Phase II randomized trial comparing metronomic anthracycline-containing chemotherapy versus standard schedule in untreated HER2 negative advanced breast cancer: activity and quality of life results of the GOIM 21003 trial.

BACKGROUND: Optimizing chemotherapy to achieve disease and symptoms control is a noteworthy purpose in advanced breast cancer (ABC). We reported the activity and quality of life of a phase II study, comparing metronomic regimen with standard schedule as first line chemotherapy for ABC. METHODS: Patients with HER2 negative ABC were randomized to non-pegylated liposomal doxorubicin (NPLD, 60 mg/m2 every 3 weeks) and cyclophosphamide (CTX, 600 mg/m2 every 3 weeks) (Arm A) or NPLD (20 mg/m2 day, on day 1, 8 and 15 every 4 weeks) and metronomic daily oral CTX 50 mg (ARM B). Primary end-points were overall response rate (ORR) and quality of life, secondary progression-free survival (PFS), overall survival (OS) and toxicity. RESULTS: From August 2012 to December 2017, 121 patients were enrolled, 105 evaluable. Median follow-up was 21.3 months. Most patients had hormone receptor positive. ORR was 43 % in arm A and 50 % in arm B. Median PFS was 8.9 months in arm A and 6,4 months in arm B. There was no difference in OS. Total score was not clinically different between the two arms. Grade 4 neutropenia was observed in 12 patients and 16 patients respectively; alopecia G2 in 41 % (77 %) vs 14 (27 %) in arm A and in arm B respectively. One cardiac toxicity was observed (arm A). CONCLUSIONS: First line metronomic chemotherapy for HER2 negative ABC had similar clinical activity and quite better tolerability than standard schedule and could be considered a further treatment option when chemotherapy is indicated.

Second line trastuzumab emtansine following horizontal dual blockade in a real-life setting.

Despite relevant medical advancements, metastatic breast cancer remains an uncurable disease. HER2 signaling conditions tumor behavior and treatment strategies of HER2 expressing breast cancer. Cancer treatment guidelines uniformly identify dual blockade with pertuzumab and trastuzumab plus a taxane as best first line and trastuzumab emtansine as preferred second line choice. However, there is no prospectively designed available study focusing on the sequence and outcomes of patients treated with T-DM1 following the triplet. In the following report, data concerning a wide series of patients treated in a real-life setting are presented. Results obtained in terms of response and median progression free survival suggests a significant role for T-DM1 in disease control of metastatic HER2 expressing breast cancer.

Is There Still a Role for Endocrine Therapy Alone in HR+/HER2- Advanced Breast Cancer Patients? Results from the Analysis of Two Data Sets of Patients Treated with High-Dose Fulvestrant as First-Line Therapy in the Real-World Setting: The EVA and GIM-13 AMBRA Studies.

BACKGROUND: Different studies suggest that fulvestrant 500 mg every 28 days (HD-FUL) could be an active treatment in HR+ advanced breast cancer (ABC) patients even treated with aromatase inhibitors in the adjuvant setting. The aim of this analysis is to describe the outcome of ABC patients treated with HD-FUL as first-line treatment in terms of median duration of treatment and the overall response rate in a real-world setting. METHODS: For the purpose of the present analysis, we considered two data sets of HR+ ABC patients collected in Italy between 2012 and 2015 (EVA and GIM-13 AMBRA studies). RESULTS: Eighty-one and 91 patients have been identified from the two data sets. The median age was 63 years (range 35-82) for the EVA and 57.8 years (range 35.0-82.3) for the AMBRA patients. ORRs were 23.5 and 24.3% in the whole population, 26.9% in the patients with bone only, and 21.8 and 21.4% in those with visceral metastases. The median duration of HD-FUL was 11.6 months (range 1-48) and 12.4 months (range 2.9-70.0) in the two data sets, respectively. CONCLUSION: These data suggest that HD-FUL should still continue to play a significant role as first-line therapy in HR+ ABC patients.

Bevacizumab in Combination With Either FOLFOX-4 or XELOX-2 in First-line Treatment of Patients With Metastatic Colorectal Cancer: A Multicenter Randomized Phase II Trial of the Gruppo Oncologico dell'Italia Meridionale (GOIM 2802).

INTRODUCTION: Biweekly schedule of XELOX-2 (capecitabine plus oxaliplatin) showed interesting results in first-line therapy of patients with metastatic colorectal cancer (mCRC). Bevacizumab plus FOLFOX-4 (oxaliplatin, folinic acid, and infusional 5-fluorouracil) is among standard first-line treatment options in this setting. We performed a phase II randomized trial in order to evaluate the activity of bevacizumab plus either FOLFOX-4 or XELOX-2 in first-line therapy of patients with mCRC. MATERIALS AND METHODS: Patients with mCRC were randomized, in a 1:2 ratio, to first-line bevacizumab plus either FOLFOX-4 (Arm A), as calibration arm, or XELOX-2 (Arm B), up to 12 cycles. Patients without progression were further randomized to maintenance bevacizumab alone or with the same induction fluoropyrimidine. The primary endpoint was objective response rate (ORR); secondary endpoints included progression-free survival, overall survival, and toxicity. The study design was formally non-comparative, but exploratory comparison was performed. RESULTS: Forty-five patients were randomized in arm A and 87 in arm B with an ORR of 55.6% versus 48.3% (P = .43), respectively. After a median follow-up of 47.2 months, progression-free survival was 10.0 versus 9.9 months (hazard ratio, 0.96; 95% confidence interval, 0.65-1.41; P = .84) and overall survival was 29.8 versus 25.0 months (hazard ratio, 1.21; 95% confidence interval, 0.77-1.92; P = .41), respectively. The main grade 3 to 4 toxicities (% A/B) were: neutropenia 15/3 and nausea 9/5. CONCLUSION: This exploratory analysis showed that biweekly XELOX-2 plus bevacizumab has a comparable ORR with FOLFOX-4 plus bevacizumab in patients with mCRC.

Eribulin plus trastuzumab in pretreated HER2-positive advanced breast cancer patients: safety and efficacy. An Italian experience.

BACKGROUND: Chemotherapy plus targeted therapy is the established treatment for human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer (BC). Limited data regarding the safety and activity of the combination of eribulin and trastuzumab (E/T) in pretreated HER2-positive advanced BC (ABC) are available. The aim of this observational, retrospective, multicenter study was to examine the tolerability and the clinical activity of E/T in this setting. METHODS: Patients treated with eribulin mesylate plus standard dose of trastuzumab were included. Data on overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety were reported. RESULTS: Between October 2012 and November 2015, 24 consecutive patients with HER2-positive ABC were included. All patients were heavily pretreated: the median number of prior chemotherapy regimens for ABC was 3 (range 2-9). The median number of cycles with E/T was 11.5 (range 2-26). The ORR was 41.7%. Median PFS was 5.4 months, median postprogression survival was 5.4 months, and median OS was 8 months. Neutropenia was the most common grade 3/4 clinical adverse event (16.7%). CONCLUSIONS: Tolerability and clinical activity of the E/T combination schedule are encouraging. The results of this study indicate that this combination might be considered for treatment of pretreated HER2 ABC.

Exploratory findings from a prematurely closed international, multicentre, academic trial: RAVELLO, a phase III study of regorafenib versus placebo as maintenance therapy after first-line treatment in RAS wild-type metastatic colorectal cancer.

BACKGROUND: In patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC), the role of maintenance therapy after first-line treatment with chemotherapy plus antiepidermal growth factor receptor (EGFR) monoclonal antibodies (MoAb) is still an object of debate. METHODS: We assessed the efficacy and safety of regorafenib as a switch maintenance strategy after upfront 5-fluorouracil-based chemotherapy plus an anti-EGFR MoAb in patients with RAS WT mCRC. RAVELLO was a phase III, international, double-blind, placebo-controlled, academic trial. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival and toxicity. Regorafenib or placebo were administered daily for 3 weeks of 4-week cycle until disease progression or unacceptable toxicity, up to 24 months. RESULTS: The study was stopped prematurely due to slow accrual and lack of funding after the randomisation of 21 patients: 11 in the regorafenib arm and 10 in the placebo arm. The small sample size precludes any statistical analysis. Toxicity was acceptable and consistent with the known regorafenib safety profile. Median PFS was similar in the two arms. However, a subgroup of patients treated with regorafenib experienced a remarkably long PFS. Three patients were progression free at 9 months in the regorafenib arm versus one patient in the placebo arm, whereas at 12 months two regorafenib-treated patients were still progression free versus none in the placebo arm. CONCLUSION: RAVELLO trial demonstrated that growing financial and bureaucratic hurdles affect the feasibility of independent academic research. Although stopped prematurely and within the limited sample size, RAVELLO suggests that regorafenib has not a major activity in maintenance setting after upfront chemotherapy and anti-EGFR MoAb. However, a subgroup of patients experienced a remarkable long PFS, indicating that a better refinement of the patient population would help to identify subjects that might benefit from a regorafenib personalised approach in the switch maintenance setting.

Correction: Everolimus (EVE) and exemestane (EXE) in patients with advanced breast cancer aged ≥ 65 years: new lessons for clinical practice from the EVA study.

[This corrects the article DOI: 10.18632/oncotarget.25874.].

Exemestane and Everolimus combination treatment of hormone receptor positive, HER2 negative metastatic breast cancer: A retrospective study of 9 cancer centers in the Campania Region (Southern Italy) focused on activity, efficacy and safety.

Exemestane (Exe) in combination with Everolimus (Eve) represents an important treatment option for patients diagnosed with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer (MBC), which was previously treated with non-steroidal aromatase inhibitors (NSAI). Data from unselected populations may be useful for defining the optimal therapeutic algorithm within a clinical setting. Data from 264 HR+, HER2-MBC patients who received Exe-Eve treatment in combination, following the failure of NSAIs was retrospectively analyzed. Different lines of endocrine treatment (ET) were investigated to evaluate the efficacy and toxicity of the treatment within the 'everyday clinical practice' population. The disease control rate (DCR) was 73.1%, with no statistically significant difference among the different settings. At a median follow-up of 42 months, the median progression free survival (PFS) was 11.6, 9.7 and 7.5 months for patients treated with Exe-Eve as first, second or third line therapy, respectively. There was a statistically significant correlation with younger age, no previous adjuvant chemotherapy (CT), no previous adjuvant endocrine therapy (ET), HT duration ≥36 months, involvement of liver and/or lung, no prior CT for metastatic disease and PS=0 at the start of treatment. The median overall survival (OS) was 33.0 months; at a median follow-up of 67 months, the median OS was 43.1, 31.7 and 27.9 months in patients treated with Exe-Eve in first, second or third line therapy, respectively. On multivariate analysis, diabetes and previous CT for metastatic disease were revealed to correlate with a worse outcome. Conversely, the presence of mucositis was significantly associated with long-term survival. Overall, Exe-Eve was typically well tolerated and the majority toxicities were G1 or 2, while treatment discontinuation due to unacceptable toxicity was only required in 5.7% of patients. Despite the limitations due to the observational nature of this study, the findings suggest that treatment with Exe-Eve is an active and safe therapeutic option for endocrine-sensitive MBC patients in a real-world clinical setting, regardless of treatment lines.

Everolimus (EVE) and exemestane (EXE) in patients with advanced breast cancer aged ≥ 65 years: new lessons for clinical practice from the EVA study.

BACKGROUND: The present analysis focuses on real-world data of Everolimus-Exemestane in advanced HR+ve, HER2-ve elderly breast cancer patients (aged 65 years) included in the EVA study, with unique findings in those aged 70 years. METHODS: Data are collected from clinical records and analysed according to age cut-off (< 65 years; 65 - 69 years and {greater than or equal to} 70 years). Relationship of analyzed variables with response were tested by mean of a Mantel-Haenszel chi square test. Time to event analysis was described by Kaplan Meier approach and association with baseline characteristics was analysed by stratified log-rank test and proportional hazard model. RESULTS: From July 2013 to December 2015, the EVA study enrolled overall 404 pts. 154 patients out of 404 (38,1%) were aged {greater than or equal to} 65 years, of whom 87 were {greater than or equal to} 70 years. Median duration of EVE treatment was 28.5 weeks (95% CI 19.0 - 33.8) in patients aged 65-69 years and 24,4 weeks (95% CI 19,2 - 33,2) in those aged {greater than or equal to} 70 years. Fewer patients aged 65 years received the highest EVE Dose-Intensity (>7.5 mg/day) in comparison to younger patients (49,6% vs. 66,8%). Grade 3-4 toxicities occurred to 55 patients (35,7%), mainly stomatitis (10,9%), rash (5,8%) and non-infectious pneumonitis (NIP) (3,6%). Some toxicities, such as weight loss and anaemia were peculiarly observed in patients aged {greater than or equal to} 70 years. Five treatment-related deaths were collected (3,2%). CONCLUSIONS: EVE-EXE combination remains one of the potential treatments in HR+ patients also for elderly ones.

Eribulin Treatment in Patients with Liver Metastatic Breast Cancer: Eight Italian Case Reports.

Liver metastases are very common in metastatic breast cancer (MBC); current treatments for these lesions are based on systemic chemotherapy, endocrine- or human epidermal growth factor receptor 2 (HER2)-targeted therapy, and palliative therapy. However, no standard approach has been clearly identified for second and further chemotherapy lines in MBC patients. In the phase III clinical trial EMBRACE, eribulin was particularly effective in reducing liver lesions and improving both overall survival and progression-free survival in liver MBC patients. In this series, we collected 8 case reports of Italian clinical practice in which eribulin has shown significant efficacy in reducing liver metastases in MBC patients: complete response was reported in 2 patients, and 4 patients achieved partial response. The treatment was well tolerated, thus confirming that eribulin is a suitable therapeutic option for elderly patients and for those who have metastatic HER2-negative disease. In the setting of MBC, the sequencing of therapeutic agents should consider expected response, side effects, tumor characteristics, and patient's preferences, in order to successfully tailor the most appropriate therapy beyond earlier lines.

Correction 2: Everolimus (EVE) and exemestane (EXE) in patients with advanced breast cancer aged ≥ 65 years: new lessons for clinical practice from the EVA study.

[This corrects the article DOI: 10.18632/oncotarget.25874.].

Eribulin for metastatic breast cancer (MBC) treatment: a retrospective, multicenter study based in Campania, south Italy (Eri-001 trial).

BACKGROUND: On the basis of the results of two pivotal phase III clinical trials, eribulin mesylate is currently approved in EU for the treatment of advanced breast cancer (aBC) in patients who have previously received an anthracycline and a taxane in either the adjuvant or the metastatic setting, and at least one chemotherapeutic regimen for metastatic disease. METHODS: In our study, we investigated the efficacy and tolerability of eribulin as second or further line chemotherapy in 137 women affected by aBC. RESULTS: Eribulin as monotherapy provided benefit in terms of progression-free survival (PFS), response rate (RR) and disease control rate (DCR) independently of its use as second or late-line therapy. The overall RR and DCR were 17.5% and 64%, respectively. In particular, DCR and overall RR were 50% and 13.6%, 65.4% and 21.1%, 70.4% and 14.8% and 66.7% and 16.7% in second, third, fourth and further lines of treatment, respectively. Median PFS (mPFS) according to the line of therapy was 5.7, 6.3, 4.5 and 4.0 months in patients treated with eribulin in second, third, fourth and over the fourth line, respectively. No significant difference in terms of mPFS was found between the various BC subtypes. Overall, eribulin resulted safe and most adverse events were of grade 1 or 2 and easily manageable. Grades 3-4 toxicities were neutropaenia and neurotoxicity. CONCLUSIONS: With the limitations due to the observational nature of our findings, eribulin was shown to be an effective and safe therapeutic option in heavily pretreated patients with aBC.

Dose intensity and efficacy of the combination of everolimus and exemestane (EVE/EXE) in a real-world population of hormone receptor-positive (ER+/PgR+), HER2-negative advanced breast cancer (ABC) patients: a multicenter Italian experience.

AIM: This retrospective analysis focused on the effect of treatment with EVE/EXE in a real-world population outside of clinical trials. We examined the efficacy of this combination in terms of PFS and RR related to dose intensity (5 mg daily versus 10 mg daily) and tolerability. METHODS: 163 HER2-negative ER+/PgR+ ABC patients, treated with EVE/EXE from May 2011 to March 2016, were included in the analysis. The primary endpoints were the correlation between the daily dose and RR and PFS, as well as an evaluation of the tolerability of the combination. Secondary endpoints were RR, PFS, and OS according to the line of treatment. Patients were classified into three different groups, each with a different dose intensity of everolimus (A, B, C). RESULTS: RR was 29.8% (A), 27.8% (B) (p = 0.953), and not evaluable (C). PFS was 9 months (95% CI 7-11) (A), 10 months (95% CI 9-11) (B), and 5 months (95% CI 2-8) (C), p = 0.956. OS was 38 months (95% CI 24-38) (A), median not reached (B), and 13 months (95% CI 10-25) (C), p = 0.002. Adverse events were stomatitis 57.7% (11.0% grade 3-4), asthenia 46.0% (6.1% grade 3-4), hypercholesterolemia 46.0% (0.6% grade 3-4), and hyperglycemia 35.6% (5.5% grade 3-4). The main reason for discontinuation/interruption was grade 2-3 stomatitis. CONCLUSIONS: No correlation was found between dose intensity (5 vs. 10 mg labeled dose) and efficacy in terms of RR and PFS. The tolerability of the higher dose was poor in our experience, although this had no impact on efficacy.

NAB-paclitaxel and gemcitabine in metastatic pancreatic ductal adenocarcinoma (PDAC): from clinical trials to clinical practice.

BACKGROUND: Pancreatic adenocarcinoma is an aggressive disease with poor prognosis. In a randomized phase III trial, combination of Nab-paclitaxel (Nab-P) plus gemcitabine showed superior activity and efficacy in first-line treatment compared with gemcitabine alone. METHODS: Nab-P is not dispensed in Italy; however, we obtained this drug from our Ethics Committee for compassionate use. The aim of this study was to evaluate the efficacy and safety profile of this Nab-P and gemcitabine combination in a cohort of patients treated outside clinical trials. From January 2012 to May 2014, we included 41 patients with advanced pancreatic adenocarcinoma receiving combination of 125 mg/m(2) Nab-P and 1 g/m(2) gemcitabine on days 1, 8 and 15 of a 28-day cycle, as first-line treatment. Median age of patients was 67 (range 41-77) years, and 11 patients were aged ≥70 years. RESULTS: Eastern Co-operative Oncology Group performance status was 0 or 1 in 32 patients (78 %) and 2 in nine patients (22 %). Primary tumor was located in the pancreatic head or body/tail in 24 (58.5 %) and 17 (41.5 %) patients, respectively, and nine patients had received biliary stent implantation before starting chemotherapy. Median carbohydrate antigen 19-9 level was 469 U/l (range 17.4-61546 U/l) and 29 patients (70.7 %) had referred pain at the time of diagnosis. Patients received a median six cycles (range 1-14) of treatment. Overall response rate was 36.6 %; median progression-free survival was 6.7 months [(95 % confidence interval (CI) 5.966-8.034), and median overall survival was 10 months (95 % CI 7.864-12.136). Treatment was well tolerated. No grade 4 toxicity was reported. Grade 3 toxicity included neutropenia in 10 patients (24.3 %), thrombocytopenia in five (12 %), anemia in three (7.3 %), diarrhea in four (9.7 %), nausea and vomiting in two (4.9 %), and fatigue in six (14.6 %). Finally, pain control was achieved in 24 of 29 patients (82.3 %) with a performance status improvement of 10 % according to the Karnofsky scale. CONCLUSIONS: Our results confirm that combination of gemcitabine plus Nab-P is effective both in terms of overall response rate, progression-free survival and overall survival, with a good safety profile.

Biomarker analysis of the MITO2 phase III trial of first-line treatment in ovarian cancer: predictive value of DNA-PK and phosphorylated ACC.

BACKGROUND: No biomarker is available to predict prognosis of patients with advanced ovarian cancer (AOC) and guide the choice of chemotherapy. We performed a prospective-retrospective biomarker study within the MITO2 trial on the treatment of AOC. PATIENTS AND METHODS: MITO2 is a randomised multicentre phase 3 trial conducted with 820 AOC patients assigned carboplatin/paclitaxel (carboplatin: AUC5, paclitaxel: 175 mg/m², every 3 weeks for 6 cycles) or carboplatin/PLD-pegylated liposomal doxorubicin (carboplatin: AUC5, PLD: 30 mg/m², every 3 weeks for 6 cycles) as first line treatment. Sixteen biomarkers (pathways of adhesion/invasion, apoptosis, transcription regulation, metabolism, and DNA repair) were studied in 229 patients, in a tissue microarray. Progression-free and overall survival were analysed with multivariable Cox model. RESULTS: After 72 months median follow-up, 594 progressions and 426 deaths were reported; there was no significant difference between the two arms in the whole trial. No biomarker had significant prognostic value. Statistically significant interactions with treatment were found for DNA-dependent protein kinase (DNA-PK) and phosphorylated acetyl-coenzymeA carboxylase (pACC), both predicting worse outcome for patients receiving carboplatin/paclitaxel. CONCLUSION: These data show that in presence of DNA-PK or pACC overexpression, carboplatin/paclitaxel might be less effective than carboplatin/PLD as first line treatment of ovarian cancer patients. Further validation of these findings is warranted.

Cancer drug related cardiotoxicity during breast cancer treatment.

INTRODUCTION: Breast cancer (BC) is the most common cancer in women. Although therapeutic armamentarium like chemotherapy, endocrine and target agents have increased survival, cardiovascular side effects have been observed. A comprehensive risk assessment, early detection and management of cardiac adverse events is therefore needed. AREAS COVERED: In this review we focus on cardiotoxicity data deriving from Phase III randomized trials, systematic reviews and meta-analysis in BC patients. We provide insight into advances that have been made in the molecular mechanisms, clinical presentation and management of such adverse event. EXPERT OPINION: Despite the large number of data from Phase III trials about cardiac events incidence, there are poor evidences for detection, monitoring and management of cardiotoxicity during BC treatment. Future cardiotoxicity-oriented clinical cancer research can help to predict the risk of cardiac adverse events and improve patients' outcome. Multidisciplinary approach as well as integration of blood biomarkers with imaging will be desirable.

Cancer-Associated Immune Resistance and Evasion of Immune Surveillance in Colorectal Cancer.

Data from molecular profiles of tumors and tumor associated cells provide a model in which cancer cells can acquire the capability of avoiding immune surveillance by expressing an immune-like phenotype. Recent works reveal that expression of immune antigens (PDL1, CD47, CD73, CD14, CD68, MAC387, CD163, DAP12, and CD15) by tumor cells "immune resistance," combined with prometastatic function of nonmalignant infiltrating cells, may represent a strategy to overcome the rate-limiting steps of metastatic cascade through (a) enhanced interactions with protumorigenic myeloid cells and escape from T-dependent immune response mediated by CD8+ and natural killer (NK) cells; (b) production of immune mediators that establish a local and systemic tumor-supportive environment (premetastatic niche); (c) ability to survive either in the peripheral blood as circulating tumor cells (CTCs) or at the metastatic site forming a cooperative prometastatic loop with foreign "myeloid" cells, macrophages, and neutrophils, respectively. The development of cancer-specific "immune resistance" can be orchestrated either by cooperation with tumor microenvironment or by successive rounds of genetic/epigenetic changes. Recognition of the applicability of this model may provide effective therapeutic avenues for complete elimination of immune-resistant metastatic cells and for enhanced antitumor immunity as part of a combinatorial strategy.

Cancer-related CD15/FUT4 overexpression decreases benefit to agents targeting EGFR or VEGF acting as a novel RAF-MEK-ERK kinase downstream regulator in metastatic colorectal cancer.

BACKGROUND: Cancer-related immune antigens in the tumor microenvironment could represent an obstacle to agents targeting EGFR "cetuximab" or VEGF "bevacizumab" in metastatic colorectal cancer (mCRC) patients. METHODS: Infiltrating immune cells into tumor tissues, cancer-related expression of immune antigens (CD3, CD8, CD68, CD73, MPO, CD15/FUT4) from 102 mCRC patients receiving first-line Cetuximab or Bevacizumab plus chemotherapy were assessed by immunohistochemistry and validated in an independent tissue microarrays of 140 patients. Genome-wide expression profiles from 436 patients and 60 colon cancer cell lines were investigated using bioinformatics analysis. In vitro kinase assays of target genes activated by chemokines or growth factors were performed. RESULTS: Here, we report that cancer-related CD15/FUT4 is overexpressed in most of mCRCs patients (43 %) and associates with lower intratumoral CD3+ and CD8+ T cells, higher systemic inflammation (NLR at diagnosis >5) and poorer outcomes, in terms of response and progression-free survival than those CD15/FUT4-low or negative ones (adjusted hazard ratio (HR) = 2.92; 95 % CI = 1.86-4.41; P < 0.001). Overexpression of CD15/FUT4 is induced through RAF-MEK-ERK kinase cascade, suppressed by MEK inhibitors and exhibits a close connection with constitutive oncogenic signalling pathways that respond to ERBB3 or FGFR4 activation (P < 0.001). CD15/FUT4-high expressing colon cancer cells with primary resistance to cetuximab or bevacizumab are significantly more sensitive to MEK inhibitors than CD15/FUT4-low counterparts. CONCLUSION: Cancer-related CD15/FUT4 overexpression participates in cetuximab or bevacizumab mechanisms of resistance in mCRC patients. CD15/FUT4 as a potential target of the antitumor immune response requires further evaluation in clinical studies.