficacy and safety of FGFR2b-targeting therapies. However, features of FGFR2b-expressing tumors and co-occurrence of FGFR2b expression with currently actionable biomarkers in gastric cancer remain unclear.We carried out a single-institution retrospective cohort study of patients who initiated systemic therapy for GC/GEJC to evaluate features of FGFR2b-positive tumors, first-line (1L) treatments received, and co-occurrence with select actionable biomarkers [human epidermal growth factor receptor 2 (HER2), mismatch repair, programmed death-ligand 1 (PD-L1), claudin-18 isoform 2]. A sample was deemed FGFR2b-positive when any (>0%) tumor cells exhibiting moderate (2+) or strong (3+) membrane staining were detected ('any 2+/3+'). Other biomarkers were assessed based on current clinical guidelines. FGFR2b-stratified real-world overall survival (OS) was estimated using the Kaplan-Meier and Cox proportional regression models.Of 547 GC/GEJC patients identified, 492 (89.9%) met inclusion/exclusion criteria, had evaluable FGFR2b staining, and had complete clinical data. Estimated prevalence of FGFR2b any 2+/3+ was 15.4% [95% confidence interval (CI) 12.4% to 19.0%] in the full cohort of patients and 29.8% (95% CI 22.0% to 38.7%) in patients with samples collected within 1.5 years of study initiation. The majority (53.9%; 95% CI 42.1% to 65.5%) of FGFR2b any 2+/3+ tumor specimens were negative for other assessed biomarkers at a PD-L1 cut-off of combined positive score ≥5. In HER2-negative patients treated in 1L with chemotherapy alone, median OS was 11.5 months (95% CI 10.0-16.3 months) and 15.3 months (95% CI 13.0-16.8 months) for FGFR2b any 2+/3+ and FGFR2b 0/1+, respectively. There was no association between FGFR2b overexpression level and OS [adjusted hazard ratio (HR) 1.14, 95% CI 0.84-1.55].This study revealed limited overlap of FGFR2b overexpression with currently actionable biomarkers, suggesting FGFR2b is a novel biomarker that identifies a distinct GC/GEJC patient population who may benefit most from an FGFR2b-targeting therapy.

BACKGROUND: Early detection of cancer and precise recurrence monitoring remain major unmet needs in oncology. Conventional screening is limited to a few cancer types, leaving nearly half of cancers without established programs. Multi-cancer early detection (MCED) tests based on circulating tumor biomarkers have shown promise, but sensitivity for early-stage remains a challenge. In parallel, detection of molecular residual disease (MRD) using circulating tumor DNA (ctDNA) has emerged as a powerful prognostic and predictive tool, though current assays remain limited in sensitivity and specificity. This study aims to integrate multi-omics data to develop more refined and highly sensitive MCED and MRD assays. METHODS: This study leverages clinical information and biospecimens from patients with cancer and cancer-naïve individuals. Samples from patients with cancers will be derived from the MONSTAR-SCREEN-3 study, while those from cancer-naïve individuals will be obtained from the Tohoku Medical Megabank Project. Comprehensive analyses will include whole-genome sequencing (WGS), whole-exome sequencing (WES), whole-transcriptome sequencing (WTS), proteomics, metabolomics, and microbiome profiling using stool and saliva. Artificial intelligence (AI)-based multi-omics integration will be performed to develop novel MCED and MRD assays and to evaluate their clinical performance. The primary endpoints are the sensitivity and specificity of MCED and MRD assays. DISCUSSION: This is the first large-scale study to integrate comprehensive multi-omics profiling with AI for MCED and MRD assay development. The findings are expected to advance precision oncology by improving early diagnosis and recurrence monitoring. TRIAL REGISTRATION: UMIN000053815, approved by the Institutional Review Board of the National Cancer Center Hospital East.

"NeoRAS WT" refers to the loss of RAS mutations (MTs) following first-line treatment in metastatic colorectal cancer (mCRC). We evaluate the incidence and clinicopathological characteristics of NeoRAS WT mCRC using next-generation sequencing of plasma circulating tumor DNA. Patients with mCRC enrolled in the GOZILA study initially diagnosed with tissue RAS MT mCRC and received subsequent systemic therapy are eligible. NeoRAS WT is defined as the absence of detectable RAS MT in plasma and assessed in all eligible patients (Group A) and in a subgroup with at least one somatic alteration detected in plasma (Group B). Overall, 478 patients are included. NeoRAS WT prevalence is 19.0% (91/478) in Group A and 9.8% (42/429) in Group B. Absence of liver or lymph node metastasis and tissue RAS MTs other than KRAS exon 2 MTs are significantly associated with NeoRAS WT emergence. Overall, 1/6 and 2/6 patients with NeoRAS WT treated with anti-EGFR monoclonal antibodies (mAbs) show partial response and stable disease for ≥6 months, respectively. NeoRAS WT mCRC is observed at a meaningful prevalence, and anti-EGFR mAb-based therapy may be effective.

Background: Evaluating multiple biomarkers including human epidermal growth factor receptor 2 (HER2), mismatch repair (MMR) status, programed death-ligand 1 (PD-L1), and claudin 18.2 (CLDN18.2) is essential for selecting appropriate first-line therapy of metastatic gastroesophageal adenocarcinoma (mGEA). However, this can be challenging if tumor tissue amount is limited and may cause delays in the initiation of chemotherapy. Therefore, we assessed the feasibility of multiple biomarkers testing in routine clinical practice. Materials and methods: We reviewed the medical records of treatment-naïve patients with mGEA who underwent prospective multiple biomarkers testing between April 2022 and October 2023 in our institution. Eight biomarker status including HER2, MMR, PD-L1, CLDN18.2, Epstein–Barr virus, fibroblast growth factor receptor 2, epidermal growth factor receptor and mesenchymal epithelial transition expressions were simultaneously examined using biopsy or surgical specimens. Results: A total of 203 patients with mGEA were analyzed. Most patients underwent gastroendoscopy and tumor biopsy shortly after referral to our institution. Biomarkers testing was successfully completed on the first attempt in 198 patients (97.5%). With additional steps including additional biopsy or asking remaining tumor samples from the referring hospital, the biomarker results were eventually available in all cases. The median turnaround time from sample collection to reporting results was 7 days. Consequently, 178 patients (87.7%) could receive first-line treatment after obtaining the biomarker status. Conclusions: Multiple biomarkers testing for patients with mGEA was feasible in clinical practice. Establishment of a testing infrastructure based on the collaboration with multiple departments is essential for implementing biomarker-driven precision treatment.

BACKGROUND: In this study, we evaluated the prognostic value of Immunoscore in patients with stage I−III colon cancer (CC) in the Asian population. These patients were originally included in an international study led by the Society for Immunotherapy of Cancer (SITC) on 2681 patients with AJCC/UICC-TNM stages I−III CC. METHODS: CD3+ and cytotoxic CD8+ T-lymphocyte densities were quantified in the tumor and invasive margin by digital pathology. The association of Immunoscore with prognosis was evaluated for time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS). RESULTS: Immunoscore stratified Asian patients (n = 423) into different risk categories and was not impacted by age. Recurrence-free rates at 3 years were 78.5%, 85.2%, and 98.3% for a Low, Intermediate, and High Immunoscore, respectively (HR[Low-vs-High] = 7.26 (95% CI 1.75−30.19); p = 0.0064). A High Immunoscore showed a significant association with prolonged TTR, OS, and DFS (p < 0.05). In Cox multivariable analysis stratified by center, Immunoscore association with TTR was independent (HR[Low-vs-Int+High] = 2.22 (95% CI 1.10−4.55) p = 0.0269) of the patient’s gender, T-stage, N-stage, sidedness, and MSI status. A significant association of a High Immunoscore with prolonged TTR was also found among MSS (HR[Low-vs-Int+High] = 4.58 (95% CI 2.27−9.23); p ≤ 0.0001), stage II (HR[Low-vs-Int+High] = 2.72 (95% CI 1.35−5.51); p = 0.0052), low-risk stage-II (HR[Low-vs-Int+High] = 2.62 (95% CI 1.21−5.68); p = 0.0146), and high-risk stage II patients (HR[Low-vs-Int+High] = 3.11 (95% CI 1.39−6.91); p = 0.0055). CONCLUSION: A High Immunoscore is significantly associated with the prolonged survival of CC patients within the Asian population.

Background: Liquid biopsy is an alternative to tissue specimens for tumour genotyping. However, the frequency of genomic alterations with low circulating-tumour DNA (ctDNA) shedding is shown in pancreatic ductal adenocarcinoma (PDAC). We, therefore, investigated the prevalence of KRAS mutations and ctDNA fraction by the metastatic site in patients with PDAC. Methods: This study enrolled previously treated PDAC patients from a plasma genomic profiling study; ctDNA analysis was performed using Guardant360 at disease progression before initiating subsequent treatment. Results: In 512 patients with PDAC, KRAS mutations were detected in 57%. The frequency of KRAS mutation in ctDNA differed depending on the metastatic organ; among patients with single-organ metastasis (n = 296), KRAS mutation detection rate was significantly higher in patients with metastasis to the liver (78%). In addition, the median maximum variant allele frequency (VAF) was higher with metastasis to the liver (1.9%) than with metastasis to the lungs, lymph nodes, peritoneum or with locally advanced disease (0.2%, 0.4%, 0.2% and 0.3%, respectively). Conclusion: The prevalence of KRAS mutations and maximum VAF were higher in patients with metastasis to the liver than in those with metastasis to other sites. This study indicated the clinical utility of ctDNA analysis, especially in PDAC with liver metastases.

Meta-analysis based on individual participant data (IPD) is a powerful methodology for synthesizing evidence by combining information drawn from multiple trials. Hitherto, its principal application has been in questions of clinical management, but an increasingly important use is in clarifying trials methodology, for instance in the selection of endpoints, as discussed in this review. In oncology, the Aide et Recherche en Cancérologie Digestive (ARCAD) Metastatic Colorectal Cancer Database is a leader in the use of IPD-based meta-analysis in methodological research. The ARCAD database contains IPD from more than 38 000 patients enrolled in 46 studies and continues to collect phase III trial data. Here, we review the principal findings of the ARCAD project in respect of endpoint selection and examine their implications for cancer trials. Analysis of the database has confirmed that progression-free survival (PFS) is no longer a valid surrogate endpoint predictive of overall survival in the first-line treatment of colorectal cancer. Nonetheless, PFS remains an endpoint of choice for most first-line trials in metastatic colorectal cancer and other solid tumors. Only substantial PFS effects are likely to translate into clinically meaningful benefits, and accordingly, we advocate an oncology research model designed to identify highly effective treatments in carefully defined patient groups. We also review the use of the ARCAD database in assessing clinical response including novel response metrics and prognostic markers. These studies demonstrate the value of IPD as a tool for methodological studies and provide a reference point for the expansion of this approach within clinical cancer research.

Background: Universal tumor screening (UTS) for Lynch syndrome (LS) is cost-effective in Western countries; however, cost-effectiveness varies based on the frequency of hereditary diseases and testing costs. This study aimed to clarify the clinical utility and cost-effectiveness of UTS in identifying LS in patients with stage II/III colorectal cancer (CRC) in Japan. Methods: This single-center, prospective cohort study evaluated 591 consecutive patients who underwent surgical resection for Stage II/III colorectal adenocarcinoma between 2016 and 2018. Immunohistochemistry (IHC) was used to evaluate mismatch repair (MMR) proteins. In patients with MMR deficiency, BRAF V600E mutational testing and genetic counseling/testing were performed to identify LS based on MMR deficiency patterns. Genetic counseling/testing was also conducted for blood relatives upon request. The cost-effectiveness of implementing UTS was evaluated from the perspective of healthcare payers using a Markov state-transition model, with the incremental cost-effectiveness ratio (ICER) per quality-adjusted life year (QALY) gained as the reference value. Results: A total of 40 cases (6.8%) exhibited MMR deficiency; 12 cases (2.0%) had LS, of whom 2 (16.7%) did not meet Amsterdam criteria II or any criteria of the revised Bethesda guidelines. Eleven relatives of five LS probands underwent genetic testing, and six (54.5%) were diagnosed with LS. The ICER for UTS was JPY 0.6 million per QALY gained, substantially below the Japanese threshold of JPY 5.0–6.0 million per QALY. Conclusions: The UTS of LS in patients with stage II/III CRC is a useful and cost-effective tool in Japan.

Background: Identification of homologous recombination deficiency (HRD) remains a challenge in advanced pancreatic cancer (APC). We investigated the utility of circulating tumour DNA (ctDNA) profiling in the assessment of BRCA1/2 and ATM mutation status and treatment selection in APC. Methods: We analysed clinical and ctDNA data of 702 patients with APC enroled in GOZILA, a ctDNA profiling study using Guardant360. Results: Inactivating BRCA1/2 and ATM mutations were detected in 4.8% (putative germline, 3.7%) and 4.4% (putative germline, 0.9%) of patients, respectively. Objective response (63.2% vs. 16.2%) and PFS (HR 0.55, 95% CI 0.32–0.93) on platinum-containing chemotherapy were significantly better in patients with putative germline BRCA1/2 (gBRCA) mutation than those without. In contrast, putative gBRCA mutation had no impact on the efficacy of gemcitabine plus nab-paclitaxel. In 2 patients treated with platinum-containing therapy, putative BRCA2 reversion mutations were detected. Three of seven patients with somatic BRCA mutations responded to platinum-containing therapy, while only one of four with putative germline ATM mutations did. One-third of somatic ATM mutations were in genomic loci associated with clonal haematopoiesis. Conclusion: Comprehensive ctDNA profiling provides clinically relevant information regarding HRD status. It can be a practical, convenient option for HRD screening in APC.

Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome, associated with substantially increased risks of colorectal and gynecologic malignancies. Endometrial cancer may serve as a sentinel cancer for LS, placing gynecologists and gynecologic oncologists in a key position for early recognition and long-term management. This joint statement was developed through a multidisciplinary process involving the Japan Society of Gynecologic Oncology, the Japan Society of Clinical Oncology, the Japanese Society of Hereditary Tumors, and the Japanese Society for Cancer of the Colon and Rectum. It aims to clarify the clinical utility of diagnosing LS in gynecologic oncology within the Japanese healthcare system. We outline a tumor-first paradigm in which universal mismatch repair immunohistochemistry and/or microsatellite instability testing for endometrial cancer facilitates LS detection and provides actionable biomarkers for systemic therapy. This statement summarizes the clinical impact of LS diagnosis across gynecologic oncology. We highlight patterns of synchronous and metachronous malignancies and the prevalence of LS in ovarian cancer, particularly in endometrioid and clear–cell subtypes. We discuss surgical implications, including risk-reducing hysterectomy with bilateral salpingo-oophorectomy, consideration of concomitant gynecologic risk-reducing surgery during colorectal cancer resection, and individualized ovarian preservation in selected early-stage endometrial cancer or atypical endometrial hyperplasia. We also review the treatment relevance of deficient mismatch repair/microsatellite instability-high status for immune checkpoint inhibitors and emerging fertility-preserving approaches, and address surveillance, cascade testing for relatives, implementation barriers, and the need for multidisciplinary pathways and healthcare system–level support to ensure equitable access to genetic counseling and testing.

28Background: CheckMate 8HW (CA209-8HW), a Phase 3, randomized, 3-arm open-label study, evaluated nivolumab monotherapy (nivo: Arm A), nivolumab plus ipilimumab combination therapy (nivo+ipi: Arm B) or investigator’s choice chemotherapy (chemo: Arm C) for the treatment of subjects with deficient mismatch repair/microsatellite instability- high (dMMR/MSI-H) metastatic colorectal cancer (mCRC). The Idylla companion diagnostic (CDx) MSI Test was used as an investigational method, next to an IHC MMR method, to centrally and retrospectively confirm MSI-H status in trial participants enrolled by local MSI-H/dMMR assays. Methods: Clinical utility of the Idylla CDx MSI Test (Idylla) in the intended use population was assessed by evaluating: (1) progression-free survival (PFS) and the corresponding hazard ratio (HR) of nivo+ipi vs. chemotherapy in the 1st line (1L) therapy of mCRC, (2) PFS HR of nivo+ipi vs. nivo in all lines, and (3) objective response rates (ORR) of nivo+ipi and nivo in all lines. Enrollment of patients in the trial was based on local dMMR/MSI-H status per at least one of the three methods (IHC, PCR, NGS), referred as the Clinical Trial Assay positive (CTA+) population. The Idylla test was used at the central laboratory to retrospectively evaluate the patients’ MSI status by testing the submitted tumor specimens. A bridging study between the efficacies of the trial randomized population (CTA+) and the intended use population of the Idylla CDx MSI Test was conducted to demonstrate the clinical utility of the test. Results: Of the 837 CTA+ subjects randomized to all arms, 725 subjects had valid Idylla results by central testing. From the remaining 112 subjects, 7 were tested by the Idylla but resulted in an invalid result and 105 were unevaluable by Idylla as they did not meet the test or other quality requirements. In all CTA+ subjects in 1L, the PFS HR for nivo+ipi (n=200) vs chemo (n=101) was 0.32 (95% CI of 0.22 - 0.45). In comparison, in the CTA+ subjects centrally determined as MSI-H by Idylla, the PFS HR for nivo+ipi (n=147) vs chemo (n=71), in 1L was 0.20 (95% CI: 0.12–0.31). In addition, in CTA+ subjects centrally determined to be MSS by Idylla, the PFS HR of nivo+ipi (n=30) vs chemo (n=15) in 1L was 1.51 (95%CI: 0.68-3.33). In the nivo+ipi vs nivo comparison in all lines of therapy, the PFS HR for centrally determined Idylla MSI-H group (n=504) was 0.60 (95% CI: 0.45–0.80 ) compared to PFS HR of 0.63 (95% CI: 0.51–0.79) in CTA+ (n=705). The ORRs for nivo monotherapy and for nivo+ipi in centrally determined Idylla MSI-H group were 58.7% (95% CI, 52.3, 64.9) and 73.5% (95% CI: 67.7, 78.8), respectively, in all lines of therapy. Conclusions: The Idylla CDx MSI Test can effectively identify MSI-H mCRC patients who may benefit from treatment with nivolumab as a monotherapy and/or treatment with nivolumab in combination with ipilimumab.

Background: The clinical utility of upfront ctDNA genomic profiling is not established in treatment (tx)-naïve pts with mCRC. Methods: GOZILA is a nationwide plasma genomic profiling study using Guardant360 CDx for advanced solid tumors. We assessed ctDNA molecular profile and its association with treatment efficacy in pts with mCRC who were enrolled in GOZILA from January 2018 to July 2022 and underwent ctDNA genotyping before initiation of first-line systemic tx. ctDNA fraction was defined as the maximum variant allelic frequency of somatic alteration and pts were classified into three groups based on ctDNA fraction: low (<1%), middle (≥1% and <10%) and high (≥10%) ctDNA fraction groups. Results: This study included 418 pts with mCRC receiving upfront ctDNA genotyping. Median turnaround time of ctDNA test was 7 days, comparable with standard-of-care (SOC) tissue RAS/BRAF testing (7 days) and microsatellite instability (MSI) testing (8 days). Pathogenic alterations were detected in 384 pts (92%), and concordance rates for RAS and BRAF mutation (mut) compared to SOC tissue-based testing were 91% and 97%, respectively. Based on biomarkers identified by ctDNA genotyping, 142 (40%) pts were treated with matched targeted tx: anti-EGFR antibody for RAS/BRAF wild-type (n=137), BRAF inhibitor for BRAF V600E mutation (n=4), and anti-PD-1 antibody for MSI high (n=1). Low, middle, and high ctDNA fraction groups included 87, 97 and 234 pts, respectively, and had significantly different median progression-free survival (PFS) (p<0.01, table) and overall survival (OS) (p<0.01, table), respectively. In 13 pts who repeated ctDNA test before second-line tx, those with elevated ctDNA fraction compared to upfront ctDNA had significantly shorter PFS (median, 3.8 vs. 8.1 months; HR, 5.7, 95% CI, 0.9 to 35.1) and OS (median, 8.2 vs. 17.4 months; HR, 11.3, 95% CI, 1.2 to 105.9) of second-line tx that those with not elevated ctDNA fraction. Conclusions: Upfront ctDNA genotyping successfully identified actionable genomic alterations in pts with mCRC. ctDNA fraction in upfront ctDNA was significantly associated with efficacy of first-line tx and ctDNA fraction monitoring may be useful in determination of subsequent tx.