Dynamic changes in RAS gene status in circulating tumour DNA: a phase II trial of first-line FOLFOXIRI plus bevacizumab for RAS-mutant metastatic colorectal cancer (JACCRO CC-11).

BACKGROUND: Few prospective studies have used liquid biopsy testing in RAS-mutant metastatic colorectal cancer (mCRC), and its clinical significance remains unknown. Therefore, this study aimed to carry out a biomarker analysis by liquid biopsy using updated data of the phase II trial of FOLFOXIRI plus bevacizumab as first-line chemotherapy for RAS-mutant mCRC. MATERIALS AND METHODS: A total of 64 patients who received modified FOLFOXIRI regimen (irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, levofolinate 200 mg/m2, and fluorouracil 2400 mg/m2) plus bevacizumab biweekly were enrolled. The primary endpoint was the objective response rate (ORR). Plasma samples were collected at pre-treatment, 8 weeks after treatment, and progression in participants included in the biomarker study. The levels of circulating tumour DNA (ctDNA) and specific KRAS and NRAS variants were evaluated using real-time PCR assays. RESULTS: There were 62 patients (median age: 62.5 years, 92% performance status 0, 27% right side) who were assessable for efficacy and 51 for biomarker analysis. ORR was 75.8% (95% confidence interval 65.1% to 86.5%). The median progression-free survival was 12.1 months, and the median overall survival (OS) was 30.2 months. In 78% of patients, RAS mutations disappeared in the ctDNA at 8 weeks after treatment; these patients tended to have better outcomes than those with RAS mutations. Interestingly, RAS mutations remained undetectable during progression in 62% of patients. Survival analysis indicated that the median OS from progression was significantly longer in patients with RAS mutation clearance than in those with RAS mutation in the ctDNA at disease progression (15.1 versus 7.3 months, hazard ratio: 0.21, P = 0.0046). CONCLUSIONS: Our biomarker study demonstrated no RAS mutations in ctDNA at disease progression in 62% of patients with RAS-mutant mCRC. Both OS and post-progression survival were better in patients with clearance of RAS mutations in ctDNA after triplet-based chemotherapy.

Nivolumab plus low-dose ipilimumab in previously treated patients with microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer: 4-year follow-up from CheckMate 142.

BACKGROUND: In the phase II multicohort CheckMate 142 study, nivolumab plus low-dose (1 mg/kg) ipilimumab provided robust and durable clinical benefit with a manageable safety profile in previously treated patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) at 13.4- and 25.4-month median follow-up (Overman MJ, Lonardi S, Wong KYM et al. Durable clinical benefit with nivolumab plus ipilimumab in DNA mismatch repair-deficient/microsatellite instability-high metastatic colorectal cancer. J Clin Oncol. 2018;36:773-779. Overman MJ, Lonardi S, Wong KYM, et al. Nivolumab plus low-dose ipilimumab in previously treated patients with microsatellite instability-high/mismatch repair deficient metastatic colorectal cancer: long-term follow-up. J Clin Oncol. 2019;37:635). Here, we present results from the 4-year follow-up of these patients. PATIENTS AND METHODS: Patients received nivolumab (3 mg/kg) plus low-dose (1 mg/kg) ipilimumab every 3 weeks (four doses) followed by nivolumab (3 mg/kg) every 2 weeks until disease progression. Primary endpoint was investigator-assessed objective response rate (ORR; as per RECIST version 1.1). RESULTS: A total of 119 patients were treated; 76% had ≥2 prior lines of therapy. Median follow-up was 50.9 months (range 46.9-62.7 months). Median duration of therapy was 24.9 months [95% confidence interval (CI) 15.8-33.2 months]. Investigator-assessed ORR increased from 55% (95% CI 45% to 64%) at 13.4 months to 65% (95% CI 55% to 73%) at 50.9 months with a disease control rate of 81% (95% CI 72% to 87%). The complete response rate increased from 3% at 13.4 months to 13% at 50.9 months. Partial responses were observed in 52% of patients; 21% had stable disease, and 12% had progressive disease. Median time to response was 2.8 months (range 1.1-37.1 months), and median duration of response was not reached (range 1.4+ to 58.0+ months). At data cut-off, 37 (48%) patients had ongoing responses. Median progression-free survival was not reached [95% CI 38.4 months-not estimable (NE)], and median overall survival was not reached (95% CI NE). Grade 3-4 treatment-related adverse events (TRAEs) were observed in 32% of patients; 13% of patients had any-grade TRAEs leading to discontinuation. CONCLUSIONS: The results confirm long-term benefit of nivolumab plus low-dose ipilimumab for previously treated patients with MSI-H/dMMR mCRC. The safety profile was manageable with no new safety signals.

Distinct genomic landscapes of gastroesophageal adenocarcinoma depending on PD-L1 expression identify mutations in RAS-MAPK pathway and TP53 as potential predictors of immunotherapy efficacy.

BACKGROUND: The impact of molecular alterations on programmed death-ligand 1 (PD-L1) combined positive score (CPS) is not well studied in gastroesophageal adenocarcinomas (GEAs). We aimed to characterize genomic features of tumors with different CPSs in GEAs. PATIENTS AND METHODS: Genomic alterations of 2518 GEAs were compared in three groups (PD-L1 CPS ≥ 10, high; CPS = 1-9, intermediate; CPS < 1, low) using next-generation sequencing. We assessed the impact of gene mutations on the efficacy of immune checkpoint inhibitors (ICIs) and tumor immune environment based on the Memorial Sloan Kettering Cancer Center and The Cancer Genome Atlas databases. RESULTS: High, intermediate, and low CPSs were seen in 18%, 54% and 28% of GEAs, respectively. PD-L1 positivity was less prevalent in women and in tissues derived from metastatic sites. PD-L1 CPS was positively associated with mismatch repair deficiency/microsatellite instability-high, but independent of tumor mutation burden distribution. Tumors with mutations in KRAS, TP53, and RAS-mitogen-activated protein kinase (MAPK) pathway were associated with higher PD-L1 CPSs in the mismatch repair proficiency and microsatellite stability (pMMR&MSS) subgroup. Patients with RAS-MAPK pathway alterations had longer overall survival (OS) from ICIs compared to wildtype (WT) patients [27 versus 13 months, hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.19-0.7, P = 0.016] and a similar trend was observed in the MSS subgroup (P = 0.11). In contrast, patients with TP53 mutations had worse OS from ICIs compared to TP53-WT patients in the MSS subgroup (5 versus 21 months, HR = 2.39, 95% CI: 1.24-4.61, P = 0.016). CONCLUSIONS: This is the largest study to investigate the distinct genomic landscapes of GEAs with different PD-L1 CPSs. Our data may provide novel insights for patient selection using mutations in TP53 and RAS-MAPK pathway and for the development of rational combination immunotherapies in GEAs.

Neutropenia and survival outcomes in metastatic colorectal cancer patients treated with trifluridine/tipiracil in the RECOURSE and J003 trials.

BACKGROUND: The phase II J003 (N = 169) and phase III RECOURSE (N = 800) trials demonstrated a significant improvement in survival with trifluridine (FTD)/tipiracil (TPI) versus placebo in patients with refractory metastatic colorectal cancer. This post hoc analysis investigated pharmacokinetic data of FTD/TPI exposure and pharmacodynamic markers, such as chemotherapy-induced neutropenia (CIN) and clinical outcomes. PATIENTS AND METHODS: A total of 210 patients from RECOURSE were enrolled in this substudy. A limited sampling approach was used, with three pharmacokinetic samples drawn on day 12 of cycle 1. Patients were categorized as being above or below the median area under the plasma concentration-time curve (AUC) for FTD and TPI. We conducted a post hoc analysis using the entire RECOURSE population to determine the correlations between CIN and clinical outcome. We then carried out a similar analysis on the J003 trial to validate the results. RESULTS: In the RECOURSE subset, patients in the high FTD AUC group had a significantly increased CIN risk. Analyses of the entire population demonstrated that FTD/TPI-treated patients with CIN of any grade in cycles 1 and 2 had significantly longer median overall survival (OS) and progression-free survival (PFS) than patients who did not develop CIN and patients in the placebo group. Patients who required an FTD/TPI treatment delay had increased OS and PFS versus those in the placebo group and those who did not develop CIN. Similar results were obtained in the J003 cohort. CONCLUSIONS: In RECOURSE, patients with higher FTD drug exposure had an increased CIN risk. FTD/TPI-treated patients who developed CIN had improved OS and PFS versus those in the placebo group and those who did not develop CIN. Similar findings were reported in the J003 cohort, thus validating the RECOURSE results. The occurrence of CIN may be a useful predictor of treatment outcomes for FTD/TPI-treated patients. CLINICALTRIALS. GOV IDENTIFIER: NCT01607957 (RECOURSE). JAPAN PHARMACEUTICAL INFORMATION CENTER NUMBER: JapicCTI-090880 (J003).

Consensus molecular subgroups (CMS) of colorectal cancer (CRC) and first-line efficacy of FOLFIRI plus cetuximab or bevacizumab in the FIRE3 (AIO KRK-0306) trial.

BACKGROUND: FIRE-3 compared first-line therapy with FOLFIRI plus either cetuximab or bevacizumab in 592 KRAS exon 2 wild-type metastatic colorectal cancer (mCRC) patients. The consensus molecular subgroups (CMS) are grouping CRC samples according to their gene-signature in four different subtypes. Relevance of CMS for the treatment of mCRC has yet to be defined. PATIENTS AND METHODS: In this exploratory analysis, patients were grouped according to the previously published tumor CRC-CMSs. Objective response rates (ORR) were compared using chi-square test. Overall survival (OS) and progression-free survival (PFS) times were compared using Kaplan-Meier estimation, log-rank tests. Hazard ratios (HR) were estimated according to the Cox proportional hazard method. RESULTS: CMS classification could be determined in 438 out of 514 specimens available from the intent-to-treat (ITT) population (n = 592). Frequencies for the remaining 438 samples were as follows: CMS1 (14%), CMS2 (37%), CMS3 (15%), CMS4 (34%). For the 315 RAS wild-type tumors, frequencies were as follows: CMS1 (12%), CMS2 (41%), CMS3 (11%), CMS4 (34%). CMS distribution in right- versus (vs) left-sided primary tumors was as follows: CMS1 (27% versus 11%), CMS2 (28% versus 45%), CMS3 (10% versus 12%), CMS4 (35% versus 32%). Independent of the treatment, CMS was a strong prognostic factor for ORR (P = 0.051), PFS (P < 0.001), and OS (P < 0.001). Within the RAS wild-type population, OS observed in CMS4 significantly favored FOLFIRI cetuximab over FOLFIRI bevacizumab. In CMS3, OS showed a trend in favor of the cetuximab arm, while OS was comparable in CMS1 and CMS2, independent of targeted therapy. CONCLUSIONS: CMS classification is prognostic for mCRC. Prolonged OS induced by FOLFIRI plus cetuximab versus FOLFIRI plus bevacizumab in the FIRE-3 study appears to be driven by CMS3 and CMS4. CMS classification provides deeper insights into the biology to CRC, but at present time has no direct impact on clinical decision-making.The FIRE-3 (AIO KRK-0306) study had been registered at ClinicalTrials.gov: NCT00433927.

Nintedanib for the treatment of patients with refractory metastatic colorectal cancer (LUME-Colon 1): a phase III, international, randomized, placebo-controlled study.

Background: Angiogenesis is critical to colorectal cancer (CRC) growth and metastasis. Phase I/II studies have demonstrated the efficacy of nintedanib, a triple angiokinase inhibitor, in patients with metastatic CRC. This global, randomized, phase III study investigated the efficacy and safety of nintedanib in patients with refractory CRC after failure of standard therapies. Patients and methods: Eligible patients (Eastern Cooperative Oncology Group performance status 0-1, with histologically/cytologically confirmed metastatic/locally advanced CRC adenocarcinoma unamenable to surgery and/or radiotherapy) were randomized 1 : 1 to receive nintedanib (200 mg twice daily) or placebo (twice daily), until disease progression or undue toxicity. Patients were stratified by previous regorafenib, time from onset of metastatic disease to randomization, and region. Co-primary end points were overall survival (OS) and progression-free survival (PFS) by central review. Secondary end points included objective tumor response and disease control by central review. Results: From October 2014 to January 2016, 768 patients were randomized; 765 were treated (nintedanib n = 384; placebo n = 381). Median follow-up was 13.4 months (interquartile range 11.1-15.7). OS was not improved [median OS 6.4 months with nintedanib versus 6.0 months with placebo; hazard ratio (HR), 1.01; 95% confidence interval (CI), 0.86-1.19; P = 0.8659]. There was a significant but modest increase in PFS with nintedanib versus placebo (median PFS 1.5 versus 1.4 months, respectively; HR 0.58; 95% CI 0.49-0.69; P < 0.0001). There were no complete or partial responses. Adverse events (AEs) occurred in 97% of 384 nintedanib-treated patients and 93% of 381 placebo-treated patients. The most frequent grade ≥3 AEs were liver-related AEs (nintedanib 16%; placebo 8%) and fatigue (nintedanib 9%; placebo 6%). Conclusions: The study failed to meet both co-primary end points. Nintedanib did not improve OS and was associated with a significant but modest increase in PFS versus placebo. Nintedanib was well tolerated. ClinicalTrials.gov number: NCT02149108 (LUME-Colon 1).

A genetic variant in Rassf1a predicts outcome in mCRC patients treated with cetuximab plus chemotherapy: results from FIRE-3 and JACCRO 05 and 06 trials.

The Hippo pathway is involved in colorectal cancer (CRC) development and progression. The Hippo regulator Rassf1a is also involved in the Ras signaling cascade. In this work, we tested single nucleotide polymorphisms within Hippo components and their association with outcome in CRC patients treated with cetuximab. Two cohorts treated with cetuximab plus chemotherapy were evaluated (198 RAS wild-type (WT) patients treated with first-line FOLFIRI plus Cetuximab within the FIRE-3 trial and 67 Ras WT patients treated either with first-line mFOLFOX6 or SOX plus Cetuximab). In these two populations, Rassf1a rs2236947 was associated with overall survival (OS), as patients with a CC genotype had significantly longer OS compared with those with CA or AA genotypes. This association was stronger in patients with left-side CRC (hazard ratio (HR): 1.79 (1.01-3.14); P=0.044 and HR: 2.83 (1.14-7.03); P=0.025, for Fire 3 and JACCRO cohorts, respectively). Rassf1a rs2236947 is a promising biomarker for patients treated with cetuximab plus chemotherapy.

Prognostic impact of FOXF1 polymorphisms in gastric cancer patients.

A recent genome-wide association study identified seven single-nucleotide polymorphisms (SNPs) in region 16q24, near the Forkhead box-F1 (FOXF1) gene, which confer susceptibility to esophageal adenocarcinoma. We examined whether these SNPs are associated with clinical outcomes in gastric cancer (GC) patients in Japan and the United States. A total of 362 patients were included in this study: 151 Japanese GC patients treated with first-line S1 plus CDDP (training cohort) and 211 GC patients from Los Angeles County (LAC; validation cohort). Genomic DNA was isolated from whole blood or tumor tissue and analyzed by PCR-based direct DNA sequencing. Cox proportional hazard regression analyses were used to assess relationships between FOXF1 SNPs and progression-free survival (PFS) and overall survival (OS). FOXF1 rs3950627 was significantly associated with survival in both the training and validation cohorts. Japanese patients with the C/C genotype had a longer PFS (median 8.2 vs 5.3 months, hazard ratio (HR) 1.44, P=0.037) and OS (median 16.4 vs 12.2 months, HR 1.44, P=0.043) compared to patients with any A allele. Similarly, LAC patients with the C/C genotype had improved OS (3.9 vs 2.3 years, HR 1.5, P=0.022). Subgroup analyses showed these associations were specific to male patients and primary tumor subsite. Our findings suggest that FOXF1 rs3950627 might be a promising prognostic marker in GC patients.

DNA methylation aberrancies delineate clinically distinct subsets of colorectal cancer and provide novel targets for epigenetic therapies.

Colorectal cancer (CRC) is a worldwide health concern with respect to both incidence and mortality, and as a result, CRC tumorigenesis, progression and metastasis have been heavily studied, especially with respect to identifying genetic, epigenetic, transcriptomic and proteomic profiles of disease. DNA methylation alterations are hallmarks of CRC, and epigenetic driver genes have been identified that are thought to be involved in early stages of tumorigenesis. Moreover, distinct CRC patient subgroups are organized based on DNA methylation profiles. CRC tumors displaying CpG island methylator phenotypes (CIMPs), defined as DNA hypermethylation at specific CpG islands in subsets of tumors, show high concordance with specific genetic alterations, disease risk factors and patient outcome. This review details the DNA methylation alterations in CRC, the significance of CIMP status, the development of treatments based on specific molecular profiles and the application of epigenetic therapies for CRC patient treatment.

Clinical relevance of EMT and stem-like gene expression in circulating tumor cells of metastatic colorectal cancer patients.

Using approved methods, circulating tumor cells (CTCs) are only isolated from blood in 30%-50% of metastatic colorectal cancer (mCRC) patients. We previously validated a technique to isolate circulating tumor cells (CTCs) in a cohort of mCRC patients by combining immunomagnetic enrichment of EpCAM+/CD45- cells with qRT-PCR amplification of CK20 and survivin expression. Here, we examined the prognostic utility of CTC epithelial-mesenchymal transition (EMT) and stem cell gene expression. An 8 ml blood sample was collected from 78 consecutive mCRC patients before treatment with investigational and standard chemotherapeutics. The mRNA expression of EMT (PI3Kα, Akt-2, Twist1) and stem cell (ALDH1) markers was measured. Associations between CTC gene expression and progression-free survival (PFS) and overall survival (OS) were determined using Cox regression models. Among patients without CK20 or survivin-expressing CTCs (n=17), 55% had expression of ALDH1, PI3Kα and/or Akt-2. Patients with positive CTC Akt-2 expression had a significantly shorter median PFS (3.0 versus 4.0 months) compared with those without CTC Akt-2 expression in univariable (hazard ratio (HR)=1.61; log-rank P=0.034) and multivariable analyses (HR=1.70; adjusted P=0.041). In univariable analysis, CTC ALDH1 expression was associated with shorter OS (10.0 versus 38.6 months; HR=2.04, P=0.021). Patients with CTCs expressing ALDH1, PI3Kα and/or Akt-2 had a significantly inferior PFS (3.0 versus 7.7 months; HR=1.88, P=0.015) and OS (10.0 versus 26.8+ months; HR=2.25, P=0.050) in univariable, but not multivariable, analysis. CONCLUSIONS: CTC Akt-2 expression may serve as a clinically useful prognostic marker in mCRC patients and warrants further evaluation in prospective trials.

Impact of genetic variations in the MAPK signaling pathway on outcome in metastatic colorectal cancer patients treated with first-line FOLFIRI and bevacizumab: data from FIRE-3 and TRIBE trials.

BACKGROUND: The MAPK-interacting kinase 1 (MKNK1) is localized downstream of the RAS/RAF/ERK and the MAP3K1/MKK/p38 signaling pathway. Through phosphorylation MKNK1 regulates the function of eukaryotic translation initiation factor 4E, a key player in translational control, whose expression is often upregulated in metastatic colorectal cancer patients (mCRC). Preclinical data suggest that MKNK1 increases angiogenesis by upregulating angiogenic factors. We therefore hypothesize that variations in the MKNK1 gene predict outcome in mCRC patients treated with first-line FOLFIRI and bevacizumab (bev). PATIENTS AND METHODS: A total of 567 patients with KRAS wild-type mCRC in the randomized phase III FIRE-3 and TRIBE trials treated with first-line FOLFIRI/bev (discovery and validation cohorts) or FOLFIRI and cetuximab (cet) (control cohort) were included in this study. Five single-nucleotide polymorphisms in the MAPK signaling pathway were analyzed. RESULTS: AA genotype carriers of the MKNK1 rs8602 single-nucleotide polymorphism treated with FOLFIRI/bev in the discovery cohort (FIRE-3) had a shorter progression-free survival (PFS) than those harboring any C (7.9 versus 10.3 months, Hazard ratio (HR) 1.73, P = 0.038). This association could be confirmed in the validation cohort (TRIBE) in multivariable analysis (PFS 9.0 versus 11.0 months, HR 3.04, P = 0.029). Furthermore, AA carriers in the validation cohort had a decreased overall response rate (25% versus 66%, P = 0.049). Conversely, AA genotype carriers in the control group receiving FOLFIRI/cet did not show a shorter PFS. By combining both FOLFIRI/bev cohorts the worse outcome among AA carriers became more significant (PFS 9.0 versus 10.5 months) in univariable (HR 1.74, P = 0.015) and multivariable analysis (HR 1.76, P = 0.022). Accordingly, AA carriers did also exhibit an inferior overall response rate compared with those harboring any C (36% versus 65%, P = 0.005). CONCLUSION: MKNK1 polymorphism rs8602 might serve as a predictive marker in KRAS wild-type mCRC patients treated with FOLFIRI/bev in the first-line setting. Additionally, MKNK1 might be a promising target for drug development.

Prognostic and predictive value of primary tumour side in patients with RAS wild-type metastatic colorectal cancer treated with chemotherapy and EGFR directed antibodies in six randomized trials.

BACKGROUND: There is increasing evidence that metastatic colorectal cancer (mCRC) is a genetically heterogeneous disease and that tumours arising from different sides of the colon (left versus right) have different clinical outcomes. Furthermore, previous analyses comparing the activity of different classes of targeted agents in patients with KRAS wild-type (wt) or RAS wt mCRC suggest that primary tumour location (side), might be both prognostic and predictive for clinical outcome. METHODS: This retrospective analysis investigated the prognostic and predictive influence of the localization of the primary tumour in patients with unresectable RAS wt mCRC included in six randomized trials (CRYSTAL, FIRE-3, CALGB 80405, PRIME, PEAK and 20050181), comparing chemotherapy plus EGFR antibody therapy (experimental arm) with chemotherapy or chemotherapy and bevacizumab (control arms). Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) for patients with left-sided versus right-sided tumours, and odds ratios (ORs) for objective response rate (ORR) were estimated by pooling individual study HRs/ORs. The predictive value was evaluated by pooling study interaction between treatment effect and tumour side. RESULTS: Primary tumour location and RAS mutation status were available for 2159 of the 5760 patients (37.5%) randomized across the 6 trials, 515 right-sided and 1644 left-sided. A significantly worse prognosis was observed for patients with right-sided tumours compared with those with left-sided tumours in both the pooled control and experimental arms for OS [HRs = 2.03 (95% CI: 1.69-2.42) and 1.38 (1.17-1.63), respectively], PFS [HRs = 1.59 (1.34-1.88) and 1.25 (1.06-1.47)], and ORR [ORs = 0.38 (0.28-0.50) and 0.56 (0.43-0.73)]. In terms of a predictive effect, a significant benefit for chemotherapy plus EGFR antibody therapy was observed in patients with left-sided tumours [HRs = 0.75 (0.67-0.84) and 0.78 (0.70-0.87) for OS and PFS, respectively] compared with no significant benefit for those with right-sided tumours [HRs = 1.12 (0.87-1.45) and 1.12 (0.87-1.44) for OS and PFS, respectively; P value for interaction <0.001 and 0.002, respectively]. For ORR, there was a trend (P value for interaction = 0.07) towards a greater benefit for chemotherapy plus EGFR antibody therapy in the patients with left-sided tumours [OR = 2.12 (1.77-2.55)] compared with those with right-sided tumours [OR = 1.47 (0.94-2.29)]. Exclusion of the unique phase II trial or the unique second-line trial had no impact on the results. The predictive effect on PFS may depend of the type of EGFR antibody therapy and on the presence or absence of bevacizumab in the control arm. CONCLUSION: This pooled analysis showed a worse prognosis for OS, PFS and ORR for patients with right-sided tumours compared with those with left-sided tumours in patients with RAS wt mCRC and a predictive effect of tumour side, with a greater effect of chemotherapy plus EGFR antibody therapy compared with chemotherapy or chemotherapy and bevacizumab, the effect being greatest in patients with left-sided tumours. These predictive results should be interpreted with caution due to the retrospective nature of the analysis, which was carried out on subpopulations of patients included in these trials, and because none of these studies contemplated a full treatment sequence strategy.

Genetic variants of DNA repair-related genes predict efficacy of TAS-102 in patients with refractory metastatic colorectal cancer.

Background: Tri-phosphorylated trifluridine (FTD) incorporation into DNA is TAS-102's main anti-tumor action. We tested whether genetic polymorphisms in homologous recombination (HR) and cell cycle checkpoint pathway for DNA repair is associated with outcomes in refractory metastatic colorectal cancer (mCRC) patients treated with TAS-102. Patients and methods: We analyzed genomic DNA extracted from 233 samples of three cohorts: an evaluation cohort of 52 patients receiving TAS-102, a validation cohort of 129 patients receiving TAS-102 and a control cohort of 52 patients receiving regorafenib. Single nucleotide polymorphisms of genes involved in HR (ATM, BRCA1, BRCA2, XRCC3, FANCD2, H2AX, RAD51) and cell cycle checkpoint (ATR, CHEK1, CHEK2, CDKN1A, TP53, CHE1, PIN1, PCNA) were analyzed by PCR-based direct sequencing. Results: In univariate analysis for the evaluation cohort, patients with any G allele in ATM rs609429 had longer overall survival (OS) than those with the C/C variant (8.7 vs. 4.4 months, HR 0.37, 95% CI: 0.14-0.99, P = 0.022). Patients carrying any A allele in XRCC3 rs861539 had significantly longer progression-free survival (PFS) (3.8 vs. 2.3 months, HR 0.44, 95% CI: 0.21-0.92, P = 0.024) and OS (15.6 vs. 6.3 months, HR 0.25, 95% CI: 0.08-0.79, P = 0.012) than those with the G/G variant. In multivariable analysis, ATM rs609429 remained significant for OS (P = 0.020). In the validation cohort, patients having ATM rs609429 with any G allele showed longer OS and PFS; the G/A variant in XRCC3 rs861539 showed longer OS, though without statistical significance. Conclusion: Genetic variants in the HR pathway may predict clinical outcome in mCRC patients receiving TAS-102.

Genetic variants associated with colorectal brain metastases susceptibility and survival.

Colorectal brain metastases (BM) are rare (1-2%) and a late-stage disease manifestation. Molecular mechanisms for BM development are not well understood. We tested whether variants within genes involved in overcoming the blood-brain barrier (BBB) are associated with BM susceptibility and survival in patients with BM. Germline single-nucleotide polymorphisms (SNPs, n=17) in seven genes (CXCR4, MMP9, ST6GALNAC5, ITGAV, ITGB1, ITGB3, KLF4) were analyzed from germline DNA in patients with resected BM (n=70) or no clinical evidence of BM after at least 24 months from diagnosis (control group, n=45). SNPs were evaluated for association with BM susceptibility and overall survival (OS) from BM diagnosis. ST6GALNAC5 rs17368584 and ITGB3 rs3809865 were significantly associated with BM susceptibility. In multivariable analysis adjusted for patient characteristics, KLF4 rs2236599, ITGAV rs10171481, ST6GALNAC5 rs1883778, CXCR4 rs2680880 and ITGB3 rs5918 were significant for OS. This study shows for the first time that variants within genes involved in breaching the BBB are associated with BM susceptibility and survival. These findings warrant further validation to develop better screening guidelines and to identify novel therapy targets for patients with BM.

Estrogen receptor-beta genetic variations and overall survival in patients with locally advanced gastric cancer.

Estrogen has been shown not only to reduce the incidence of colorectal cancer but also gastric cancer (GC). Polymorphisms in estrogen receptor ß gene, ESR2, correlate with colorectal cancer survival. To better understand the role of ESR2 in GC, genomic DNA extracted from 169 Japanese patients and 172 patients from Los Angeles County (LAC) was analyzed for association of overall survival (OS) with three ESR2 polymorphisms, which are of biological significance using multivariable Cox proportional hazard regression. ESR2 rs1271572 (C>A) and rs3020443 (T>G) had univariate and multivariable associations with OS in the Japanese cohort, whereas the C allele of ESR2 rs2978381 (T>C) predicted favorable OS in the Japanese cohort but worse OS in the LAC cohort. The interaction term of the ESR2 rs2978381 and cohort group reached statistical significance. Our study provides evidence that genetic variations in ESR2 gene are significantly associated with survival in patients with locally advanced GC.

Genetic variations in immunomodulatory pathways to predict survival in patients with locoregional gastric cancer.

Immunomodulator-targeting therapies are under development in gastric cancer (GC). However, the role of genes modulating anti-tumor immunity in GC remains poorly understood. We investigated the association of variations in genes involved in immunomodulatory pathways with overall survival (OS) in locoregional GC patients. Extracted genomic DNA was analyzed for 35 functional single-nucleotide polymorphisms in genes, PDCD1, CD274, CTLA4, FOXP3, LAG3, ADORA2A, NT5E and IDO1, in 162 Japanese patients as discovery set and 277 US patients as validation set. The C allele of PDCD1 rs10204525 had univariate and multivariable associations with shorter OS in Japanese cohort (P=0.015, P=0.043, respectively). In US cohort the C allele predicted worse OS (P=0.007). Univariate and multivariable analyses revealed IDO1 rs9657182 associated with OS in the Japanese cohort; moreover, the association was confirmed in the US cohort. Genetic predisposition of the host in the immunomodulators may serve as a prognostic biomarker in patients with locoregional GC.

CXCR4 polymorphism predicts progression-free survival in metastatic colorectal cancer patients treated with first-line bevacizumab-based chemotherapy.

We analyzed associations between CXCR4/CXCL12 single-nucleotide polymorphisms and outcomes in metastatic colorectal cancer (mCRC) patients who underwent first-line bevacizumab-based chemotherapy. A total of 874 patients were included in this study: 144 treated with bevacizumab and FOLFOX or XELOX (training cohort), 653 treated with bevacizumab and FOLFIRI or FOLFOXIRI (validation cohort A or B) and 77 treated with cetuximab- and oxaliplatin-based regimens (control cohort). One CXCR4 polymorphism (rs2228014) and two CXCL12 polymorphisms (rs1801157 and rs3740085) were analyzed by PCR-based direct sequencing. Patients with a C/C genotype had a prolonged progression-free survival (PFS) compared with those with any T allele (P=0.030) in the training cohort. Similarly, patients with the C/C genotype had a superior PFS in the validation cohorts, but not in the control cohort. Our findings suggest that a common genetic variant, CXCR4 rs2228014, could predict PFS and may guide therapeutic decisions in mCRC patients receiving first-line bevacizumab-based chemotherapy.

Germline polymorphisms as biomarkers of tumor response in colorectal cancer patients treated with anti-EGFR monoclonal antibodies: a systematic review and meta-analysis.

Studies of germline polymorphisms as predictors of tumor response to anti-epidermal growth factor receptor (EGFR) monoclonal antibody agents in metastatic colorectal cancer have reported inconsistent results. We performed a systematic review of studies from 1990 to September 2015, followed by random-effects meta-analyses for polymorphisms examined in at least three studies. Of 87 studies, 40 passed the criteria for systematic review and 23 for meta-analysis. The polymorphisms suitable for meta-analysis were CCND1 (rs17852153), COX2 (rs20417), EGF (rs4444903), EGFR (rs712829, rs11543848, 3'UTR CA repeat), FCGR2A (rs1801274), FCGR3A (rs396991), IL8 (rs4073), KRAS (rs61764370) and VEGFA (rs3025039). Meta-analysis yielded nominal significance (at α=0.05) for rs4444903 and rs11543848, but showed no significant results after multiple testing correction; this was unchanged by sensitivity analyses to address subgroups, funnel-plot asymmetries, and study quality. This highlights a tendency for lack of replication in the face of initial positive results, and possibly the unsuitability of relying on tumor response as a surrogate marker in this setting.