The Peptidoglycan Recognition Protein 1 confers immune evasive properties on pancreatic cancer stem cells.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) has limited therapeutic options, particularly with immune checkpoint inhibitors. Highly chemoresistant 'stem-like' cells, known as cancer stem cells (CSCs), are implicated in PDAC aggressiveness. Thus, comprehending how this subset of cells evades the immune system is crucial for advancing novel therapies. DESIGN: We used the KPC mouse model (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) and primary tumour cell lines to investigate putative CSC populations. Transcriptomic analyses were conducted to pinpoint new genes involved in immune evasion. Overexpressing and knockout cell lines were established with lentiviral vectors. Subsequent in vitro coculture assays, in vivo mouse and zebrafish tumorigenesis studies, and in silico database approaches were performed. RESULTS: Using the KPC mouse model, we functionally confirmed a population of cells marked by EpCAM, Sca-1 and CD133 as authentic CSCs and investigated their transcriptional profile. Immune evasion signatures/genes, notably the gene peptidoglycan recognition protein 1 (PGLYRP1), were significantly overexpressed in these CSCs. Modulating PGLYRP1 impacted CSC immune evasion, affecting their resistance to macrophage-mediated and T-cell-mediated killing and their tumourigenesis in immunocompetent mice. Mechanistically, tumour necrosis factor alpha (TNFα)-regulated PGLYRP1 expression interferes with the immune tumour microenvironment (TME) landscape, promoting myeloid cell-derived immunosuppression and activated T-cell death. Importantly, these findings were not only replicated in human models, but clinically, secreted PGLYRP1 levels were significantly elevated in patients with PDAC. CONCLUSIONS: This study establishes PGLYRP1 as a novel CSC-associated marker crucial for immune evasion, particularly against macrophage phagocytosis and T-cell killing, presenting it as a promising target for PDAC immunotherapy.

Randomized phase 2 study of valproic acid combined with simvastatin and gemcitabine/nab-paclitaxel-based regimens in untreated metastatic pancreatic adenocarcinoma patients: the VESPA trial study protocol.

BACKGROUND: Metastatic pancreatic ductal adenocarcinoma (mPDAC) patients have very poor prognosis highlighting the urgent need of novel treatments. In this regard, repurposing non-oncology already-approved drugs might be an attractive strategy to offer more-effective treatment easily tested in clinical trials. Accumulating evidence suggests that epigenetic deregulation is a hallmark of cancer contributing to treatment resistance in several solid tumors, including PDAC. Histone deacetylase inhibitors (HDACi) are epigenetic drugs we have investigated preclinically and clinically as anticancer agents. Valproic acid (VPA) is a generic low-cost anticonvulsant and mood stabilizer with HDAC inhibitory activity, and anticancer properties also demonstrated in PDAC models. Statins use was reported to be associated with lower mortality risk in patients with pancreatic cancer and statins have been shown to have a direct antitumor effect when used alone or in combination therapy. We recently showed capability of VPA/Simvastatin (SIM) combination to potentiate the antitumor activity of gemcitabine/nab-paclitaxel in vitro and in vivo PDAC preclinical models. METHODS/DESIGN: VESPA is a patient-centric open label randomized multicenter phase-II investigator-initiated trial, evaluating the feasibility, safety, and efficacy of VPA/SIM plus first line gemcitabine/nab-paclitaxel-based regimens (AG or PAXG) (experimental arm) versus chemotherapy alone (standard arm) in mPDAC patients. The study involves Italian and Spanish oncology centers and includes an initial 6-patients safety run-in-phase. A sample size of 240 patients (120 for each arm) was calculated under the hypothesis that the addition of VPA/SIM to gemcitabine and nab-paclitaxel-based regimens may extend progression free survival from 6 to 9 months in the experimental arm. Secondary endpoints are overall survival, response rate, disease control rate, duration of response, CA 19.9 reduction, toxicity, and quality of life. The study includes a patient engagement plan and complementary biomarkers studies on tumor and blood samples. CONCLUSIONS: VESPA is the first trial evaluating efficacy and safety of two repurposed drugs in oncology such as VPA and SIM, in combination with standard chemotherapy, with the aim of improving mPDAC survival. The study is ongoing. Enrollment started in June 2023 and a total of 63 patients have been enrolled as of June 2024. TRIAL REGISTRATION: EudraCT number: 2022-004154-63; ClinicalTrials.gov identifier NCT05821556, posted 2023/04/20.

Differential distribution and enrichment of non-coding RNAs in exosomes from normal and Cancer-associated fibroblasts in colorectal cancer.

Exosome production from cancer-associated fibroblasts seems to be an important driver of tumor progression. We report the first in-depth biotype characterization of ncRNAs, analyzed by Next Generation Sequencing and Bioinformatics, expressed in established primary human normal and cancer-associated fibroblasts (CAFs) from cancer and normal mucosa tissues from 9 colorectal cancer patients, and/or packaged in their derived exosomes. Differential representation and enrichment analyses based on these ncRNAs revealed a significant number of differences between the ncRNA content of exosomes and the expression patterns of the normal and cancer-associated fibroblast cells. ncRNA regulatory elements are specifically packaged in CAF-derived exosomes, supporting a specific cross-talk between CAFs and colon cancer cells and/or other stromal cells, mediated by exosomes. These sncRNAs are potential biomarkers present in cancer-associated fibroblast-derived exosomes, which should thereby contribute to developing new non-invasive diagnostic, prognostic and predictive methods for clinical applications in management of cancer patients.

Circulating tumor cells (Ctc) and kras mutant circulating free Dna (cfdna) detection in peripheral blood as biomarkers in patients diagnosed with exocrine pancreatic cancer.

BACKGROUND: Pancreatic cancer remains one of the most difficult cancers to treat with the poorest prognosis. The key to improving survival rates in this disease is early detection and monitoring of disseminated and residual disease. However, this is hindered due to lack reliable diagnostic and predictive markers which mean that the majority of patients succumb to their condition within a few months. METHODS: We present a pilot study of the detection circulating free DNA (cfDNA) combined with tumor specific mutation detection by digital PCR as a novel minimally invasive biomarker in pancreatic ductal adenocarcinoma (PDAC). This was compared to the detection of CTC by the CellSearch® system and a novel CTC enrichment strategy based on CD45 positive cell depletion. The aim of the study was to assess tumor specific DNA detection in plasma and CTC detection as prognostic markers in PDAC. RESULTS: We detected KRAS mutant cfDNA in 26% of patients of all stages and this correlated strongly with Overall Survival (OS), 60 days (95% CI: 19-317) for KRAS mutation positive vs 772 days for KRAS mutation negative (95% CI: 416-1127). Although, the presence of CTC detected by the CellSearch® system did correlate significantly with OS, 88 days (95% CI: 27-206) CTC positive vs 393 days CTC negative (95% CI: 284-501), CTC were detected in only 20% of patients, the majority of which had metastatic disease, whereas KRAS mutant cfDNA was detected in patients with both resectable and advanced disease. CONCLUSIONS: Tumor specific cfDNA detection and CTC detection are promising markers for the management of patients with PDAC, although there is a need to validate these results in a larger patient cohort and optimize the detection of CTC in PDAC by applying the appropriate markers for their detection.

Nab-Paclitaxel plus Gemcitabine and FOLFOX in Metastatic Pancreatic Cancer.

BACKGROUND: Sequential nab-paclitaxel plus gemcitabine followed by modified FOLFOX-6 (oxaliplatin, leucovorin, and 5-fluorouracil) (nab-P/Gem-mFOLFOX) showed a good safety and clinical profile in metastatic pancreatic ductal adenocarcinoma (mPDAC) in the phase I SEQUENCE trial. METHODS: The safety and efficacy of sequential nab-P/Gem-mFOLFOX was compared with standard nab-paclitaxel plus gemcitabine (nab-P/Gem) as first-line treatment in a multi-institutional, randomized, open-label, phase II trial in patients with untreated mPDAC. We randomly assigned patients in a 1:1 ratio to receive nab-P/Gem on days 1, 8, and 15 followed by mFOLFOX on day 29 of a 6-week cycle (experimental group) or nab-P/Gem on days 1, 8, and 15 of a 4-week cycle (control group). The primary end point was the 12-month overall survival rate. RESULTS: A total of 157 patients were randomly assigned: 78 to nab-P/Gem-mFOLFOX and 79 to nab-P/Gem. Patients receiving nab-P/Gem-mFOLFOX had a 12-month overall survival of 55.3% (95% confidence interval [CI], 44.2 to 66.5) versus 35.4% (95% CI, 24.9 to 46) in the control group (P=0.02). Similarly, the 24-month survival was 22.4% (95% CI, 13 to 31.8) with nab-P/Gem-mFOLFOX versus 7.6% (95% CI, 1.8 to 13.4) with control treatment. The median overall survival was 13.2 months (95% CI, 10.1 to 16.2) with nab-P/Gem-mFOLFOX and 9.7 months (95% CI, 7.5 to 12) with nab-P/Gem (hazard ratio for death, 0.68; 95% CI, 0.48 to 0.95). The safety profile showed a higher incidence of grade 3 or higher neutropenia (35 of 76 vs. 19 of 79 patients, P=0.004), grade 3 or higher thrombocytopenia (18 of 78 vs. 6 of 79 patients, P=0.007), and two treatment-related deaths (2.6%) with nab-P/Gem-mFOLFOX compared with none with control treatment. CONCLUSIONS: Sequential nab-P/Gem-mFOLFOX showed a significantly higher 12-month survival when compared with the standard nab-P/Gem treatment; this came with greater treatment toxicity. (Funded by Celgene; EuCT number, 2014-005350-19; ClinicalTrials.gov number, NCT02504333.)

Nanomedicine and epigenetics: New alliances to increase the odds in pancreatic cancer survival.

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers worldwide, primarily due to its robust desmoplastic stroma and immunosuppressive tumor microenvironment (TME), which facilitate tumor progression and metastasis. In addition, fibrous tissue leads to sparse vasculature, high interstitial fluid pressure, and hypoxia, thereby hindering effective systemic drug delivery and immune cell infiltration. Thus, remodeling the TME to enhance tumor perfusion, increase drug retention, and reverse immunosuppression has become a key therapeutic strategy. In recent years, targeting epigenetic pathways has emerged as a promising approach to overcome tumor immunosuppression and cancer progression. Moreover, the progress in nanotechnology has provided new opportunities for enhancing the efficacy of conventional and epigenetic drugs. Nano-based drug delivery systems (NDDSs) offer several advantages, including improved drug pharmacokinetics, enhanced tumor penetration, and reduced systemic toxicity. Smart NDDSs enable precise targeting of stromal components and augment the effectiveness of immunotherapy through multiple drug delivery options. This review offers an overview of the latest nano-based approaches developed to achieve superior therapeutic efficacy and overcome drug resistance. We specifically focus on the TME and epigenetic-targeted therapies in the context of PDAC, discussing the advantages and limitations of current strategies while highlighting promising new developments. By emphasizing the immense potential of NDDSs in improving therapeutic outcomes in PDAC, our review paves the way for future research in this rapidly evolving field.

Establishment of Pancreatic Cancer-Derived Tumor Organoids and Fibroblasts From Fresh Tissue.

Tumor organoids are three-dimensional (3D) ex vivo tumor models that recapitulate the biological key features of the original primary tumor tissues. Patient-derived tumor organoids have been used in translational cancer research and can be applied to assess treatment sensitivity and resistance, cell-cell interactions, and tumor cell interactions with the tumor microenvironment. Tumor organoids are complex culture systems that require advanced cell culture techniques and culture media with specific growth factor cocktails and a biological basement membrane that mimics the extracellular environment. The ability to establish primary tumor cultures highly depends on the tissue of origin, the cellularity, and the clinical features of the tumor, such as the tumor grade. Furthermore, tissue sample collection, material quality and quantity, as well as correct biobanking and storage are crucial elements of this procedure. The technical capabilities of the laboratory are also crucial factors to consider. Here, we report a validated SOP/protocol that is technically and economically feasible for the culture of ex vivo tumor organoids from fresh tissue samples of pancreatic adenocarcinoma origin, either from fresh primary resected patient donor tissue or patient-derived xenografts (PDX). The technique described herein can be performed in laboratories with basic tissue culture and mouse facilities and is tailored for wide application in the translational oncology field.

A randomised phase 2 study comparing different dose approaches of induction treatment of regorafenib in previously treated metastatic colorectal cancer patients (REARRANGE trial).

PURPOSE: The purpose of this article is to evaluate the safety of two regorafenib dose-escalation approaches in refractory metastatic colorectal cancer (mCRC) patients. PATIENTS AND METHODS: Patients with mCRC and progression during or within 3 months following their last standard chemotherapy regimen were randomised to receive the approved dose of regorafenib of 160 mg QD (arm A) or 120 mg QD (arm B) administered as 3 weeks of treatment followed by 1 week off, or 160 mg QD 1 week on/1 week off (arm C). The primary end-point was the percentage of patients with G3/G4 treatment-related adverse events (AEs) in each arm. RESULTS: There were 299 patients randomly assigned to arm A (n = 101), arm B (n = 99), or arm C (n = 99); 297 initiated treatments (arm A n = 100, arm B n = 98, arm C n = 99: population for safety analyses). G3/4 treatment-related AEs occurred in 60%, 55%, and 54% of patients in arms A, B, and C, respectively. The most common G3/4 AEs were hypertension (19, 12, and 20 patients), fatigue (20, 14, and 15 patients), hypokalemia (11, 7, and 10 patients), and hand-foot skin reaction (8, 7, and 3 patients). Median overall survival was 7.4 (IQR 4.0-13.7) months in arm A, 8.6 (IQR 3.8-13.4) in arm B, and 7.1 (IQR 4.4-12.4) in arm C. CONCLUSIONS: The alternative regorafenib dosing schedules were feasible and safe in patients with mCRC who had been previously treated with standard therapy. There was a higher numerical improvement on the most clinically relevant AEs in the intermittent dosing arm, particularly during the relevant first two cycles. GOV IDENTIFIER: NCT02835924.

Somatic Mutation Profiling in the Liquid Biopsy and Clinical Analysis of Hereditary and Familial Pancreatic Cancer Cases Reveals KRAS Negativity and a Longer Overall Survival.

Pancreatic ductal adenocarcinoma (PDAC) presents many challenges in the clinic and there are many areas for improvement in diagnostics and patient management. The five-year survival rate is around 7.2% as the majority of patients present with advanced disease at diagnosis that is treatment resistant. Approximately 10-15% of PDAC cases have a hereditary basis or Familial Pancreatic Cancer (FPC). Here we demonstrate the use of circulating free DNA (cfDNA) in plasma as a prognostic biomarker in PDAC. The levels of cfDNA correlated with disease status, disease stage, and overall survival. Furthermore, we show for the first time via BEAMing that the majority of hereditary or familial PDAC cases (around 84%) are negative for a KRAS somatic mutation. In addition, KRAS mutation negative cases harbor somatic mutations in potentially druggable genes such as KIT, PDGFR, MET, BRAF, and PIK3CA that could be exploited in the clinic. Finally, familial or hereditary cases have a longer overall survival compared to sporadic cases (10.2 vs. 21.7 months, respectively). Currently, all patients are treated the same in the clinic with cytotoxic agents, although here we demonstrate that there are different subtypes of tumors at the genetic level that could pave the way to personalized treatment.

Correction: Earl et al. Somatic Mutation Profiling in the Liquid Biopsy and Clinical Analysis of Hereditary and Familial Pancreatic Cancer Cases Reveals KRAS Negativity and a Longer Overall Survival. Cancers 2021, 13, 1612.

The authors wish to make the following corrections to this paper [...].

Biomarkers Associated with Regorafenib First-Line Treatment Benefits in Metastatic Colorectal Cancer Patients: REFRAME Molecular Study.

First-line treatment with regorafenib in frail metastatic colorectal cancer (mCRC) patients has shown some benefit. To accurately identify such patients before treatment, we studied blood biomarkers and primary tumor molecules. We unveiled serum microRNAs (miRNAs), single-nucleotide polymorphisms (SNPs) in angiogenic-related genes, and Notch 1 expression as biomarkers associated with response or toxicity. MicroRNA array profiling and genotyping of selected SNPs were performed in the blood of fragile mCRC patients treated with regorafenib. Notch 1 and CRC-associated miRNA expression was also analyzed in tumors. High levels of miR-185-5p in serum, rs7993418 in the vascular endothelial growth factor receptor 1 (VEGFR1) gene, and Notch 1 expression in biopsies were associated with a favorable response to treatment. Serum levels of miR-126-3p and miR-152-3p and tumor expression of miR-92a-1-5p were associated with treatment toxicity, particularly interesting in patients exhibiting comorbidities, and high levels of miR-362-3p were associated with asthenia. Additionally, several miRNAs were associated with the presence of metastasis, local recurrence, and peritoneal metastasis. Besides, miRNAs determined in primary tumors were associated with tumor-node-metastasis (TNM) staging. The rs2305948 and rs699947 SNPs in VEGFR2 and VEGFA, respectively, were markers of poor prognosis correlating with locoregional relapse, a higher N stage, and metastatic shedding. In conclusion, VEGF and VEGFR SNPs, miRNAs, and Notch 1 levels are potential useful biomarkers for the management of advanced CRC under regorafenib treatment.

Albumin-bound paclitaxel as new treatment for metastatic cholangiocarcinoma: A case report.

BACKGROUND: Cholangiocarcinomas are rare and very aggressive tumors. Most patients have advanced-stage or unresectable disease at presentation, and the systemic therapies have limited efficacy. Albumin-bound paclitaxel (nab-paclitaxel) is a solvent-free taxane that has been approved for the treatment of some cancers such as breast, non-small cell lung and pancreatic cancer, however it has not been applied to treat cholangiocarcinoma. We have both preclinical and clinical evidence of the efficacy of nab-paclitaxel in cholangiocarcinoma, yet no phase 3 trials have been made. CASE SUMMARY: A 63-year-old man was diagnosed in December 2016 with stage III B intrahepatic cholangiocarcinoma. Surgery was performed, followed by adjuvant chemotherapy treatment with capecitabine and gemcitabine; although, the gemcitabine was suspended due to allergic reaction after two cycles. In April 2019, metastatic cholangiocarcinoma relapse was diagnosed, and a first-line treatment with FOLFOX scheme was started. Eight cycles were administered, producing an initial clinical improvement and decrease in blood tumor marker levels. Radiological and serological progression was noted in September 2019. As a second-line treatment, FOLFIRI was not recommended due to risk of worsening the patient's tumor-related diarrhea. A combination therapy with gemcitabine was not feasible, as the patient had previously suffered from an allergic reaction to this treatment. We decided to use nab-paclitaxel as a second-line treatment, and four cycles were administered. Both clinical and serological responses were observed, and a radiological mixed response was also noted. CONCLUSION: Advanced cholangiocarcinoma could be treated with nab-paclitaxel monotherapy, which should be studied in combination with other types of treatment (chemotherapy, fibroblast growth factor receptor inhibitors).

Phase I/II trial of sequential treatment of nab-paclitaxel in combination with gemcitabine followed by modified FOLFOX chemotherapy in patients with untreated metastatic exocrine pancreatic cancer: Phase I results.

BACKGROUND: Although occasioned through different mechanisms, the potential neurotoxicity and also haematological toxicity of nab-paclitaxel and oxaliplatin-based chemotherapy regimen were studied in this trial, which aimed to determine the maximum-tolerated dose (MTD) and to evaluate safety and efficacy of the combination in a sequential regimen of nab-paclitaxel, gemcitabine (GEM) and modified FOLFOX (mFOLFOX) in untreated patients with metastatic pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: Treatment consisted of nab-paclitaxel (125/100 mg/m2) plus GEM (1000/800 mg/m2) on days 1, 8 and 15, followed by mFOLFOX (oxaliplatin [85/75/65 mg/m2], 5-FU bolus [400/300/200 mg/m2], 5-FU infusion [2400/2000/1600 mg/m2]) on day 28, of a 42-day cycle. Patients were enrolled at the highest dose level with a subsequent 3 + 3 dose de-escalation plan. RESULTS: Eleven patients (median age = 61, 64% with performance status [PS] = 1) were eligible. All patients received the highest dose level. No de-escalation was needed. A dose-limiting toxicity was reported, an upper gastrointestinal haemorrhage. The MTD was nab-paclitaxel 125 mg/m2, GEM 1000 mg/m2, oxaliplatin 85 mg/m2, 5-FU bolus 400 mg/m2 and 5-FU infusion 2400 mg/m2. Common all-grade toxicities were neutropenia (73%), anaemia (55%), thrombocytopenia (55%) and asthenia (55%). Other relevant toxicities were paraesthesia (46%), nausea (36%), dysesthesia (27%) and pyrexia (27%). Objective response rate was 50% and disease control rate was 80%. CONCLUSIONS: The regimen of nab-paclitaxel plus GEM followed by mFOLFOX showed favourable safety and tolerability profiles with significant anti-tumor activity. More data are being achieved in a randomised phase II trial, to confirm efficacy rates and dismiss long-term neurotoxicity concerns regarding the sequencing of nab-paclitaxel and oxaliplatin.

A comprehensive analysis of candidate genes in familial pancreatic cancer families reveals a high frequency of potentially pathogenic germline variants.

BACKGROUND: The 5-year survival rate of patients with pancreatic ductal adenocarcinoma (PDAC) is around 5% due to the fact that the majority of patients present with advanced disease that is treatment resistant. Familial pancreatic cancer (FPC) is a rare disorder that is defined as a family with at least two affected first degree relatives, with an estimated incidence of 4%-10%. The genetic basis is unknown in the majority of families although around 10%-13% of families carry germline mutations in known genes associated with hereditary cancer and pancreatitis syndromes. METHODS: Panel sequencing was performed of 35 genes associated with hereditary cancer in 43 PDAC cases from families with an apparent hereditary pancreatic cancer syndrome. FINDINGS: Pathogenic variants were identified in 19% (5/26) of PDAC cases from pure FPC families in the genes MLH1, CDKN2A, POLQ and FANCM. Low frequency potentially pathogenic VUS were also identified in 35% (9/26) of PDAC cases from FPC families in the genes FANCC, MLH1, PMS2, CFTR, APC and MUTYH. Furthermore, an important proportion of PDAC cases harboured more than one pathogenic, likely pathogenic or potentially pathogenic VUS, highlighting the multigene phenotype of FPC. INTERPRETATION: The genetic basis of familial or hereditary pancreatic cancer can be explained in 21% of families by previously described hereditary cancer genes. Low frequency variants in other DNA repair genes are also present in 35% of families which may contribute to the risk of pancreatic cancer development. FUNDING: This study was funded by the Instituto de Salud Carlos III (Plan Estatal de I + D + i 2013-2016): ISCIII (PI09/02221, PI12/01635, PI15/02101 and PI18/1034) and co-financed by the European Development Regional Fund ''A way to achieve Europe'' (ERDF), the Biomedical Research Network in Cancer: CIBERONC (CB16/12/00446), Red Temática de investigación cooperativa en cáncer: RTICC (RD12/0036/0073) and La Asociación Española contra el Cáncer: AECC (Grupos Coordinados Estables 2016).

A Randomized Phase II Study of Axitinib as Maintenance Therapy After First-line Treatment for Metastatic Colorectal Cancer.

INTRODUCTION: The aim of this study was to evaluate the efficacy and safety of maintenance therapy with axitinib versus placebo following induction therapy in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: In this double-blinded, phase II trial, patients with mCRC who had not progressed after 6 to 8 months of first-line chemotherapy were randomized to receive axitinib (5 mg twice a day) (arm A) or placebo (arm B). RESULTS: Forty-nine patients were included: 25 in arm A and 24 in arm B. The median follow-up was 26.07 months (95% confidence interval [CI], 18.44-31.73 months). Progression-free survival (PFS) rate at 6 months was 40.00% (95% CI, 21.28%-58.12%) in the axitinib arm versus 8.33% (95% CI, 1.44%-23.30%) in the placebo arm (P = .0141). The median PFS was statistically significantly longer in the axitinib group than in the placebo group (4.96 vs. 3.16 months; hazard ratio, 0.46; 95% CI, 0.25-0.86; P = .0116). Median overall survival was also longer in the axitinib arm but did not reach statistical significance (27.61 vs. 19.99 months; hazard ratio, 0.68; 95% CI, 0.31-1.48; P = .3279). Grade 3 to 4 treatment-related toxicities were experienced by 7 patients (28%) in cohort A and 1 patient (4%) in cohort B (P = .0488). The most frequent grade 3 to 4 treatment-related toxicities were hypertension, diarrhea, and asthenia. There were no toxic deaths. The study was prematurely closed because of slow recruitment. CONCLUSIONS: In our study, maintenance treatment with axitinib monotherapy showed a significant increase in PFS and a good safety profile. Axitinib should be further explored as a possible option for first-line chemotherapy maintenance treatment in patients with mCRC.