Nationwide Cancer Genome Screening Project Research Articles

Abstract PO1-13-02: Circulating tumor DNA mutation landscape in HR+/HER2− patients with mBC treated with cyclin-dependent kinase 4/6 inhibitors in the SCRUM-Japan MONSTAR-SCREEN study

Abstract Introduction: Combination of cyclin-dependent kinase 4 and 6 inhibitors (CDK 4/6i) + endocrine therapy (ET) is recommended as first- or second-line treatment (1L or 2L Tx) for hormone receptor-positive, human epidermal growth factor receptor-2-negative metastatic breast cancer (HR+/HER2− mBC). In this study, we assessed cancer-specific genetic alterations in circulating tumor DNA (ctDNA) and tissues in abemaciclib-treated patients with HR+/HER2− mBC in Japan. Methods: MONSTAR-SCREEN is a multicenter study and part of a nation-wide cancer genome screening project for patients with advanced solid tumors (SCRUM Japan). Regardless of the Tx line, the current analysis included abemaciclib-treated patients with HR+/HER2− mBC (N=97). Data were collected between Jan 2020 and Dec 2021. Blood samples collected at ≤21 days before abemaciclib initiation (baseline; n=77) and at disease progression or Tx discontinuation (paired post-Tx; n=33) were tested with the FoundationOne® Liquid Companion Diagnostic panel. Additionally, archival or fresh tissue biopsy samples (n=79) were tested with the FoundationOne® Companion Diagnostic panel. Patient characteristics, baseline genetic alterations, neoplastic burden (measured by shedding rate and maximum variant allele frequency [VAF]), and alterations at clinical progression were reported. Results: The total population (N=97) included patients with next generation sequencing ctDNA and/or tissue data. All were female with median age of 57 years (interquartile range 50, 67). Bone, either alone or with other sites, was the most common metastatic site (61%). 78% of patients received abemaciclib in the first or second line of Tx (LoT). Fulvestrant with or without gonadotropin-releasing hormone (55%), letrozole (24%), and anastrozole (11%) were the most common concomitant drugs. Among patients with baseline ctDNA data (n=77), 30% and 21% had received prior ET and prior chemotherapy, respectively. In baseline ctDNA samples, PIK3CA (37%) and TP53 (28%) alterations were detected most frequently across all LoT; while ESR1 (16%), GATA3 (11%), and FGF3/4/19 (9%) were more frequently detected in samples from later LoT. The frequency of ESR1 alterations (p< 0.01), shedding rate, and maximum VAF (both p< 0.05) were significantly higher in prior ET recipients than those who did not receive prior ET. Frequency of post-Tx ESR1 alterations numerically decreased from baseline in patients on fulvestrant (23% to 18%) and numerically increased in patients on aromatase inhibitors (27% to 45%). Other genes showed either a numeric increase or similar alteration frequency between the baseline and post-tx. Newly acquired post-Tx alterations were detected in FGF3/4/19 (18%); PIK3CA, TP53, and RB1 (all 15%) and ESR1 (12%). The table shows PIK3CA and ESR1 alterations detected at baseline and post-Tx. In the tissue samples (n=79), TP53 (32% vs 20%) and ESR1 (14% vs 7%) alterations were numerically more frequent in metastatic versus primary lesions. Other gene alteration frequencies were similar. Conclusion: PIK3CA alterations were the most frequently detected genetic alterations in both pre- and post- abemaciclib Tx patients with HR+/HER2− mBC. Patients with prior ET had more frequent ESR1 alterations and higher neoplastic burden. Evidence from this study provides insight into the ctDNA dynamics and potential resistance mechanisms in patients with HR+/HER2− mBC. PIK3CA and ESR1 alterations detected in circulating tumor DNA at baseline and post abemaciclib treatment Citation Format: Masaya Hattori, Victoria Serelli-Lee, Yoichi Naito, Takashi Yamanaka, Hiroyuki Yasojima, Rikiya Nakamura, Takao Fujisawa, Mitsuho Imai, Yoshiaki Nakamura, Hideaki Bando, Tsutomu Kawaguchi, Takayuki Yoshino, Hiroji Iwata. Circulating tumor DNA mutation landscape in HR+/HER2− patients with mBC treated with cyclin-dependent kinase 4/6 inhibitors in the SCRUM-Japan MONSTAR-SCREEN study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-13-02.

Evaluation of a real-world clinico-genomics database of patients with upper gastrointestinal (GI) malignancies in Japan.

400 Background: The genomic profile of gastrointestinal (GI) cancers provides essential information for precision medicine, however, there is limited availability of real-world data in Asian populations as they are not well-represented in most publicly accessible clinico-genomic databases. In this retrospective study, we evaluated the clinical and genomic characteristics of upper GI cancer patients in the database from an academia-industry collaborative nationwide cancer genome screening project in Japan. Methods: The Screening Projectfor Individualized Medicine in Japan (J-SCRUM) GI-SCREEN enrolled advanced GI cancer patients from 26 sites before planned or during systemic therapy from 2015 to 2019. Archived formalin-fixed paraffin-embedded tumor tissue was analyzed by next-generation sequencing (NGS) using Oncomine Cancer Research Panel and Oncomine Comprehensive Assay. Patients with gastric (GC), esophageal (EC) and pancreatic (PC) cancers were identified in the database. The frequency of key actionable genomic alterations in each cancer cohort was explored and compared to similar upper GI cohorts in The Cancer Genome Atlas (TCGA), a publicly available genomics database initiated in 2005 and concluded sample collection in 2013 with most samples from White cancer patients. Results: A total of 872 GC (mean age at registration [SD]: 64y [12]; percent males: 65%), 265 EC (64y [9]; 78%) and 495 PC (64y [10]; 60%) patients were identified. The majority (>70%) of samples were obtained from primary sites. Adenocarcinoma was the most common histological type for GC (85%) ad PC (76%), while squamous cell (76%) was the most common among EC patients. In the GC cohort, the prevalence of key actionable genomic alterations in J-SCRUM GI-SCREEN vs TCGA (N = 380) was, TP53 mutation (49% vs 49%), ERBB2 amplification (14% vs 13%), PIK3CA mutation (11% vs 14%), MYC amplification (9% vs 12%) and MET amplification (2% vs 3%). In the EC cohort, the prevalence in J-SCRUM vs TCGA (N = 182) was TP53 mutation (77% vs 87%), NFE2L2 mutation (21% vs 10%), PIK3CA mutation (9% vs 9%) and CDKN2A mutation (8% vs 8%). In the PC cohort, the prevalence in J-SCRUM vs TCGA (N = 150) was KRAS hotspot mutation (90% vs 93%), KRAS G12D (43% vs 41%), KRAS G12V (32% vs27%), TP53 mutation (58% vs 64%), BRCA1/2 deleterious mutation (5% vs 5%), ATM deleterious mutation (6% vs 5%) and MYC amplification (5% vs 5%). Conclusions: As part of a nationwide cancer genome screening project, J-SCRUM GI SCREEN database provides comprehensive genomic information for Asian population (Japan). The prevalence of key actionable gene alterations in each tumor type was highly comparable between J-SCRUM GI-SCREEN and TCGA data.

94P Sidedness-dependent prognostic impact of gene alterations in metastatic colorectal cancer in the nationwide cancer genome screening project in Japan (SCRUM-Japan GI-SCREEN)

94P Sidedness-dependent prognostic impact of gene alterations in metastatic colorectal cancer in the nationwide cancer genome screening project in Japan (SCRUM-Japan GI-SCREEN)

Sidedness-Dependent Prognostic Impact of Gene Alterations in Metastatic Colorectal Cancer in the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN).

The treatment strategies and prognoses of patients with metastatic colorectal cancer (CRC) differ according to the sidedness of the primary tumor. TP53 gain-of-function (GOF) and non-GOF variants have been reported to be differentially associated with prognosis by sidedness. We aimed to evaluate the sidedness-dependent prognostic impact of gene alterations in metastatic CRC. Patients enrolled between April 2017 and March 2019 were included in this study. Those excluded were individuals whose tumor tissues were obtained after chemotherapy and those who were enrolled in the study more than six months after starting first-line chemotherapy. Finally, we assessed 531 patients who underwent complete gene sequencing. The study revealed a significant difference in overall survival between individuals with left-sided CRC (n = 355) and right-sided colon cancer (CC) (n = 176) when considering the TP53 non-GOF variant, KRAS wild-type, NOTCH1 wild-type, NOTCH1 covariant, NOTCH3 sole variant, and MYC amplification. Multivariate analysis on each side revealed that the TP53 GOF and KRAS variants were independent poor prognostic factors for left-sided CRC (p = 0.03 and p < 0.01, respectively), and the TP53 non-GOF variant, BRAF V600E, and MYC amplification for right-sided CC (p < 0.05, p < 0.01, and p = 0.02, respectively). The NOTCH3 sole variant was an independent and favorable prognostic factor for left-sided CRC (p < 0.01). The prognostic significance of gene alterations differed between left-sided CRC and right-sided CC.

NOTCH gene alterations in metastatic colorectal cancer in the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN).

Activated Notch receptor signaling has been implicated in tumor growth and progression in colorectal cancer (CRC). However, the pathogenic relevance of NOTCH gene alterations remains unclear. The aim of this study was to clarify mutational landscapes and assess their clinical significance in patients with metastatic CRC. Pre-chemotherapy tumor tissues obtained from 1154 metastatic CRC patients in the Nationwide Cancer Genome Screening Project in Japan between April 2017 and March 2019 were studied using the Oncomine Comprehensive Assay. The frequencies of NOTCH1, NOTCH2, and NOTCH3 nonsynonymous sequence variants were 11.5%, 4.4%, and 10.4%, respectively. The majority of variants were missense of unknown significance that were distributed across all domains of all three NOTCH genes. The gain-of-function mutations in NOTCH reported in multiple malignancies were not identified. The NOTCH amplification rate was less than 1%. No NOTCH fusions were detected. In patients who were registered before, or within 1year of, first-line chemotherapy, overall survival for 51 patients with only NOTCH3 variants was significantly longer than for 540 patients with no NOTCH variants (median, 40.2months vs 27.7months; P = 0.04). Multivariate analysis revealed that variant NOTCH3 was an independent prognostic factor for increased survival (hazard ratio 0.61, 95% confidence interval, 0.39-0.94; P = 0.03) besides poor prognostic factors associated with mutant TP53, KRAS, and BRAF, as well as amplified MYC. NOTCH genes are unlikely to harbor driver mutations and amplifications in patients with metastatic CRC. NOTCH3 variant should be further investigated as a favorable prognostic marker.

60MO Gut microbiota and efficacy of immune-checkpoint inhibitors (ICIs) in patients (pts) with advanced solid tumor: SCRUM-Japan MONSTAR-SCREEN

MONSTAR-SCREEN is the nationwide cancer genome screening project of prospectively assessing gut microbiota and circulating tumor DNA in 2,000 pts with advanced solid tumor at 31 Japanese institutions. Recently, several studies have showed that gut microbiota modulates efficacy of ICIs across cancer types. Here we report an initial analysis of association between alpha diversity index (ADI) of fecal microbiome and efficacy of ICIs between Sep 2019 and Sep 2020.

617P Genomic profiling of circulating tumor DNA in advanced genitourinary cancer patients: SCRUM-Japan MONSTAR SCREEN Nationwide Cancer Genome Screening Project

Circulating tumor DNA (ctDNA) is an emerging resource for the diagnosis and prognosis of various types of cancer. However, characteristics and clinical utility of ctDNA is still largely unknown, especially in patients with genitourinary (GU) cancers.

MO37-3 Is bronchoscopic cytology pellets useful for oncomine comprehensive assay? – from the samples submitted to LC-SCRUM

Gene mutation screening in lung cancer is performed on formalin-fixed paraffin-embedded (FFPE), but there are some cases that cannot be analyzed. Lung cancer genomic screening project for individualized medicine in Japan (LC-SCRUM) is nationwide cancer genome screening project as academic industrial collaboration for individualized medicine in Japan. In LC-SCRUM, fresh frozen tissues or bronchoscopic pellet samples are analyzed by Oncomine Comprehensive Assay version 3 (OCA v3) Thermo Fisher SCIENTIFIC, and the measurement principle is the same as that of Oncomine Dx Target Test. We investigated the amount of extracted DNA/RNA and the feasibility of gene mutation analysis in fresh frozen tissues and pellet samples prepared from lavage of bronchoscopic device. We compared the background factors of frozen tissues or pellet samples submitted to LC-SCRUM after being diagnosed with lung cancer from May 2016 to March 2020 at our hospital. DNA/RNA concentration and the success rate of gene mutation analysis by OCA v3 were examined. There were 67 enrolled cases, 26 frozen tissues and 41 pellets. The DNA analysis rate was 100%, the RNA analysis rate was 81%, and the overall analysis success rate for both was 78%. The median DNA /RNA extraction amount was 0.065/0.01 (μg/μL) in the tissues and 0.07/0.01 (μg/μL) in the pallets with no significant differences. The analysis success rate was 76.9% in the tissues and 78% in the pellets. In the pellets group, the samples from EBUS-TBNA was 34%, which was higher than that in the tissue group (8%). The amount of DNA extracted from the EBUS-TBNA samples was significantly larger than that from transbronchial biopsy (0.16 vs 0.03 (μg/μL), P<0.001). In OCA, gene mutation analysis using bronchial pellets may be as useful as that in frozen tissues, especially in the EBUS-TBNA samples.

SCRUM-Japan genesis virtual sequencing (VSQ) project: A novel algorithm combining deep learning (DL) with pathological diagnostics to enable the prediction of BRAF mutations and microsatellite instability (MSI) in advanced colorectal cancer (CRC).

112 Background: Numerous genetic and epigenetic abnormalities may lead to various morphologies of cancer. However, exactly which gene abnormality causes which morphology is unknown. The VSQ Project aims at investigating a novel algorithm by synergistically fusing DL technology and pathological diagnostics for the prediction of cancer genome abnormalities. This was achieved by elucidating the association between the morphological findings and genetic abnormalities, including BRAF V600E mutations and MSI status directly linked to the therapeutic strategies for advanced CRC patients (pts). Methods: Clinicopathological-genomic integrated DB derived from SCRUM-Japan GI-SCREEN, a nation-wide cancer genome screening project including CRC, were used. A total of 1,657 images of thin sections (one representative image per pt) cut from formalin-fixed and paraffin-embedded (FFPE) tissue specimens from primary or metastatic tumors with genetic abnormalities confirmed by next-generation sequencing (NGS) were investigated; 1,234 and 423 images (one per pt) were used for training and validation cohorts, respectively. First, we developed image-prediction models based on the morphological features precisely annotated by the single central pathologist, and then constructed the DL algorithms (gene-prediction models) that enabled the prediction of gene abnormalities by using images filtered by the image-prediction models. Results: We achieved high accuracy of AUC &gt; 0.90 for 12 features among the 33 morphological features analyzed. Next, we created several DL algorithms that enabled the prediction of BRAF mutations and MSI. The prediction level reached a high accuracy of AUC = 0.955 for the BRAF mutations and AUC = 0.857 for MSI in the training cohort. We verified the AUCs in the validation cohort and achieved AUC = 0.831 and 0.883 for BRAF mutations and MSI, respectively. Conclusions: Our findings suggest that VSQ can appropriately predict BRAF mutation and MSI status in advanced CRC, potentially without performing NGS tests. VSQ may also enable prompt initiation of systemic treatments in CRC patients as well as establish an unprecedented next-generation pathology in the near future.

Expression of PD-L1 and PD-L2 in colorectal cancer (CRC): A post-hoc integrated analysis of SCRUM-Japan GI-SCREEN CRC.

120 Background: PD-1, PD-L1/L2 axis is responsible for cancer immune escape which facilitate disease progression. However, expression of these proteins in CRC and its significance in clinical prognosis are yet to be fully clarified. Methods: This was a post-hoc analysis using FFPE tumor samples from the Nationwide Cancer Genome Screening Project, SCRUM-Japan GI-SCREEN for metastatic CRC. Patients (Pts) with MSI-H or BRAF V600E mutant tumors were prioritized to be included. PD-L1 (22C3) and PD-L2 expressions were centrally assessed using immunohistochemical assays at QualTek and NeoGenomics, respectively. Tumor infiltrating lymphocytes (TILs) were morphologically evaluated by H&amp;E staining. Clinical information including biomarker status and overall survival (OS) were extracted from SCRUM-Japan GI-SCREEN database. Results: In total, 200 pts were included in this study with a median age of 65 (range, 29–88) years; male/female (116/84); MSI status MSI-H/non-MSI-H/unknown (8/189/3); RAS wild-type/mutant (113/87); and BRAF V600E wild-type/mutant (173/27). Positivity rate of PD-L1 in tumor cells (TC), immune cells (IC), PD-L2 on TC and IC were 10.8%, 46.9%, 0% and 20.3%, respectively. Expression of PD-L1 on TC or IC and PD-L2 on IC were associated with TIL (p = 0.023, p = 0.009, respectively). PD-L1 on TC was highly seen in BRAF V600E-mutated tumors (p = 0.043), but not related to other factors including RAS and MSI status. The pts with PD-L1+ tumors on TC or IC had longer OS than those with PD-L1- (Median, 31.9 vs 23.5 months; HR = 0.67, 95% CI, 0.46–0.99; p = 0.040), while OS in pts with PD-L2+ tumors was similar to that with PD-L2- (Median, 21.4 vs 27.3 months; HR = 0.87, 95% CI, 0.53–1.44; p = 0.60). The PD-L1 expression was also associated with the longer OS in pts with BRAF wild-type or non-MSI-H tumors. Conclusions: Our study suggested different prognostic impact of PD-L1 and PD-L2 expression in CRC pts, which require further evaluations as potential therapeutic targets for CRC. Clinical trial information: UMIN000016343.

SL-1 Activity on Nationwide Cancer Genome Screening Project for Advanced Solid Tumors; SCRUM-Japan GI-/MONSTAR-SCREEN

Advances in precision oncology have made genotyping mandatory for most advanced solid tumors to ensure proper therapy selection. However, the innovations remains limited by the realities of patient identification-actionable targets are present in only a small fraction of patients. We initiated a nationwide cancer genome screening project, SCRUM-Japan GI- (from 2015 to 19)/MONSTAR-SCREEN (since 2019) with the purpose of matching patients with interventional IND trials. We revealed requirement for tissue samples hampers recruitment, and genotyping using archival tumor samples provides information only at a single spatial and temporal point and fail to detect chronological tumor evolution and intratumoral heterogeneity, both of which are obstacles for proper therapy selection. We also demonstrated circulating tumor DNA (ctDNA) analysis using next-generation sequencing (NGS)-based methods have the potential of ctDNA analysis for genomic profiling as an alternative for tissue genotyping. Recently, gut microbiome has the promise in predictive value of therapy. Serial analyses with ctDNA and microbiome at pre- and post- cancer therapies are ongoing. Updated results will be presented.

FMS-like tyrosine kinase 3 (FLT3) amplification in patients with metastatic colorectal cancer.

FMS‐like tyrosine kinase 3 (FLT3) plays a key role in hematopoiesis. However, the oncogenic role of FLT3 amplification in patients with metastatic colorectal cancer (mCRC) remains unclear. Here, we aimed to evaluate the characteristics, prognosis, and treatment efficacy of an FLT3 inhibitor (regorafenib) in patients with mCRC with FLT3 amplifications. Tumor tissue samples from 2329 patients were sequenced using NGS in the Nationwide Cancer Genome Screening Project in Japan. The effects of clinicopathological features, co‐altered genes, prognosis, and efficacy of regorafenib were investigated. Between April 2015 and June 2018, 85 patients with mCRC with FLT3 amplification were observed. There were no differences in baseline characteristics between patients with or without FLT3 amplification. The frequency of RAS or other gene co‐alterations was inversely correlated with the copy number status. Median survival time in patients with FLT3 amplification was significantly shorter compared with those with non‐FLT3 amplification. Further investigations of FLT3 amplification as a potential treatment target in mCRC are warranted.

Impact of DNA integrity on the success rate of tissue-based next-generation sequencing: Lessons from nationwide cancer genome screening project SCRUM-Japan GI-SCREEN.

In the nationwide cancer genome screening project SCRUM‐Japan GI‐SCREEN, 2590 archival formalin‐fixed paraffin‐embedded (FFPE) tumor tissues from 19 institutions were analyzed with two tissue‐based next‐generation sequencing (NGS) panels at the Clinical Laboratory Improvement Amendments (CLIA)‐certified College of American Pathologists (CAP)‐accredited central laboratory. The Oncomine Cancer Research Panel (OCP; 143 genes) succeeded in producing validated results for only 68.3% of the samples (%OCP‐success). CE‐IVD (25 genes) succeeded in 45.9% of the OCP‐failed samples, leading to an overall NGS success (%combined‐success) rate as high as 82.9%. Among 2573 samples, the DNA‐integrity (ΔC t)‐high (ΔC t < 4.4, n = 1253) samples showed significantly higher %OCP‐ and %combined‐success rates (90.2% and 97.4%, respectively) than the DNA‐integrity‐intermediate (4.4 < ΔC t < 6.3, n = 911; 68.9% and 88.7%) and DNA‐integrity‐low ones (ΔC t > 6.3 or polymerase chain reaction‐failed, n = 409; 5.6% and 24.7%). Other factors associated with NGS success included the FFPE‐sample storage period (<4 years), the specimen type (surgical) and the primary tumor site (colorectal). Multivariable analysis revealed DNA integrity as the factor with the strongest independent association with NGS success, although it was suggested that other institution‐specific factors contribute to the discordance of inter‐institutional NGS success rates. Our results emphasize the importance of DNA quality in FFPE samples for NGS tests and the impact of DNA integrity on quality monitoring of pathology specimens for achieving successful NGS.

A basket trial of trastuzumab deruxtecan, a HER2-targeted antibody-drug conjugate, for HER2-amplified solid tumors identified by circulating tumor DNA analysis (HERALD trial).

TPS3650 Background: Trastuzumab deruxtecan, a new HER2-targeting antibody-drug conjugate, has been approved for unresectable or metastatic HER2-positive breast cancer by the Food and Drug Administration. In a phase I/II trial, trastuzumab deruxtecan showed a manageable safety profile and antitumor activity in HER2-positive various cancer types. In addition, a tissue-based HER2 test occasionally cannot identify accurate HER2 status due to spatial and temporal intratumoral heterogeneity, leading to potentially missing an opportunity for responders to receive benefit from anti-HER2-targeted therapy. Circulating tumor DNA (ctDNA) analysis can detect comprehensive somatic genome alterations by assessment of spatial and temporal intratumoral heterogeneity with minimal invasiveness. Methods: We designed an investigator-initiated multicenter phase II basket trial to evaluate efficacy and safety of trastuzumab deruxtecan in advanced solid tumor malignancies with HER2 amplification identified by Guardant360, a 74-gene sequencing ctDNA panel, as a part of the Nationwide Cancer Genome Screening Project (GOZILA study, UMIN000029315). The key eligibility criteria are as follows: 1) Histopathologically confirmed advanced solid tumor malignancy; 2) Identified HER2 amplification by Guardant360; 3) Failed prior standard therapy. The participants will receive intravenously 5.4 mg/kg of trastuzumab deruxtecan every 3 weeks. The primary endpoint is objective response rate (ORR). The planned sample size is 55-65. A Bayesian model considering the potential heterogeneity across cancer types will be applied to detect ORR of 5% versus 25% to a certain level while maintaining the false-positive error rate in each cancer type at 10%. Furthermore, tumor tissue, ctDNA and circulating tumor cells are serially collected and analyzed to investigate the predictive biomarkers and resistance mechanisms. The trial was activated in late 2019. At the time of the abstract submission, 2 patients have been enrolled. This trial is granted by AMED under Grant Number JP18lk0201084. Clinical trial information: JapicCTI-194707 .

Activity on Nationwide Cancer Genome Screening Project for Metastatic Colorectal Cancer in Japan; SCRUM-Japan GI-SCREEN

Abstract Several cancer genome alterations have been identified as important targets for mCRC treatment, which include BRAF mutation, HER-2 amplification/expression, microsatellite instability-high (MSI-H) and etc., for which corresponding agents showed promising activity in clinical trials. In addition, emerging concept in clinical development targeting microsatellite stable (MSS) mCRC comes into question which compound adding on an immune checkpoint inhibitor evokes immunity. Successful combination strategy evoking immunity will break out of the paradigm. Current clinical development of corresponding agents in molecularly characterized cohorts of cancer patients as well as in acquired targets by means of NGS- and blood-based molecular testing may represent more substantial progress toward precision medicine. We initiated the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN) since 2015 to detect orphan-fractionated cancer subtypes. In addition, we also launched circulating tumor DNA (ctDNA) analysis-based cancer genome screening project since February 2018. On the basis of cancer genome alterations by NGS- and blood-based molecular testing, umbrella & basket-type investigator-initiated clinical trials with the National Patient Registry are anticipated to contribute to the establishment of the appropriate infrastructure in terms of the promotion of clinical development for orphan-fractionated cancer subtypes, which are regarded as having the low priority for pharmaceutical companies, but as having the high priority for cancer patients. Updates on activity in SCRUM-Japan GI-SCREEN will be presented.

636P - Prognostic and predictive impact on FMS-like tyrosine kinase 3 (FLT3) amplification in patients with metastatic colorectal cancer

BackgroundFMS-like tyrosine kinase 3 (FLT3) plays a key role in hematopoiesis, and FLT3-associated molecular alterations are an established predictor for the treatment with FLT3 inhibitors in acute myeloid leukemia. However, the oncogenic role of FLT3 amplification (amp) in patients (pts) with metastatic colorectal cancer (mCRC) has not yet been well established. MethodsTumor tissue samples from 2,329 mCRC pts were sequenced using next-generation sequencing (NGS) with Oncomine Comprehensive Assay in the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN). Clinicopathological features, co-altered genes, prognosis and regorafenib efficacy on FLT3 amp (defined as copy number ≥ 7.0) vs. non-FLT3 amp mCRC were investigated. ResultsBetween Apr 2015 and Jun 2018, a total of 85 pts (3.6%) with mCRC with FLT3 amp were observed. There were no clear differences in baseline characteristics between pts with or without FLT3 amp. The enrichment of TP53 mutation in FLT3 amp mCRC was observed more frequently than non-FLT3 amp (74.1% vs. 64.7%, P=0.08), but RAS mutation frequency was similar in both (48.2% vs. 42.8%, P=0.31). In contrast, activating alterations in BRAF (1.1% vs. 7.1%, P=0.053) and PIK3CA (1.1% vs 7.0%, P=0.03) mutations were both less frequent in FLT3 amp vs. non-FLT3 amp mCRC. Median OS from 1st-line chemotherapy in FLT3 amp mCRC was significantly shorter than those in non-FLT3 amp (30.2 vs. 43.4 months, P=0.002). Furthermore, in 20 pts receiving regorafenib, a multikinase inhibitor with a mild inhibitory activity of FLT3, the disease control rate (DCR) was higher in FLT3 amp mCRC pts (n=7) compared with non-FLT3 amp (57.1% vs. 23.0 %, P=0.13). ConclusionsFLT3 amp was associated with a significantly worse survival and a higher DCR from regorafenib, suggesting it has a distinct oncogenic role in mCRC. Further investigation of the oncogenic role of FLT3 amp in mCRC is warranted in clinical trials. Clinical trial identificationUMIN000016344. Legal entity responsible for the studySCRUM-Japan. Funding17 SCRUM-Japan Collaborating Pharmaceutical Companies, AMED, NCC. DisclosureH. Taniguchi: Research grant / Funding (self): Takeda; Advisory / Consultancy: Chugai; Advisory / Consultancy: Taiho. T. Kato: Honoraria (self): Chugai Pharmaceutical; Advisory / Consultancy: Takeda; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Bayer; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Yakult Honsya. S. Yuki: Speaker Bureau / Expert testimony: Chugai Pharma; Speaker Bureau / Expert testimony: Bristol-Myers Squibb; Speaker Bureau / Expert testimony: Bayer Yakuhin; Speaker Bureau / Expert testimony: Ono Pharmaceutical; Speaker Bureau / Expert testimony: Pharma International; Speaker Bureau / Expert testimony: Daiichi Sankyo; Speaker Bureau / Expert testimony: Takeda Pharmaceutical; Speaker Bureau / Expert testimony: Eli Lilly Japan; Speaker Bureau / Expert testimony: Taiho Pharmaceutical; Speaker Bureau / Expert testimony: Sanofi; Speaker Bureau / Expert testimony: Yakult Honsha; Speaker Bureau / Expert testimony: Merck Biopharma. T. Masuishi: Honoraria (self): Eli Lilly; Honoraria (self): Chugai Pharma; Honoraria (self): Merck Serono; Honoraria (self): Taiho Pharmaceutical; Honoraria (self): Yakult Honsya. K. Kato: Research grant / Funding (self): Shionogi; Research grant / Funding (self): Ono Pharmaceutical; Research grant / Funding (self): Merck Serono. N. Izawa: Advisory / Consultancy: Taiho Pharmaceutical; Advisory / Consultancy: Sanofi; Advisory / Consultancy: MSD; Advisory / Consultancy: Bayer; Advisory / Consultancy: Bristol-Myers; Advisory / Consultancy: Lilly; Advisory / Consultancy: Merck Serono. T. Moriwaki: Speaker Bureau / Expert testimony, Research grant / Funding (institution): Taiho Pharmaceutical; Research grant / Funding (institution): MSD; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Takeda; Research grant / Funding (institution): Yakult Honsha; Research grant / Funding (institution): Eisai; Speaker Bureau / Expert testimony: Chugai Pharma; Speaker Bureau / Expert testimony: Yakult Honsha; Speaker Bureau / Expert testimony: Merck Serono; Speaker Bureau / Expert testimony: Sanofi; Speaker Bureau / Expert testimony: Liliy Japan; Speaker Bureau / Expert testimony: Bayer; Speaker Bureau / Expert testimony: Ono Pharmaceutical. Y. Kagawa: Speaker Bureau / Expert testimony: Chugai; Speaker Bureau / Expert testimony: Eli Lilly; Advisory / Consultancy: Sanofi; Speaker Bureau / Expert testimony: Taiho. W. Okamoto: Research grant / Funding (institution): MSD. Y. Nakamura: Research grant / Funding (institution): Ono Pharmaceutical; Research grant / Funding (institution): Taiho Pharmaceutical. K. Yamazaki: Honoraria (self): Daiichi Sankyo; Honoraria (self): Chugai Pharmaceutical; Honoraria (self): Eli Lilly; Honoraria (self): Merck Serono; Honoraria (self), Research grant / Funding (institution): Taiho Pharma; Honoraria (self): Bayer Yakuhin. T. Yoshino: Research grant / Funding (institution): Chugai pharma; Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): Sumitomo Dainippon pharma; Research grant / Funding (institution): Glaxo SmithKline. All other authors have declared no conflicts of interest.

108P - Biological difference of tumour mutational burden (TMB) and microsatellite instability (MSI) status in patients (pts) with somatic vs germline BRCA1/2-mutated advanced gastrointestinal (GI) cancers using cell-free DNA (cfDNA) sequencing analysis in the GOZILA study

108P - Biological difference of tumour mutational burden (TMB) and microsatellite instability (MSI) status in patients (pts) with somatic vs germline BRCA1/2-mutated advanced gastrointestinal (GI) cancers using cell-free DNA (cfDNA) sequencing analysis in the GOZILA study

Latest Advance and Future Perspective for the Treatment of Metastatic Colorectal Cancer (mCRC)

Abstract Several cancer genome alterations have been identified as important targets for mCRC treatment, which include BRAF mutation, HER-2 amplification/expression, microsatellite instability-high (MSI-H) and etc., for which corresponding agents showed promising activity in clinical trials. In addition, emerging concept in clinical development targeting microsatellite stable (MSS) mCRC comes into question which compound adding on an immune checkpoint inhibitor evokes immunity. Successful combination strategy evoking immunity will break out of the paradigm. Current clinical development of corresponding agents in molecularly characterized cohorts of cancer patients as well as in acquired targets by means of NGS- and blood-based molecular testing may represent more substantial progress toward precision medicine. We initiated the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN) since 2015 to detect orphan-fractionated cancer subtypes. In addition, we also launched circulating tumor DNA (ctDNA) analysis-based cancer genome screening project since February 2018. On the basis of cancer genome alterations by NGS- and blood-based molecular testing, umbrella & basket-type investigator-initiated clinical trials with the National Patient Registry are anticipated to contribute to the establishment of the appropriate infrastructure in terms of the promotion of clinical development for orphan-fractionated cancer subtypes, which are regarded as having the low priority for pharmaceutical companies, but as having the high priority for cancer patients.

109P - Cell-Free DNA to detect focal versus non-focal MET amplification in metastatic colorectal cancer patients: Combined analysis from Japan and the United States

BackgroundMET amplification (amp) is rare in untreated metastatic colorectal cancer (mCRC), but cell-free DNA (cfDNA) analysis identifies it in ∼20% with anti-EGFR monoclonal antibody (mAb)-refractory disease. CfDNA analysis reveals both focal gene amp and gene copy number gain due to chromosomal aneuploidy (non-focal MET amp). We analyzed cfDNA from Japanese (JPN) and United States (US) patients (pts) with anti-EGFR mAb-refractory mCRC to investigate the prevalence of focal and non-focal MET amp. MethodsWe studied MET amp in pts with mCRC in the Nationwide Cancer Genome Screening Project in JPN (GOZILA; UMIN000029315; JPN cohort) and in a phase I/II trial of cabozantinib (C) +/- panitumumab (P) in pts with RAS wild-type mCRC (NCT02008383; US cohort). MET amp was detected with the Guardant360 assay. Focal MET amp was defined as either the only amp on chromosome (chr) 7q or MET copy number ³4. Non-focal MET amp was defined as co-amp with ³1 other genes (CDK6 or BRAF) located on chr 7q and MET copy number <4. Results244 JPN cohort pts were analyzed from 2/2018-12/2018, and 81 pts in the US cohort, from 8/2014-2/2018. In pts with prior anti-EGFR mAb (JPN: n=184; US: n=70), focal and non-focal MET amp were detected in 8 (4.3%) and 30 (16.3%) pts in the JPN cohort, and in 9 (12.9%) and 4 (5.7%) US pts. Without prior anti-EGFR mAb (JPN: n=60; US: n=11), focal and non-focal MET amp were detected in 1 (1.7%) and 4 (6.7%) pts in the JPN cohort, and 0 (0%) and 1 (9.1%) US pts. The focal MET amp rate combined was 6.7% (17/254) with prior anti-EGFR mAb. In the US cohort, 4/6 pts with focal MET amp treated with C or C+P had a reduction in RECIST lesions as best response, with one PR, while 2 pts with non-focal MET amp had tumor growth as best response. ConclusionsThe prevalence of focal MET amp detected by cfDNA analysis in mCRC pts was similar in the JPN and US cohorts. Given preliminary efficacy results from the US trial, focal MET amp may be a [A1] predictor of benefit from a MET inhibitor. A clinical trial evaluating a MET inhibitor in mCRC pts with focal MET amp is underway. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureA. Kawazoe: Honoraria (self), Research grant / Funding (institution): Ono Oharmaceutical; Honoraria (self), Research grant / Funding (institution): Taiho Pharmaceutical; Research grant / Funding (institution): Dainippon Sumitomo Pharma; Research grant / Funding (institution): Takeda Pharmaceutical; Research grant / Funding (institution): Astellas Pharmaceutical; Research grant / Funding (institution): MSD. Y. Nakamura: Research grant / Funding (institution): Ono Pharmaceutical; Research grant / Funding (institution): Taiho Pharmaceutical. J.I. Odegaard: Full / Part-time employment: Guardant Health. M.I. Lefterova: Full / Part-time employment: Guardant Health. R. Lanman: Full / Part-time employment: Guardant Health. T. Yoshino: Research grant / Funding (institution): Novartis Pharma K.K.; Research grant / Funding (institution): MSD.K.K.; Research grant / Funding (institution): Sumitomo Dainippon Pharma Co., Ltd.; Research grant / Funding (institution): CHUGAI PHARMACEUTICAL CO., LTD.; Research grant / Funding (institution): Sanofi K.K.; Research grant / Funding (institution): DAIICHI SANKYO COMPANY, LIMITED; Research grant / Funding (institution): PAREXEL International Inc.; Research grant / Funding (institution): ONO PHARMACEUTICAL CO., LTD.. J.H. Strickler: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Amgen; Honoraria (self), Advisory / Consultancy: Bayer; Honoraria (self): Chugai; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Seattle Genetics; Advisory / Consultancy, Research grant / Funding (institution): Genentech/Roche; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy, Leadership role, Research grant / Funding (institution): OncoMed; Advisory / Consultancy: Celgene; Advisory / Consultancy: Proteus Digital Health; Advisory / Consultancy: Chengdu Kanghong Biotechnology Co., Ltd; Research grant / Funding (institution): Exelixis; Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): Nektar; Research grant / Funding (institution): Abbvie; Research grant / Funding (institution): Gilead Sciences; Research grant / Funding (institution): Macrogenics; Research grant / Funding (institution): Leap Therapeutics; Research grant / Funding (institution): MedImmune. All other authors have declared no conflicts of interest.

1557P - A large scale prospective concordance study of oncogene driver detection between plasma- and tissue-based NGS analysis in advanced non-small cell lung cancer (NSCLC)

1557P - A large scale prospective concordance study of oncogene driver detection between plasma- and tissue-based NGS analysis in advanced non-small cell lung cancer (NSCLC)