Circulating tumor DNA to guide rechallenge with panitumumab in metastatic colorectal cancer: the phase 2 CHRONOS trial

State of the art of the molecular hyperselection to guide treatment with anti-EGFR antibodies in RAS WT mCRC: implications for clinical practice and future perspectives

INTRODUCTION

Adding monoclonal antibodies to chemotherapy drastically changed the landscape of advanced colorectal cancer. The prediction of benefit from anti-EGFR therapies is mainly based on the absence of mutations in RAS and BRAF genes, the primary tumor sidedness and microsatellite MSS/MSI status. Molecular hyperselection may optimize the outcome of patients receiving anti-EGFR while detecting additional resistance alterations, both in chemo-naïve and in chemo-refractory settings.

AREAS COVERED

Our review focuses on negative molecular hyperselection, both on tissue samples and ctDNA, and the impact of this further patient selection on response rate and survival outcomes. We searched electronic database, selecting relevant English-language publications from 2017 to 2024.

EXPERT OPINION

Negative hyperselection beyond RAS and BRAF in advanced colorectal cancer appears to be a powerful tool for predicting outcomes to anti-EGFR therapy and spare patients from unnecessary treatment. This improvement appears in both naïve and pre-treated patients. However, data come mainly from retrospective studies. Therefore, to validate and integrate these findings in the clinical practice, prospective studies should be conducted. It will be interesting to elucidate the role of ctDNA in this setting and the choice of molecular techniques, considering costs and accessibility, to guarantee its implementation in the clinic.

Circulating tumor DNA in colorectal cancer: biology, methods and applications

In the practice of colorectal cancer (CRC), traditional tumor tissue analysis is limited by intratumoral and intertumoral heterogeneity and its invasive nature. Circulating tumor DNA (ctDNA) analysis, a promising liquid biopsy approach, has been increasingly explored in clinical studies. Biologically, ctDNA is characterized by tumor-specific diversity and rapid clearance from circulation, enabling real-time, dynamic, and repeatable assessments. Technologically, PCR- and NGS-based downstream analysis methods have been developed and validated. However, variables in pre-analytical and analytical procedures underscores the need for standardized protocols. Compared with clinicopathology-based risk stratification, ctDNA-based molecular residual disease detection has demonstrated significant potential in guiding treatment decisions. Qualitative and quantitative changes in ctDNA have also shown predictive and prognostic value during neoadjuvant or adjuvant treatment, as well as in later-line treatment for metastatic CRC. Specific molecular aberrations in ctDNA can not only assist in identifying candidates for targeted therapies but also reveal resistance mechanisms. Additionally, emerging research is exploring the potential of ctDNA in early cancer detection. Overall, as a novel biomarker, ctDNA holds substantial promise in advancing clinical practice. This review focuses on the biological characteristics, pre-analytical variables, and downstream analysis methods of ctDNA and summarizes its role across various clinical scenarios in CRC.

Exploration of mRNA-modifying METTL3 oncogene as momentous prognostic biomarker responsible for colorectal cancer development

Background

Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide, emphasizing the need for improved prognostic biomarkers. Recent studies have identified the mRNA-modifying METTL3 oncogene as a potential biomarker in CRC progression.

Objective

This study aimed to investigate the expression patterns of METTL3 in CRC, assess its association with clinical outcomes, identify interacting proteins and biological pathways, and explore its correlation with immune cell infiltration.

Methods

Comprehensive analyses were conducted using public datasets, including transcriptome profiles from The Cancer Genome Atlas and the GSE103512 dataset. Protein-protein interaction (PPI) networks, pathway enrichment, and immune infiltration analyses were performed to elucidate METTL3's role in CRC progression.

Results

METTL3 expression was significantly higher in CRC tissues compared to normal tissues (p < 0.001). Mutations in METTL3 were detected in approximately 6% of CRC cases, with fusion events involving the SRPK2 gene. PPI analysis identified ten interacting proteins, including METTL4, EIF3H, RBM15B1, CBLL1, WTAP, NCBP1, RBM15, ZC3H13, METTL14, and KIAA1429. METTL3 expression showed a positive correlation with METTL4, METTL14, NCBP1, and WTAP expression (R > 0.5, p < 0.001). Higher METTL3 expression was associated with immunosuppressive phenotypes, such as increased infiltration of tumor-associated macrophages, regulatory T cells, and cancer-associated fibroblasts (p < 0.001). Pathway enrichment analysis revealed METTL3's involvement in crucial pathways, including the cell cycle and renal cell carcinoma (p < 0.01). Gene ontology analysis highlighted its role in mRNA and RNA-related processes.

Conclusion

The study supports the potential of METTL3 as a prognostic biomarker in CRC and highlights its involvement in immune modulation and cancer progression. These findings lay the groundwork for future studies aimed at developing targeted therapies and improving patient outcomes.

Circulating tumor DNA to monitor treatment response in solid tumors and advance precision oncology

Circulating tumor DNA (ctDNA) has emerged as a dynamic biomarker in cancer, as evidenced by its increasing integration into clinical practice. Carrying tumor specific characteristics, ctDNA can be used to inform treatment selection, monitor response, and identify drug resistance. In this review, we provide a comprehensive, up-to-date summary of ctDNA in monitoring treatment response with a focus on lung, colorectal, and breast cancers, and discuss current challenges and future directions.

Comprehensive genomic profiling by liquid biopsy portrays metastatic colorectal cancer mutational landscape to predict antitumor efficacy of FOLFIRI plus cetuximab in the CAPRI-2 GOIM trial

BACKGROUND

Limited evidence is currently available on the role of liquid biopsy (LBx) in predicting the efficacy of anti-epidermal growth factor receptor (EGFR) therapies in metastatic colorectal cancer (mCRC).

METHODS

The CAPRI-2 GOIM is a phase II trial investigating the use of LBx-comprehensive genomic profiling (CGP)-guided, cetuximab-based treatment through three subsequent lines of therapy in patients with RAS/BRAF wild-type (WT) mCRC. LBx-CGP is carried out at baseline and at progressive disease to first- and second-line therapies. In case of RAS/BRAF WT circulating tumor DNA at progressive disease, EGFR therapeutic blockade is continued by combining cetuximab with a different chemotherapy backbone. The primary endpoint is overall response rate (ORR) by RECIST 1.1 criteria. Tumor molecular characteristics by LBx-CGP are correlated with treatment efficacy.

RESULTS

One hundred and ninety-two RAS/BRAF WT microsatellite stable mCRC patients treated with FOLFIRI plus cetuximab with baseline LBx-CGP and assessable for response were included in the analysis. One hundred and thirty-seven patients with WT tumors for potential anti-EGFR drug resistance genes (RAS/BRAF/EGFR/PIK3CA/MAP2K1/MET/RET/ALK/ROS1/NTRK/NF1/FGFR, and HER2 amplification; 'negatively hyper-selected' cases) had 78.1% ORR compared with 54.5% ORR for patients with mutations [odds ratio 2.95, 95% confidence interval (CI) 1.44-6.10, P = 0.001]. 'Negatively hyper-selected' patients had median progression-free survival of 12.35 months (95% CI 10.58-15.4 months) compared with 8.68 months (95% CI 4.87-12.1 months) for patients with mutations (hazard ratio 0.64, 95% CI 0.44-0.92, P = 0.017). High cancer cell clonality of pathogenic variants (PVs) correlated with worse median progression-free survival (3.55 months, 95% CI 2.57 months to NE) compared with low cancer cell clonality of PV (9.63 months, 95% CI 7.16 months to NE, P = 0.21). After first-line therapy failure, approximately one out of five patients had acquired PVs of potential anti-EGFR drug resistance genes, whereas RAS/BRAF WT circulating tumor DNA was maintained in most patients (78.5%).

CONCLUSIONS

These results support the integration of LBx-CGP for implementing the efficacy and for optimizing the use of anti-EGFR therapies in RAS/BRAF WT mCRC.

ctDNA variations according to treatment intensity in first-line metastatic colorectal cancer

BACKGROUND

Circulating tumor DNA variations (∆ctDNA) were reported to be associated with treatment efficacy in metastatic colorectal cancer (mCRC). The present study evaluated ∆ctDNA according to first-line treatment intensity.

METHODS

Patients from two prospective ctDNA collections were divided into Group ≤ 2 drugs and Group ≥ 3 drugs. ∆ctDNA were analysed from baseline to cycle 3 or 4 (C3-4) according to three predefined subgroups: ∆ctDNA ≥ 80%_ undetectable, ∆ctDNA ≥ 80%_ detectable, and ∆ctDNA < 80%. Impact of ∆ctDNA on progression-free survival (PFS) and overall survival (OS) were analysed.

RESULTS

Pretreatment ctDNA was detected in 129/152 (84.9%) of patients. A ∆ctDNA ≥ 80%_undetectable was more frequent in Group ≥ 3 than ≤ 2 drugs (respectively 51.5% vs. 32.7%, p = 0.015). Patients with ∆ctDNA ≥ 80%_undetectable had longer survival than other ∆ctDNA subgroups, in Group ≥ 3 drugs (mPFS 11.5 vs 7.8 vs 6.3 months, p = 0.02: mOS 30.2 vs 18.1 vs 16.4 month, p = 0.04) and in Group ≤ 2 drugs (mPFS 8.4 vs 6.0 vs 5.3 months, p = 0.05; mOS 29.6 vs 14.6 vs 14.6 months, p = 0.007).

DISCUSSION

Early ∆ctDNA are associated to treatment intensity in first line mCRC with a significant impact on prognosis.

What Is Next for Refractory Colorectal Cancer CRC? Looking Beyond SUNLIGHT, FRESCO2, RECURSE and CORRECT

The treatment landscape of metastatic colorectal cancer (mCRC) has undergone significant evolution, with the introduction of targeted therapies and immunotherapy dramatically altering the management of microsatellite instability-high (MSI-H) tumors. However, the majority of patients, particularly those with microsatellite-stable (MSS) disease, remain refractory to immunotherapy, necessitating the exploration of alternative therapeutic strategies. This review summarizes the current treatment options for heavily pretreated mCRC patients who are not eligible for targeted therapies or clinical trials. Approved therapies for refractory mCRC, including regorafenib, trifluridine/tipiracil (FTD/TPI), and fruquintinib, demonstrate modest survival benefits but are often associated with significant toxicities. Additionally, innovative approaches targeting specific mutations such as KRAS G12C, HER2 amplification, and BRAF V600E are discussed, highlighting emerging combination regimens with immune checkpoint inhibitors and other agents to overcome resistance mechanisms. The potential of rechallenge strategies using previously administered therapies, such as oxaliplatin and anti-EGFR agents, is examined, supported by retrospective and prospective studies. Furthermore, the role of older drugs like mitomycin C in combination with capecitabine is revisited, offering insights into their viability in advanced treatment settings. Ongoing clinical trials with novel agents and combinations are expected to provide further clarity on optimizing sequential treatment regimens and personalizing therapy for mCRC patients. This review emphasizes the need for comprehensive molecular profiling and shared decision-making to improve outcomes and quality of life in this challenging patient population.

Liquid Biopsies in the Early Diagnosis, Prognosis, and Tailored Treatment of Colorectal Cancer

INTRODUCTION

Liquid biopsies provide a less-invasive option to tissue biopsies for the early diagnosis, prognosis, and tailored therapy of colorectal cancer (CRC). CRC is a major cause of cancer-related death, and early identification is essential for improving patient outcomes.

REVIEW

Conventional diagnostic techniques, including colonoscopy and tissue biopsy, may be enhanced by liquid biopsies that examine circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), extracellular vesicles (EVs), and other indicators present in body fluids. These markers provide significant insights into tumor biology, heterogeneity, and therapeutic response. CTCs detected in early-stage CRC have prognostic significance for disease recurrence and survival, while ctDNA investigation may uncover genetic mutations, epigenetic alterations, and tumor development. The identification of ctDNA in minimal residual disease (MRD) postsurgery correlates with an elevated risk of recurrence and unfavorable prognosis, underscoring its use in assessing treatment effectiveness. Furthermore, non-coding RNAs (ncRNAs) contained inside EVs provide potential prospective biomarkers and therapeutic targets, facilitating diagnosis and treatment assessment. Notwithstanding the potential of liquid biopsies, obstacles persist in assay standardization, sensitivity enhancement, and the management of tumor heterogeneity. Additional extensive research is required to determine their function in clinical practice.

CONCLUSION

Overall, liquid biopsies serve as a potential instrument for real-time monitoring, evaluating therapy responses, and directing individualized therapeutic strategies in CRC patients.

Rationale and Design of the COPERNIC Trial: A Study of On-treatment ctDNA Changes in Chemo-refractory Colorectal Cancer Patients

BACKGROUND

Evidence suggests that ctDNA may be a reliable biomarker to monitor metastatic colorectal cancer (CRC) evolution. Nevertheless, evidence on the potential of liquid biopsy in this setting is still low quality, mostly consisting of retrospective studies.

METHODS

COPERNIC is an international, multicenter clinical trial. The pilot study aims to confirm the predictive potential of early on-treatment ctDNA dynamics, and inform the design of a larger ctDNA-driven trial. Advanced CRC patients who are candidates for ≥3rd lines of systemic therapy undergo longitudinal blood sample collection during treatment (day 1, 15 and 29 for 2- or 4-weekly treatment regimens; day 1, 22 and 43 for 3-weekly treatment regimens) and at each imaging assessment. ctDNA analyses are carried out with the FoundationOne Liquid CDx and FoundationOneMonitor assays, and ctDNA changes during treatment are correlated with radiologic response (as assessed every 8-12 weeks by RECIST v1.1). The primary objective is to select the optimal timepoint and cut-off value for early ctDNA changes (at day 15/22) to predict progressive disease as best radiological response with a high positive predictive value. The cut-off value for ctDNA will be defined based on nonparametric ROC-curves with bootstrapping. Based on the expected rate of progressive disease and statistical assumptions, 109 patients are needed to be screened to have 87 assessable patients. COPERNIC is sponsored by the Institut Jules Bordet, and supported by Roche and Foundation Medicine. Recruitment is open in 13 centres across Belgium and France. The study is registered with clinicaltrials.gov (NCT05487248).

Chemotherapy Rechallenge or Reintroduction Compared to Regorafenib or Trifluridine/Tipiracil for Pretreated Metastatic Colorectal Cancer Patients: A Propensity Score Analysis of Treatment Beyond Second Line (Proserpyna Study)

BACKGROUND

The optimal treatment for metastatic colorectal cancer (mCRC) beyond second line is still questioned. Besides the standard of care agents (regorafenib, REG, or trifluridine/tipiracil, FTD/TPI), chemotherapy rechallenge or reintroduction (CTr/r) are commonly considered in clinical practice, despite weak supporting evidence. The prognostic performance of CTr/r, REG and FTD/TPI in this setting are herein evaluated.

PATIENTS AND METHODS

PROSERpYNa is a multicenter, observational, retrospective study, in which patients with refractory mCRC, progressing after at least 2 lines of CT, treated with CTr/r, REG or FTD/TPI, are considered eligible and were enrolled in 2 independent data sets (exploratory and validation). Primary endpoint was overall survival (OS); secondary endpoints were investigator-assessed progression-free survival (PFS), objective response rate (RR) and safety. A propensity score adjustment was accomplished for survival analyses.

RESULTS

Data referring to patients treated between Jan-10 and Jan-19 from 3 Italian institutions were gathered (341 and 181 treatments for exploratory and validation data sets respectively). In the exploratory cohort, median OS (18.5 vs. 6.5 months), PFS (6.1 vs. 3.5 months) and RR (28.6% vs. 1.4%) were significantly longer for CTr/r compared to REG/FTD/TPI. Survival benefits were retained at the propensity score analysis, adjusted for independent prognostic factors identified at multivariate analysis. Moreover, these results were confirmed within the validation cohort analyses.

CONCLUSIONS

Although the retrospective fashion, CTr/r proved to be a valuable option in this setting in a real-world context, providing superior outcomes compared to standard of care agents at the price of a moderate toxicity.

Circulating Tumor DNA Dynamics and Clinical Outcome in Metastatic Colorectal Cancer Patients Undergoing Front-Line Chemotherapy

PURPOSE

We tested whether circulating tumor DNA (ctDNA) changes may be used to assess early response and clinical outcomes in patients with metastatic colorectal cancer (mCRC) undergoing first-line systemic anticancer therapy (SACT).

EXPERIMENTAL DESIGN

Eight hundred sixty-two plasma samples were collected 4-weekly from baseline (BL) until disease progression in patients with mCRC receiving first-line SACT. ctDNA was tested using tissue-agnostic next-generation sequencing panels. ctDNA normalization was defined as ≥99% clearance after 1 month of therapy (Mo1) in the three variants with the highest allele frequency in BL ctDNA.

RESULTS

Eighty-three paired samples from 75 patients were available for analysis. Twelve pairs (14.4%) showed no variants in either BL or Mo1. In the remaining 71 comparisons (65 patients), 37 (52.1%) showed ctDNA normalization at Mo1. Patients who cleared ctDNA had significantly longer overall (45.6 months) and progression-free survival (13.9 months) compared with nonnormalized patients [overall survival = 22.6 months (log-rank P = 0.01) and progression-free survival = 10.7 months (log-rank P = 0.036), respectively]. In addition, a higher response rate was observed in patients with ctDNA clearance (72.9%) compared with nonnormalized cases (38.2%). Longitudinal sequencing of at least four time points in patients with a progression-free survival of >10 months showed emerging variants in 47.8% of cases; in all these patients, the trajectory of these new "outlier" variants seemed in stark contrast with the clinical-radiological course of disease and the trend in other mutations.

CONCLUSIONS

ctDNA clearance represents an early indicator of benefit from SACT in patients with mCRC; serial tracking of multiple variants is warranted to improve specificity and avoid misleading information due to the emergence of mutations of unknown clinical significance.

A scoping review of factors influencing the implementation of liquid biopsy for cancer care

BACKGROUND

Liquid biopsy (LB) offers a promising, minimally invasive alternative to traditional tissue biopsies in cancer care, enabling real-time monitoring and personalized treatment. Despite its potential, the routine implementation of LB in clinical practice faces significant challenges. This scoping review examines the barriers and facilitators influencing the implementation of liquid biopsies into standard cancer care.

METHODS

Four academic databases (PubMed, Scopus, Embase, and Web of Science) were systematically searched without language restrictions. We included peer-reviewed articles that were published between January 2019 and March 2024 that focused on the implementation of LB in cancer care or described barriers and facilitators to its implementation. Data relevant to the review objective, including key article characteristics; barriers and facilitators of implementation; and recommendations for advancement or optimisation; were extracted and analysed using thematic and visual network analyses.

RESULTS

The majority of the included articles were narrative review articles (84%), with most from China (24.2%) and the United States (20%). Thematic analysis identified four main categories and their associated barriers and facilitators to the implementation of LB in cancer care: (1) Laboratory and personnel requirements; (2) Disease specificity; (3) Biomarker-based liquid biopsy; and (4) Policy and regulation. The majority of barriers identified were concentrated in the pre-analytical phase, highlighting the lack of standardization in LB technologies and outcomes.

CONCLUSIONS

Through a thematic analysis of the barriers and facilitators to LB implementation, we present an integrated tool designed to encourage the standardization of testing methods for clinical practice guidelines in the field.

Genomic landscape of clinically acquired resistance alterations in patients treated with KRASG12C inhibitors

BACKGROUND

Mutant-selective inhibitors of KRASG12C (KRASG12Ci) have demonstrated efficacy in KRASG12C cancers. However, resistance invariably develops, resulting in short-lived responses. We aimed to define the genomic landscape of acquired resistance to KRASG12Ci and to elucidate whether novel classes of KRAS inhibitors can overcome these resistance mechanisms.

METHODS

To assess clinical frequencies of acquired resistance alterations, we evaluated genomic sequencing data from postprogression cell-free DNA samples in patients treated with KRASG12Ci at two United States cancer centers, alongside data from six previously published studies. Cell viability assays using engineered cell models were employed to functionally validate candidate resistance drivers and to evaluate novel classes of KRAS inhibitors.

RESULTS

A total of 143 patients were analyzed. Most patients had non-small-cell lung cancer (NSCLC, n = 68) or colorectal cancer (CRC, n = 58) and were treated with single-agent KRASG12Ci (n = 109) or combined with anti-EGFR antibodies (n = 30). RAS/MAPK alterations emerged in 46% of patients (n = 66), with 39% developing one or more new KRAS alterations (n = 56) and 23% (n = 33) showing multiple concurrent alterations. The genomic landscape of acquired alterations included KRAS-activating mutations (25% of patients), KRAS amplifications (22%), RAF/MAPK mutations/fusions (21%), KRAS switch-II pocket mutations (14%), and NRAS/HRAS mutations (8%). Notably, the proportion of patients with one or more acquired RAS/MAPK alteration was significantly higher in CRC compared with NSCLC (69% versus 26%, P < 0.001). Functional studies confirmed most alterations as resistance drivers. Sotorasib, adagrasib, and divarasib demonstrated distinct activity against KRAS switch-II pocket mutations, yet all were responsive to the RAS(ON) G12C-selective tri-complex inhibitor RM-018. The KRAS-selective inhibitor Pan KRAS-IN-1 effectively targeted KRAS-activating mutations, and the RAS(ON) multiselective tri-complex inhibitor RMC-7797 demonstrated high potency across all RAS alterations.

CONCLUSIONS

Acquired RAS/MAPK alterations are recurrent drivers of resistance to KRASG12Ci detected in CRC and, less frequently, in NSCLC. Preclinical data suggest that novel (K)RAS inhibitors may overcome many of these resistance alterations.

Baseline Liquid Biopsy in Relation to Tissue-Based Parameters in Metastatic Colorectal Cancer: Results From the Randomized FIRE-4 (AIO-KRK-0114) Study

PURPOSE

The FIRE-4 study randomly assigned patients with first-line RAS wild-type (RASwt) metastatic colorectal cancer to either flourouracil (FU), folinic acid, and irinotecan (FOLFIRI) plus cetuximab until progression or intolerable toxicity (standard arm) or to FOLFIRI plus cetuximab followed by a switch maintenance treatment using FU plus bevacizumab (experimental arm). Here, we investigate the relevance of liquid biopsy (LB) RAS and BRAF testing compared with tissue-based analyses.

PATIENTS AND METHODS

LBs were taken at baseline and during treatment and were analyzed for RAS and BRAFV600E mutations using the in vitro diagnostics-certified ONCOBEAM RAS procedure (Sysmex Inostics) and digital-droplet polymerase chain reaction technology.

RESULTS

Six hundred seventy-two RASwt patients were randomly assigned. LBs of 540 patients were evaluable at baseline. Of those, 70 (13%) were RAS mutant (RASmut) and 38 (7%) BRAFV600E mutant. RASmut patients had significantly shorter survival compared with RASwt patients (progression-free survival [PFS], 9.0 months v 11.5 months; P < .001; hazard ratio [HR], 1.66; overall survival [OS], 22.1 months v 33.6 months; P < .001; HR, 1.85). RASmut patients had a numerically greater benefit from early switch maintenance compared with continuation of FOLFIRI/cetuximab (PFS, 10.1 months v 6.4 months; HR, 0.82; OS, 24.9 months v 16.3 months; HR, 0.57). Patients with a BRAFV600E mutation in LB showed poor outcome (PFS, 5.4 months; OS, 12.0 months). On the basis of serial LB analyses, the conversion rate from RASwt to RASmut at disease progression was significantly higher in the arm with continuous cetuximab administration than in the switch maintenance arm.

CONCLUSION

LB allows the detection of RAS and BRAF mutations in patients deemed RASwt on the basis of tissue analyses. These patients show outcome characteristics expected for RAS- and BRAF-mutant patients in tissue. The study thus confirms the high clinical relevance of LB performed at baseline before the start of therapy.

When molecular biology transforms clinical oncology: the EGFR journey in colorectal cancer

The discovery of growth factors and their involvement in cancer represents the foundation of precision oncology. The preclinical and clinical development of agents targeting epidermal growth factor receptor (EGFR) in colorectal cancer (CRC) were accompanied by big hype and hopes, though the clinical testing of such agents clashed with intrinsic and acquired resistance, greatly limiting their therapeutic value. However, a better understanding of the biology of the EGFR signaling pathway in CRC, coupled with the development of liquid biopsy methodologies to study cancer evolution in real time, fostered the clinical refinement of anti-EGFR treatment in CRC. Such a workflow, based on the co-evolution of biology knowledge and clinical development, allowed to couple the discovery of relevant therapy resistance mechanisms to the development of strategies to bypass this resistance. A broader application of this paradigm could prove successful and create an effective shortcut between the bench and the bedside for treatment strategies other than targeted therapy.

Comprehensive review of signaling pathways and therapeutic targets in gastrointestinal cancers

Targeted therapy, the milestone in the development of human medicine, originated in 2004 when the FDA approved the first targeted agent bevacizumab for colorectal cancer treatment. This new development has resulted from drug developers moving beyond traditional chemotherapy, and several trials have popped up in the last two decades with an unprecedented speed. Specifically, EGF/EGFR, VEGF/VEGFR, HGF/c-MET, and Claudin 18.2 therapeutic targets have been developed in recent years. Some targets previously thought to be undruggable are now being newly explored, such as the RAS site. However, the efficacy of targeted therapy is extremely variable, especially with the emergence of new drugs and the innovative use of traditional targets for other tumors in recent years. Accordingly, this review provides an overview of the major signaling pathway mechanisms and recent advances in targeted therapy for gastrointestinal cancers, as well as future perspectives.

What the Clinician Needs to Know About Laboratory Analyses of Circulating Tumor DNA

Liquid biopsies offer the possibility to evaluate cancer patients using noninvasive approaches. Circulating cell-free DNA (ccfDNA) is 1 of the most used and promising sources. Detecting tumor DNA among ccfDNA (ctDNA) can be used for early cancer detection, treatment response assessment, prognosis, and predictive evaluations. Providing analyses that can increase the quality of patient treatment is very much a joint effort between laboratory scientists and clinicians. With its use approaching clinical practice, it is important for clinicians to be familiar with the basic concepts and analyses behind ctDNA results in a similar way as laboratory scientists should have knowledge of the clinical needs to provide relevant analyses. In this Perspective, we describe the whole process of ctDNA analyses, from the preanalytical standards to reporting/analyzing results, and highlight some important factors that need to be addressed in the process of implementing them to clinical practice.

Late-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm

Over the past few years, several novel systemic treatments have emerged for patients with treatment-refractory metastatic colorectal cancer, thus making selection of the most effective later-line therapy a challenge for medical oncologists. Over the past decade, regorafenib and trifluridine-tipiracil were the only available drugs and often provided limited clinical benefit compared to best supportive care. Results from subsequent practice-changing trials opened several novel therapeutic avenues, both for unselected patients (such as trifluridine-tipiracil plus bevacizumab or fruquintinib) and for subgroups defined by the presence of actionable alterations in their tumours (such as HER2-targeted therapies or KRASG12C inhibitors) or with no acquired mechanisms of resistance to the previously received targeted agents in circulating tumour DNA (such as retreatment with anti-EGFR antibodies). In this Review, we provide a comprehensive overview of advances in the field over the past few years and offer a practical perspective on translation of the most relevant results into the daily management of patients with metastatic colorectal cancer using an evidence-based algorithm. Finally, we discuss some of the most appealing ongoing areas of research and highlight approaches with the potential to further expand the therapeutic armamentarium.

Panitumumab plus 5-fluorouracil and folinic acid or 5-fluorouracil and folinic acid alone as maintenance therapy in RAS wild-type metastatic colorectal cancer (PanaMa, AIO KRK 0212): final efficacy analysis of a randomised, open-label, phase 2 trial

Background

The PanaMa trial aimed to compare the efficacy of 5-fluorouracil and folinic acid (FU/FA) ± panitumumab maintenance in untreated RAS wild-type metastatic colorectal cancer (mCRC) patients.

Methods

In this final phase 2 trial analysis, adult mCRC patients responding to six cycles of FU/FA, oxaliplatin and panitumumab were randomized (1:1, open-label) to maintenance of either FU/FA + panitumumab or FU/FA alone. The primary endpoint was superiority of progression-free survival of maintenance (PFS; time from random assignment to progression/death) in favour of FU/FA + panitumumab. Secondary endpoints included PFS of re-induction (PFS re-ind.), time to failure of strategy (TFS) and overall survival (OS). The trial is registered with ClinicalTrials.gov (NCT01991873).

Findings

In 248 patients of the Full Analysis Set recruited between May 2014 and February 2021, with a median observation of 64.0 (range 12.5-86.3) months and 59.7 (range 3.7-97.3) months in the treatment arms, 230 events for PFS (92.7%) and 196 events for OS (79.0%) were recorded. Adding panitumumab to FU/FA resulted in significantly longer PFS (8.8 versus 5.8 months, HR = 0.73 (95% CI 0.56-0.94), P = 0.015), shorter PFS re-ind. (4.1 versus 7.4 months, HR = 1.93 (95% CI 1.33-2.82), P < 0.001), comparable TFS (17.1 versus 15.7 months, HR = 0.98 (95% CI 0.68-1.42), P = 0.92) and numerically longer OS (29.9 versus 24.7 months, HR = 0.85 (95% CI 0.64-1.12), P = 0.24). The most frequent adverse event (AE) grade ≥3 was rash (FU/FA + panitumumab: n = 15, 12.0%, FU/FA: n = 17, 6.9%). 141 patients (37.3%) experienced at least one serious AE One treatment-related death occurred (neutropenic sepsis, FU/FA).

Interpretation

Panitumumab plus FU/FA might be considered a standard of care maintenance regimen since a potential re-induction therapy with panitumumab cannot be guaranteed at the time of maintenance treatment decision.

Funding

Amgen.

The Evolving Role of Genomics in Colorectal Cancer

Approximately 75% of colorectal cancers (CRCs) harbour an identifiable driver mutation, 5% of which are heritable. These drivers have recognised implications for prognosis and therapy selection. In addition, potential germline mutations require investigations to inform testing of relatives, as well as surveillance for other malignancies. With increasing numbers of targeted drugs being approved, judicious testing is required to ensure sufficient tumour sample is available for testing and at the right point in the cancer pathway. Liquid biopsy with circulating tumour DNA (ctDNA) in the blood presents an exciting adjunct to tumour tissue testing for molecular drivers, as well as escalation and de-escalation of therapy. Here, we review the most frequent molecular alterations in CRC, how genomic testing should be integrated into the treatment pathway for CRC, and sources of further education.

Anti-EGFR Rechallenge in Metastatic Colorectal Cancer and the Role of ctDNA: A Systematic Review and Meta-analysis

BACKGROUND

Metastatic colorectal cancer (mCRC) remains a significant clinical challenge. While anti-EGFR inhibitors have improved survival rates, their long-term efficacy is limited by disease progression, which is often associated with the development of acquired resistance mutations. However, some patients may regain sensitivity to anti-EGFR agents after alternative therapies, suggesting a potential benefit for rechallenge strategies. Our study aims to conduct a systematic review and meta-analysis to comprehensively evaluate the efficacy and safety of EGFR rechallenge in patients with mCRC.

METHODS

A systematic search of the MEDLINE, EMBASE, and Cochrane databases was conducted between October 28 and December 24, 2023, to identify clinical trials investigating treatment regimens incorporating panitumumab or cetuximab as a rechallenge strategy. Pooled proportions or hazard ratios (HR) were calculated using a random effects model. Inter-study heterogeneity was assessed using the I2.

RESULTS

Among the 2105 articles identified through the search, 13 met the predetermined inclusion criteria. Of these, 12 were phase II studies, encompassing 92.3% of the patient population. Cetuximab was administered to 302 patients (75.1%), whereas panitumumab was utilized in 100 patients (24.9%).A pooled analysis of eight studies demonstrated an objective response rate of 20.50% (95% CI 7.94 to 33.07) and a disease control rate of 67.35% (95% CI 58.60 to 76.09). The median progression-free survival was estimated at 3.5 months (95% CI 2.68-6.69), with a median OS of 9.8 months (95% CI 6.71-12.89). Patients exhibiting RAS wild-type status in circulating tumor DNA (ctDNA) analysis derived enhanced benefits from anti-EGFR rechallenge (HR: 0.41; 95% CI 0.28-0.60, I2 = 60%). Common grade 3 or higher treatment-related adverse events included neutropenia (22.8%) and rash (14.9%).

CONCLUSION

This meta-analysis underscores the efficacy and safety of anti-EGFR rechallenge as a promising therapeutic approach for a subset of patients afflicted with mCRC. The observed correlation between wild-type RAS status, as determined through ctDNA analysis, and improved OS signals the prospect of precision oncology in guiding treatment decisions.

Ongoing Clinical Trials and Future Research Scenarios of Circulating Tumor DNA for the Treatment of Metastatic Colorectal Cancer

Liquid biopsy using circulating tumor DNA (ctDNA) has emerged as a minimally invasive, timely approach to provide molecular diagnosis and monitor tumor evolution in patients with cancer. Since the molecular landscape of metastatic colorectal cancer (mCRC) is substantially heterogeneous and dynamic over space and time, ctDNA holds significant advantages as a biomarker for this disease. Numerous studies have demonstrated that ctDNA broadly recapitulates the molecular profile of the primary tumor and metastases, and have mainly focused on the genotyping of RAS and BRAF, that is propaedeutic for anti-EGFR treatment selection. However, ctDNA soon broadened its scope towards the assessment of early tumor response, as well as the identification of drug resistance biomarkers to drive potential molecular actionability. In this review article, we provide an overview of the current state-of-the-art of this methodology and its applications, focusing on ongoing clinical trials that employ ctDNA to prospectively guide treatment in patients with mCRC.

Optimizing outcomes and personalizing care with targeted agents in advanced cholangiocarcinoma

Traditional chemotherapy and immunotherapy-based systemic treatments for locally advanced or metastatic cholangiocarcinoma have been associated with poor clinical outcomes driven partly by molecular heterogeneity promoting early treatment resistance and a higher toxicity profile associated with these regimens. Few patients are eligible for upfront surgical resection and clinical studies have been traditionally difficult to conduct due to the orphan nature of this disease. However, increasing use of genomic profiling in clinical practice have led to active investigations of aberrant albeit promising mechanistic therapeutic targets such as IDH-1, FGFRs, BRAFV600E, HER-2 and NTRK. This review article aims to highlight the complex genomic landscape of this difficult-to-treat disease, followed by a discussion of evidence-based biological mechanisms that can be actioned using targeted agents. We explore the clinical rationale behind a targeted therapeutic strategy, the role of liquid biopsies in guiding clinical decisions and future treatment pathways for cholangiocarcinoma management. We also discuss the challenges and opportunities originating from recent clinical trials evaluating targeted treatments and our own institutional experience at UCLH that have aimed to address some of these biological complexities and have translated into improved patient outcomes via effective molecularly driven patient selection strategies. We also provide perspectives on emerging novel, next generation targeted inhibitors overcoming treatment resistance to previous targeted agents with demonstrated clinical value in a challenging patient population.

Comprehensive genomic profiling by liquid biopsy captures tumor heterogeneity and identifies cancer vulnerabilities in patients with RAS/BRAFV600E wild-type metastatic colorectal cancer in the CAPRI 2-GOIM trial

BACKGROUND

Emerging evidence supports tumor tissue-based comprehensive genomic profiling (CGP) in metastatic colorectal cancer (mCRC). Data on liquid biopsy-based circulating tumor DNA (ctDNA) CGP are scarce and mainly retrospective. Prospective comparison between the two tests is not currently available.

MATERIALS AND METHODS

The CAPRI 2-GOIM trial investigates efficacy and safety of ctDNA-driven, cetuximab-based sequence of three treatment lines in patients with RAS/BRAFV600E wild-type (WT) mCRC, as determined by the local laboratory. Before first-line therapy, CGP is carried out with FoundationOne (F1) CDx and F1 Liquid (F1L) CDx (324 genes) on tumor tissue DNA and plasma ctDNA, respectively.

RESULTS

For 2/207 (0.96%) patients, no ctDNA was detected by F1L CDx. No patient displayed tumor fraction (TF) below 1%, whereas elevated ctDNA (TF ≥ 10%) was detected among 140/205 (68.3%) patients. One thousand and thirteen genomic variants were identified. F1L CDx found KRAS, NRAS, or BRAFV600E alterations in 19 patients, whose tumors were classified as RAS/BRAFV600E WT by the local laboratory. Both F1 CDx and F1L CDx were available for 164/205 (80%) patients. A concordance of 61.4% between the two tests was observed. The concordance increased to 72.7% for F1L CDx with TF ≥ 10%. Concordance for genes potentially involved in anti-epidermal growth factor receptor resistance was found in 137/164 (83%) patients, increasing to 91.5% for F1L CDx with TF ≥ 10%. A higher number of genomic alterations was detected by F1L CDx compared with F1 CDx, including six cases with KRAS and NRAS alterations. Overall, 109/205 (53.2%) patients displayed at least one actionable genomic alteration (I to IIIB), according to the European Society for Medical Oncology Scale for Clinical Actionability of Molecular Targets (ESCAT).

CONCLUSION

Baseline liquid biopsy-based CGP is feasible, has high concordance with tumor tissue-based CGP, could better recapitulate tumor heterogeneity, and is clinically informative by identifying additional actionable genomic alterations in approximately half of RAS/BRAFV600E WT mCRC patients.

Prognostic and Predictive Determinants of Colorectal Cancer: A Comprehensive Review

Colorectal cancer (CRC) remains a significant global health burden, necessitating a thorough understanding of prognostic and predictive factors to enhance patient outcomes. This systematic review aims to comprehensively evaluate prognostic and predictive determinants in CRC, encompassing both traditional and emerging biomarkers. A systematic search of major electronic databases was conducted to identify relevant studies published from 1995 up to 2024. Eligible articles were critically appraised, and data extraction was performed according to predefined criteria. The prognostic determinants examined included clinicopathological features such as tumor stage, grade, and lymph node involvement, as well as molecular biomarkers including RAS, BRAF, and MSI status. Predictive determinants encompassed biomarkers influencing response to targeted therapies and immunotherapy, such as HER2 and Immunoscore. The review also explores novel prognostic and predictive markers, including tumor microenvironment characteristics and liquid biopsy-based biomarkers. Synthesizing evidence from diverse studies, this review provides insights into the prognostic and predictive landscape of CRC, highlighting the potential clinical implications of identified determinants. Understanding the multifaceted nature of prognostic and predictive factors in CRC is imperative for the advancement of personalized treatment strategies and improvement of patient outcomes.

Neo-RAS Wild Type or RAS Conversion in Metastatic Colorectal Cancer: A Comprehensive Narrative Review

The management of metastatic colorectal cancer in patients harboring RAS mutations primarily involves chemotherapy, often combined with bevacizumab, as a standard first-line treatment. However, emerging evidence suggests that tumors in a subset of these patients may experience a conversion from RAS-mutant status to RAS wild type (wt) during or after chemotherapy, a process referred to as "RAS conversion" or "neo-RAS wt". Understanding the mechanisms driving the neo-RAS wt phenomenon is crucial for its application in personalized medicine. Hypotheses suggest that selective pressure from chemotherapy may lead to a decrease in the number of mutant RAS clones or an outgrowth of pre-existing RAS wt clones. Further research is needed to validate these mechanisms and understand the impact of the neo-RAS wt phenomenon on long-term outcomes, such as overall survival and progression-free survival. This review provides a comprehensive overview of the current understanding of the neo-RAS wt phenomenon, including its incidence, potential mechanisms, and clinical implications.

Base editing screens define the genetic landscape of cancer drug resistance mechanisms

Drug resistance is a principal limitation to the long-term efficacy of cancer therapies. Cancer genome sequencing can retrospectively delineate the genetic basis of drug resistance, but this requires large numbers of post-treatment samples to nominate causal variants. Here we prospectively identify genetic mechanisms of resistance to ten oncology drugs from CRISPR base editing mutagenesis screens in four cancer cell lines using a guide RNA library predicted to install 32,476 variants in 11 cancer genes. We identify four functional classes of protein variants modulating drug sensitivity and use single-cell transcriptomics to reveal how these variants operate through distinct mechanisms, including eliciting a drug-addicted cell state. We identify variants that can be targeted with alternative inhibitors to overcome resistance and functionally validate an epidermal growth factor receptor (EGFR) variant that sensitizes lung cancer cells to EGFR inhibitors. Our variant-to-function map has implications for patient stratification, therapy combinations and drug scheduling in cancer treatment.

Clinical Applications of Circulating Tumor DNA Profiling in GI Cancers

Over the next few years, the analysis of circulating tumor DNA (ctDNA) through liquid biopsy is expected to enter clinical practice and revolutionize the approach to biomarker testing and treatment selection in GI cancers. In fact, growing evidence support the use of ctDNA testing as a noninvasive, effective, and highly specific tool for molecular profiling in GI cancers. Analysis of blood ctDNA has been investigated in multiple settings including early tumor detection, minimal residual disease evaluation, tumor diagnosis and evaluation of prognostic/predictive biomarkers for targeted treatment selection, longitudinal monitoring of treatment response, and identification of resistance mechanisms. Here, we review the clinical applications, advantages, and limitations of ctDNA profiling for precision oncology in GI cancers.

Evaluation of blood MSI burden dynamics to trace immune checkpoint inhibitor therapy efficacy through the course of treatment

Analysis of serial liquid biopsy (LB) samples has been found to be a promising approach for the monitoring of tumor dynamics in the course of therapy for patients with colorectal cancer (CRC). Currently, somatic mutations are used for tracing the dynamics of the tumor via LB. However, the analysis of the dynamic changes in the molecular signatures such as microsatellite instability (MSI) is not currently used. We hypothesized that changes in blood MSI burden (bMSI) could be registered using serial LB sampling in the course of immune checkpoint inhibitors (ICI), and that its changes could potentially correlate with treatment outcomes. We report the preliminary findings of the observational trial launched to study (NCT06414304) the dynamics of bMSI in 9 MSI-positive CRC patients receiving ICI. NGS-based MSI testing was performed on both pre-treatment FFPE and serial LB samples. For patients who had detectable bMSI burden in any of the LB samples (n = 8, 89%), median bMSI was 1.4% (range, 0.01-40%). Among patients with detectable MSI in available FFPE samples, median MSI burden was 29.3% (range, 10-40%). bMSI detected in baseline LB and FFPE samples were positively correlated (Pearson's R 0.47). Maximal variant allele frequencies of driver mutations observed in LB were also positively correlated with bMSI burden (Pearson's R 0.7). Patients who had clinical benefit had undetectable bMSI burden at follow-up. Our results provide the rationale for further validation of bMSI as a predictive biomarker of ICI in MSI-positive patients.

Clinical Trial Data Review of the Combination FTD/TPI + Bevacizumab in the Treatment Landscape of Unresectable Metastatic Colorectal Cancer

OPINION STATEMENT

Recommended first and second line treatments for unresectable metastatic colorectal cancer (mCRC) include fluorouracil-based chemotherapy, anti-vascular endothelial growth factor (VEGF)-based therapy, and anti-epidermal growth factor receptor-targeted therapies. In third line, the SUNLIGHT trial showed that trifluridine/tipiracil + bevacizumab (FTD/TPI + BEV) provided significant survival benefits and as such is now a recommended third line regimen in patients with refractory mCRC, irrespective of RAS mutational status and previous anti-VEGF treatment. Some patients are not candidates for intensive combination chemotherapy as first-line therapy due to age, low tumor burden, performance status and/or comorbidities. Capecitabine (CAP) + BEV is recommended in these patients. In the SOLSTICE trial, FTD/TPI + BEV as a first line regimen in patients not eligible for intensive therapy was not superior to CAP + BEV in terms of progression-free survival (PFS). However, in SOLSTICE, FTD/TPI + BEV resulted in similar PFS, overall survival, and maintenance of quality of life as CAP + BEV, with a different safety profile. FTD/TPI + BEV offers a possible first line alternative in patients for whom CAP + BEV is an unsuitable treatment. This narrative review explores and summarizes the clinical trial data on FTD/TPI + BEV.

Third-line treatment and beyond in metastatic colorectal cancer: What do we have and what can we expect?

Colorectal cancer remains the third most common cancer worldwide and the second cause of cancer-related death. Treatment advances and precision oncological medicine for these tumours have been stalled in comparison to those for other common tumours such as lung and breast cancer. However, the recent publication of the SUNLIGHT trial results with the trifluridine/tipiracil (TAS-102)-bevacizumab combination and the irruption of new molecular targets with guided treatments have opened new possibilities in third-line metastatic colorectal cancer management. Anti-EGFR rechallenge, anti-HER2 targeted therapies or the promising results of Pressurised Intraperitoneal Aerosol Chemotherapy (PIPAC), are some of the available options that may modify what is presumably third-line colorectal treatment. Hereby, we present the evidence of the different treatment options in third-line colorectal cancer and beyond, as well as the possibilities of sequencing them.

Identification of circulating tumor DNA as a biomarker for diagnosis and response to therapies in cancer patients

The sampling of circulating biomarkers provides an opportunity for non-invasive evaluation and monitoring of cancer activity. In modern day practice, this has typically been in the form of circulating tumor DNA (ctDNA) detected in plasma. The field of ctDNA has been a burgeoning technology, with prominent applications for blood-based cancer screening and in disease status assessment, especially after curative-intent surgery to evaluate for minimal residual disease (MRD). Clinical applications for the latter show an incredibly high sensitivity in certain cancer types with a need for additional studies to determine how much clinical decision-making should be adapted based on ctDNA results and which cancer types, stages, and treatments are best informed by ctDNA results. This chapter provides an overview of ctDNA detection as tool for cancer screening, detecting MRD, and/or molecularly characterizing a cancer, highlighting the rapidly amassing research as a prognostic biomarker and emerging data on ctDNA as a predictive biomarker.

Tislelizumab plus cetuximab and irinotecan in refractory microsatellite stable and RAS wild-type metastatic colorectal cancer: a single-arm phase 2 study

Immunotherapy confers little to no benefit in the treatment of microsatellite stable (MSS) metastatic colorectal cancer (mCRC). Mechanistic insights suggested that epidermal growth factor receptor (EGFR) antibody plus irinotecan might augment the tumor immune response in mCRC. Therefore, we conducted a proof-of-concept, single-arm, phase 2 study (ChiCTR identifier: ChiCTR2000035642) of a combination treatment regimen including tislelizumab (anti-PD-1), cetuximab (anti-EGFR) and irinotecan in 33 patients with MSS and RAS wild-type (WT) mCRC who were previously treated with ≥2 lines of therapy. The primary endpoint was met, with a confirmed objective response rate of 33%. As secondary endpoints, the disease control rate was 79%, and the median progression-free survival and overall survival were 7.3 and 17.4 months respectively. Among the 33 patients, 32 (97.0%) had treatment-related adverse events (AEs). Three (9.1%) reported grade ≥ 3 AEs, including rash (n = 1), neutropenia (n = 2). The post-hoc evaluation of dynamic circulating tumor DNA using next generation sequencing and the analysis of peripheral immune proteomics landscape using Olink revealed that lower variant allele frequency (VAF) at baseline, greater reduction in VAF on treatment, and a hot peripheral macroenvironment were associated with the treatment response independently. Our study showed the antitumor activity of tislelizumab, cetuximab, and irinotecan combination with a tolerable safety profile in previously treated MSS and RAS WT mCRC.

Advances in Personalized Oncology

Advances in next-generation sequencing (NGS) have catalyzed a paradigm shift in cancer treatment, steering the focus from conventional, organ-specific protocols to precision medicine. Emerging targeted therapies offer a cutting-edge approach to cancer treatment, while companion diagnostics play an essential role in aligning therapeutic choices with specific molecular changes identified through NGS. Despite these advances, interpreting the clinical implications of a rapidly expanding catalog of genetic mutations remains a challenge. The selection of therapies in the presence of multiple mutations requires careful clinical judgment, supported by quality-centric genomic testing that emphasizes actionable mutations. Molecular tumor boards can play an increasing role in assimilating genomic data into clinical trials, thereby refining personalized treatment approaches and improving patient outcomes.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

Efficacy of anti-epidermal growth factor antibody rechallenge in RAS/BRAF wild-type metastatic colorectal cancer: a multi-institutional observational study

PURPOSE

To investigate circulating tumor DNA (ctDNA) RAS mutant (MT) incidence before salvage-line treatment and the clinicopathological features and molecular biological factors associated with the efficacy of anti-epithelial growth factor receptor (EGFR) monoclonal antibody (mAb) rechallenge for tissue RAS/BRAF wild type (WT) metastatic colorectal cancer (mCRC).

METHODS

This multi-institutional retrospective observational study included 74 patients with mCRC with tissue RAS/BRAF WT refractory to first-line chemotherapy containing anti-EGFR mAb. ctDNA RAS status was assessed using the OncoBEAM™ RAS CRC Kit. We explored the clinicopathological features associated with ctDNA RAS status and the factors related to anti-EGFR mAb rechallenge efficacy in multivariate Cox proportional hazard regression.

RESULTS

The incidence of RAS MT in ctDNA was 40.5% (30/74), which was associated with primary tumor resection (P = 0.016), liver metastasis (P < 0.001), and high tumor marker levels (P < 0.001). Among the 39 patients treated with anti-EGFR mAb rechallenge, those with ctDNA RAS WT showed significantly longer progression-free survival (PFS) than those with ctDNA RAS MT (median 4.1 vs. 2.7 months, hazard ratio [HR] = 0.39, P = 0.045). Patients who responded to first-line anti-EGFR mAb showed significantly longer PFS (HR = 0.21, P = 0.0026) and overall survival (OS) (HR = 0.23, P = 0.026) than those with stable disease.

CONCLUSIONS

The incidence of ctDNA RAS MT mCRC was 40.5%, which was associated with liver metastases and high tumor volumes. Anti-EGFR mAb rechallenge may be effective for patients with mCRC who responded to first-line chemotherapy containing anti-EGFR mAb. No patients with RAS MT in ctDNA responded to anti-EGFR mAb rechallenge.

Colorectal cancer

Despite decreased incidence rates in average-age onset patients in high-income economies, colorectal cancer is the third most diagnosed cancer in the world, with increasing rates in emerging economies. Furthermore, early onset colorectal cancer (age ≤50 years) is of increasing concern globally. Over the past decade, research advances have increased biological knowledge, treatment options, and overall survival rates. The increase in life expectancy is attributed to an increase in effective systemic therapy, improved treatment selection, and expanded locoregional surgical options. Ongoing developments are focused on the role of sphincter preservation, precision oncology for molecular alterations, use of circulating tumour DNA, analysis of the gut microbiome, as well as the role of locoregional strategies for colorectal cancer liver metastases. This overview is to provide a general multidisciplinary perspective of clinical advances in colorectal cancer.

Clinical application of liquid biopsy in colorectal cancer: detection, prediction, and treatment monitoring

Colorectal cancer (CRC) is one of the most prevalent malignancies affecting the gastrointestinal tract and is ranked third among cancers with the highest incidence and second-highest mortality rate worldwide. CRC exhibits a slow progression providing a wide treatment window. The currently employed CRC screening methods have shown great potential to prevent CRC and reduce CRC-related morbidity and mortality. The diagnosis of CRC is achieved by colonoscopy and tissue biopsy, with studies showing that liquid biopsy is more effective in detecting and diagnosing early CRC patients. Increasing number of studies have shown that the tumor components shed into circulating blood can be detected in liquid form, and can be applied in the clinical management of CRC. Analysis of circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), or tumor-associated platelets (TEPs) in the blood can be used for early screening and diagnosis of CRC, aid tumor staging, treatment response monitoring, and prediction of CRC recurrence and metastasis in a minimally invasive manner. This chapter provides an updated review of CTCs, ctDNA, and TEPs as novel biomarkers for CRC, highlighting their strengths and limitations.

Targeting the EGFR signalling pathway in metastatic colorectal cancer

Epidermal growth factor receptor (EGFR) and its activated downstream signalling pathways play a crucial role in colorectal cancer development and progression. After four decades of preclinical, translational, and clinical research, it has been shown that blocking the EGFR signalling pathway at different molecular levels represents a fundamental therapeutic strategy for patients with metastatic colorectal cancer. Nevertheless, the efficacy of molecularly targeted therapies is inescapably limited by the insurgence of mechanisms of acquired cancer cell resistance. Thus, in the era of precision medicine, a deeper understanding of the complex molecular landscape of metastatic colorectal cancer is required to deliver the best treatment choices to all patients. Major efforts are currently ongoing to improve patient selection, improve the efficacy of available treatments targeting the EGFR pathway, and develop novel combination strategies to overcome therapy resistance within the continuum of care of metastatic colorectal cancer.

Monitoring advanced gastrointestinal stromal tumor with circulating tumor DNA

PURPOSE OF REVIEW

This review explores the role of circulating tumor (ct)DNA as a biomarker for clinical decision-making and monitoring purposes in metastatic gastrointestinal stromal tumor (GIST) patients. We discuss key insights from recent clinical trials and anticipate the future perspectives of ctDNA profiling within the clinical landscape of GIST.

RECENT FINDINGS

The identification and molecular characterization of KIT/platelet-derived growth factor receptor alpha (PDGFRA) mutations from ctDNA in metastatic GIST is feasible and reliable. Such identification through ctDNA serves as a predictor of clinical outcomes to tyrosine-kinase inhibitors (TKIs) in metastatic patients. Additionally, conjoined ctDNA analysis from clinical trials reveal the evolving mutational landscapes and increase in intratumoral heterogeneity across treatment lines. Together, this data positions ctDNA determination as a valuable tool for monitoring disease progression and guiding therapy in metastatic patients. These collective efforts culminated in the initiation of a ctDNA-based randomized clinical trial in GIST, marking a significant milestone in integrating ctDNA testing into the clinical care of GIST patients.

SUMMARY

The dynamic field of ctDNA technologies is rapidly evolving and holds significant promise for research. Several trials have successfully validated the clinical utility of ctDNA in metastatic GIST, laying the foundations for its prospective integration into the routine clinical management of GIST patients.

Rechallenge with Anti-EGFR Treatment in RAS/BRAF wt Metastatic Colorectal Cancer (mCRC) in Real Clinical Practice: Experience of the GITuD Group

BACKGROUND

There are few third- and fourth-line therapeutic options for metastatic colorectal cancer (mCRC). In RAS/BRAF wild-type (wt) mCRC previously treated with anti-epidermal growth factor receptor (anti-EGFR) (first-line) and relapsed after a good response, retreatment with anti-EGFR (rechallenge) emerges as a therapeutic alternative.

OBJECTIVE

The aim was to show the activity and safety of anti-EGFR rechallenge in RAS/BRAF wt mCRC in real-world practice.

PATIENTS AND METHODS

A multicenter, retrospective, observational study (six hospitals of the Galician Group of Research in Digestive Tumors) was conducted. Adult patients with RAS/BRAF wt mCRC, evaluated by liquid biopsy, were included. They received anti-EGFR rechallenge (cetuximab, panitumumab) as monotherapy, or combined with chemotherapy, in third- or subsequent lines. Efficacy (overall response rate [ORR], disease control rate [DCR], overall survival [OS], and progression-free survival [PFS]) and safety (incidence of adverse events [AEs]) were assessed.

RESULTS

Thirty-one patients were analyzed. Rechallenge (median 6 cycles [range 1-27], mainly cetuximab [80.7%]), started at a median anti-EGFR-free time of 18.4 months (1.7-37.5 months) after two (38.7%) or more (61.3%) lines of treatment; 64.5% of patients received a full dose. Median OS and PFS were 9.8 months (95% confidence interval [CI] 8.2-11.4) and 2.6 months (95% CI 1.7-3.4), respectively. ORR was 10%, and DCR was 30%. The most common AEs were diarrhea (35.5%), anemia (29%), emesis (6.4%), and neutropenia (6.4%); < 5% grade ≥ 3; 48.4% of patients reported anti-EGFR-related skin toxicity (grade > 1). Hypomagnesemia required supplements in 29% of patients. Dose delays (≥ 3 days) and reduction (≥ 20%) were reported in 11 (35.5%) and seven patients (22.6%), respectively.

CONCLUSIONS

In RAS/BRAF wt mCRC patients, an anti-EGFR rechallenge provides a feasible therapeutic option with clinical benefit (survival) and a manageable safety profile.

Radiomic Parameters for the Evaluation of Response to Treatment in Metastatic Colorectal Cancer Patients with Liver Metastasis: Findings from the CAVE-GOIM mCRC Phase 2 Trial

BACKGROUND

CAVE is a single arm, Phase 2 trial, that demonstrated anti-tumor activity of cetuximab rechallenge plus avelumab in patients with RAS wild type (wt) metastatic colorectal cancer (mCRC).

OBJECTIVE

We conducted a post hoc analysis to identify potential radiomic biomarkers for patients with CRC liver metastasis (LM).

PATIENTS AND METHODS

Patients with LM that could be measured by enhanced contrast phase computed tomography (CT) imaging at baseline and at first response evaluation were included. Multiple texture parameters were extracted with the LifeX Software. Delta-texture (D-TA) variations were calculated by comparing data at baseline and after treatment.

RESULTS

Overall, 55/77 patients (71%) had LM; 39 met the inclusion criteria for the current analysis. The D-TA parameters that significantly correlated at univariate analysis with median progression-free survival (mPFS) were EntropyHistogram (p = 0.021), HomogeneityGLCM (p < 0.001) and Dissimilarity GLCM (p = 0.002). At multivariate analysis, only HomogeneityGLCM resulted significant for PFS (p = 0.001). Patients (19/39, 48.7%) with reduction of HomogeneityGLCM experienced better mPFS (4.6 vs 2.9 months; HR 0.45; 95% CI 0.23-0.88; p = 0.021) and median overall survival (mOS) (17.3 vs 6.8 months; HR 0.40, 95% CI 0.21-0.80; p = 0.010). A trend to better mPFS, was also observed in patients with RAS/BRAF wt circulating tumor DNA and reduction of HomogeneityGLCM. Overall survival was significantly better in this subgroup of patients with low HomogeneityGLCM: mOS was 17.8 (95% CI 15.5-20.2) versus 6.8 months (95% CI 3.6-10.0) (HR 0.34, 95% CI 0.14-0.81; p = 0.016).

CONCLUSION

Reduction in the D-TA parameter HomogeneityGLCM by radiomic analysis correlates with improved outcomes in patients with LM receiving cetuximab rechallenge plus avelumab therapy. Larger prospective studies are needed to validate and confirm these findings.

Clinicopathological significance and prognostic analysis of p21 and EGFR in colorectal cancer: a retrospective analysis on 12 319 cases in China

AIMS

Colorectal cancer (CRC) is the third most common malignancy worldwide. Accurate pathological diagnosis and predictive abilities for treatment response and prognosis are crucial for patients with CRC. This study aims to analyse the expressions of p21 and EGFR in CRC and their relationships with clinicopathological characteristics and prognosis to enhance diagnostic and prognostic evaluations.

METHODS

This study conducted a retrospective analysis of p21 and EGFR expressions in 12 319 Chinese patients with CRC using immunohistochemistry. The relationships between these expressions and clinicopathological characteristics and survival outcomes were explored through statistical and survival analyses.

RESULTS

Differential expressions of p21 and EGFR in CRC were closely related to clinicopathological characteristics and significantly impacted overall survival (OS). p21 expression was associated with the primary tumour site, mucinous subtype, lymphovascular invasion, perineural invasion, circumferential resection margin, T stage, N stage, tumour, node, metastases (TNM) stage, and mismatch repair status. EGFR expression was related to mucinous subtype, tumour differentiation, lymphovascular invasion, perineural invasion, tumour size, T stage, N stage, TNM stage and BRAF gene mutation. p21 and EGFR expressions were positively correlated (r=0.11). High p21 expression correlated with favourable OS, whereas high EGFR expression predicted poorer OS. A prognostic nomogram incorporating these biomarkers and clinical variables demonstrated robust predictive power for patient survival rates.

CONCLUSION

p21 and EGFR serve as potential indicators for pathological diagnosis, risk stratification, and predicting treatment efficacy and prognosis in patients with CRC. The study's findings provide valuable references for personalised treatment and prognosis evaluation in clinical practice.

Putting comprehensive genomic profiling of ctDNA to work: 10 proposed use cases

Liquid biopsy profiling of circulating tumor DNA (ctDNA) has become established as a compelling, pragmatic diagnostic in the care of cancer patients and is now endorsed by multiple cancer care guidelines. Moreover, ctDNA profiling technologies have advanced significantly and offer increasingly comprehensive and reliable insights into cancer. In this review, we focus on applications of ctDNA and propose that a critical untapped opportunity is in considering how we utilize these accessible, scalable technologies across diverse potential applications. With a specific focus on clinical applications, rather than research uses, we describe 10 use cases for ctDNA profiling across four categories: (1) established and (2) emerging applications of ctDNA profiling for therapy selection, (3) incidental detection of secondary genomic findings, and (4) quantification of plasma DNA tumor content.

Epidermal growth factor receptor antagonists in colorectal cancer: emerging strategies for precision therapy

INTRODUCTION

The global prevalence of colorectal cancer highlights the need to enhance treatment strategies for improved patient outcomes. The pivotal role of epidermal growth factor receptor (EGFR) signaling in regulating cellular processes for this disease pinpoints its value as a therapeutic target, despite the emergence of resistance mechanisms over time.

AREAS COVERED

This review discusses the clinical evidence supporting the use of EGFR inhibitors in molecularly-selected patients based on molecular characteristics (notably BRAF V600E and KRAS G12C) including combination approaches targeting different points in in the signaling pathway, as well as strategies such as EGFR inhibitor rechallenge. The role of HER2 inhibitors and emerging approaches such as bispecific antibodies are also reviewed.

EXPERT OPINION

Recently, inhibitors targeting the KRAS G12C variant have emerged, albeit with modest monotherapy activity compared to other tumor types, emphasizing the influence of histologic origins on the EGFR signaling pathway. Integration of EGFR inhibitors into precision medicine has facilitated tailored therapies addressing resistance mechanisms. Patient selection for EGFR inhibitor rechallenge guided by ctDNA findings is crucial, with ongoing investigations exploring novel combinations to enhance EGFR blockade, highlighting the transformative potential of precision medicine in shaping the future of mCRC treatment toward personalized and targeted approaches.

A panorama of colon cancer in the era of liquid biopsy

Colon cancer (CC) is one of the most frequent cancers worldwide being responsible for over 500 thousand deaths in 2022. Its financial and human burden is expected to increase in the next decades accompanying the growing and aging of the global population. Much of this burden could be alleviated considering that the lethality of CC is mostly due to its late diagnosis and failure in the individualized management of patients. Coordinated government actions and implementation of better diagnostic tools capable of detecting CC earlier and of tracking tumoral evolution are mandatory to achieve a reduction in CC's social impact. CtDNA-based liquid biopsy (LB) has great potential to contribute to patients' screening adhesion, CC earlier detection, and to longitudinal tumor follow-up. In this review, we will discuss the latest epidemiological data on CC disease, diagnostic, subtypes, genetics, and treatment management focusing on the advantages and limitations of ctDNA-based LB, including important bottlenecks and solutions necessary for its clinical translation. The latest ctDNA-directed CC clinical trials will also be examined.

State-of-the-Art Management of Colorectal Cancer: Treatment Advances and Innovation

Colorectal cancer (CRC) remains a significant global health challenge, ranking among the leading causes of cancer-related morbidity and mortality worldwide. Recent advancements in molecular characterization have revolutionized our understanding of the heterogeneity within colorectal tumors, particularly in the context of tumor sidedness. Tumor sidedness, referring to the location of the primary tumor in either the right or left colon, has emerged as a critical factor influencing prognosis and treatment responses in metastatic CRC. Molecular underpinnings of CRC, the impact of tumor sidedness, and how this knowledge guides therapeutic decisions in the era of precision medicine have led to improved outcomes and better quality of life in patients. The emergence of circulating tumor DNA as a prognostic and predictive tool in CRC heralds promising advancements in the diagnosis and monitoring of the disease. This innovation facilitates better patient selection for exploration of additional treatment options. As the field progresses, with investigational agents demonstrating potential as future treatments for refractory metastatic CRC, new avenues for enhancing outcomes in this challenging disease are emerging.