Dual inhibition of VEGF and PARP suppresses KRAS-mutant colorectal cancer

The addition of bevacizumab to chemotherapy has prolonged overall and progression-free survival rates for metastatic colorectal cancer (mCRC). However, KRAS-mutant (KRAS-mut) CRC, lacking an ideal targeted agent, represents an inferior-response subgroup of patients. In the present study, we investigated a combination approach of bevacizumab + olaparib in KRAS-mut CRC in a preclinical setting. The combined therapy effectively prevented tumor growth in a KRAS-mut cancer cell-derived xenograft model, although this effect was not observed in vitro. Under bevacizumab treatment, we detected intratumor hypoxia and impaired homologous recombination repair (HRR), accompanied by vascular regression. We explored the underlying mechanism of this combined therapy by mimicking a hypoxic condition in vitro using cobalt chloride (CoCl2). The results showed that hypoxia impairs HRR and therefore sensitized KRAS-mut CRC cell lines HCT-116, SW620, and Lovo to olaparib. Furthermore, under this hypoxic condition, olaparib could arrest the cell cycle in the G2/M phase, increase DNA damage and dramatically induce cell apoptosis in KRAS-mut CRC cells. Taken together, these results indicated that the combination of bevacizumab + olaparib could be a potential therapeutic approach in a KRAS-mut CRC cohort.

Analytical and clinical validation of a novel amplicon-based NGS assay for the evaluation of circulating tumor DNA in metastatic colorectal cancer patients

Background Evaluating the tumor RAS/BRAF status is important for treatment selection and prognosis assessment in metastatic colorectal cancer (mCRC) patients. Correction of artifacts from library preparation and sequencing is essential for accurately analyzing circulating tumor DNA (ctDNA) mutations. Here, we assessed the analytical and clinical performance of a novel amplicon-based next-generation sequencing (NGS) assay, Firefly™, which employs a concatemer-based error correction strategy. Methods Firefly assay targeting KRAS/NRAS/BRAF/PIK3CA was evaluated using cell-free DNA (cfDNA) reference standards and cfDNA samples from 184 mCRC patients. Plasma results were compared to the mutation status determined by ARMS-based PCR from matched tissue. Samples with a mutation abundance below the limit of detection (LOD) were retested again by droplet digital polymerase chain reaction (ddPCR) or NGS. Results The Firefly assay demonstrated superior sensitivity and specificity with a 98.89% detection rate at an allele frequency (AF) of 0.2% for 20 ng cfDNA. Generally, 40.76% and 48.37% of the patients were reported to be positive by NGS of plasma cfDNA and ARMS of FFPE tissue, respectively. The concordance rate between the two platforms was 80.11%. In the pre-treatment cohort, the concordance rate between plasma and tissue was 93.33%, based on the 17 common exons that Firefly™ and ARMS genotyped, and the positive percent agreement (PPA) and negative percent agreement (NPA) for KRAS/NRAS/BRAF/PIK3CA were 100% and 99.60%, respectively. Conclusions Total plasma cfDNA detected by Firefly offers a viable complement for mutation profiling in CRC patients, given the high agreement with matched tumor samples. Together, these data demonstrate that Firefly could be routinely applied for clinical applications in mCRC patients.

The Landmark Series: Randomized Control Trials Examining Perioperative Chemotherapy and Postoperative Adjuvant Chemotherapy for Resectable Colorectal Liver Metastasis

Surgical resection remains the only curative treatment option for patients with colorectal liver metastases (CLM). However, the high recurrence rate after resection has led physicians to investigate multidisciplinary treatments combining surgery and medical therapy. Currently, the evidence to support medical therapy in patients with resectable CLM is limited. For patients with resectable CLM, the National Comprehensive Cancer Network Guidelines (version 2.2020) for colon and rectal cancer recommends either upfront surgery and postoperative adjuvant chemotherapy or preoperative chemotherapy followed by surgery and postoperative adjuvant chemotherapy. This article reviews randomized control trials regarding medical therapy before and after curative resection of CLM, and summarizes the updated long-term report of the New EPOC trial which investigated the addition of cetuximab to perioperative chemotherapy for patients with resectable CLM.

Controversies in the treatment of RAS wild-type metastatic colorectal cancer

Objective

To provide guidance for the management of RAS wild-type (wt) metastatic colorectal cancer (mCRC) in daily practice.

Methods

Nominal group and Delphi techniques were used. A steering committee of seven experts analyzed the current management of RAS wt mCRC, through which they identified controversies, critically analyzed the available evidence, and formulated several guiding statements for clinicians. Subsequently, a group of 30 experts (the expert panel) was selected to test agreement with the statements, through two Delphi rounds. The following response categories were established in both rounds: 1 = totally agree, 2 = basically agree, 3 = basically disagree, 4 = totally disagree. Agreement was defined if ≥ 75% of answers were in categories 1 and 2 (consensus with the agreement) or 3 and 4 (consensus with the disagreement).

Results

Overall, 71 statements were proposed, which incorporated the following areas: (1) overarching principles; (2) tumor location; (3) triplets; (4) maintenance; (5) second-line and beyond treatments; (6) Rechallenge and liquid biopsy. After the two Delphi rounds, only six statements maintained a lack of clear consensus.

Conclusions

This document aims to describe the expert’s attitude when dealing with several common clinical questions regarding patients with RAS wt mCRC.

Electronic supplementary material

The online version of this article (10.1007/s12094-020-02475-8) contains supplementary material, which is available to authorized users.

Delivery of Personalized Care for Locally Advanced Rectal Cancer: Incorporating Pathological, Molecular Genetic, and Immunological Biomarkers Into the Multimodal Paradigm

Approximately one-third of all newly diagnosed colorectal cancer (CRC) is composed of rectal cancer, with the incidence rising in younger patients. The principal neoadjuvant treatments consist of neoadjuvant short-course radiotherapy and long-course chemoradiation. Locally advanced rectal cancer (LARC) is particularly challenging to manage given the anatomical constrictions of the pelvis and the risk for local recurrence. In appropriately treated patients, 5- and 10-year overall survival is estimated at 60 and 50%, respectively. The prognosis for LARC has improved in recent years with more access to screening, advances in surgical techniques, and perioperative care. Furthermore, the refinement of the multidisciplinary team with combined-modality management strategies has improved outcomes. These advancements have been augmented by significant improvements in the understanding of the underlying tumor biology. However, there are many instances where patient outcomes do not match those for their tumor stage and accurate prognostic information for individual patients can be difficult to estimate owing to the heterogeneous nature of LARC. Many new combinations of chemotherapy with radiotherapy, including total neoadjuvant therapy with targeted therapies that aim to diminish toxicity and increase survival, are being evaluated in clinical trials. Despite these advances, local recurrence and distant metastasis remain an issue, with one-third of LARC patients dying within 5 years of initial treatment. Although much of the new pathological, molecular genetics, and immunological biomarkers allow refinement in the classification and prognostication of CRC, the relative importance of each of these factors with regards to the development and progression of LARC remains incompletely understood. These factors are often insufficiently validated and seldom consider the individual characteristics of the host, the tumor and its location, the local available expertise, or the probable location of recurrence. Appreciating the mechanisms behind these differences will allow for a more comprehensive, personalized approach and more informed treatment options, leading to ultimately superior outcomes. This review aims to first outline the current multidisciplinary context in which LARC care should be delivered and then discuss how some key prognosticators, including novel histopathological, molecular genetics, and immunological biomarkers, might fit into the wider context of personalized LARC management in the coming years.

Experimental Treatment of Mucinous Peritoneal Metastases Using Patient-Derived Xenograft Models

Mucinous peritoneal metastases (PM) generally respond poorly to systemic treatment, and there is a clear unmet need for new treatment strategies to improve survival and quality of life for patients with PM. In this work, the growth inhibitory effect of five drugs (oxaliplatin (OXA; 5 mg/kg), irinotecan (IRI; 60 mg/kg), cabazitaxel (CBZ; 15 or 30 mg/kg), regorafenib (REG; 10, 30 or 60 mg/kg), and capecitabine (CAP; 359 or 755 mg/kg) was investigated in three orthotopic patient-derived xenograft models that mimic mucinous PM. Drugs were administered intraperitoneally (i.p.) as monotherapy weekly for 4 weeks (OXA, IRI), as one single i.p. injection (CBZ), or orally (REG, CAP) daily 5 of 7 days per week for four weeks, and i.p. tumor growth and survival were monitored and compared between treatment groups. The i.p. administered drugs (OXA, IRI, CBZ) had the strongest growth inhibitory effect, with OXA being most efficacious, completely inhibiting tumor growth in the majority of the animals. CBZ and IRI also strongly inhibited tumor growth, but with more variation in efficacy between the models. A moderate reduction in tumor growth was observed in all models treated with REG, while CAP had little to no growth inhibitory effect. Targeted next-generation-sequencing has identified mutational profiles typically associated with PM (mutations in KRAS, GNAS, and BRAF oncogenes), supporting the representativeness of the models. The results presented in this work support the continued exploration of i.p. treatment protocols for PM, with OXA remaining and CBZ emerging as particularly interesting candidates for further studies.

Biomarkers in Colorectal Cancer: Current Research and Future Prospects

Colorectal cancer (CRC) is a leading cause of death worldwide, despite progress made in detection and management through surgery, chemotherapy, radiotherapy, and immunotherapy. Novel therapeutic agents have improved survival in both the adjuvant and advanced disease settings, albeit with an increased risk of toxicity and cost. However, metastatic disease continues to have a poor long-term prognosis and significant challenges remain due to late stage diagnosis and treatment failure. Biomarkers are a key tool in early detection, prognostication, survival, and predicting treatment response. The past three decades have seen advances in genomics and molecular pathology of cancer biomarkers, allowing for greater individualization of therapy with a positive impact on survival outcomes. Clinically useful predictive biomarkers aid clinical decision making, such as the presence of KRAS gene mutations predicting benefit from epidermal growth factor receptor (EGFR) inhibiting antibodies. However, few biomarkers have been translated into clinical practice highlighting the need for further investigation. We review a range of protein, DNA and RNA-based biomarkers under investigation for diagnostic, predictive, and prognostic properties for CRC. In particular, long non-coding RNAs (lncRNA), have been investigated as biomarkers in a range of cancers including colorectal cancer. Specifically, we evaluate the potential role of lncRNA plasmacytoma variant translocation 1 (PVT1), an oncogene, as a diagnostic, prognostic, and therapeutic biomarker in colorectal cancer.

Effectiveness of bevacizumab in first- and second-line treatment for metastatic colorectal cancer: ITACa randomized trial

Background:

Cancer trials involving multiple treatment lines substantially increase our understanding of therapeutic strategies. However, even when the primary end-point of these studies is progression-free survival (PFS), their statistical analysis usually focuses on each line separately, or does not consider repeated events, thus missing potentially relevant information. Consequently, the evaluation of the effectiveness of treatment strategies is highly impaired.

Methods:

We evaluated the potentially different effect of bevacizumab (B) administered for the first- or second-line treatment of metastatic colorectal cancer (mCRC) in the ITACa (Italian Trial in Advanced Colorectal Cancer) randomized trial. The ITACa trial consisted of two arms: first-line chemotherapy (CT)+B followed by second-line CT alone versus first-line CT alone followed by second-line CT+B or CT+B+cetuximab according to KRAS status. Cox models for repeated disease progression were performed, and potential selection bias was adjusted using the inverse probability of censoring weighting method. Hazard ratios (HR) [95% confidence interval (CI)] for PFS (primary endpoint) were reported.

Results:

The overall effect of B across the two lines resulted in a HR = 0.80 (95% CI 0.68–0.95, p = 0.008). Evaluating the differential effect of B in first- and second-line, the addition of B to first-line chemotherapy (CT) produced a 10% risk reduction (HR = 0.90, 95% CI 0.72–1.12, p = 0.340) versus CT alone; B added to second-line CT produced a 36% risk reduction (HR = 0.64, 95% CI 0.49–0.84, p = 0.0011) versus CT alone.

Conclusion:

Our results seem to suggest that B confers a PFS advantage when administered in combination with second-line chemotherapy, which could help to improve current international guidelines on optimal sequential treatment strategies.

Addition of Bevacizumab to First-Line Palliative Chemotherapy in Patients with Metastatic Small Bowel Adenocarcinoma: A Population-Based Study

BACKGROUND

Data about the use and effectiveness of targeted therapy in metastatic small bowel adenocarcinoma (SBA) are scarce.

OBJECTIVE

The aim of this population-based study was to obtain insights into the use and effectiveness of targeted therapy in patients with synchronous metastases of SBA.

PATIENTS AND METHODS

Data were retrieved from the Netherlands Cancer Registry. Patients treated with palliative chemotherapy and/or targeted therapy for synchronous metastatic SBA between 2007 and 2016 were included (n = 187). Differences in treatment and the subsequent effects on overall survival (OS) were evaluated.

RESULTS

In first-line treatment, 25 patients (13%) received additional targeted therapy, exclusively bevacizumab, and mostly in combination with CAPOX/FOLFOX (n = 24). A primary ileal tumour was predictive for receiving bevacizumab in first-line treatment (odds ratio 3.2, 95% confidence interval (CI) 1.06-9.93). Median OS for patients in whom bevacizumab was added to first-line chemotherapy was 9.3 months, compared to 9.1 months with chemotherapy only (p = 0.85). Median OS for patients receiving first-line treatment only was 8.5 months with and 6.4 months without the addition of bevacizumab, respectively (p = 0.54). In multivariable survival analyses, the addition of bevacizumab was no prognostic factor (hazard ratio 1.01, 95% CI 0.65-1.59).

CONCLUSIONS

Bevacizumab was the only prescribed targeted therapy in first-line treatment. Considering the limited number of patients receiving first-line bevacizumab and the unknown reasons to prescribe additional targeted therapy, the corresponding survival rates of patients treated with and without additional bevacizumab in first-line treatment might suggest a limited clinical effect of bevacizumab in addition to first-line palliative chemotherapy on OS. Future research should focus on identifying the subgroup of patients who might benefit from anti-VEGF therapy in metastatic SBA.

A meta-analysis comparing regorafenib with TAS-102 for treating refractory metastatic colorectal cancer

Objective

We performed this meta-analysis to compare the efficacy and toxicity of regorafenib and TAS-102.

Methods

Electronic databases were searched to identify studies comparing the efficacy and safety of regorafenib and TAS-102 in patients with chemotherapy-refractory metastatic colorectal cancer using pooled analyses.

Results

Three clinical trials were included in this analysis. Regarding the reasons for treatment discontinuation, regorafenib was significantly associated with disease progression (odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.21–0.50) and adverse events (OR = 4.38, 95% CI = 2.69–7.13). However, overall (OR = 0.97, 95% CI = 0.81–1.17) and progression-free survival (OR = 1.01, 95% CI = 0.86–1.18) did not significantly differ between the groups. The most common treatment-related adverse events in the regorafenib group were neutropenia (OR = 0.06, 95% CI = 0.03–0.11), hand–foot syndrome (OR = 50.34, 95% CI = 10.44–242.84), and liver dysfunction (OR = 34.51, 95% CI = 8.30–143.43). Conversely, the incidence of thrombocytopenia did not differ between the two groups.

Conclusions

Regorafenib and TAS-102 have similar efficacy but different adverse event profiles. Differences in the toxicity profiles of the two drugs will help guide treatment selection.

[BRAF V600E-mutant colorectal cancers: Where are we?]

The BRAF^V600E mutation, observed in 8 % of colorectal cancers (CRC), introduces a particular phenotype and a poor prognosis at the localized or metastatic stage. BRAF mutant CRCs are more often localized in the right colon, poorly differentiated and mucinous. They affect an older population (more often female) and are associated with a more frequent metastatic lymph node and peritoneal evolution. The BRAF^V600E mutation is associated with a sporadic microsatellite instability (MSI) status in 20 to 40% of cases. In localized colon cancer, it does not imply any modification of the adjuvant treatment. In metastatic CRC, the first action must be the systematic search for an MSI phenotype, given its frequent association with the presence of a BRAF mutation, in order to propose immunotherapy that has been demonstrated to be very effective in MSI metastatic CRC. In non-MSI CRC, a first-line trichimiotherapy associated with bevacizumab is an option to be favored in patients in good general condition but the association with an anti-EGFR can be discussed, especially when the objective is tumor response. At the same time, surgical resection must be systematically discussed in the case of resectable hepatic metastases since the presence of a BRAF^V600E mutation is not a risk factor for recurrence and that prolonged survival may be observed after surgery. In the second or third line, the triplet encorafenib, binimetinib and cetuximab, as well as the doublet encorafenib and cetuximab are superior to the association of irinotecan plus cetuximab in terms of response and survival (phase III study BEACON) and represent a new therapeutic standard. Their use on the front line is under study.

Investigating the utility of extended mutation analysis in gastrointestinal peritoneal metastasis

BACKGROUND AND OBJECTIVES

Outcomes for gastrointestinal peritoneal metastases (GI-PM) are worse compared to systemic metastases, with a paucity of data exploring extended mutation profiling. An exploratory mutation analysis in GI-PMs was performed as a "proof of concept" of potential predictive values of profiling in GI-PM and rates of actionable mutations.

METHODS

The study included 40 GI-PM patients: 14 low-grade mucinous carcinoma peritonei and 26 HG-PM (12 colons, 10 appendix, 4 small bowels). Demographics, histologies, peritoneal cancer indexes, cytoreduction scores, and survival data were collected. NGS 50-gene mutation profiling was performed on 38 specimens. The association of mutations with survival was evaluated in high-grade PM.

RESULTS

KRAS, TP53, and SMAD4 mutations were observed in 61%, 29%, and 8% of cases across all tumor histologies. In 66% cases >1 mutations occurred, associated with decreased survival in HG-PM: 32 vs 73 months, P = .03. TP53 or SMAD4 mutations were associated with decreased survival in HG-PM: 22 vs 48 months, P = .02. Actionable mutations were detected in 70%.

CONCLUSION

Actionable mutations were detected at high rates. GI-PMs have similar mutational profiles and TP53, SMAD4, and/or >1 mutation were associate with decreased survival in HG-PM. This data supports the concept of the extended mutation profiling utility in GI-PM warranting further investigation.

Survival benefit of surgical resection after first-line triplet chemotherapy and bevacizumab in patients with initially unresectable metastatic colorectal cancer

BACKGROUND

Surgical resection of metastatic disease in patients with initially non-resectable colorectal cancer (CRC) has improved overall survival. Intensified chemotherapy regimens have increased the probability of converting unresectable metastasis to resectable. Here, we report the result of combining intensive chemotherapy (triplet) and surgical resection of metastatic lesions in patients with metastatic CRC.

PATIENTS AND METHODS

Patients with unresectable metastatic CRC were enrolled in phase I/II trial of triplet chemotherapy consisting of capecitabine, oxaliplatin, irinotecan, and bevacizumab. Patients were given 5-8 cycles induction chemotherapy of the above regimen followed by maintenance capecitabine and bevacizumab until disease progression, unacceptable toxicity, or patient request. All patients were assessed at a multidisciplinary conference for possible surgical resection of their metastatic disease at the time of inclusion in the trial and 2 monthly intervals thereafter. Patients who underwent R0 resection of their metastatic disease received adjuvant oxaliplatin and capecitabine to complete a total of 6 months of chemotherapy.

RESULTS

Fifty-three patients were enrolled. The median age was 52 years (range 23-74), 29 (55%) were males, ECOG PS 0-1 was 13 (66%), 11 (42%) had a right-sided tumor, 29 (55%) had resection of their primary tumor, 22 (42%) had a single metastatic site, and 8 (15.1%) had a liver-limited disease. Thirteen patients (24.5%) underwent surgical resection of residual metastatic disease +/- the primary tumor with 10 (18.9%) of them were R0. The surgical group had a higher incidence of males compared to the non-surgical group (69.3% vs 47.2%, p = 0.2), equal performance status, lower median number of metastatic sites (1 vs 2, p = 0.09), higher mutant Kras (53.8% vs 34.2%, p = 0.3), and higher response rate (84.6% vs 56.2%, p = 0.3). With a median follow-up duration of 89 months, the median PFS for the whole group was 16.1 months [95% confidence interval (CI) 9.1-20] and the median OS was 28.2 months (95% CI 22.5-53.3). The median PFS for the surgery group was 18.9 months (95% CI 12.6-not reached) compared to 9.6 months (95% CI 7.0-18.3) for the non-surgical group, log-rank p = 0.0165. The median OS for both groups was not reached (95% CI 53.3-not reached) and 23.2 months (95% CI 17.0-28.4) respectively, log-rank p = 0.0006. Five-year PFS and OS for the surgery group were 46.2% and 67.6% respectively.

CONCLUSIONS

Patients with unresectable metastatic CRC and fit for triplet chemotherapy should have the benefit of combining this intensified regimen and surgical resection of their metastatic disease if possible.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT01311050 , registered March 6, 2011, retrospectively registered.

KRAS and BRAF Concomitant Mutations in a Patient with Metastatic Colon Adenocarcinoma: An Interesting Case Report

A 68-year-old female patient with tenesmus and blood in the stool was admitted to the S.G. Moscati Hospital of Taranto. Investigations revealed infiltrative mucinous colon adenocarcinoma accompanied by lymph node metastases. Following surgery and adjuvant chemotherapy, computed tomography (CT) and carcinoembryonic antigen screening were negative. Two years later, CT demonstrated a liver lesion. Histologic and genetic analyses confirmed the diagnosis of metastatic colorectal cancer with the coexistence of KRAS and BRAF mutations in hepatic metastases and the presence of the BRAF V600E in the primary tumour. It is unclear whether the lack of response was due to BRAF mutations, but the data suggest that mutated BRAF confers resistance to anti-epidermal growth factor receptor therapy. In our patient, BRAF mutation turned out to be a negative prognostic factor, and it may have been the cause of clinical implications for disease progression and therapeutic responses.

NCCN Guidelines Insights: Rectal Cancer, Version 6.2020

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E- or HER2 amplification-positive disease.

Efficacy of Panitumumab and Cetuximab in Patients with Colorectal Cancer Previously Treated with Bevacizumab; a Combined Analysis of Individual Patient Data from ASPECCT and WJOG6510G

Background: Phase-III ASPECCT and randomised phase-II WJOG6510G trials demonstrated the noninferiority of panitumumab, when compared with cetuximab, for overall survival in patients with chemotherapy-refractory wild-type KRAS exon 2 metastatic colorectal cancer. Methods: The subgroup that received bevacizumab either prior to panitumumab or cetuximab monotherapy (ASPECCT) or in combination with irinotecan (WJOG6510G) was included. Multivariate Cox models were created, including the treatment arms as covariates together with patient, disease and treatment characteristics. Results: We included 185 and 189 patients in the panitumumab and cetuximab arms, respectively. The median overall survival was 12.8 and 10.1 months [p = 0.0031; log-rank test, stratified by trial; hazard ratio (HR), 0.72; 95% confidence interval (CI), 0.58–0.90], and the median progression-free survival was 4.7 and 4.1 months, in the panitumumab and cetuximab arms, respectively (p = 0.0207; HR, 0.79; 95% CI, 0.64–0.97). The treatment regimen was an independent prognostic factor of overall survival (adjusted HR, 0.69; 95% CI, 0.54–0.87; p = 0.0013). Conclusions: Panitumumab significantly prolonged the overall survival and progression-free survival, when compared with cetuximab in the cohort that previously received bevacizumab in the included studies. Clinical Trial Registration: ASPECCT trial registered with ClinicalTrials.gov (NCT01001377) and WJOG6510G trial registered with UMIN-CTR (UMIN000006643).

Definitive chemoradiotherapy plus cetuximab for cancer in the oesophagus or gastro-oesophageal junction

BACKGROUND

Chemoradiotherapy is standard treatment for localized oesophageal cancer unsuitable for surgery. We aimed to evaluate the efficacy of cetuximab in combination with chemoradiotherapy.

METHODS

This non-randomised multicentre phase II trial recruited patients aged 18-75 with WHO performance status 0-2 having squamous cell carcinoma or adenocarcinoma in the oesophagus or gastro-oesophageal junction, T2-4, N0-3, M0 not suitable for surgery. Chemotherapy was three 21-day cycles of fluorouracil 750 mg/m2 D1-5 and oxaliplatin D1 (cycle 1:130mg/m 2, cycle 2-3:85 mg/m 2). Radiotherapy was 50Gy in 2Gy/fraction, 5 days a week, concurrent with cycle 2 and 3 and weekly cetuximab. The primary objective was loco-regional control at one year.

RESULTS

52 patients were included. 51 were eligible for toxicity and survival analysis and 46 for recurrence analysis. Full radiotherapy dose was delivered to 80%, 75% received all three cycles of chemotherapy and 75% received four or more doses of cetuximab. The most common related grade III-IV adverse events were gastro-intestinal(16), hypersensitivity(6) and infection(5). There were two drug-related deaths. Within six months from the end of treatment, six patients died from complications from fistulas. The loco-regional control rate at one year was 47.3%(95%CI 30.9%-62.1%). Overall survival at three years was 29.1%(95% CI 17.4-41.9%).

CONCLUSIONS

Oxaliplatin and fluorouracil given concurrent with radiotherapy and cetuximab had an acceptable safety profile and showed a clinical response in patients with locoregionally advanced oesophageal cancer unsuitable for surgery. However, the primary end-point was not met, and the addition of cetuximab to definitive chemoradiotherapy cannot be recommended.

Analysis of cancer-related mutations in extracellular vesicles RNA by Droplet Digital™ PCR

Extracellular vesicles (EVs) are taking their place as potential biomarkers in the field of liquid biopsy. In this study, EVs were isolated from plasma samples of 31 patients with colorectal cancer and melanoma via differential centrifugation and Droplet Digital™ PCR (Bio-Rad, CA, USA) was used to profile BRAF V600E/K, KRAS G12A/C/D/V and KRAS G13D mutations from EV-derived cDNA. The concordance rates with corresponding tissue were 54% and 44% in the colorectal cancer and melanoma cohort, respectively. Two patients displayed mutations in EVs not previously detected in tissue as evidence for emerging molecular resistance to anti-EGFR and BRAF/MEK inhibitor therapy prior to radiological evidence of tumor progression. We concluded that EV-derived nucleic acids may provide clinically relevant diagnostic information and mirror evolution of the disease.

Anti-EGFR therapy in metastatic colorectal cancer: mechanisms and potential regimens of drug resistance

Cetuximab and panitumumab, as the highly effective antibodies targeting epidermal growth factor receptor (EGFR), have clinical activity in the patients with metastatic colorectal cancer (mCRC). These agents have good curative efficacy, but drug resistance also exists at the same time. The effects of KRAS, NRAS, and BRAF mutations and HER2 amplification on the treatment of refractory mCRC have been elucidated and the corresponding countermeasures have been put forward. However, the changes in EGFR and its ligands, the mutations or amplifications of PIK3CA, PTEN, TP53, MET, HER3, IRS2, FGFR1, and MAP2K1, the overexpression of insulin growth factor-1, the low expression of Bcl-2-interacting mediator of cell death, mismatch repair-deficient, and epigenetic instability may also lead to drug resistance in mCRC. Although the emergence of drug resistance has genetic or epigenetic heterogeneity, most of these molecular changes relating to it are focused on the key signaling pathways, such as the RAS/RAF/mitogen-activated protein kinase or phosphatidylinositol 3-kinase/Akt/mammalian target of the rapamycin pathway. Accordingly, numerous efforts to target these signaling pathways and develop the novel therapeutic regimens have been carried out. Herein, we have reviewed the underlying mechanisms of the resistance to anti-EGFR therapy and the possible implications in clinical practice.

BRAF and KRAS mutations in metastatic colorectal cancer: future perspectives for personalized therapy

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide and 30% of patients with CRC experience metastasis. Patients with metastatic colorectal cancer (mCRC) have a 5-year overall survival rate of <10%. V-raf murine sarcoma viral oncogene homolog B1 (BRAF) and V-Ki-ras2 Kirsten ratsarcoma viral oncogene homolog (KRAS) mutations are mostly studied in mCRC, as clinical trials found that first-line chemotherapy with anti-epidermal growth factor receptor agent confers limited efficacy for mCRC. Treatment decisions for early-stage mCRC do not consider BRAF or KRAS mutations, given the dramatically poor prognosis conferred by these mutations in clinical trials. Thus, it is necessary to identify patients with mCRC harboring BRAF or KRAS mutations to formulate rational therapeutic strategies to improve prognosis and survival. BRAF and KRAS mutations occur in ∼10% and ∼44% of patients with mCRC, respectively. Although the survival rate of patients with mCRC has improved in recent years, the response and prognosis of patients with the aforementioned mutations are still poor. There is a substantial unmet need for prospective personalized therapies for patients with BRAF- or KRAS-mutant mCRC. In this review, we focus on BRAF and KRAS mutations to understand the mechanisms underlying resistance and improving the response rate, outcomes, and prognosis of patients with mCRC bearing these mutations and to discuss prospective personalized therapies for BRAF- and KRAS-mutant mCRC.

Randomised phase II study of panitumumab plus irinotecan versus cetuximab plus irinotecan in patients with KRAS wild-type metastatic colorectal cancer refractory to fluoropyrimidine, irinotecan and oxaliplatin (WJOG 6510G)

BACKGROUND

Cetuximab has been shown to be clinically active when given in combination with irinotecan in patients with irinotecan-refractory metastatic colorectal cancer (mCRC). However, it has remained unclear whether panitumumab is effective when combined with irinotecan. We compared efficacies of both regimens in this randomised phase II study.

PATIENTS AND METHODS

Patients with wild-type KRAS exon 2 mCRC previously treated with fluorouracil-, oxaliplatin- and irinotecan-based chemotherapies were randomised (1:1) to either panitumumab plus irinotecan (panitumumab arm) or cetuximab plus irinotecan (cetuximab arm). The primary end-point was progression-free survival (PFS). The planned sample size was 120, expecting a hazard ratio (HR) of 1.0 with non-inferiority margin of 1.3 (one-sided alpha error 0.2 and power 0.7). Major secondary end-points were overall survival (OS), response rate and safety.

RESULTS

From December 2011 to September 2014, 121 patients were enrolled, and 61 and 59 patients were randomised to the panitumumab and cetuximab arms, respectively (1 patient excluded). Most patients (97%) had received prior chemotherapies containing bevacizumab. The median PFS was 5.42 months in the panitumumab arm and 4.27 months in the cetuximab arm (HR = 0.64, 95% confidence interval [CI] = 0.44-0.94, P < 0.001 for non-inferiority, P = 0.058 for superiority), and median OS was 14.85 and 11.53 months (HR = 0.66, 95% CI = 0.44-1.00, P = 0.050 for superiority), respectively. The incidence of grade 3 or 4 hypomagnesaemia was higher in the panitumumab arm than that in the cetuximab arm (17% vs. 7%).

CONCLUSION

Panitumumab may be non-inferior to cetuximab in combination with irinotecan in survival of patients with irinotecan-refractory mCRC.

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.

Chemotherapeutic Effectiveness of Combining Cetuximab for Metastatic Colorectal Cancer Treatment: A System Review and Meta-Analysis

This meta-analysis used the database including PubMed, Medline, Cochrane Library, CNKI, Chinese-Cqvip, and Wanfang for randomized controlled trials (RCTs) to investigate the clinical effectiveness for combining cetuximab treatment with chemotherapy for treating metastatic colorectal cancer (mCRC). A total of 12 RCTs involved 7,108 patients with mCRC were included. The patients received chemotherapy with (3,521 cases) or without cetuximab (3,587 cases). Outcomes were overall survival (OS), progression-free survival (PFS), disease control rate (DCR), overall response rate (ORR), odd ratio (OR), and risk ratio (HR). Our results showed that the chemotherapy alone group has shorter OS, PFS, and ORR than the chemotherapy plus cetuximab group, with significant differences (PFS:HR = 0.77, 95% CI = 0.72–0.82, P < 0.00001; OS:HR = 0.88, 95% CI = 0.79–0.99, P = 0.03; ORR:OR = 1.79, 95% CI = 1.30–2.47; P = 0.0003). Results of subgroup analysis showed that cetuximab treatment prolonged PFS and OS in KRAS wild-type patients, with statistically significant differences (PFS:HR = 0.79, 95% CI = 0.65–0.95, P = 0.01; OS:HR = 0.85, 95% CI = 0.74–0.98, P = 0.02). Combining cetuximab with chemotherapy, the PFS and OS of wild-type KRAS patients and the ORR of all patients were significantly improved.

Blocking histone methyltransferase SETDB1 inhibits tumorigenesis and enhances cetuximab sensitivity in colorectal cancer

The histone methyltransferase SETDB1 catalyzes the addition of methyl groups to histone H3 at lysine 9, and upregulation of SETDB1 is associated with poor prognosis in cancer patients. Here, we describe how overexpression of SETDB1 contributes to colorectal cancer (CRC) tumorigenesis and drug resistance. We show that SETDB1 is upregulated in CRC, and its level correlates with poor clinical outcome. SETDB1 attenuation inhibits CRC cell proliferation Mechanistically, SETDB1 promotes cell proliferation by upregulating Akt activation. Further, SETDB1 is essential for the tumorigenic activity of Akt. Functional characterization revealed that inhibition of SETDB1 reduces cell growth in CRC resistant to targeted treatments in vitro and in vivo, KRAS-mutated CRC included. Taken together, our results indicate that SETDB1 is a major driver of CRC and may serve as a potential target for the treatment of KRAS-mutated CRC.

Update of the recommendations for the determination of biomarkers in colorectal carcinoma: National Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology

In this update of the consensus of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica—SEOM) and the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica—SEAP), advances in the analysis of biomarkers in advanced colorectal cancer (CRC) as well as susceptibility markers of hereditary CRC and molecular biomarkers of localized CRC are reviewed. Recently published information on the essential determination of KRAS, NRAS and BRAF mutations and the convenience of determining the amplification of human epidermal growth factor receptor 2 (HER2), the expression of proteins in the DNA repair pathway and the study of NTRK fusions are also evaluated. From the pathological point of view, the importance of analysing the tumour budding and poorly differentiated clusters, and its prognostic value in CRC is reviewed, as well as the impact of molecular lymph node analysis on lymph node staging in CRC. The incorporation of pan-genomic technologies, such as next-generation sequencing (NGS) and liquid biopsy in the clinical management of patients with CRC is also outlined. All these aspects are developed in this guide, which, like the previous one, will remain open to any necessary revision in the future.

Sorafenib Plus Irinotecan Combination in Patients With RAS-mutated Metastatic Colorectal Cancer Refractory To Standard Combined Chemotherapies: A Multicenter, Randomized Phase 2 Trial (NEXIRI-2/PRODIGE 27)

BACKGROUND

No treatment option was available for patients with RAS-mutated (RASmt) metastatic colorectal cancer (mCRC) who progress after standard combined chemotherapies at the time of the study. After promising results in phase II, the aim of the present NEXIRI-2/PRODIGE 27 trial was to assess the 2-month non-progression rate for sorafenib (NEX) plus irinotecan (IRI), that is, NEXIRI, treatment.

METHODS

Patients with RASmt mCRC after failure of oxaliplatin, IRI, fluoropyrimidines, and bevacizumab were randomized between NEXIRI (IRI 120-180 mg/m² intravenous, D1 = D15 plus oral NEX 400 mg twice a day) versus IRI (180 mg/m²) versus NEX. Primary endpoint was the 2-month non-progression rate. Secondary endpoints included progression-free and overall survival (PFS and OS), safety, and germline cyclin D1 (CCND1) rs9344 polymorphisms analyses.

RESULTS

A total of 173 patients were included, 59 in NEXIRI, 57 in IRI, and 57 in NEX arms. The 2-month non-progression rate was 52.6% (95% confidence interval [CI]: 39%-66%), 21.4% (10%-33%), and 19.3% (9%-30%) for NEXIRI, IRI, and NEX. Median PFS was 3.6 (95% CI: 2-4.2), 1.7 (1.7-1.8), and 2 (1.8-2.3) months and the median OS was 7.2 (5.8-9.4), 6.3 (4.8-8), and 5.6 (3.9-7.7) months for NEXIRI, IRI, and NEX, respectively. For NEXIRI rs9344CCND1 A/A genotype patients, OS was 19.6 months (95% CI: 4.8-not reached). Main grade 3 toxicities included neutropenia, febrile neutropenia, diarrhea, hand-foot syndrome, and hypertension.

CONCLUSIONS

In patients with RASmt mCRC who progressed after standard combined chemotherapies, the results of 2-month non-progression rate and median PFS in the NEXIRI arm were in favor of an increase of the time before progression.

MicroRNAs in Colon and Rectal Cancer - Novel Biomarkers from Diagnosis to Therapy

Colorectal cancer (CRC) is one of the most common cancers and a significant cause of tumor- related deaths worldwide. Traditional biomarkers, such as CEA and CA199, are not sensitive enough to provide useful information for early diagnosis and treatment and are rather used to track the clinical progression of the disease. There is growing evidence that microRNAs (miRNA) are potentially superior to traditional biomarkers as promising non-invasive biomarkers for the timely diagnosis and prediction of prognosis or treatment response in the management of CRC. In this review, the latest studies on the dysregulation of miRNAs expression in CRC and the potential for miRNAs to serve as biomarkers were collected. Given the limitations of miRNA, as discussed in this paper, its clinical applications as a diagnostic biomarker should be limited to use in combination with other biomarkers. Further research is necessary to elucidate the clinical applications of miRNA in therapy for CRC.

Clinicopathological differences and correlations between right and left colon cancer

BACKGROUND

The differences in histopathology and molecular biology between right colon cancer (RCC) and left colon cancer (LCC) were first reported in the literature by Bufill in 1990. Since then, a large number of studies have confirmed their differences in epidemiology, clinical presentation, comorbidities and biological behaviours, which may be related to the difference in prognosis and overall survival (OS) between the two groups.

AIM

To investigate statistically significant differences between Greek patients with LCC and RCC.

METHODS

The present observational study included 144 patients diagnosed with colon cancer of any stage who received chemotherapy in a Greek tertiary oncology hospital during a 2.5-year period. Clinical information, comorbidities, histopathologic characteristics and molecular biomarkers were collected from the patients’ medical records retrospectively, while administered chemotherapy regimens, targeted agents, progression-free survival (PFS) periods with first- and second-line chemotherapy and OS were recorded retroactively and prospectively. Data analysis was performed with the SPSS statistical package.

RESULTS

Eighty-six males and 58 females participated in the study. One hundred (69.4%) patients had a primary lesion in the left colon, and 44 (30.6%) patients had a primary lesion in the right colon. Patients with RCC were more likely to display anaemia than patients with LCC [odds ratio (OR) = 3.09], while LCC patients were more likely to develop rectal bleeding (OR = 3.37) and a feeling of incomplete evacuation (OR = 2.78) than RCC patients. Considering comorbidities, RCC patients were more likely to suffer from diabetes (OR = 3.31) and coronary artery disease (P = 0.056) than LCC patients. The mucinous differentiation rate was higher in the right-sided group than in the left-sided group (OR = 4.49), as was the number of infiltrated lymph nodes (P = 0.039), while the percentage of high-grade differentiation was higher in the group of patients with left-sided colon cancer than in RCC patients (OR = 2.78). RAS wild-type patients who received anti-epidermal growth factor receptor (EGFR): Treatment experienced greater benefit (PFS: 16.5 mo) than those who received anti-vascular endothelial growth factor treatment (PFS: 13.7 mo) (P = 0.05), while among RAS wild-type patients who received anti-EGFR treatment, LCC patients experienced greater benefit (PFS: 15.8 mo) than the RCC subgroup (PFS: 5.5 mo) in the first-line chemotherapy setting (P = 0.034). BRAF-mutant patients had shorter PFS (9.3 mo) than BRAF wild-type patients (14.5 mo) (P = 0.033). RCC patients showed a shorter tumour recurrence period (7.7 mo) than those with LCC (14.5 mo) (P < 0.001), as well as shorter (OS) (58.4 mo for RCC patients; 82.4 mo for LCC patients) (P = 0.018).

CONCLUSION

RCC patients present more comorbidities, worse histological and molecular characteristics and a consequently higher probability of tumour recurrence, poor response to targeted therapy and shorter OS than LCC patients.

Ex Vivo Organoid Cultures Reveal the Importance of the Tumor Microenvironment for Maintenance of Colorectal Cancer Stem Cells

Colorectal cancer (CRC) is a heterogeneous disease, with varying clinical presentations and patient prognosis. Different molecular subgroups of CRC should be treated differently and therefore, must be better characterized. Organoid culture has recently been suggested as a good model to reflect the heterogeneous nature of CRC. However, organoid cultures cannot be established from all CRC tumors. The study examines which CRC tumors are more likely to generate organoids and thus benefit from ex vivo organoid drug testing. Long-term organoid cultures from 22 out of 40 CRC tumor specimens were established. It was found that organoid cultures were more difficult to establish from tumors characterized as microsatellite instable (MSI), BRAF-mutated, poorly differentiated and/or of a mucinous type. This suggests that patients with such tumors are less likely to benefit from ex vivo organoid drug testing, but it may also suggest biological difference in tumor growth. RNA sequencing analysis of tumor sections revealed that the in vivo maintenance of these non-organoid-forming tumors depends on factors related to inflammation and pathogen exposure. Furthermore, using TCGA data we could show a trend towards a worse prognosis for patients with organoid-forming tumors, suggesting also clinical differences. Results suggest that organoids are more difficult to establish from tumors characterized as MSI, BRAF-mutated, poorly differentiated and/or of a mucinous type. We further suggest that the maintenance of cell growth of these tumors in vivo may be promoted by immune-related factors and other stromal components within the tumor microenvironment.

Curcumin β-D-glucuronide exhibits anti-tumor effects on oxaliplatin-resistant colon cancer with less toxicity in vivo

The NF‐kappa B (NF‐κB) pathway plays a pivotal role in tumor progression and chemoresistance, and its inhibition has been shown to suppress tumor growth in a variety of preclinical models. Recently, we succeeded in synthesizing a water‐soluble injectable type of curcumin β‐D‐glucuronide (CMG), which is converted into a free‐form of curcumin by β‐glucuronidase in vivo. Herein, we aimed to clarify the efficacy, safety and pharmacokinetics of CMG in a xenograft mouse model. First, we confirmed that the presence of KRAS/TP53 mutations significantly increased the IC₅₀ of oxaliplatin (L‐OHP) and NF‐κB activity in HCT116 cells in vitro. Then, we tested the efficacy of CMG in an HCT116 colon cancer xenograft mice model. CMG demonstrated superior anticancer effects compared to L‐OHP in an L‐OHP‐resistant xenograft model. With regard to safety, significant bodyweight loss, severe myelosuppression and AST/ALT elevation were observed in L‐OHP‐treated mice, whereas none of these toxicity was noted in CMG‐treated mice. The combination of CMG and L‐OHP exhibited additive effects in these xenograft models without increasing toxicity. Pharmacokinetic analysis revealed that high levels of free‐form curcumin were maintained in the tumor tissue after 48 hours following CMG administration, but it was not detected in other major organs, such as the heart, liver and spleen. Immunohistochemistry revealed reduced NF‐κB activity in the tumor tissue extracted from CMG‐treated mice compared with that from control mice. These results indicated that CMG could be a promising anticancer prodrug for treating colon cancer with minimal toxicity.

Novel biomarkers for the diagnosis and prognosis of colorectal cancer

Colorectal cancer (CRC) is among the most common malignancies and remains a major cause of cancer-related death worldwide. Despite recent advances in surgical and multimodal therapies, the overall survival of advanced CRC patients remains very low. Cancer progression, including invasion and metastasis, is a major cause of death among CRC patients. The underlying mechanisms of action resulting in cancer progression are beginning to unravel. The reported molecular and biochemical mechanisms that might contribute to the phenotypic changes in favor of carcinogenesis include apoptosis inhibition, enhanced tumor cell proliferation, increased invasiveness, cell adhesion perturbations, angiogenesis promotion, and immune surveillance inhibition. These events may contribute to the development and progression of cancer. A biomarker is a molecule that can be detected in tissue, blood, or stool samples to allow the identification of pathological conditions such as cancer. Thus, it would be beneficial to identify reliable and practical molecular biomarkers that aid in the diagnostic and therapeutic processes of CRC. Recent research has targeted the development of biomarkers that aid in the early diagnosis and prognostic stratification of CRC. Despite that, the identification of diagnostic, prognostic, and/or predictive biomarkers remains challenging, and previously identified biomarkers might be insufficient to be clinically applicable or offer high patient acceptability. Here, we discuss recent advances in the development of molecular biomarkers for their potential usefulness in early and less-invasive diagnosis, treatment, and follow-up of CRC.

Personalized Medicine-Current and Emerging Predictive and Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide and is heterogeneous both morphologically and molecularly. In an era of personalized medicine, the greatest challenge is to predict individual response to therapy and distinguish patients likely to be cured with surgical resection of tumors and systemic therapy from those resistant or non-responsive to treatment. Patients would avoid futile treatments, including clinical trial regimes and ultimately this would prevent under- and over-treatment and reduce unnecessary adverse side effects. In this review, the potential of specific biomarkers will be explored to address two key questions—1) Can the prognosis of patients that will fare well or poorly be determined beyond currently recognized prognostic indicators? and 2) Can an individual patient’s response to therapy be predicted and those who will most likely benefit from treatment/s be identified? Identifying and validating key prognostic and predictive biomarkers and an understanding of the underlying mechanisms of drug resistance and toxicity in CRC are important steps in order to personalize treatment. This review addresses recent data on biological prognostic and predictive biomarkers in CRC. In addition, patient cohorts most likely to benefit from currently available systemic treatments and/or targeted therapies are discussed in this review.

Comprehensive review of targeted therapy for colorectal cancer

Colorectal cancer (CRC) is among the most lethal and prevalent malignancies in the world and was responsible for nearly 881,000 cancer-related deaths in 2018. Surgery and chemotherapy have long been the first choices for cancer patients. However, the prognosis of CRC has never been satisfying, especially for patients with metastatic lesions. Targeted therapy is a new optional approach that has successfully prolonged overall survival for CRC patients. Following successes with the anti-EGFR (epidermal growth factor receptor) agent cetuximab and the anti-angiogenesis agent bevacizumab, new agents blocking different critical pathways as well as immune checkpoints are emerging at an unprecedented rate. Guidelines worldwide are currently updating the recommended targeted drugs on the basis of the increasing number of high-quality clinical trials. This review provides an overview of existing CRC-targeted agents and their underlying mechanisms, as well as a discussion of their limitations and future trends.

A phase 1 study evaluating safety and pharmacokinetics of losatuxizumab vedotin (ABBV-221), an anti-EGFR antibody-drug conjugate carrying monomethyl auristatin E, in patients with solid tumors likely to overexpress EGFR

Losatuxizumab vedotin (formerly ABBV-221) is a second-generation antibody-drug conjugate targeting epidermal growth factor receptor (EGFR). In this multicenter phase 1 study, eligible patients with EGFR-dependent solid tumors received losatuxizumab vedotin (3 + 3 design) intravenously at starting dose of 0.3 mg/kg over 3 h per 21-day cycle, with alternate dosing schedules utilized (2 weeks on/1 week off or weekly) to mitigate infusion reactions. Forty-five patients received ≥1 doses of losatuxizumab vedotin (13 colon, 6 non-small cell lung cancer, 5 head and neck [HNC], 5 glioblastoma multiforme, 2 breast, 14 other). Tumor samples were evaluated for EGFR protein expression by immunohistochemistry, EGFR and EGFR ligand mRNA expression by RNAseq, and results compared with outcome. Most common adverse events were infusion-related reaction (22/45; 49%) and fatigue (20/45; 44%). While most infusion reactions were grade ≤ 2, four patients experienced grade ≥3 infusion reactions. Several infusion reaction mitigation strategies were explored. Because of the high incidence of infusion reactions, the trial was stopped and the maximum tolerated dose was not reached. The last cleared dose: 6 mg/kg/cycle. Nineteen patients (42%) had stable disease; 4 remained on study >6 months. One HNC patient with increased levels of EGFR and EGFR ligands (amphiregulin, epiregulin) achieved a confirmed partial response. Pharmacokinetic analysis of losatuxizumab vedotin showed exposures appeared to be approximately dose-proportional. The high frequency of infusion reactions necessitated early closure of this trial. The detailed mitigation strategies used in this protocol for infusion-related reactions may provide beneficial information for trial design of agents with high infusion reaction rates.

Outcomes Among Minority Patients With Metastatic Colorectal Cancer in a Safety-net Health Care System

BACKGROUND

Metastatic colorectal cancer (CRC) outcomes continue to improve, but they vary significantly by race and ethnicity. We hypothesize that these disparities arise from unequal access to care.

MATERIALS AND METHODS

The Harris Health System (HHS) is an integrated health delivery network that provides medical care to the underserved, predominantly minority population of Harris County, Texas. As the largest HHS facility and an affiliate of Baylor College of Medicine's Dan L. Duncan Comprehensive Cancer Center, Ben Taub Hospital (BTH) delivers cancer care through multidisciplinary subspecialty that prioritize access to care, adherence to evidence-based clinical pathways, integration of supportive services, and mitigation of financial toxicity. We performed a retrospective analysis of minority patients diagnosed with and treated for metastatic CRC at BTH between January 2010 and December 2012. Kaplan-Meier survival curves were compared with survival curves from randomized control trials reported during that time period.

RESULTS

We identified 103 patients; 40% were black, 49% were Hispanic, and 12% were Asian or Middle Eastern. Thirty-five percent reported a language other than English as their preferred language. Seventy-four percent of patients with documented coverage status were uninsured. Eighty-four percent of patients received standard chemotherapy with a clinician-reported response rate of 63%. Overall survival for BTH patients undergoing chemotherapy was superior to that of subjects enrolled in the CRYSTAL (Cetuximab Combined with Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer) trial (median, 24.0 vs. 19.9 months; P = .014).

CONCLUSION

HHS provides a health delivery infrastructure through which minority patients with socioeconomic challenges experience clinical outcomes comparable with highly selected patients enrolled in randomized control trials. Efforts to resolve CRC disparities should focus on improving access of at-risk populations to high-quality comprehensive cancer care.

Comprehensive tumor profiling reveals unique molecular differences between peritoneal metastases and primary colorectal adenocarcinoma

BACKGROUND AND OBJECTIVES

Peritoneal metastases (PM) from primary colorectal cancer (pCRC) are associated with poor outcomes; however, molecular differences are not well defined.

METHODS

We compared unpaired tumor profiles of patients with pCRC and PM from Caris Life Sciences. Testing included next-generation sequencing of 592 genes, microsatellite instability (MSI) and tumor mutational burden (TMB). Mutations were test-defined as pathogenic (PATH).

RESULTS

Six hundred seventeen pCRC and 348 PM patients had similar gender (55% male) and age (median 59). PATHs were similar between PM and pCRC in KRAS, BRAF, SMAD2, SMAD4, and PTEN. pCRC PATHs were increased in APC (76% vs 48%, P < .01), ARID1A (29% vs 12%, P < .05), TP53 (72% vs 53%, P < .01), PIK3CA (22% vs 15%, P < .05), and FBXW7 (13% vs 7%, P < .01) compared with PM. Mucinous PM had more PATHs in GNAS (19% vs 8%, P = .032) while nonmucinous PM had more PATHs in BRAF (13% vs 8%, P = .027). Right-sided PM had decreased PATHs in APC (39% vs 68%, P < .0001), ARID1A (7% vs 38%, P < .004), and TP53 (48% vs 65%, P = .033) while there were no difference for left-sided PM. Nine percent of pCRC and 6% of PM were MSI-high (P = NS). There was no difference in TMB-high, TMB-intermediate, or TMB-low between PM and pCRC.

CONCLUSIONS

PM have similar rates of KRAS mutation with increased PATHs in GNAS (mucinous) and BRAF (nonmucinous) compared to pCRC. No differences in MSI or TMB were identified between PM and pCRC tumors. These findings inform future study into the molecular profile of PM.

A study of capecitabine metronomic chemotherapy is non-inferior to conventional chemotherapy as maintenance strategy in responders after induction therapy in metastatic colorectal cancer

BACKGROUND

The aim of this study is to demonstrate that capecitabine metronomic chemotherapy is non-inferior to capecitabine conventional chemotherapy as maintenance treatment, in patients who have responded to 16-18 weeks first-line chemotherapy in metastatic colorectal cancer (mCRC).

METHODS

The study design is a prospective, randomized, open label, phase II clinical trial. Those patients with mCRC who respond well after 16-18 weeks of standard doublet chemotherapy as induction may be enrolled into this study, and randomly assigned to the capecitabine metronomic group or standard dosage group. The duration of disease control after randomization and progression-free survival after enrollment are the primary endpoints. Overall survival, safety, and quality of life are the secondary endpoints. The sample size required to achieve the research objectives of this project is 79 patients in each group. The study recently started on 1 January 2018, and will last for 36 months.

DISCUSSION

This project is intended to study the efficacy and safety of capecitabine metronomic chemotherapy in the maintenance treatment of advanced colorectal cancer, and to explore the strategy of "low toxicity, high efficiency, economy, and individualization", which is suitable for China's national conditions and pharmacoeconomics. It has great prospects for clinical application and a clear socioeconomic value.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03158610. Registered on 15 May 2017.

Current challenges in the implementation of precision oncology for the management of metastatic colorectal cancer

Over the last few decades, molecularly targeted agents have been used for the treatment of metastatic colorectal cancer. They have made remarkable contributions to prolonging the lives of patients. The emergence of several biomarkers and their introduction to the clinic have also aided in guiding such treatment. Recently, next-generation sequencing (NGS) has enabled clinicians to identify these biomarkers more easily and reliably. However, there is considerable uncertainty in interpreting and implementing the vast amount of information from NGS. The clinical relevance of biomarkers other than NGS are also subjects of debate. This review covers controversial issues and recent findings on such therapeutics and their molecular targets, including VEGF, EGFR, BRAF, HER2, RAS, actionable fusions, Wnt pathway and microsatellite instability for comprehensive understanding of obstacles on the road to precision oncology in metastatic colorectal cancer.

Systemic chemotherapy with or without cetuximab in patients with resectable colorectal liver metastasis (New EPOC): long-term results of a multicentre, randomised, controlled, phase 3 trial

BACKGROUND

The interim analysis of the multicentre New EPOC trial in patients with resectable colorectal liver metastasis showed a significant reduction in progression-free survival in patients allocated to cetuximab plus chemotherapy compared with those given chemotherapy alone. The focus of the present analysis was to assess the effect on overall survival.

METHODS

New EPOC was a multicentre, open-label, randomised, controlled, phase 3 trial. Adult patients (aged ≥18 years) with KRAS wild-type (codons 12, 13, and 61) resectable or suboptimally resectable colorectal liver metastases and a WHO performance status of 0-2 were randomly assigned (1:1) to receive chemotherapy with or without cetuximab before and after liver resection. Randomisation was done centrally with minimisation factors of surgical centre, poor prognosis cancer, and previous adjuvant treatment with oxaliplatin. Chemotherapy consisted of oxaliplatin 85 mg/m2 administered intravenously over 2 h, l-folinic acid (175 mg flat dose administered intravenously over 2 h) or d,l-folinic acid (350 mg flat dose administered intravenously over 2 h), and fluorouracil bolus 400 mg/m2 administered intravenously over 5 min, followed by a 46 h infusion of fluorouracil 2400 mg/m2 repeated every 2 weeks (regimen one), or oxaliplatin 130 mg/m2 administered intravenously over 2 h and oral capecitabine 1000 mg/m2 twice daily on days 1-14 repeated every 3 weeks (regimen two). Patients who had received adjuvant oxaliplatin could receive irinotecan 180 mg/m2 intravenously over 30 min with fluorouracil instead of oxaliplatin (regimen three). Cetuximab was given intravenously, 500 mg/m2 every 2 weeks with regimen one and three or a loading dose of 400 mg/m2 followed by a weekly infusion of 250 mg/m2 with regimen two. The primary endpoint of progression-free survival was published previously. Secondary endpoints were overall survival, preoperative response, pathological resection status, and safety. Trial recruitment was halted prematurely on the advice of the Trial Steering Committee on Nov 1, 2012. All analyses (except safety) were done on the intention-to-treat population. Safety analyses included all randomly assigned patients. This trial is registered with ISRCTN, number 22944367.

FINDINGS

Between Feb 26, 2007, and Oct 12, 2012, 257 eligible patients were randomly assigned to chemotherapy with cetuximab (n=129) or without cetuximab (n=128). This analysis was carried out 5 years after the last patient was recruited, as defined in the protocol, at a median follow-up of 66·7 months (IQR 58·0-77·5). Median progression-free survival was 22·2 months (95% CI 18·3-26·8) in the chemotherapy alone group and 15·5 months (13·8-19·0) in the chemotherapy plus cetuximab group (hazard ratio [HR] 1·17, 95% CI 0·87-1·56; p=0·304). Median overall survival was 81·0 months (59·6 to not reached) in the chemotherapy alone group and 55·4 months (43·5-71·5) in the chemotherapy plus cetuximab group (HR 1·45, 1·02-2·05; p=0·036). There was no significant difference in the secondary outcomes of preoperative response or pathological resection status between groups. Five deaths might have been treatment-related (one in the chemotherapy alone group and four in the chemotherapy plus cetuximab group). The most common grade 3-4 adverse events reported were: neutrophil count decreased (26 [19%] of 134 in the chemotherapy alone group vs 21 [15%] of 137 in the chemotherapy plus cetuximab group), diarrhoea (13 [10%] vs 14 [10%]), skin rash (one [1%] vs 22 [16%]), thromboembolic events (ten [7%] vs 11 [8%]), lethargy (ten [7%] vs nine [7%]), oral mucositis (three [2%] vs 14 [10%]), vomiting (seven [5%] vs seven [5%]), peripheral neuropathy (eight [6%] vs five [4%]), and pain (six [4%] vs six [4%]).

INTERPRETATION

Although the addition of cetuximab to chemotherapy improves the overall survival in some studies in patients with advanced, inoperable metastatic disease, its use in the perioperative setting in patients with operable disease confers a significant disadvantage in terms of overall survival. Cetuximab should not be used in this setting.

FUNDING

Cancer Research UK.

Evolution of RAS testing over time: factors influencing mutation rates in metastatic colorectal cancer patients

Aim: Correct identification of RAS gene variants is key for targeted treatment decisions in patients with metastatic colorectal cancer. Published RAS mutation rates differ and could be influenced by several factors including testing methods. This study aimed to describe the performance of laboratories to correctly identify RAS variants over time and to understand how RAS testing has evolved in Europe. Materials & methods: Misclassification and test failure rates were calculated and related to the used test methodology for 239 unique laboratories participating in external quality assessment for metastatic colorectal cancer between 2013 and 2018. In addition, 33 laboratories completed a survey aiming to obtain more details on their routine testing strategies, number of samples analyzed and RAS mutation rates between 2013 and 2017. Results: The mutation status was correctly analyzed in 96.1% (N = 5471) RAS and BRAF tests. A total of 4.6% (N = 2860) RAS tests included false-negative results. In 1.6% (N = 5562) RAS and BRAF tests, an analysis failure occurred. Misclassifications and technical failures both decreased between 2013 and 2018. The number of next-generation sequencing users increased from 6.9% (N = 130) in 2013 to 44.6% (N = 112) in 2018. Over time, more codons were included in the methodologies, yet 23.2% (N = 112) did not offer full RAS testing (exon 2, 3, 4) in 2018. Based on the survey the overall RAS mutation rate was estimated as 45.2% (N = 27,325). Conclusion: This is the largest observational study reporting RAS mutation rates to-date. There was no trend of RAS mutation rates over time despite having a clear shift to more sensitive tests and increased quality of testing.

BRAF mutant colorectal cancer: ErbB2 expression levels as predictive factor for the response to combined BRAF/ErbB inhibitors

BACKGROUND

Colorectal cancer (CRC) is a heterogeneous disease with a complex biology and a wide number of altered genes such as BRAF, KRAS and PIK3CA. Advances with new-targeted therapies have been achieved and available treating options have prolonged patient's survival. However, BRAF-mutated CRC patients remain unresponsive to available therapies with RAF inhibitors (RAFi) alone or combined with ErbB inhibitors (ErbBi). These unmet needs require further exploitation of oncogenic signaling in order to set up individualized treatments.

METHODS

To this end, we tested the efficacy of single agent or combined treatments using the BRAFi, vemurafenib and two different ErbBi: panitumumab and afatinib in CRC cells characterized by different molecular phenotypes.

RESULTS

Combination strategies with BRAFi and ErbBi achieved a better response in BRAFV600E mutated cells expressing high levels of ErbB2.

CONCLUSIONS

Our findings support the importance of ErbB2 evaluation in BRAF-mutated CRC patients and its role as a positive predictor factor of response to BRAFi/ErbBi combination.

Cost-effectiveness analysis of cetuximab combined with chemotherapy as a first-line treatment for patients with RAS wild-type metastatic colorectal cancer based on the TAILOR trial

OBJECTIVES

Cetuximab plus leucovorin, fluorouracil and oxaliplatin (FOLFOX-4) is superior to FOLFOX-4 alone as a first-line treatment for patients with metastatic colorectal cancer with RAS wild-type (RAS wt mCRC), with significantly improved survival benefit by TAILOR, an open-label, randomised, multicentre, phase III trial. Nevertheless, the cost-effectiveness of these two regimens remains uncertain. The following study aims to determine whether cetuximab combined with FOLFOX-4 is a cost-effective regimen for patients with specific RAS wt mCRC in China.

DESIGN

A cost-effectiveness model combined decision tree and Markov model was built to simulate pateints with RAS wt mCRC based on health states of dead, progressive and stable. The health outcomes from the TAILOR trial and utilities from published data were used respectively. Costs were calculated with reference to the Chinese societal perspective. The robustness of the results was evaluated by univariate and probabilistic sensitivity analyses.

PARTICIPANTS

The included patients were newly diagnosed Chinese patients with fully RAS wt mCRC.

INTERVENTIONS

First-line treatment with either cetuximab plus FOLFOX-4 or FOLFOX-4.

MAIN OUTCOME MEASURES

The primary outcomes are costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs).

RESULTS

Baseline analysis disclosed that the QALYs was increased by 0.383 caused by additional cetuximab, while an increase of US$62 947 was observed in relation to FOLFOX-4 chemotherapy. The ICER was US$164 044 per QALY, which exceeded the willingness-to-pay threshold of US$28 106 per QALY.

CONCLUSIONS

Despite the survival benefit, cetuximab combined with FOLFOX-4 is not a cost-effective treatment for the first-line regime of patients with RAS wt mCRC in China.

TRIAL REGISTRATION NUMBER

TAILOR trial (NCT01228734); Post-results.

Multiple treatment lines and prognosis in metastatic colorectal cancer patients

The proportion of patients with metastatic colorectal cancer (mCRC) receiving second or further lines of treatment has not been widely studied. To shed light on this issue, we retrospectively analysed the treatments administered for metastatic disease, and investigated prognostic factors after a diagnosis of metastases, in a consecutive cohort of mCRC patients. Three hundred forty-six mCRC patients were enrolled: 173 were stage II or III (metachronous group), and 173 stage IV (synchronous group) at diagnosis. Survival was calculated between the date of metastatic disease and the date of death or last follow-up. Patients with synchronous lesions more frequently had multiple disease sites, peritoneal carcinomatosis and massive liver deposits, whereas significantly more patients with metachronous lesions developed lung metastases as the sole disease site. 97.4% patients received at least one, 62.4% two, 41.9% three and 23.7% four treatment lines. Patients with metachronous metastases more frequently underwent surgery of metastases in first-line treatment (48.5 versus 24.8%), and more of them were progression-free at the time of the analysis (44 versus 34.9%). At univariate analysis, age > 70 years, multiple disease sites and peritoneal carcinomatosis were associated with significantly decreased survival, whereas surgery of metastases and isolated lung metastases predicted better survival. At multivariate analysis, only peritoneal carcinomatosis and surgery of metastases independently affected survival. The percentage of patients who received an active treatment decreased going from first- to fourth-line treatment. However, the proportion of patients who received efficacious treatment in advanced line remained high. Surgery of metastases was the most important prognostic factors.

Pembrolizumab for the treatment of colorectal cancer

Introduction: Colorectal cancer (CRC) is one of the most frequent and lethal cancers in the world, and therapies are still insufficient. Immune checkpoint inhibitors (ICI) in metastatic CRC (mCRC) have not revolutionized treatment to the extent that they have in melanoma or renal carcinoma. Their use is limited to a molecular niche of mCRC with microsatellite instability (MSI). This review summarizes clinical data published with pembrolizumab in mCRC and also tries to identify potential new strategies.Areas covered: This paper focuses on pembrolizumab in mCRC. We screened all trials on PubMed and ClinicalTrials.gov and describe the most significant ones in our opinion.Expert opinion: Pembrolizumab seems to be effective in tumors with MSI-high status. It defines a new horizon for therapeutic strategy called 'agnostic' medicine. For microsatellite stable (MSS) colorectal cancers, the future challenge will be to successfully redraw the immune microenvironment to make it immunogenic with new therapeutic combinations, including ICI.

Survival Following Liver Transplantation for Patients With Nonresectable Liver-only Colorectal Metastases

OBJECTIVE

To determine overall survival and disease-free survival in selected patients with nonresectable liver-only colorectal cancer receiving liver transplantation.

BACKGROUND

Patients with nonresectable colorectal cancer receiving palliative chemotherapy has a 5-year overall survival of about 10%. Liver transplantation provided an overall survival of 60% in a previous study (SECA-I). Risk factors for death were carcinoembryonic antigen (CEA) >80 μg/L, progressive disease on chemotherapy, size of largest lesion>5.5 cm, and less than 2 years from resection of the primary tumor to transplantation.

METHODS

In this prospective (SECA-II) study, we included colorectal cancer patients with nonresectable liver-only metastases determined by computed tomography (CT)/magnetic resonance imaging/positron emission tomography scans and at least 10% response to chemotherapy. Time from diagnosis to liver transplant was required to be more than 1 year.

RESULTS

At a median follow-up of 36 months, Kaplan-Meier overall survival at 1, 3, and 5 years were 100%, 83%, and 83%, respectively. Disease-free survival at 1, 2, and 3 years were 53%, 44%, and 35%, respectively. Overall survival from time of relapse at 1, 2, and 4 years were 100%, 73%, and 73%, respectively. Recurrence was mainly slow growing pulmonary metastases amenable to curative resection. Fong Clinical Risk Score of 1 to 2 at the time of diagnosis resulted in longer disease-free survival than score 3 to 4 (P = 0.044). Patients included in the present study had significantly better prognostic factors than the previous SECA-I study.

CONCLUSION

Liver transplantation provides the longest overall survival reported in colorectal cancer patient with nonresectable liver metastases. Improved selection criteria give patients with nonresectable colorectal liver metastases a 5-year overall survival comparable to other indications for liver transplantation.

Selection criteria related to long-term survival following liver transplantation for colorectal liver metastasis

Patients with nonresectable colorectal cancer receiving palliative chemotherapy have a 5-year overall survival rate of about 10%. Liver transplant provided a Kaplan-Meier-estimated 5-year overall survival of up to 83%. The objective of the study was to evaluate the ability of different scoring systems to predict long-term overall survival after liver transplant. Patients with colorectal cancer with nonresectable liver-only metastases determined by computed tomography (CT)/magnetic resonance imaging/positron emission tomography (PET)-CT scans from 2 prospective studies (SECA-I and -II) were included. All included patients had previously received chemotherapy. PET-CT was performed within 90 days of the liver transplant. Overall survival, disease-free survival, and survival after relapse based on the Fong Clinical Risk Score, total PET liver uptake (metabolic tumor volume), and Oslo Score were compared. At median follow-up of 85 months for live patients, Kaplan-Meier overall survival rates at 5 years were 100%, 78%, and 67% in patients with Fong Clinical Risk Score 0 to 2, metabolic tumor volume-low group, and Oslo Score 0 to 2, respectively. Median overall survival was 101, 68, and 65 months in patients with Fong Clinical Risk Score 0 to 2, metabolic tumor volume-low, and Oslo Score 0 to 2. These selection criteria may be used to obtain 5-year overall survival rates comparable to other indications for liver transplant.

Colorectal Cancer Modeling with Organoids: Discriminating between Oncogenic RAS and BRAF Variants

RAS and BRAF proteins are frequently mutated in colorectal cancer (CRC) and have been associated with therapy resistance in metastatic CRC patients. RAS isoforms are considered to act as redundant entities in physiological and pathological settings. However, there is compelling evidence that mutant variants of RAS and BRAF have different oncogenic potentials and therapeutic outcomes. In this review we describe similarities and differences between various RAS and BRAF oncogenes in CRC development, histology, and therapy resistance. In addition, we discuss the potential of patient-derived tumor organoids for personalized therapy, as well as CRC modeling using genome editing in preclinical model systems to study similarities and discrepancies between the effects of oncogenic MAPK pathway mutations on tumor growth and drug response.