Multicenter Phase I/II Trial of Napabucasin and Pembrolizumab in Patients with Metastatic Colorectal Cancer (EPOC1503/SCOOP Trial)

PURPOSE

This is a phase I/II trial to assess the efficacy and safety of napabucasin plus pembrolizumab for metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Phase I was conducted to determine the recommended phase 2 dose (RP2D) in a dose escalation design of napabucasin (240 to 480 mg twice daily) with 200 mg pembrolizumab every 3 weeks. Phase II included cohort A (n = 10, microsatellite instability high, MSI-H) and cohort B (n = 40, microsatellite stable, MSS). The primary endpoint was immune-related objective response rate (irORR). PD-L1 combined positive score (CPS), genomic profiles, and the consensus molecular subtypes (CMS) of colorectal cancer were assessed.

RESULTS

A total of 55 patients were enrolled in this study. In phase I, no patients experienced dose-limiting toxicities, and napabucasin 480 mg was determined as RP2D. The irORR was 50.0% in cohort A and 10.0% in cohort B. In cohort B, the irORR was 0%, 5.3%, and 42.9% in CPS < 1, 1≤ CPS <10, and CPS ≥ 10, respectively. Patients with objective response tended to have higher tumor mutation burden than those without. Of evaluable 18 patients for CMS classification in cohort B, the irORR was 33.3%, 0%, 33.3%, and 33.3% in CMS1, CMS2, CMS3, and CMS4, respectively. The common grade 3 or higher treatment-related adverse events included fever (10.0%) in cohort A and decreased appetite (7.5%) and diarrhea (5.0%) in cohort B.

CONCLUSIONS

Napabucasin with pembrolizumab showed antitumor activity with acceptable toxicities for patients with MSS mCRC as well as MSI-H mCRC, although it did not meet the primary end point. The impact of related biomarkers on the efficacy warrants further investigations in the additional cohort.See related commentary by Nusrat, p. 5775.

Survival Outcomes of Resected BRAF V600E Mutant Colorectal Liver Metastases: A Multicenter Retrospective Cohort Study in Japan

BACKGROUND

Although the prognosis for patients with resected BRAF mutant colorectal liver metastases (CRLM) is poor, the survival impact of the BRAF V600E mutation in such cases remains unclear.

METHODS

A multicenter retrospective cohort study was performed to investigate the survival outcomes of patients who underwent initial hepatectomy for histologically confirmed BRAF V600E mutant CRLM between January 2005 and December 2017.

RESULTS

Thirty-three patients from 6 institutions were included in this study. During the median duration of the post-hepatectomy follow-up period of 49.2 months, 31 patients (93.9%) developed recurrence after a median period of 5.3 months and the 1-year recurrence-free survival (RFS) rate was 24.2%. Only two patients underwent repeated surgery for recurrence. The other 29 patients had unresectable recurrent lesions, and 27 of them received systemic chemotherapy. The median overall survival (OS) period was 31.1 months and the 5-year OS rate was 18.2%. The factors for a poor RFS prognosis were an elevated serum CA19-9 level (≥ 37 IU/ml) at hepatectomy (HR: 2.139, 95% CI: 1.009-4.534, P = 0.047) and R1 resection (HR: 5.827, 95% CI: 1.585-21.42, P = 0.008), and that for OS was R1 resection only (HR: 4.129, 95% CI: 1.104-15.45, P = 0.035).

CONCLUSIONS

Since the early onset unresectable recurrence rate was very high, systemic chemotherapy should be considered for resectable BRAF V600E mutant CRLM. A novel perioperative treatment strategy is needed to improve the survival of such patients.

A Multicenter Phase 2 Trial to Evaluate the Efficacy of mFOLFOX6 + Cetuximab as Induction Chemotherapy to Achieve R0 Surgical Resection for Advanced Colorectal Liver Metastases (NEXTO Trial)

BACKGROUND

The effect of cetuximab plus mFOLFOX on downsizing of the tumors for curative resection has yet to be assessed for patients with advanced colorectal liver metastases (CRLMs). This study aimed to assess the oncologic benefit of cetuximab plus mFOLFOX for wild-type KRAS patients with advanced CRLMs.

METHODS

In this multicenter phase 2 trial, patients with technically unresectable tumor and/or five or more CRLMs harboring wild-type KRAS were treated with mFOLFOX plus cetuximab. The patients were assessed for resectability after 4 treatments, and then every 2 months up to 12 treatments. Patients with resectable disease were offered surgery after a waiting period of 1 month. The primary end point of the study was the R0 resection rate. The secondary end points were safety, progression-free survival (PFS), and overall survival (OS). The study is registered with the University Hospital Medical Information Network-Clinical Trials Registry Clinical Trials Registry (no. C000007923).

RESULTS

Between 2012 and 2015, 50 patients from 13 centers were enrolled in this trial. Two patients were excluded because they had not received induction therapy. The 48 patients had a complete response rate of 0% and a partial response rate of 64.6%. For 26 R0 resections (54.2%) and 5 R1 resections (10.4%), no mortality occurred. During a median follow-up period of 31 months, the median OS for all the patients was calculated to be 41 months (95% confidence interval, 28-not reached). The 3-year OS rate was 59%.

CONCLUSION

For patients with advanced CRLMs harboring wild-type KRAS, cetuximab administered in combination with mFOLFOX yields high response rates, leading to significantly high R0 resection rates and favorable prognoses.

Abstract A37: Early change in circulating tumor DNA as a potential predictor of response to chemotherapy in patients with metastatic colorectal cancer

The impact of the change in ctDNA levels after chemotherapy on the clinical outcomes of patients with metastatic colorectal cancer (mCRC) remains unclear. The present study evaluated the clinical implications of the early change in ctDNA levels as a predictor of objective response and the clinical outcome in mCRC patients who received chemotherapy. We investigated the effects of after/before ratio of ctDNA levels 2 and 8 weeks after initiation of second-line chemotherapy on objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). ctDNA was detected using amplicon-based deep sequencing with a molecular barcode that includes &gt;240 hotspot mutations in 14 colon cancer-related genes. Patients with lower ctDNA level (≤ 50%) 8 weeks after initiation of chemotherapy compared to baseline showed significantly longer PFS and OS than the patients with higher (&gt; 50%) ctDNA level in multivariate analysis. In patients achieving partial response or stable disease, the after/before ratio of ctDNA level 8 weeks after initiation of chemotherapy was significantly lower than those in patients with progressive disease. The present study suggests that an early change in the ctDNA level might serve as a biomarker to predict the chemotherapeutic efficacy and clinical outcomes in patients with mCRC.

Citation Format: Hitoshi Zembutsu, Hiroki Osumi, Eiji Shinozaki, Kensei Yamaguchi. Early change in circulating tumor DNA as a potential predictor of response to chemotherapy in patients with metastatic colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A37.

Clinical utility of polyethylene glycol conjugated granulocyte colony-stimulating factor (PEG-G-CSF) for preventing severe neutropenia in metastatic colorectal cancer patients treated with FOLFOXIRI plus bevacizumab: a single-center retrospective study

Background

This study aimed to evaluate the efficacy and the safety of polyethylene glycol conjugated granulocyte colony-stimulating factor (PEG-G-CSF) for preventing neutropenia in metastatic colorectal cancer (mCRC) patients that received fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI) plus bevacizumab (Bev) in clinical practice.

Methods

We retrospectively analyzed mCRC patients who received FOLFOXIRI plus Bev between December 2015 and December 2017. We evaluated the efficacy of PEG-G-CSF as preventing or treating grade 3 or 4 neutropenia, the overall response rate (ORR) according to the Response Evaluation Criteria in Solid Tumors version 1.1, progression-free survival (PFS), overall survival (OS), and adverse events of FOLFOXIRI plus Bev based on the Common Terminology Criteria for Adverse Events version 4.0.

Results

A total of 26 patients (median age 53.5 years) were included. The ORR rate was 65.3%, the median PFS was 9.6 months (7.2–16.9), and the median OS was 24.2 months (13.6–NA). Grade 3 or 4 neutropenia occurred in 53.8% of the patients, and febrile neutropenia occurred in 7.7%. PEG-G-CSF was given to 77.0% of the patients, including prophylactically (n = 9) and after the development of grade 3 or 4 neutropenia (n = 11). No patients experienced grade 3 or 4 neutropenia after the administration of PEG-G-CSF. In seven of the nine patients who received PEG-G-CSF prophylactically (77.8%), no dose adjustment was required.

Conclusions

PEG-G-CSF is useful in preventing severe neutropenia in mCRC patients treated with FOLFOXIRI plus Bev.

Treatment efficacy of ramucirumab-based chemotherapy in patients with alpha-fetoprotein producing gastric cancer (AFPGC)

389

Background: AFPGC is an aggressive subgroup of gastric cancer and is associated with a worsened survival because of a high incidence of liver metastasis. Ramucirumab-based chemotherapy is the standard treatment as a second line in advanced gastric cancer. Recently ramucirumab has showed survival benefit in hepatocellular carcinoma, but only those with higher AFP levels. However, the efficacy of ramucirumab in AFPGC is unknown. Methods: We retrospectively assessed 283 patients who received paclitaxel or nab-paclitaxel combined with ramucirumab between July 2015 and December 2018. AFPGC was defined when serum AFP levels were elevated and correlated with the disease state during treatment. Non-AFPGC was defined when serum AFP levels were normal when diagnosed. Other patients were excluded. Patients’ demographics, progression-free survival (PFS), overall survival (OS) and objective response rates (ORR) were compared between the two groups. Results: Among the 283 patients, 24 patients were AFPGC and 189 patients were non-AFPGC. AFPGC was associated with high incidences of intestinal histology (46%) and liver metastasis (63%), while AFPGC was associated with a low incidence of peritoneal metastasis (21%), compared with non-AFPGC. There was no significant difference in PFS and OS between the two groups. Median PFS were 5.4 (95%CI 3.6-6.7) months in AFPGC and 4.1 (3.7-5.1) months in non-AFPGC (HR 0.93 95%CI 0.60-1.46, p = 0.788), respectively. Median OS were 19.0 (95%CI 13.2-NA) months in AFPGC and 19.3 (17.9-20.1) months in non-AFPGC (HR 1.21 95%CI 0.70-2.10, p = 0.494), respectively. Regarding with ORR, AFPGC showed higher ORR with 52.6% (95%CI 30.2-75.1), while 37.3% (95%CI 26.4-48.3) in non-AFPGC (p = 0.296), although this was not statistically significant. Conclusions: Ramucirumab showed comparable survival and higher ORR in AFPGC than in non-AFPGC. Considering the generally poor prognosis of AFPGC, it is speculated that ramucirumab may have compensated for disadvantage in survival.

Scoop: Multicenter phase I/II trial of BBI608 and pembrolizumab in patients with metastatic colorectal cancer (EPOC1503)

107

Background: The anti–PD-1 antibody pembrolizumab (P) provides response rates of 28-57% in patients (pts) with MSI-H metastatic colorectal cancer (mCRC) vs 0% in those with non-MSI-H cancers. STAT3 has been previously reported as a potential key driver of immune evasion. This study investigates efficacy and safety for the combination of BBI608 (napabucasin), which blocks phosphorylated STAT3 and downregulates IDO1 and PD-L1, with P, in pts with mCRC. BBI608 480 mg BID with P was determined as the recommended phase II dose in phase I. Methods: Phase II included Cohorts A (MSI-H) and B (non-MSI-H). Pts with mCRC not responding to or intolerant of standard chemotherapies were enrolled. The primary endpoint was immune-related objective response rate (irORR), according to irRECIST. The sample size for Cohort A (10 pts) was derived in an exploratory manner. In Cohort B, assuming null and alternative hypotheses of irORR = 5% and 20% led to an estimated required sample size of 40 pts, with a 1-sided alpha of 5% and power of 90%. Genomic profiles and the consensus molecular subtypes (CMS) of colorectal cancer were determined by whole exome sequencing and RNA sequencing as previously described. Results: From Feb/2017 to Jun/2018, 10 pts were enrolled in Cohort A and 40 in Cohort B. The irORR was 50% (5 of 10 pts) in Cohort A and 10% (95% CI 2.8 to 23.7) (4 of 40 pts) in Cohort B. Of evaluable 19 pts for CMS classification in Cohort B, CMS1, CMS2, CMS3, and CMS4 were detected in 3, 6, 4, and 6 cases, respectively. The irORR was 33% (1 of 3 pts), 0% (0 of 6 pts), 25% (1 of 4 pts), 33% (2 of 6 pts) in CMS1, CMS2, CMS3, and CMS4, respectively. One CMS3 patient with partial response had POLE mutation, while 1 CMS1 and 2 CMS4 pts with partial response did not. The most common grade 3 or higher treatment-related adverse events included fever (10%) in Cohort A, and diarrhea (5%) and appetite loss (7.5%) in Cohort B, without unexpected safety signals. No treatment-related deaths occurred. Conclusions: BBI608 with P showed encouraging anti-tumor activity with acceptable toxicity for non-MSI-H mCRC pts as well as MSI-H mCRC pts. Impact of CMS on the efficacies of this combination warrants further investigation in the additional cohort of this study. Clinical trial information: NCT02851004.

A unique ex vivo tumor model: 3D cocultured system with cancer and stromal cells including blood microvessels

211

Background: Importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and tolerance against treatment. Although 2D culture and spheroid consisting only cancer cells still remains the preferred platform for most laboratory preclinical studies while these provide only limited information about tumor microenvironment. In order to mimic the patient tumor tissue, ex vivo model which recaptures the tumor microenvironment is required. Methods: Layered 3D stromal tissues comprising microvascular network were produced by culturing fibroblasts and endothelial cells coated with the extra-cellular matrix (ECM) and natural polysaccharide, namely collagen and heparin. The layered 3D stromal tissues and co-cultured tumor were morphologically evaluated by HE stain, immunohistochemistry and immunofluorescence (IF). Their gene expression and secretome profile were characterized by RNA-sequencing and bio-plex suspension array technologies. Furthermore, drug sensitivity assay were conducted using popular colorectal cancer cell lines, and patient-derived cell lines (PDCs) established in the laboratory of JFCR. Remaining cancer cells post drug treatment were quantified by IF and imaging analysis. Results: The 3D stromal tissues including CD31 positive luminal structure were multi-layered (approximately 20 layers), and the tendency that dense microvascular network was formed nearby cancer cells was observed. In comparison with 2D culture or 3D mono-cultured spheroid model, decreased drug sensitivities were represented in the layered 3D co-cultured model. Omics profiles difference among models suggest that our 3D model has some similarity to in vivo tumor. Conclusions: We developed the layered 3D stromal tissue culture system including blood micro-vessels. Drug sensitivity in the co-cultured tumors may reflect the response of cancer cells in in vivo. Our unique 3D ex vivo model appear to be a valuable tool for drug evaluation, and thus testing approved and/or developing compounds with patient-derived cells would enable better prediction their efficacy.

Changes in the neutrophil-to-lymphocyte ratio during nivolumab monotherapy are associated with gastric cancer survival

PURPOSE

In the ATTRACTION-2 trial, nivolumab significantly improved the survival of advanced gastric cancer patients. The pretreatment neutrophil-to-lymphocyte ratio (NLR) is prognostic in patients receiving immune checkpoint inhibitors (ICIs) to treat various cancers. However, a few reports have explored the relationships between NLR changes during ICI treatment and patient survival. Here, we evaluated factors (including NLR changes in patients on nivolumab monotherapy) prognostic for gastric cancer patients.

METHODS

We retrospectively analyzed 98 gastric cancer patients who received nivolumab (3 mg/kg or 240 mg/body bi-weekly) at our institution between December 2014 and September 2018. We evaluated pretreatment data, and those obtained 30 and 60 days after treatment commenced. We explored the prognostic utility of relative NLR changes in terms of the overall survival (OS) of patients on nivolumab monotherapy.

RESULTS

Over a median of 4.9 months of follow-up, 98 gastric cancer patients received a median of four treatment courses. The overall response and disease-control rates were 25% and 52%, respectively. The median OS was 6.4 months (95% confidence interval [CI] 4.6-9.1). On multivariate analysis, factors poorly prognostic in terms of OS were an ECOG performance status of 0-1, a pretreatment NLR > 3, and an NLR difference ≧ 2 over the 60 days before and after nivolumab administration (∆NLR₆₀). Patients with ∆NLR₆₀ values < 2 survived significantly longer than did those with ∆NLR₆₀ values ≧ 2 (median OS 9.2 months [95% CI 6.4-11.6] vs. 4.0 months [2.1-4.9]; P = 0.0002).

CONCLUSIONS

Nivolumab monotherapy was efficacious in gastric cancer patients. NLR changes during such therapy may be predictive of outcomes.

Rationale and design of the BRAVERY study (EPOC1701): a multicentre phase II study of eribulin in patients with BRAF V600E mutant metastatic colorectal cancer

Background

BRAF V600E mutations are associated with aggressive biology and limited response to standard chemotherapy, especially during second-line and beyond therapies. BRAF V600E mutant and wild-type colorectal cancers (CRCs) differ in their expression profiles, and preclinical evidence suggests that microtubule inhibitors have an antitumour effect on xenograft models of BRAF V600E mutant CRCs. Eribulin has the best growth inhibitory activity in vitro of the microtubule inhibitors. Also, we have evidenced a hint of activity for patients with BRAF V600E mutant metastatic CRC (mCRC) with tumour shrinkage following eribulin treatment.

Trial design

The BRAVERY study is a multicentre phase II study to evaluate the efficacy and safety of eribulin in patients with BRAF V600E mutant mCRC detected in either tumour tissues (primary analysis part) or circulating tumour DNA assays (liquid biopsy part). Key eligibility criteria are refractoriness and intolerance to at least one regimen (including irinotecan or oxaliplatin) containing fluoropyrimidine and Eastern Cooperative Oncology Group performance status of 0-1. Eribulin is to be administered intravenously at a dose of 1.4 mg/m² on days 1 and 8 and repeated every 21 days. The primary endpoint is the confirmed objective response rate (ORR) by investigator's assessment. We calculated the sample size of the primary analysis part at 27 patients using a two-stage design with 25% ORR deemed promising and 5% unacceptable (one-sided α, 0.05; β, 0.1). Secondary endpoints include disease control rate, progression-free survival, overall survival and adverse events. Moreover, we will collect pretreated tissue and serial blood samples for biomarker analyses, focusing on gene expression associated with BRAF mutant-like CRC to find predictive markers and acquired gene alterations to detect resistance mechanisms to eribulin. We initiated patient enrolment in March 2018, completed the primary analysis on May 2019, and are currently continuing with the liquid biopsy part.

Trial registration number

UMIN000031221 and 000031552.

Histopathological factors affecting the extraction of high quality genomic DNA from tissue sections for next-generation sequencing

To enable the widespread application of genomic medicine, the extraction of genomic DNA from thin sections of archived formalin-fixed and paraffin-embedded (FFPE) tissue blocks for next-generation sequencing (NGS) is often necessary. However, there are currently no guidelines available on which specific regions of the microtome sections to use for macrodissection with respect to the histopathological factors observed under microscopic examination. The aim of this study was to clarify the relationship between histopathological factors and DNA quality, and to standardize the macrodissection method for more efficient implementation of NGS. FFPE tissue specimens of 218 patients from the Biomarker Research for Anti-EGFR Monoclonal Antibodies by Comprehensive Cancer Genomics study were used to investigate the relationship between 15 histopathological factors and the quantitative ratio of double-stranded DNA (dsDNA) to total nucleic acids, as well as the ∆ crossing point value of each tissue specimen. Multivariate logistic regression analysis revealed that specimen storage of ≥3 years was negatively associated with dsDNA quality (P=0.0007, OR: 4.30, 95% CI: 1.85-10.04). In contrast, the presence of a mucus pool was positively associated with dsDNA quality (P=0.0308, OR: 0.23, 95% CI: 0.06-0.87). Metastatic tumors and longer specimen storage periods were significantly associated with lower ∆Cp values (P=0.0007, OR: 4.43, 95% CI: 1.87-10.49; and P=0.0003, OR: 5.51, 95% CI: 2.18-13.95, respectively). Therefore, macrodissection should not be performed on specimens exhibiting histopathological factors associated with poor DNA quality. In particular, the use of tissue blocks with a storage period of <3 years allows the extraction of genomic DNA suitable for NGS.

Safety and efficacy of amrubicin monotherapy in patients with platinum-refractory metastatic neuroendocrine carcinoma of the gastrointestinal tract: a single cancer center retrospective study

Purpose

Patients with gastrointestinal neuroendocrine carcinoma (GI-NEC) have poor prognoses. Although platinum-based combination chemotherapy is commonly used as first-line treatment, the benefit of amrubicin (AMR) and salvage chemotherapy in those who develop platinum-refractory GI-NEC remains unknown. This study aimed to evaluate the efficacy and safety of AMR monotherapy in patients with platinum-refractory GI-NEC.

Patients and methods

Platinum-refractory GI-NEC patients who received AMR monotherapy between April 2012 and September 2017 were retrospectively analyzed. The overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events were evaluated. PFS and OS were estimated using Kaplan-Meier methods and compared using log-rank tests.

Results

In total, 16 patients were enrolled. Of them, 13 (81.3%), 1 (6.2%), and 2 (12.5%) received cisplatin plus irinotecan, cisplatin plus etoposide, and fluoropyrimidine plus platinum, respectively, before AMR monotherapy. The primary sites of NEC included the esophagus (N=3, 18.8%), stomach (N=10, 62.5%), duodenum (N=1, 6.2%) and colorectum (N=2, 12.5%). Patients were administered a median of 3 (range, 1–15) cycles of AMR. The ORR was 6.3%, and the median PFS and OS were 2.9 months (95% CI: 1.7–7.4) and 13.8 months (95% CI: 7.9–23.5), respectively. Neutropenia was the most serious adverse event. Grade 3 or higher neutropenia and febrile neutropenia occurred in 50.0% and 6.2% of patients, respectively. Other nonhematological toxicities were not severe, and no treatment-related deaths occurred. The 10 patients who received subsequent chemotherapy after AMR had significantly longer OS than those who did not (17.3 months vs 8.9 months; p=0.018). The median PFS of those who received organ-specific subsequent chemotherapy after AMR was 3.8 months, which was longer than that of those who received prior AMR.

Conclusion

AMR is feasible with minimal side effects for platinum-refractory GI-NEC. Organ-specific subsequent chemotherapy after AMR may improve patient survival.

Second-line FOLFIRI plus ramucirumab with or without prior bevacizumab for patients with metastatic colorectal cancer

PURPOSE

Few data of folinic acid, fluorouracil, and irinotecan (FOLFIRI) plus ramucirumab (RAM) obtained in bevacizumab-naïve patients in clinical trials or routine clinical practice are available. The purpose of this retrospective study was to report the results of FOLFIRI plus RAM treatment as second-line chemotherapy for metastatic colorectal cancer (mCRC).

METHODS

Seventy-four patients with mCRC who received second-line FOLFIRI + RAM mCRC therapy were stratified by previous first-line therapy to groups that had (PB) or had not (NPB) been given bevacizumab. The overall survival (OS), progression-free survival (PFS), and objective response were evaluated.

RESULTS

The overall median PFS was 6.2 months (95% CI 4.6-9.3) and median OS was 17.0 months (95% CI 11.6-NA). Median PFS was 8.0 months (95% CI 4.9-11.2) in NPB patients and 5.0 months (95% CI 3.1-7.3) in PB patients (hazard ratio = 0.72, 95% CI 0.40-1.30, p = 0.28). The response rates were 23% and 3% in NPB and PB patients, respectively. The disease control rates were 85% and 69% in NPB and PB patients, respectively.

CONCLUSIONS

The effectiveness of FOLFIRI + RAM as a second-line chemotherapy in patients with mCRC was in line with that reported in the previous RAISE phase III trial. The response was better in bevacizumab-naïve patients than those with first-line treatment that had included bevacizumab.

Optimal indication criteria for neoadjuvant chemotherapy in patients with resectable colorectal liver metastases

Background

There are no optimal indication criteria for neoadjuvant chemotherapy (NAC) in patients with resectable colorectal liver metastases (CLM). The aim of this study was to prospectively assess the survival benefit of selective NAC administration in this patient population based on tumor characteristics.

Methods

Borderline resectable CLM (BR-CLM) were defined as four or more liver metastases, CLM larger than 5 cm, or CLM with concomitant resectable extrahepatic metastases. From 2010 to 2015, NAC was administered to BR-CLM patients. Upfront surgery without NAC was performed to patients having clearly resectable CLM (less than 3 lesions, smaller than 5 cm, and no extrahepatic metastases: CR-US group). Survival outcomes of the two groups were assessed.

Results

The BR-NAC group comprised 73 patients and the CR-US group 172. All patients in the BR-NAC group underwent subsequent resection, as none showed disease progression or chemotherapy-associated liver damage. The 3- and 5-year overall survival rates of the CR-US group were 83.0% and 74.0%, while patients in the BR-NAC group had comparable 3-year and 5-year overall survivals (80.5% and 66.6%, P = 0.397).

Conclusion

Defining BR-CLM based on tumor characteristics optimizes patient selection for NAC. Favorable overall survival can be achieved by upfront surgery in patients with clearly resectable CLM and by NAC in patients with BR-CLM.

TiFFANY study: A multicenter phase II basket-type clinical trial to evaluate efficacy and safety of pan-FGFR inhibitor TAS-120 for advanced solid malignancies with FGFR alterations identified by circulating tumor DNA

TPS3156

Background: Approximately 7% of advanced solid malignancies have FGFR gene alterations. However, standard treatment for FGFR-altered malignancies has not been established. Moreover, circulating tumor DNA (ctDNA) analysis has a potential to accurately identify FGFR alterations by assessing spatial and temporal intratumoral heterogeneity, which have shown to be associated with a poor prognosis and resistance to anti-cancer therapy. Methods: We are conducting an investigator-initiated multicenter phase II basket-type trial to investigate efficacy and safety of TAS-120, a highly selective covalent pan-FGFR inhibitor, for the patients with advanced solid malignancies with FGFR alterations identified by ctDNA analysis as a part of the Nationwide Cancer Genome Screening Project (GOZILA study, UMIN000029315). Eligibility criteria include histologically confirmed unresectable advanced or recurrent solid tumors regardless of histology of origin; ECOG PS of 0 or 1; refractory or intolerant to the standard therapies; and clonal FGFR alterations ( FGFR1-3 gain-of-function mutations, FGFR1,2 amplifications and FGFR2,3 fusions) identified by a 73-gene sequencing ctDNA panel (Guardant360). Enrolled patients will receive TAS-120 20 mg once daily, orally, in a 21 day-cycle. The primary endpoint is to clarify objective response rate (ORR) assessed by investigators per RECIST v1.1. The secondary endpoints are to evaluate progression-free survival, duration of response, time to treatment failure, disease control rate, overall survival, ORR by central determination, and incidence of adverse events. Target sample size is determined as 26 to test the null hypothesis of ORR as 5% with one-sided alpha level of 2.5% and power of 80% to detect an expected value of ORR as 25%. Furthermore, tumor tissue and ctDNA will be serially collected and analyzed to investigate the resistance mechanisms and provide clinically meaningful biomarker which may be used for identifying and implementing treatment changes. Clinical trial information: 194624.

Non-V600E BRAF mutations and EGFR signaling pathway in colorectal cancer

The Raf murine sarcoma viral oncogene homolog B (BRAF^V600E ) mutation (MT) in metastatic colorectal cancer (CRC) is a well-known prognostic indicator and a negative predictive biomarker for antiepidermal growth factor receptor (EGFR) treatment. However, the clinical characteristics and significance of BRAF^non-V600E MTs remain unclear. Here, we evaluated the clinical characteristics of BRAF^non-V600E MTs vs. those of other MTs in the EGFR signaling pathway, including BRAF^V600E . Consecutive CRC patients in our institute from June 2012 to November 2013 were enrolled in our study. Multiplex genotyping of the EGFR pathway was performed with archival samples using a Luminex Assay for BRAF^V600E /BRAF^non-V600E , KRAS/NRAS exons 2-4, and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA). We analyzed correlations among the MT profiles, clinical data and primary tumor locations in CRC. All statistical analyses were performed using R software. CRC samples (824) from 374 (45.4%) male and 450 (54.6%) female patients were analyzed, of which 154 (18.7%), 202 (24.5%), 270 (32.8%) or 198 (24.0%) had Stages I, II, III or IV or recurrent CRC, respectively. The frequencies of BRAF^V600E /BRAF^non-V600E , KRAS (including exons 2-4), NRAS and PIK3CA MTs were 5.3/1.7, 41.4, 3.3 and 9.6%, respectively. The characteristics of patients with the BRAF^V600E MT were an age of ≥65 years old, a right-sided primary tumor location, poorly differentiated histology and an advanced disease stage. In contrast, the characteristics of patients with BRAF^non-V600E MTs were a left-sided primary tumor location and well-differentiated histology. BRAF^non-V600E MTs were relatively rare and showed different characteristics compared to the BRAF^V600E MT. These results may contribute to future precision medicine.

Enrichment of CLDN18-ARHGAP fusion gene in gastric cancers in young adults

Gastric cancer in young adults has been pointed out to comprise a subgroup associated with distinctive clinicopathological features, including an equal gender distribution, advanced disease, and diffuse‐type histology. Comprehensive molecular analyses of gastric cancers have led to molecular‐based classifications and to specific and effective treatment options. The molecular traits of gastric cancers in young adults await investigations, which should provide a clue to explore therapeutic strategies. Here, we studied 146 gastric cancer patients diagnosed at the age of 40 years or younger at the Cancer Institute Hospital (Tokyo, Japan). Tumor specimens were examined for Helicobacter pylori infection, Epstein‐Barr virus positivity, and for the expression of mismatch repair genes to indicate microsatellite instability. Overexpression, gene amplifications, and rearrangements of 18 candidate driver genes were examined by immunohistochemistry and FISH. Although only a small number of cases were positive for Epstein‐Barr virus and microsatellite instability (n = 2 each), we repeatedly found tumors with gene fusion between a tight‐junction protein claudin, CLDN18, and a regulator of small G proteins, ARHGAP, in as many as 22 cases (15.1%), and RNA sequencing identified 2 novel types of the fusion. Notably, patients with the CLDN18‐ARHGAP fusion revealed associations between aggressive disease and poor prognosis, even when grouped by their clinical stage. These observations indicate that a fusion gene between CLDN18 and ARHGAP is enriched in younger age‐onset gastric cancers, and its presence could contribute to their aggressive characteristics.

Phase II Trial of Neoadjuvant Chemotherapy, Chemoradiotherapy, and Laparoscopic Surgery with Selective Lateral Node Dissection for Poor-Risk Low Rectal Cancer

PURPOSE

The aim of this study is to evaluate the safety and efficacy of induction modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus bevacizumab followed by S- 1-based chemoradiotherapy in magnetic resonance imaging (MRI)-defined poor-risk locally advanced low rectal cancer.

PATIENTS AND METHODS

This was a prospective phase II trial at a single comprehensive cancer center. The primary endpoint was the pathological complete response (pCR) rate. Eligible patients had clinical stage II-III low rectal adenocarcinoma with any of the following MRI-defined poor-risk features: circumferential resection margin (CRM) ≤ 1 mm, cT4, positive lateral nodes, mesorectal N2 disease, and/or requiring abdominoperineal resection. Patients received six cycles of mFOLFOX6 with 5 mg/kg bevacizumab followed by oral S-1 (80 mg/m²/day on days 1-14 and 22-35) plus radiotherapy (50.4 Gy). Surgery was conducted through a laparoscopic approach. Lateral node dissection was selectively added when the patient had enlarged lateral nodes.

RESULTS

A total of 43 patients were enrolled. Grade 3-4 adverse events occurred in nine patients during induction chemotherapy and in five patients during chemoradiotherapy. One patient declined surgery with a clinical complete response. Forty-two patients underwent surgery, and 16 had pCR [37.2%, 95% confidence interval (CI) 24.4-52.1%]. All underwent R0 resection without conversion, including combined resection of adjacent structures (n = 14) and lateral node dissection (n = 30). Clavien-Dindo grade 3-4 complications occurred in six patients (14.3%). With median follow-up of 52 months, six developed recurrences (lung n = 5, local n = 1; 3-year relapse-free survival 86.0%).

CONCLUSIONS

This study achieved a high pCR rate with favorable toxicity and postoperative complications in poor-risk locally advanced low rectal cancer. Multicenter study is warranted to evaluate this regimen.

Clinical utility of circulating tumor DNA for colorectal cancer

Colorectal cancer (CRC) is currently the most common type of cancer in Japan, and its prognosis has improved because of development of diagnosis and advancement in treatments including surgery and chemotherapy. However, because of intratumor heterogeneity and clonal evolution, tumors often develop resistance to treatment. Genotyping tumor tissue in search of somatic genetic alterations for actionable information has become routine examination in clinical practice. However, the inherent molecular heterogeneity of metastatic tumors and the ability of cancer genomes to dynamically evolve are not properly captured by tissue specimens only. Circulating tumor DNA (ctDNA) carrying tumor‐specific genetic or epigenetic alterations is released into the circulation from tumor cells undergoing apoptosis or necrosis. Analysis of ctDNA has the potential to change clinical practice by exploiting blood rather than tissue, as a source of information. Here, we provide an overview of the characteristics of ctDNA and focus on detection methods for ctDNA, and the feasibility of use of ctDNA to monitor tumor dynamics for patients with colorectal cancer.

Feasibility study of diet counseling (DC) with oral nutritional supplements (ONS) for advanced esophageal and gastric cancer during chemotherapy (CT) or chemoradiotherapy (CRT): First report of ONS compliance from a prospective randomized controlled clinical study (DiCON study)

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Background: Most advanced esophageal and gastric cancer patients(pts) experience fatigue, anorexia, and may arise malnutrition and sarcopenia, for which effective treatment has not been established. Nutritional support especially protein supplementations may prevent loss of body mass related with malnutrition and sarcopenia. We therefore, conducted a prospective randomized study to explore compliance and the best available ONS intake for pts undergoing CT or CRT. Methods: Eligibility criteria included: chemo-naïve advanced gastric cancer or esophageal cancer; performance status (PS) of 0–1; pts who can eat more than as 50% as usual; age over 20 years. Pts were randomly allocated into four groups within each strata, i.e. esophageal or gastric cancer, Group A: Diet counseling (DC) only, Group B-1: DC and ONS 1 pack/day, Group B-2: DC and ONS 2 packs/day, and Group B-3: DC and ONS 3 packs/day. We use jelly type ONS which is easy to intake and include rich branched-chain amino acid. We assessed ONS compliance, the change of nutritional index (body weight, albumin, pre-albumin, and muscle mass), diet record (daily), and toxicity before CT or CRT and 14 days after administration of CT. Results: Among forty pts (11 in A, 11 in B-1,8 in B-2,10 in B-3) were enrolled from August 2017 to August 2018, median age was 64 years (range 46-81), median BMI was 20.6 (range 15-29), and 28 gastric cancer, 12 esophageal cancer. Median intake was 12 packs/2w (range 0-14), 15 packs/2w (3-28), 12 packs/2w (2-28), in B-1, B-2, and B-3 respectively. Mean compliance of ONS was 72.7%, 50.0% and 33.1%, in B-1, B-2, and B-3 respectively. There was a significant linear trend across the 3 groups (P = 0.0104). B-1 was significantly better than B-3 (P = 0.0270). There were no pts in group B-3 who could intake ONS for 14 consecutive days. Over 80% of pts in B-1 group were able to intake for 14 consecutive days. Conclusions: We found ONS 3 packs/day was clearly denied because of compliance. Choice of 1 or 2 packs/day should be determined by taking into account the total calories of foods. Clinical trial information: 000026705.

Liquid biopsy for optimizing the rechallenge of cetuximab in metastatic colorectal cancer: Additional study of E-Rechallenge Trial

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Background: Several previous reports indicated that cetuximab (Cmab) rechallenge may be efficacious in some patients for whom Cmab was previously effective. Liquid biopsy can detect the some emerging mutations for resistance with Cmab. Considering the plasticity and elasticity of sensitive clone, we assumed we could identify the patients with benefit from Cmab rechallenge by liquid biopsy. This current study investigates the predictability of efficacy for Cmab rechallenge by liquid biopsy in the E-Rechallenge Trial. Methods: The E-Rechallenge Trial is a multicenter phase II study in mCRC patients who have become refractory to fluoropyrimidines, L-OHP, CPT-11, Cmab, and bevacizumab, and in whom previous treatment with Cmab was effective in any earlier line (achieving CR, PR, or SD that persisted for ≥ 6 months). The other main eligibility criteria are; RAS wild type, measurable disease, aEFI ≥ 16 weeks between the last dose of Cmab during previous treatment and the start of Cmab rechallenge. Protocol treatment is the combination of weekly Cmab with biweekly CPT-11. Additional research of ctDNA was conducted optionally. Baseline plasma samples were analyzed for KRAS, NRAS, BRAF and EGFR S492R mutations using digital PCR (LBx probe, RIKEN GENESIS). A cut-off of the mutation allele frequency was > 0.1%. Results: Between Dec. 2014 and Oct. 2017, 33 patients were enrolled. The primary endpoint; the rates of PR/SD/PD were PR 15.6%/SD 40.6%/PD 43.8%. Twenty-four of 33 patients participated in the additional research. In the additional cohort, the rates of PR/SD/PD were PR 12.5%/SD 50.0%/PD 37.5%. The mutations were detected at the baseline of Cmab rechallenge as followings; KRAS exon 2 29.2%, exon 3,4 33.3%, BRAF V600E 12.5%, EGFR S492R 12.5%. In wild type of these genes the PR and SD rate increased to 25% and 50%, respectively. Conclusions: Cmab rechallenge showed some activity in the salvage setting, in patients for whom Cmab was previously effective. KRAS, BRAF, and EGFR S492R screening by liquid biopsy may contribute to identify patients with benefit from Cmab rechallenge. The additional data of ctDNA may be provided in the conference. Clinical trial information: UMIN 000016439.