Rechallenge for Patients With RAS and BRAF Wild-Type Metastatic Colorectal Cancer With Acquired Resistance to First-line Cetuximab and Irinotecan: A Phase 2 Single-Arm Clinical Trial

Occurence of RAS reversion in metastatic colorectal cancer patients treated with bevacizumab

Background: A disappearance of RAS mutations in the plasma of about 50% of mCRCs (metastatic colorectal cancers) treated with bevacizumab-based chemotherapy has been reported. Our aim was to evaluate the same issue at tissue level.

Materials and Methods: Using next-generation sequencing and real-time PCR approaches, we characterized the primary tumor (PT) and paired liver metastases in 28 RAS mutant mCRCs. Patients were subdivided into 3 treatment groups: 1) bevacizumab plus chemotherapy; 2) chemotherapy alone; 3) any systemic therapy (control group). In groups 1 and 2, liver metastases were resected after removal of PT and subsequent neoadjuvant systemic therapy.

Results: RAS mutant alleles are at the same percentage in PT and liver metastases in the control group, while a significant reduction of the level of RAS mutations was detected in 57.1% of cases in group 1 and in 8.3% of cases in group 2. Differences among groups are statistically significant (p = 0.038).

Conclusions: Most of mCRC patients treated with bevacizumab-containing regimens experience a strong reduction of RAS mutant cells, suggesting bevacizumab as particularly active against RAS mutant cells. This finding might have potential therapeutic implications, as anti-EGFR could be reconsidered in primarily RAS mutant patients reverted to a wild-type status after bevacizumab exposure.

Combination of Anti-EGFR and Anti-VEGF Drugs for the Treatment of Previously Treated Metastatic Colorectal Cancer: A Case Report and Literature Review

The standard third-line treatment of metastatic colorectal cancer (mCRC) includes the small-molecule anti-vascular drugs (Regofenib and Fruquintinib) and the chemotherapy drug trifluridine and tipiracil hydrochloride (TAS-102). There is no standard treatment for mCRC if the third-line treatment failed. Therefore, it is a pressing need to develop new therapeutic approaches to improve the survival of patients who developed drug resistance to the third-line treatment. In this study, we report a case of mCRC with RAS/BRAF wild-type, who was successfully treated using cetuximab in combination with fruquintinib after resistance to chemotherapy, bevacizumab, cetuximab and regorafenib. This patient responded to this combination regimen. Then, we discuss the mechanisms of action of this combination. Furthermore, we introduce the clinical trials on the combination regimens of anti-EGFR with anti-vascular monoclonal antibodies. Finally, we discuss the clinical explorations of using combination of anti-EGFR with small-molecule anti-VEGF drugs and their potential benefits. The clinical effects of small-molecule anti-vascular drugs in combination with anti-EGFR in the treatment of CRC warrant further explored.

SELE gene as a characteristic prognostic biomarker of colorectal cancer

OBJECTIVE

To investigate the expression and clinical value of the E-selectin gene (SELE) in colorectal cancer (CRC).

METHODS

Using gene expression profiles and clinicopathological data for patients with CRC from The Cancer Genome Atlas, and tumor and adjacent normal tissues from 31 patients with CRC from Xianyang Central Hospital, we studied the correlation between SELE gene expression and clinical parameters using Kaplan-Meier and Cox proportional hazards regression analyses.

RESULTS

Higher expression of SELE was significantly associated with a poorer prognosis and shorter survival in patients with CRC. The median expression level of SELE was significantly higher in CRC tissues compared with healthy adjacent tissue. Cox regression analysis showed that the prognosis of CRC was significantly correlated with the expression of SELE. Immunohistochemical analysis also showed that positive expression of E-selectin increased significantly in line with increasing TNM stage.Conclusion: This study confirmed that SELE gene expression is an independent prognostic factor in patients with CRC.

Lessons to Learn for Adequate Targeted Therapy Development in Metastatic Colorectal Cancer Patients

Insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase that regulates cell growth and proliferation. Upregulation of the IGF1R pathway constitutes a common paradigm shared with other receptor tyrosine kinases such as EGFR, HER2, and MET in different cancer types, including colon cancer. The main IGF1R signaling pathways are PI3K-AKT and MAPK-MEK. However, different processes, such as post-translational modification (SUMOylation), epithelial-to-mesenchymal transition (EMT), and microenvironment complexity, can also contribute to intrinsic and acquired resistance. Here, we discuss new strategies for adequate drug development in metastatic colorectal cancer patients.

Practices and expectations on the use of circulating tumor DNA in colorectal cancer patients: A bi-national AGEO/AIOM/GERCOR/FFCD/FRENCH survey

BACKGROUND

Increasing evidence shows that circulating tumor DNA (ctDNA) is a valuable tool in providing molecular, prognostic, predictive and dynamic information in colorectal cancer (CRC) patients. This study aimed to make a picture of knowledge, practice, attitudes and expectations about ctDNA in CRC patients.

MATERIAL AND METHODS

An online CRC-ctdna survey was distributed from November 2019 to January 2020 to French and Italian cooperative and scientific groups of Hepato-Gastroenterologists (HGE), Medical Oncologists (MO), Radiotherapists (RT) and Digestive Surgeons (DS).

RESULTS

Overall, 307 physicians completed the survey (57% Italian; 43% French). Most of them were MO (62%) and HGE (24%). Affiliations were University Hospital (48%), Cancer Center (21%), General Hospital (21%) and Private Hospital (10%). Notably, half of respondents declared to have access to ctDNA in their daily practice. Of them, 53% uses ctDNA to assess RAS/BRAF status only, 46% for RAS/BRAF with other mutations and 1% only for other mutations. MO and HGE identified quick RAS profiling (P = 0.031) as the main reason of interest in the use of ctDNA. Physicians from University Hospitals and Cancer Centers prescribed more ctDNA (P < 0.001) and more often in house (P < 0.001). The main future expectations concerning ctDNA were to guide therapeutic strategies in metastatic (78%) and adjuvant (73%) settings, and to better/quicker profile disease at baseline (56%).

CONCLUSION

Half of participants can order ctDNA in their daily practice. Molecular profiling of metastatic patients remains the main goal of ctDNA use and ctDNA-based therapeutic strategies are an expectation for the future in both adjuvant and metastatic settings.

Liquid Biopsy for Prognosis and Treatment in Metastatic Colorectal Cancer: Circulating Tumor Cells vs Circulating Tumor DNA

Liquid biopsy recently gained widespread attention as a noninvasive alternative/complementary technique to tissue biopsy in patients with cancer. As technological advances have improved both feasibility and turnaround time, liquid biopsy has expanded tumor molecular analysis with acknowledgement of both spatial and temporal heterogeneity, overcoming many limitations of traditional tissue biopsy. Because of its diagnostic, prognostic, and predictive value, liquid biopsy has been extensively studied also in metastatic colorectal cancer. Indeed, as personalized medicine establishes its role in cancer treatment, genetic biomarkers unveiling the emergence of early resistance are needed. Among the wide variety of tumor analytes amenable to collection, circulating DNA and circulating tumor cells are the most adopted approaches, and both carry clinical relevance in colorectal cancer. However, few studies focused on comparing feasibility between these two approaches. In this review, we discuss the potential implications of liquid biopsy in metastatic colorectal cancer, assessing the advantages and drawbacks of circulating DNA and circulating tumor cells, and highlighting the most relevant trials for clinical practice.

Discordance of KRAS Mutational Status between Primary Tumors and Liver Metastases in Colorectal Cancer: Impact on Long-Term Survival Following Radical Resection

Simple Summary

KRAS mutational heterogeneity between primary colorectal cancer and liver metastases may present a challenge in assessing prognostic information prior to the multimodal treatment. Aim of our study is to assess the incidence of KRAS discordance in a single-center series by comparing primary colorectal tumor specimens with the corresponding liver metastasis. Mutation analyses in all patients were performed at the same institution. Impact of discordance on overall survival and risk factors associated with discordance were analyzed. Our study showed that KRAS discordance was observed in 15.9% of patients. In patients with wild-type colorectal primary tumors, subsequent acquisition of mutation in the corresponding liver metastasis was associated with worse overall survival and was significantly more frequently found in patients with multiple liver metastases. These results suggested that, in the era of precision medicine, the possibility of KRAS discordance should be taken into account within the multidisciplinary management of patients with metastatic colorectal cancer.

Abstract

If KRAS mutation status of primary colorectal tumor is representative of corresponding colorectal liver metastases (CRLM) mutational pattern, is controversial. Several studies have reported different rates of KRAS discordance, ranging from 4 to 32%. Aim of this study is to assess the incidence of discordance and its impact on overall survival (OS) in a homogenous group of patients. KRAS mutation status was evaluated in 107 patients resected for both primary colorectal tumor and corresponding CRLM at the same institution, between 2007 and 2018. Discordance rate was 15.9%. Its incidence varied according to the time interval between the two mutation analyses (p = 0.025; Pearson correlation = 0.2) and it was significantly higher during the first 6 months from the time of primary tumor evaluation. On multivariable analysis, type of discordance (wild-type in primary tumor, mutation in CRLM) was the strongest predictor of poor OS (p < 0.001). At multivariable logistic regression analysis, the number of CRLM >3 was an independent risk factor for the risk of KRAS discordance associated with the worst prognosis (OR = 4.600; p = 0.047). Results of our study suggested that, in the era of precision medicine, possibility of KRAS discordance should be taken into account within multidisciplinary management of patients with metastatic colorectal cancer.

Patient demographics and management landscape of metastatic colorectal cancer in the third-line setting: Real-world data in an australian population

BACKGROUND

Colorectal cancer is the third most common cancer and second leading cause of cancer mortality in Australia, thus carrying a significant disease burden.

AIMS

This analysis aims to explore real-world treatment landscape of metastatic colorectal cancer in the third-line setting.

METHODS

We retrospectively analysed treatment of recurrent and advanced colorectal cancer (TRACC) registry database from 2009 onwards. Patients treated with palliative intent who progressed after two lines of therapies were included. One treatment line was defined as any combination of systemic therapy given until progression.

RESULTS

Out of 1820 patients treated palliatively, 32% (590 patients) met study criteria. Of these, 43% (254 patients) proceeded to third-line therapy, equating to 14% of all metastatic patients. In KRAS mutant or unknown tumours (97 patients), fluoropyrimidine (FP)-oxaliplatin combination was the most common choice (51%), followed by FP-irinotecan (15%), trifluridine/tipiracil (11%), mono-chemotherapy (10%), regorafenib (5%) and others (7%). Majority of FP-doublet (83%) was given as rechallenge. In 157 patients with KRAS wildtype disease, monotherapy with EGFR inhibitor was most commonly used (41%), followed by EGFR inhibitor with chemotherapy (20%), FP-doublet (18%), mono-chemotherapy (6%), trifluridine/tipiracil (6%), regorafenib (1%) and others (8%). Median overall survival was 7.1 months (range 0.4-41.2), and median time on third-line treatment was 3 months (range 0.1-40).

CONCLUSIONS

In real-world Australian population, treatment choices differed based on KRAS status and will likely change with the availability of newer drugs on the pharmaceutical benefits scheme. Survival outcomes are comparable to newer agents in clinical trials for select patients.

Biomarker-Guided Anti-Egfr Rechallenge Therapy in Metastatic Colorectal Cancer

Simple Summary

The survival of patients with metastatic colorectal cancer (mCRC) has been improved over the years and now reaches 30–40 months. However, few therapeutic options are available after failure of first- and second-line treatments. In fact, prognosis of chemo-refractory mCRC remains poor. Therefore, new therapeutic strategies are needed. Emerging evidence suggest that retreatment with epidermal growth factor (EGFR) inhibitors after a treatment break, in patients that obtained a clinical benefit by previous anti-EGFR, could lead to prolonged survival. The rationale beyond this “rechallenge” strategy is that after a “treatment holiday” EGFR resistant cancer cells decay, restoring the sensibility to EGFR blockade. In this review we analyze the current knowledge of retreatment with EGFR inhibitors, examine the role of novel biomarkers that can guide the appropriate selection of patients. Finally, we discuss future perspectives and on-going clinical trials.

Abstract

The prognosis of patients with metastatic colorectal cancer (mCRC) who progressed to the first and the second lines of treatment is poor. Thus, new therapeutic strategies are needed. During the last years, emerging evidence suggests that retreatment with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MAbs) in the third line of mCRC patients, that have previously obtained clinical benefit by first-line therapy with anti-EGFR MAbs plus chemotherapy, could lead to prolonged survival. The rationale beyond this “rechallenge” strategy is that, after disease progression to first line EGFR-based therapy, a treatment break from anti-EGFR drugs results in RAS mutant cancer cell decay, restoring the sensitivity of cancer cells to cetuximab and panitumumab. In fact, rechallenge treatment with anti-EGFR drugs has shown promising clinical activity, particularly in patients with plasma RAS and BRAF wild type circulating tumor DNA, as defined by liquid biopsy analysis at baseline treatment. The aim of this review is to analyze the current knowledge on rechallenge and to investigate the role of novel biomarkers that can guide the appropriate selection of patients that could benefit from this therapeutic strategy. Finally, we discuss on-going trials and future perspectives.

Triple administration of osimertinib followed by chemotherapy for advanced lung adenocarcinoma: A case report

BACKGROUND

Osimertinib is the recommended first-line treatment for adult patients with epidermal growth factor receptor (EGFR) mutation positive advanced or metastatic non-small cell lung cancer (NSCLC). However, primary or acquired resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) seems inevitable, and when drug-resistance occurs during treatment with osimertinib, the standard of care is to discontinue the TKI.

CASE SUMMARY

A 57-year-old female patient with lung adenocarcinoma presented with an irritating cough accompanied by chest distress of one month duration. An enhanced head magnetic resonance imaging scan showed brain metastases. An EGFR mutation (exon 21 L858R) was detected in pleural fluid. The patient was treated with oral osimertinib (80 mg once daily) from January 2018 but developed progressive disease on December 2018. She was then successfully treated with re-challenge and tri-challenge with osimertinib (80 mg once daily) by resensitization chemotherapy twice after the occurrence of drug-resistance to osimertinib, and to date has survived for 31 mo.

CONCLUSION

This case may provide some selective therapeutic options for NSCLC patients with acquired drug-resistance who were previously controlled on osimertinib treatment.

Predictive and prognostic biomarkers with therapeutic targets in colorectal cancer: A 2021 update on current development, evidence, and recommendation

Although therapeutically actionable molecular alterations are widely distributed across many cancer types, only a handful of them show evidence of clinical utility and are recommended for routine clinical practice in the management of cancers of colon and rectum (CRC). This 2021 update aims to provide a succinct summary on the use of prognostic and/or predictive biomarkers (expanded RAS, BRAF, microsatellite-high [MSI-H] or deficient mismatch repair [dMMR], neurotrophic tyrosine receptor kinase [NTRK] fusion genes, and human epidermal growth factor receptor type II [HER2] gene amplification) associated with CRC. Therapeutic implications of each relevant predictive or prognostic biomarker for patients with CRC are described, along with discussion on new developments on (1) biomarker-driven therapies such as testing of BRAF, MLH1 promoter methylation and MMR germline genes in differentiating sporadic CRC or hereditary conditions such as Lynch syndrome; (2) first-line use of immune checkpoint inhibitors in metastatic CRC; (3) risk stratification and therapy selection based on primary tumor location (left-sided vs. right-sided colon cancer); (3) atypical BRAF mutations; (4) use of EGFR directed therapy in the perioperative oligometastatic disease setting; (5) re-challenge of EGFR directed therapy and (6) personalizing therapy of fluoropyrimidine and irinotecan based on new evidence in pharmacogenomic testing. Data are collected and analyzed from available systematic reviews and meta-analyses of treatments with known therapeutic targets in CRC, which may be associated with predictive and/or prognostic biomarkers. Discussions are presented in an application-based format, with goal to empower pharmacists or other clinicians to gain awareness and understanding in biomarker-driven cancer therapy issues.

Association of UGT1A1*6 polymorphism with irinotecan-based chemotherapy reaction in colorectal cancer patients: a systematic review and a meta-analysis

Colorectal cancer (CRC) is a leading cause of cancer-related deaths across the world. Irinotecan (IRI) is commonly used to treat CRC, and IRI-based chemotherapy is linked with adverse reaction and the efficacy of the treatment regimen. The gene UGT1A1 plays a central role in the IRI metabolic pathway. A polymorphism UGT1A1*6 has been widely researched which may be related to response of IRI-based chemotherapy in CRC. All relevant studies were strictly searched from PubMed, Embase, Cochrane Library and Web of Science databases to explore the associations between UGT1A1*6 and response of IRI-based chemotherapy with CRC. Nine articles comprising 1652 patients were included in the final combination. Meta-analysis showed G allele or GG had a lower risk of severe late-onset diarrhea compared with A/AA in allele model and homozygote model (G vs. A: OR = 0.53, 95% CI: 0.28–0.99, P=0.05; GG vs. AA: OR = 0.48, 95% CI: 0.23–0.99, P=0.05), no significant association was observed in other models. In addition, a significant association between UGT1A1*6 and neutropenia was observed in all models (G vs. A: OR = 0.57, 95% CI: 0.46–0.71, P=0.00; GG vs. AA: OR = 0.28, 95% CI: 0.17–0.45, P=0.01; GA vs. AA: OR = 0.42, 95% CI: 0.26–0.70, P=0.00; GG+GA vs. AA: OR = 0.32, 95% CI: 0.20–0.52, P=0.00; GG vs. AA+GA: OR = 0.40, 95% CI: 0.22–0.71, P=0.00), whereas, no relationship was found between UGT1A1*6 and clinical response among the different genotypes. UGT1A1*6 may be considered as a biomarker for IRI-based chemotherapy in CRC.

Applications of liquid biopsy in the Pharmacological Audit Trail for anticancer drug development

Anticancer drug development is a costly and protracted activity, and failure at late phases of clinical testing is common. We have previously proposed the Pharmacological Audit Trail (PhAT) intended to improve the efficiency of drug development, with a focus on the use of tumour tissue-based biomarkers. Blood-based 'liquid biopsy' approaches, such as targeted or whole-genome sequencing studies of plasma circulating cell-free tumour DNA (ctDNA) and circulating tumour cells (CTCs), are of increasing relevance to this drug development paradigm. Liquid biopsy assays can provide quantitative and qualitative data on prognostic, predictive, pharmacodynamic and clinical response biomarkers, and can also enable the characterization of disease evolution and resistance mechanisms. In this Perspective, we examine the promise of integrating liquid biopsy analyses into the PhAT, focusing on the current evidence, advances, limitations and challenges. We emphasize the continued importance of analytical validation and clinical qualification of circulating tumour biomarkers through prospective clinical trials.

Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation-positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

RAS as a positive predictive biomarker: focus on lung and colorectal cancer patients

Rat sarcoma (RAS) oncogenes have intensively been investigated during the last decades. Taking into account all human tumours, Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) gene is the most frequently mutated (about 22%) among the three isoforms, followed by Neuroblastoma RAS Viral Oncogene Homolog (NRAS) (8%) and Harvey Rat Sarcoma Viral Oncogene Homolog (HRAS) (3%). In the last years, careful attention has been paid on KRAS and NRAS gene mutations in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC) patients because of their prognostic and predictive roles. In particular, a large body of literature data has been generated investigating clinical outcomes of targeted treatments in NSCLC and CRC KRAS- and NRAS-mutated patients. The latest evidences are here reviewed, providing also an overview of the real-world RAS mutation testing practice across different Italian laboratories. On this basis, we propose a knowledge-based system, www.rasatlas.com, to support the healthcare personnel in the management of patients featuring RAS gene mutations in the landscape of precision oncology.

Tumor-Associated Macrophages Promote Oxaliplatin Resistance via METTL3-Mediated m6A of TRAF5 and Necroptosis in Colorectal Cancer

As a third-generation platinum drug, oxaliplatin (OX) is widely used as the first-line chemotherapeutic agent in the treatment of colorectal cancer (CRC). CRC cells acquire resistance to chemotherapy and develop resistance, which is a major challenge for the treatment of advanced CRC. Recent studies have suggested that the therapeutic resistance of tumors is affected by the tumor microenvironment (TME). As a critical role among TME, tumor-associated macrophages (TAMs) play an important role. However, their regulatory mechanism underlying the drug resistance in CRC remains largely unknown. In the present study, we found that the density of macrophages infiltrated into the CRC tissues from OX-resistant patients was significantly higher compared with the OX-sensitive patients. Interestingly, both the total N⁶-methyladenosine (m⁶A) RNA content and the expression of its critical methyltransferase METTL3 were increased in the CRC tissues from OX-resistant patients compared with the OX-sensitive patients. Furthermore, we demonstrated that the M2-polarized TAMs enabled the OX resistance via the elevation of METTL3-mediated m⁶A modification in cells. Through whole-genome CRISPR screening and further validation, we found that TRAF5 contributes to the METTL3-triggered OX resistance in CRC cells. This study unveiled that M2-TAMs were important mediators for the acquisition of OX resistance. Furthermore, we provided evidence that targeting of M2-TAMs and METTL3-mediated m⁶A modification might be a promising adjuvant therapeutic strategy for CRC patients, especially for OX-resistant CRC patients.

The Added Value of Baseline Circulating Tumor DNA Profiling in Patients with Molecularly Hyperselected, Left-sided Metastatic Colorectal Cancer

PURPOSE

The routine use of liquid biopsy is not recommended for the choice of initial treatment for patients with metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

We included patients with left-sided, RAS/BRAF wild-type, HER2-negative, and microsatellite stable mCRC, treated with upfront panitumumab/FOLFOX-4 in the Valentino study. We performed amplicon-based genomic profiling of 14 genes in baseline plasma samples and compared these data with tumor tissue ultra-deep sequencing results. Specific gene mutations in circulating tumor DNA (ctDNA) and their clonality were associated with progression-free survival (PFS), overall survival (OS), and radiological dynamics.

RESULTS

Ten and 15 of 120 patients had a mutation of RAS and PIK3CA in ctDNA, with a positive concordance with tissue deep sequencing of only 31.3% and 47.1%, respectively. Presence of RAS or PIK3CA mutations in baseline ctDNA was associated with worse median PFS [8 vs. 12.8 months; HR, 2.49; 95% confidence interval (CI), 1.28-4.81; P = 0.007 and 8.5 vs. 12.9 months; HR, 2.86; 95% CI, 1.63-5.04; P < 0.001] and median OS (17.1 vs. 36.5 months; HR, 2.26; 95% CI, 1.03-4.96; P = 0.042 and 21.1 vs. 38.9 months; HR, 2.18; 95% CI, 1.16-4.07; P = 0.015). RAS mutations in ctDNA were associated with worse RECIST response, early tumor shrinkage, and depth of response, while PIK3CA mutations were not. Patients with higher levels of RAS/PIK3CA variant allele fraction (VAF) in ctDNA had the worst outcomes (VAF ≥ 5% vs. all wild-type: median PFS, 7.7 vs. 13.1 months; HR, 4.02; 95% CI, 2.03-7.95; P < 0.001 and median OS, 18.8 vs. 38.9 months; HR, 4.07; 95% CI, 2.04-8.12; P < 0.001).

CONCLUSIONS

Baseline ctDNA profiling may add value to tumor tissue testing to refine the molecular hyperselection of patients with mCRC for upfront anti-EGFR-based strategies.

Updates on liquid biopsy: current trends and future perspectives for clinical application in solid tumors

Despite advances in screening and therapeutics cancer continues to be one of the major causes of morbidity and mortality worldwide. The molecular profile of tumor is routinely assessed by surgical or bioptic samples, however, genotyping of tissue has inherent limitations: it represents a single snapshot in time and it is subjected to spatial selection bias owing to tumor heterogeneity. Liquid biopsy has emerged as a novel, non-invasive opportunity of detecting and monitoring cancer in several body fluids instead of tumor tissue. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), RNA (mRNA and microRNA), microvesicles, including exosomes and tumor "educated platelets" were recently identified as a source of genomic information in cancer patients which could reflect all subclones present in primary and metastatic lesions allowing sequential monitoring of disease evolution. In this review, we summarize the currently available information concerning liquid biopsy in breast cancer, colon cancer, lung cancer and melanoma. These promising issues still need to be standardized and harmonized across laboratories, before fully adopting liquid biopsy approaches into clinical practice.

Use of Circulating Cell-Free DNA to Guide Precision Medicine in Patients with Colorectal Cancer

Patient-specific biomarkers form the foundation of precision medicine strategies. To realize the promise of precision medicine in patients with colorectal cancer (CRC), access to cost-effective, convenient, and safe assays is critical. Improvements in diagnostic technology have enabled ultrasensitive and specific assays to identify cell-free DNA (cfDNA) from a routine blood draw. Clinicians are already employing these minimally invasive assays to identify drivers of therapeutic resistance and measure genomic heterogeneity, particularly when tumor tissue is difficult to access or serial sampling is necessary. As cfDNA diagnostic technology continues to improve, more innovative applications are anticipated. In this review, we focus on four clinical applications for cfDNA analysis in the management of CRC: detecting minimal residual disease, monitoring treatment response in the metastatic setting, identifying drivers of treatment sensitivity and resistance, and guiding therapeutic strategies to overcome resistance.

Implementing anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer: challenges and future perspectives

Epidermal growth factor receptor (EGFR) inhibitors are valuable therapeutics in metastatic colorectal cancer (mCRC). Anti-EGFR monoclonal antibodies (MoAbs), such as cetuximab or panitumumab, in combination with chemotherapy are effective treatment options for patients with RAS and BRAF wild-type mCRC. Nevertheless, several issues are still open concerning the optimal use of anti-EGFR drugs in the continuum of care of mCRC. Novel approaches for increasing the efficacy of anti-EGFR therapies include better molecular selection of EGFR-dependent mCRC, intensification of chemotherapy, combination of anti-EGFR MoAbs and immune checkpoint inhibitors, and reintroduction of EGFR blockade or 'rechallenge' in selected patients who have previously responded to anti-EGFR MoAb therapy. An extensive translational research program was conducted in the Cetuximab After Progression in KRAS wIld-type colorectal cancer patients-Gruppo Oncologico dell' Italia Meridionale (CAPRI-GOIM) study with the aims of determining which subgroups of patients could benefit from the continuous inhibition of EGFR, from evaluating the role of liquid biopsy-based and its concordance with tissue-based molecular testing, and from investigating novel potential mechanisms of resistance to anti-EGFR therapies. In this review, we summarize the translational and clinical findings of the CAPRI-GOIM program in the context of the current knowledge of therapeutic strategies and of ongoing research on more appropriate uses of anti-EGFR therapies in RAS and BRAF wild-type mCRC patients.

Overcoming Resistance to Targeted Therapies in Gastrointestinal Cancers: Progress to Date and Progress to Come

Targeted therapies have transformed the treatment paradigm in diseases such as non-small cell lung cancer and melanoma but have shown relatively modest clinical benefit in gastrointestinal malignancies. Anti-EGFR therapy in RAS wild-type colorectal cancer, anti-HER2 therapy in HER2- amplified esophagogastric cancer, and FGFR and isocitrate dehydrogenase 1 (IDH1) inhibitors in FGFR2 fusion-positive and IDH1-mutant biliary tract cancers offer antitumor efficacy, but the clinical benefit and durability of response in each case are typically limited. We review targeted therapies in each of these therapeutic areas and discuss their clinical efficacy, mechanisms of primary and acquired resistance, and strategies to overcome this resistance. We discuss lessons learned that we hope will lead to an expanded role for molecularly targeted therapy options for patients with gastrointestinal cancers.

Systemic doxycycline for pre-emptive treatment of anti-EGFR-related skin toxicity in patients with metastatic colorectal cancer receiving first-line panitumumab-based therapy: a post hoc analysis of the Valentino study

INTRODUCTION

The combination of anti-EGFRs and doublet chemotherapy is considered the optimal upfront option for patients with RAS/BRAF wild-type left-sided metastatic colorectal cancer (mCRC). The prophylactic or reactive treatment with tetracyclines for EGFR inhibitor-induced skin toxicity is currently clinical practice, though non-conclusive results are available.

METHODS

We performed a post hoc analysis of the Valentino study that randomized RAS wild-type mCRC patients to two panitumumab-based maintenance regimens after the first-line induction, aimed at assessing the safety and efficacy of the administration of a pre-emptive doxycycline prophylaxis for anti-EGFR-related skin toxicity. We assessed the rate of treatment-related and panitumumab-related adverse events (AEs), treatment intensity, progression-free survival (PFS), and overall survival (OS).

RESULTS

A total of 226 patients, out of the 229 enrolled in the Valentino study, were eligible for the analysis. Overall, 143 (63%) and 83 (37%) patients received or not the antibiotic prophylaxis for skin toxicity. Any grade and G3/4 panitumumab-related AEs were reported in 89% versus 92% (p = 0.650) and 27% versus 27% (p = 1.000) patients who received or not the pre-emptive prophylaxis, respectively. Any grade and G3/4 skin rash occurred in 81% versus 90% (p = 0.085) and 27% versus 25% (p = 0.876) patients receiving or not the prophylaxis, respectively. No significant differences in terms of treatment duration, treatment delays or dose reductions, PFS, and OS were observed in the two sub-populations.

CONCLUSION

The adequate management of anti-EGFR-related skin toxicity is fundamental to optimize the outcome of mCRC patients, balancing the survival benefit with patients' quality of life, especially in the first-line setting.

Sorafenib Rechallenge and Sorafenib after Lenvatinib Failure in a Patient with Hepatocellular Carcinoma

A 70-year-old man was diagnosed with multiple lung metastases from hepatocellular carcinoma, and lenvatinib was initiated. Three months later, the response was progressive disease. Sorafenib therapy as a second-line drug was started. Three months later, the lung metastases had shrunk. After the sorafenib failure, the patient received regorafenib treatment for six months until failure. After the regorafenib failure, sorafenib rechallenge therapy as a fourth-line treatment was initiated. The sorafenib rechallenge, which continued for two months, induced a partial response. Sorafenib after lenvatinib failure and sorafenib rechallenge may be a good option, but further prospective studies are needed.

Safety and efficacy of cetuximab-containing chemotherapy after immune checkpoint inhibitors for patients with squamous cell carcinoma of the head and neck: a single-center retrospective study

Immunotherapy has been shown to prolong survival in recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN) in front-line use; however, subsequent systemic therapy has not been optimized. This study aimed to evaluate the safety and efficacy of cetuximab-containing chemotherapy after immunotherapy. We retrospectively analyzed patients with recurrent or metastatic SCCHN who underwent cetuximab-containing regimens after progression on immunotherapy. Of the 22 patients who met the inclusion criteria, 21 received paclitaxel and cetuximab, and 1 carboplatin and fluorouracil and cetuximab after immunotherapy. Nine patients achieved a partial response, 10 patients had stable disease as their best response on cetuximab-containing chemotherapy, yielding an overall response rate and disease control rate of 40.9 and 86.4%, respectively. The median progression-free survival was 5.2 months, and the median overall survival was 14.5 months. Ten patients developed grade 3-4 adverse events, including neutropenia (31.8%), acneiform rash (9.1%), anemia (4.5%), hypertransaminasemia (4.5%) and stomatitis (4.5%). The most frequent cetuximab-related toxicities across all grades were skin reactions (77.3%), hypomagnesemia (40.9%), stomatitis (27.3%), paronychia (13.6%) and keratitis (4.5%). There was no treatment-related death. Taken together, cetuximab-containing chemotherapy was effective and feasible even after immunotherapy.

Clinical Utility of Plasma KRAS, NRAS and BRAF Mutational Analysis with Real Time PCR in Metastatic Colorectal Cancer Patients-The Importance of Tissue/Plasma Discordant Cases

BACKGROUND

Tumor tissue (T) mutational analysis represents the standard for metastatic colorectal cancer (mCRC); however, circulating tumor DNA (ctDNA) detected by liquid biopsy in plasma (PL) can better represent tumor heterogeneity.

METHODS

mCRC patients undergoing standard first-line chemotherapy with known T-KRAS/NRAS/BRAF status were enrolled in the present prospective study. PL mutations were assessed within 2 weeks before chemotherapy start with real time PCR and correlated with T status and Progression free survival (PFS). Clinical and biochemical variables including also total number of tumor lesions (TNL) and the sum of maximum diameter (SMD) of all lesions were assessed as potential predictors of T/PL discordance.

RESULTS

Among 45 enrolled patients, all BRAF mutations were concordant between T and PL and there were 20% of patients RAS discordant: 9% wild type in T and mutated in PL and 11% mutated in T and wild type in PL. T mutations were significantly associated to median PFS (mPFS of 4.5, 8.3 and 22.9 months for T-BRAF mutated, T-RAS mutated, and T-wild type patients, respectively, p for trend 0.00014). PL mutations further refined prognosis: RAS wild type in T and mutated in PL had significantly shorter PFS than concordant RAS wild type in T and PL: mPFS 9.6 vs. 23.3 months, respectively, p = 0.02. Patients RAS mutated in T and wild type in PL had longer PFS than concordant RAS mutated in T and PL: 24.4 vs. 7.8 months, respectively, p = 0.008. At a multivariate cox regression analysis for PFS, PL mutations were independent prognostic factor superior to T analysis (HR 0.13, p = 0.0008). At multivariate logistic regression analysis TNL and SMD were significant predictors of discordant cases.

CONCLUSIONS

PL mutational analysis allows a better prognostication than T analysis alone and could help in mCRC treatment management.

Previous Use of Anti-Vascular Endothelial Growth Factor Receptor Agents Decreases Efficacy of Fruquintinib in Metastatic Colorectal Cancer Refractory to Standard Therapies

Purpose

Fruquintinib is an anti-vascular endothelial growth factor receptor (VEGFR) agent. The FRESCO trial demonstrated that patients with metastatic colorectal cancer (mCRC) refractory to standard therapies could benefit from fruquintinib with tolerable adverse events (AEs). However, the efficacy and safety of fruquintinib in clinical practice has scarcely been reported, especially in patients with previous use of anti-VEGFR agents.

Methods

This retrospective study investigated the efficacy and safety of fruquintinib in patients with mCRC between January 2019 and December 2019. Progression-free survival (PFS) and overall survival (OS) were assessed by a Kaplan-Meier analysis and log-rank test. A Cox regression model was performed to identify independent prognostic factors.

Results

A total of 46 patients were included. The median PFS and OS were 3.1 months (95% confidence interval [CI], 1.9–4.3 months) and 9.0 months (95% CI, 7.2–10.8 months), respectively. Patients previously treated with anti-VEGFR agents had shorter median PFS compared with those without previous use of anti-VEGFR agents (1.9 vs. 3.7 months, P = 0.006), while the median OS was similar between the two groups (8.5 vs. 9.0 months, P = 0.992). Multivariate analysis revealed that the neutrophil-lymphocyte ratio (NLR) was an independent prognostic factor in PFS (hazard ratio [HR], 2.230; 95% CI, 1.191–4.517, P = 0.014) and OS (HR, 4.221; 95% CI, 1.683–10.586; P = 0.002). The most common non-hematological and hematological AEs were hand-foot syndrome (37.0%) and anemia (39.1%), respectively.

Conclusion

Fruquintinib was an effective third-line therapy in mCRC with tolerable AEs. Efficacy of fruquintinib was decreased in patients with previous use of anti-VEGFR agents. NLR was an independent prognostic factor in PFS and OS in patients treated with fruquintinib.

Phase 2 study of irinotecan plus cetuximab rechallenge as third-line treatment in KRAS wild-type metastatic colorectal cancer: JACCRO CC-08

BACKGROUND

Regorafenib or trifluridine/tipiracil as third-line treatment have limited efficacy in metastatic colorectal cancer (mCRC).

METHODS

This Phase 2 trial evaluated the efficacy and safety of irinotecan plus cetuximab rechallenge as third-line treatment in KRAS wild-type mCRC patients who achieved clinical benefit with first-line cetuximab-containing therapy. The primary endpoint was 3-month progression-free survival (PFS) rate. A sample size was calculated; 30 patients with a 3-month PFS rate of 45% deemed promising and 15% unacceptable. Patients with greater and less than the cut-off value of cetuximab-free intervals (CFIs) were classified into the long and short CFI groups, respectively, in subgroup analyses.

RESULTS

Among 34 eligible patients who received treatment at least once, 3-month PFS rate was 44.1% (95% confidence interval, 27.4-60.8%). The median PFS and overall survival (OS) were 2.4 and 8.2 months, respectively. The response and disease control rates were 2.9 and 55.9%, respectively. PFS and OS were significantly longer in the long- than in the short CFI group.

CONCLUSIONS

Irinotecan plus cetuximab rechallenge as third-line treatment for KRAS wild-type mCRC was safe and had promising activity, especially in those with a long CFI, warranting further investigation in a Phase 3 randomised trial.

CLINICAL TRIAL REGISTRATION

UMIN000010638.

RAS Mutations in Circulating Tumor DNA and Clinical Outcomes of Rechallenge Treatment With Anti-EGFR Antibodies in Patients With Metastatic Colorectal Cancer

PURPOSE

Several trials have evaluated the efficacy of rechallenge treatment with anti–epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) in patients with metastatic colorectal cancer (mCRC). A recent trial indicated that RAS status in circulating tumor DNA (ctDNA) may potentially predict patients with RAS wild-type mCRC resistant to anti-EGFR mAb who would benefit from rechallenge treatment, and the findings should be further investigated.

MATERIAL AND METHODS

We enrolled patients whose plasma samples were collected in prospective phase II trials, the JACCRO CC-08 (n = 36) and CC-09 (n = 25), which evaluated rechallenge chemotherapy with anti-EGFR mAb for KRAS wild-type mCRC. RAS in ctDNA was analyzed at the time points of baseline, 8 weeks, and progression using OncoBEAM RAS CRC kit.

RESULTS

Sixteen patients were enrolled in this study, with a response rate of 0% and a disease control rate (DCR) of 62.5%. RAS mutations were found at baseline in six patients. The DCR was 33% in patients with RAS mutations in ctDNA, whereas it was 80% in patients without RAS mutation at baseline. Patients with RAS mutation at baseline had significantly shorter progression-free survival (PFS) and overall survival (OS) than those without RAS mutation (median PFS, 2.3 v 4.7 months; hazard ratio [HR], 6.2; P = .013; median OS, 3.8 v 16.0 months; HR, 12.4; P = .0028). Six of 10 patients without RAS mutation at baseline acquired RAS mutations at progression. Postprogression survival after rechallenge treatment was numerically shorter in patients with RAS mutation at progression.

CONCLUSION

RAS status in ctDNA was significantly associated with clinical outcomes in patients with mCRC receiving rechallenge treatment with anti-EGFR mAb. These findings could support the clinical utility of OncoBEAM RAS CRC kits for anti-EGFR mAb rechallenge in RAS wild-type mCRC.

Redefining Colorectal Cancer by Tumor Biology

Colorectal cancer treatment has undergone a paradigm shift. We no longer see this disease as a singular, anatomic tumor type but rather a set of disease subgroups. Largely because of a better understanding of cancer biology and the introduction and integration of molecular biomarkers-the premise of precision therapy-we are beginning to direct treatments toward the right tumor target(s) in the right patients. The field of molecular profiling is continually evolving, and new biomarkers are constantly being discovered that have investigational, therapeutic, and/or prognostic implications-negative or positive. To date, only a few biomarkers have sufficient actionable, clinical implication to earn international guideline-recommended routine testing. Hence, it is vital that the treating oncologist should know which biomarkers to assess, when in the treatment course to test for them, and how the test is to be done. Correct interpretation of profiling results is imperative. Herein, we focus on international guideline-recommended mutation testing for patients prior to their colorectal cancer treatment initiation. The clinical applications of circulating tumor DNA (ctDNA) in patients with metastatic disease, based on our current knowledge and capabilities, are also addressed.

Expanded Low Allele Frequency RAS and BRAF V600E Testing in Metastatic Colorectal Cancer as Predictive Biomarkers for Cetuximab in the Randomized CO.17 Trial

PURPOSE

Expanded RAS/BRAF mutations have not been assessed as predictive for single-agent cetuximab in metastatic colorectal cancer (mCRC), and low mutant allele frequency (MAF) mutations are of unclear significance. We aimed to establish cetuximab efficacy in optimally selected patients using highly sensitive beads, emulsion, amplification, and magnetics (BEAMing) analysis, capable of detecting alterations below standard clinical assays.

PATIENTS AND METHODS

CO.17 trial compared cetuximab versus best supportive care (BSC) in RAS/BRAF-unselected mCRC. We performed RAS/BRAF analysis on microdissected tissue of 242 patients in CO.17 trial using BEAMing for KRAS/NRAS (codons 12/13/59/61/117/146) and BRAF V600E. Patients without BEAMing but with previous Sanger sequencing-detected mutations were included.

RESULTS

KRAS, NRAS, and BRAF mutations were present in 53%, 4%, and 3% of tumors, respectively. Cetuximab improved overall survival [OS; HR, 0.51; 95% confidence interval (CI), 0.32-0.81; P = 0.004] and progression-free survival (PFS; HR, 0.25; 95% CI, 0.15-0.41; P < 0.0001) compared with BSC in RAS/BRAF wild-type patients. Cetuximab did not improve OS/PFS for KRAS-, NRAS-, or BRAF-mutated tumors, and tests of interaction confirmed expanded KRAS (P = 0.0002) and NRAS (P = 0.006) as predictive, while BRAF mutations were not (P = 0.089). BEAMing identified 14% more tumors as RAS mutant than Sanger sequencing, and cetuximab lacked activity in these patients. Mutations at MAF < 5% were noted in 6 of 242 patients (2%). One patient with a KRAS A59T mutation (MAF = 2%) responded to cetuximab. More NRAS than KRAS mutations were low MAF (OR, 20.50; 95% CI, 3.88-96.85; P = 0.0038).

CONCLUSIONS

We establish single-agent cetuximab efficacy in optimally selected patients and show that subclonal RAS/BRAF alterations are uncommon and remain of indeterminate significance.

Rechallenge with Anti-EGFR Therapy in Metastatic Colorectal Cancer (mCRC): Results from South Australia mCRC Registry

BACKGROUND

Anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (cetuximab or panitumumab) are today increasingly used in the first- or second-line setting for RAS wild-type metastatic colorectal cancer (CRC) patients. Following progression beyond third- or fourth-line therapy, some patients are unsuitable for further chemotherapy because of poor performance status or patient choice. However, a significant number of patients are still candidates for further therapy despite limited standard options being available. The role of rechallenge with anti-EGFR therapy, particularly in patients who had previously responded, is often considered, but there is limited evidence in the literature to support such a strategy.

OBJECTIVE

This retrospective study aims to review the outcome of metastatic CRC patients who had anti-EGFR rechallenge.

PATIENTS AND METHODS

Patients who had been rechallenged with anti-EGFR therapy were identified from the South Australian metastatic CRC database. Patient characteristics were recorded and tumor response was retrospectively assessed using Response Evaluation Criteria in Solid Tumors (RECIST). Kaplan-Meier analysis was used to assess progression free survival (PFS) for each rechallenge and overall survival (OS).

RESULTS

Twenty-two patients were eligible for inclusion in this analysis. Disease control rate (stable disease and partial response) was 45.4% (ten patients) for patients who received rechallenge anti-EGFR. Seven patients received a second rechallenge and disease control rate was 28.6% (two patients). The median interval time between initial anti-EGFR therapy and rechallenge was 13.5 months. The median PFS after rechallenge 1 was 4.1 months and after rechallenge 2 was 3.5 months. The median OS was 7.7 months from date of rechallenge.

CONCLUSIONS

Anti-EGFR rechallenge provides clinical benefit in patients with RAS wild-type metastatic CRC.

Validation of the Colon Life nomogram in patients with refractory metastatic colorectal cancer enrolled in the RECOURSE trial

BACKGROUND

The RECOURSE trial (Study of TAS-102 in Patients With Metastatic Colorectal Cancer Refractory to Standard Chemotherapies) demonstrated an overall survival (OS) benefit of trifluridine/tipiracil (FTD/TPI) vs placebo in refractory metastatic colorectal cancer (mCRC). Given the limited benefit of later line treatments, we developed the Colon Life nomogram to assess the 12-week death probability in the refractory setting.

METHODS

This post hoc analysis of RECOURSE included patients with available data to calculate the nomogram score: Eastern Cooperative Oncology Group Performance Status, primary tumor resection, lactate dehydrogenase, and peritoneal metastases. The nomogram calibration was assessed by calibration plots and C-index. The nomogram prognostic and predictive ability was assessed by Cox model analyses and the nomogram score predictive value was explored according to the cutoff identified at maximum value of the Youden index in time-dependent receiver operating characteristic curve analysis.

RESULTS

Overall, 251 trial patients were evaluable: 90 in the placebo arm and 161 in the FTD/TPI arm. The calibration was optimal in the placebo arm (C-index 0.807) and suboptimal in the FTD/TPI arm (0.657). The cutoff of the nomogram score of 23 showed the best discriminative ability for 12-week OS (hazard ratio 3.46, 95% confidence interval 2.17-5.51 for scores 40 vs 15) and had maximum value of the Youden index (0.381). Median OS and 3-month PFS were 9.0 vs 7.5 months and 39.3% vs 5.2%, respectively, for FTD/TPI vs placebo in the low-risk group (score <23) and 4.8 vs 3.4 months and 22.3% vs 9.8% in the high-risk group (score ⩾23) (interaction NS).

CONCLUSION

The Colon Life nomogram is an accurate tool for estimating life expectancy in refractory mCRC. The benefit of FTD/TPI was independent of the predicted risk of early death.

Liquid Biopsy as a Tool Exploring in Real-Time Both Genomic Perturbation and Resistance to EGFR Antagonists in Colorectal Cancer

The treatment of metastatic colorectal cancer (mCRC) has improved since the introduction of the epithelial growth factor receptor (EGFR) inhibitors as cetuximab and panitumumab. However, only patients with peculiar genomic profiles benefit from these targeting therapies. In fact, the molecular integrity of RAS genes is a predominant factor conditioning both primary and acquired resistance in non-responders although additional molecular derangements induced by selective anti-EGFR pressure may concur to the failure of those disease treatment, liquid biopsy (LB) appears as a surrogate of tissue biopsy, provides the genomic information to reveal tumor resistance to anti-EGFR agents, the detection of minimal residual disease before adjuvant therapies, and the discovery of tumor molecular status suitable for rechallenging treatments with EGFR antagonists. LB investigates circulating tumor cells (CTCs), cell-free tumor DNA (ctDNA), and tumor-derived exosomes. In mCRC, ctDNA analysis has been demonstrated as a useful method in the mutational tracking of defined genes as well as on tumor burden and detection of molecular alterations driving the resistance to anti-EGFR targeting treatments. However, despite their efficiency in molecular diagnosis and prognostic evaluation of mCRC, the affordability of these procedures is prevalently restricted to research centers, and the lack of consensus validation prevents their translation to clinical practice. Here, we revisit the major mechanisms responsible for resistance to EGFR blockade and review the different methods of LB potentially useful for treatment options in mCRC.

ctDNA as a cancer biomarker: A broad overview

Circulating tumor DNA (ctDNA) in fluids has gained attention because ctDNA seems to identify tumor-specific abnormalities, which could be used for diagnosis, follow-up of treatment, and prognosis: the so-called liquid biopsy. Liquid biopsy is a minimally invasive approach and presents the sum of ctDNA from primary and secondary tumor sites. It has been possible not only to quantify the amount of ctDNA but also to identify (epi)genetic changes. Specific mutations in genes have been identified in the plasma of patients with several types of cancer, which highlights ctDNA as a possible cancer biomarker. However, achieving detectable concentrations of ctDNA in body fluids is not an easy task. ctDNA fragments present a short half-life, and there are no cut-off values to discriminate high and low ctDNA concentrations. Here, we discuss the use of ctDNA as a cancer biomarker, the main methodologies, the inherent difficulties, and the clinical predictive value of ctDNA.

Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, 4th edition

Molecular testing to select the appropriate targeted and standard of care therapies is essential for managing patients with colorectal cancer (CRC). The Japanese Society of Medical Oncology previously published clinical guidelines for molecular testing in CRC. In the third edition published in 2018, RAS and BRAF V600E mutations should be tested prior to first‐line chemotherapy to assess the benefit of anti–epidermal growth factor receptor (EGFR) antibody therapy in patients with unresectable CRC. Microsatellite instability (MSI) testing was recommended in patients with curatively resected stage II CRC because deficient mismatch repair is associated with low risk of recurrence. MSI testing was also recommended in patients with CRC suspected to be Lynch syndrome. The main aim of this fourth edition is to reflect recent advances in comprehensive genomic profiling (CGP) tests and liquid biopsy. Here, CGP tests performed on tumor tissues are strongly recommended to assess the benefit of molecular targeted drugs in patients with CRC. Circulating tumor DNA (ctDNA)‐based CGP tests are also proposed. ctDNA testing is recommended to determine the optimal treatment based on the risk of recurrence for curatively resected CRC and evaluate the suitability and monitor the therapeutic effects of anti–EGFR antibodies in patients with unresectable CRC. While both MSI testing and immunohistochemistry are strongly recommended to determine the indication of immune checkpoint inhibitors in patients with unresectable CRC, next‐generation sequencing‐based tests are weakly recommended because these tests have not been validated in clinical trials.

ctDNA Concentration, MIKI67 Mutations and Hyper-Progressive Disease Related Gene Mutations Are Prognostic Markers for Camrelizumab and Apatinib Combined Multiline Treatment in Advanced NSCLC

Immunotherapy by immune checkpoint inhibitors (ICIs) has showed outstanding efficacy in the treatment of advanced non-small cell lung cancer (NSCLC). The combination of immunotherapy with anti-angiogenic therapy exhibited enhanced efficacy in multiline treatment. However, the potential biomarkers for predicting and monitoring the therapeutic response of the combined therapy remain undefined. In this study, we performed a pilot study by prospectively recruiting 22 advanced NSCLC patients who failed to previous lines of chemotherapy, chemoradiotherapy, TKI therapy, surgery, or any combination of the therapies, and investigated the prognostic factors for patients who received anti-PD-1 (Camrelizumab) and anti-angiogenic (Apatinib) combined therapy. The objective response rate (ORR) assessed by an independent radiology review was 22.7%, and the median progression-free survival (PFS) was 5.25 months. We found that high concentration of circulating-free DNA (cfDNA) (HR = 27.75, P = 0.003), MIKI67 mutation (HR = 114.11, P = 0.009) and gene variations related to hyper-progressive disease (HPD) (HR = 36.85, P = 0.004) were independent risk factors and exhibited significant correlation with PFS. Circulating tumor DNA (ctDNA) mutational status was also a predicting indicator for PFS. In contrast, the blood tumor mutational burden (bTMB) could not stratify the clinical benefit in this combined therapy (HR = 0.81, P = 0.137). Furthermore, we found that the variant allele fraction (VAF) of mutations in ctDNA was sensitive indicators of therapeutic response and therefore can be used to monitor the tumor relief or progression. In conclusion, cfDNA concentration, MIKI67 mutations and HPD-related mutations were independent risk factors and PFS predictors for multiline combined anti-angiogenic/ICI combined therapy. ctDNA may be a novel monitoring biomarker for therapeutic response and predicting biomarker for prognosis in future combined therapy involving PD-1 blockade.

Molecular Targets for the Treatment of Metastatic Colorectal Cancer

Over the past years, colorectal cancer (CRC) was subtyped according to its molecular and genetic characteristics, allowing the development of therapeutic strategies, based on predictive biomarkers. Biomarkers such as microsatellite instability (MSI), RAS and BRAF mutations, HER2 amplification or NTRK fusions represent major tools for personalized therapeutic strategies. Moreover, the routine implementation of molecular predictive tests provides new perspectives and challenges for the therapeutic management of CRC patients, such as liquid biopsies and the reintroduction of anti-EGFR monoclonal antibodies. In this review, we summarize the current landscape of targeted therapies for metastatic CRC patients, with a focus on new developments for EGFR blockade and emerging biomarkers (MSI, HER2, NTRK).

Immune Checkpoint Inhibitors in pMMR Metastatic Colorectal Cancer: A Tough Challenge

The introduction of checkpoint inhibitors provided remarkable achievements in several solid tumors but only 5% of metastatic colorectal cancer (mCRC) patients, i.e., those with bearing microsatellite instable (MSI-high)/deficient DNA mismatch repair (dMMR) tumors, benefit from this approach. The favorable effect of immunotherapy in these patients has been postulated to be due to an increase in neoantigens due to their higher somatic mutational load, also associated with an abundant infiltration of immune cells in tumor microenvironment (TME). While in patients with dMMR tumors checkpoint inhibitors allow achieving durable response with dramatic survival improvement, current results in patients with microsatellite stable (MSS or MSI-low)/proficient DNA mismatch repair (pMMR) tumors are disappointing. These tumors show low mutational load and absence of "immune-competent" TME, and are intrinsically resistant to immune checkpoint inhibitors. Modifying the interplay among cancer cells, TME and host immune system is the aim of multiple lines of research in order to enhance the immunogenicity of pMMR mCRC, and exploit immunotherapy also in this field. Here, we focus on the rationale behind ongoing clinical trials aiming at extending the efficacy of immunotherapy beyond the MSI-high/dMMR subgroup with particular regard to academic no-profit studies.

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.

How we treat metastatic colorectal cancer

Colorectal cancer is the second leading cause of cancer-related death worldwide. About 20% of patients suffer from metastatic disease at diagnosis, while about one-third of patients treated with curative intent relapsed. In these patients, an accurate staging allows to plan a treatment strategy within a multidisciplinary team in order to achieve predefined goals. Patient's clinical features, tumour characteristics and molecular profile (RAS/BRAF and microsatellite instability (MSI) status) should be considered during the treatment choice. Combination of chemotherapy (fluoropyrimidines, oxaliplatin and irinotecan) plus biological agents (antiepidermal growth factor receptor or antiangiogenic drugs) in addition to surgery, could give a chance of cure in resectable or potentially resectable tumours. However, in never resectable tumours, disease control and prolonging survival should be the goal to achieve simultaneously with control of symptoms. In addition to standard therapies, especially in case of unresectable oligometastatic disease, several local ablative treatment are available. In later lines, when improving quality of life become predominant, regorafenib and trifluridine/tipiracil demonstrated survival benefit, while re-challenge therapies represent an option only in selected patients. In patients with BRAFV600E-mutant tumour or with MSI, new therapies showed survival gain and probably will be a new piece in the treatment algorithm.

Molecular subtypes and the evolution of treatment management in metastatic colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease representing a therapeutic challenge, which is further complicated by the common occurrence of several molecular alterations that confer resistance to standard chemotherapy and targeted agents. Mechanisms of resistance have been identified at multiple levels in the epidermal growth factor receptor (EGFR) pathway, including mutations in KRAS, NRAS, and BRAF V600E, and in the HER2 and MET receptors. These alterations represent oncogenic drivers that may co-exist in the same tumor with other primary and acquired alterations via a clonal selection process. Other molecular alterations include DNA damage repair mechanisms and rare kinase fusions, potentially offering a rationale for new therapeutic strategies. In recent years, genomic analysis has been expanded by a more complex study of epigenomic, transcriptomic, and microenvironment features. The Consensus Molecular Subtype (CMS) classification describes four CRC subtypes with distinct biological characteristics that show prognostic and potential predictive value in the clinical setting. Here, we review the panorama of actionable targets in CRC, and the developments in more recent molecular tests, such as liquid biopsy analysis, which are increasingly offering clinicians a means of ensuring optimal tailored treatments for patients with metastatic CRC according to their evolving molecular profile and treatment history.

Evolution of RAS Mutational Status in Liquid Biopsies During First-Line Chemotherapy for Metastatic Colorectal Cancer

Treatment options for patients with metastatic colorectal cancer (mCRC) are limited. This particularly affects the largest group of patients with RAS mutations, who are considered ineligible for therapy with antiEGFR antibodies. In this liquid biopsy-based study, we performed the first in-depth analysis of the RAS mutational status in initially RAS-mutated patients during first-line therapy. RAS status of twelve patients with initially RAS-mutated mCRC was monitored longitudinally in 69 liquid biopsy samples. We focused on patients with stable disease (SD) or partial remission (PR) during first-line therapy (11 patients). Detection of fragmented RAS-mutated circulating cell-free tumor DNA (ctDNA) in plasma was performed by digital-droplet PCR (ddPCR) and BEAMing. Patients' total tumor masses were determined by measuring the tumor volumes using CT scan data. All patients with PR or SD at first follow-up showed a significant decrease of RAS mutational load. In ten patients (91%), the ctDNA-based RAS mutational status converted to wild-type in ddPCR and BEAMing. Remarkably, conversions were observed early after the first cycle of chemotherapy. Plasma concentration of ctDNA was controlled by determination of methylated WIF1-promotor ctDNA burden as a second tumor marker for mCRC. Persistent presence of methylated WIF1-promotor fragments confirmed the ongoing release of ctDNA during treatment. In patients with initially RAS-mutated mCRC, RAS mutations rapidly disappeared during first-line therapy in liquid biopsy, independent of type and intensity of chemotherapy and irrespective of anti-VEGF treatments. Following our results demonstrating conversion of RAS-mutational status, potential effectiveness of anti-EGFR antibodies in selected patients becomes an attractive hypothesis for future studies.

Refractory Metastatic Colorectal Cancer: Current Challenges and Future Prospects

Despite advances, patients with metastatic colorectal cancer (mCRC) still have poor long-term survival. Identification of molecular subtypes is important to guide therapy through standard treatment pathways and holds promise for the development of new treatments. Following standard first- and second-line chemotherapy plus targeted agents, many patients retain a reasonable performance status, and thus are seeking further effective treatment to extend life and maintain symptom control. The challenge lies in selecting the most appropriate therapy in the third- and fourth-line settings, from a range of options including the relatively new oral agents TAS-102 and regorafenib, or rechallenge with previous chemotherapy or anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies (mAB). Beyond this, therapy consists of trials involving novel agents and new combinations of treatments with theoretical synergy and/or non-overlapping toxicity. There is a great focus on enhancing immunogenicity in mCRC, to reflect the impressive results of immunotherapy drugs in the small cohort with mismatch repair deficient (dMMR) mCRC. Rare molecular subtypes of mCRC are increasingly being identified, including Her2-positive disease, NTRK fusions and others. Clinical trials exploring the efficacy of immunomodulatory and precision agents are plentiful and will hopefully yield clinically meaningful results that can be rapidly translated into routine care.

Readministration of Cancer Drugs in a Patient with Chemorefractory Metastatic Colorectal Cancer

A 63-year-old woman was admitted to our institution for severe pain in her right lower abdomen caused by the perforation of cecal cancer. She underwent emergency surgery, from which she was diagnosed with cecal carcinoma with liver, lung, and lymph node metastases. As she was taking aspirin to prevent cerebral infarction, anti-vascular endothelial growth factor (receptor) antibody and regorafenib therapy were not used. Thus, we started a modified FOLFOX 6+cetuximab regimen. This first-line treatment initially achieved a partial response (PR), but she then developed progressive disease (PD) after 14 months. We changed the regimen to FOLFIRI, followed by trifluridine/tipiracil, but her progression-free survival periods were 2.7 months and 1 month, respectively. Although we cycled through the available array of standard cancer drugs, the patient showed a good performance status, and some benefit from treatment still seemed plausible. We readministered the 5-fluorouracil oral preparation S-1, which maintained stable disease (SD) for 7 months. After PD emerged, we readministered the anti-epidermal growth factor receptor (EGFR) antibody panitumumab for 7.5 months of SD. Finally, 39 months after her diagnosis, she died from rapidly progressing disease. However, her relatively long survival implies that readministering drugs similar to those used in previous regimens might benefit patients with metastatic colorectal cancer.

Trifluridine/tipiracil: A practical guide to its use in the management of refractory metastatic colorectal cancer in Australia

Trifluridine/tipiracil is available on the Australian Pharmaceutical Benefits Scheme for the treatment of patients with metastatic colorectal cancer (mCRC) previously treated with, or not considered candidates for, fluoropyrimidine-, oxaliplatin- and irinotecan-based chemotherapies, anti-vascular endothelial growth factor agents and anti-epidermal growth factor receptor agents. This article reviews trifluridine/tipiracil clinical data and presents practical information on its use in the management of refractory mCRC in Australia. Whereas the primary mechanism of action of fluoropyrimidines such as fluorouracil (5-FU) and capecitabine is enzyme inhibition of nucleotide synthesis, trifluridine/tipiracil primarily acts by incorporation into DNA, resulting in DNA dysfunction. Trifluridine/tipiracil has activity in patients with 5-FU-resistant tumors and can be considered in patients with prior intolerance or toxicity to 5-FU. In the pivotal phase III RECOURSE trial evaluating trifluridine/tipiracil in chemotherapy-refractory mCRC, efficacy benefits were observed across all a priori prognostic subgroups including those defined by age (≥65 and ≥75 years), geographical origin, primary tumor site or KRAS status. Trifluridine/tipiracil therapy benefits appropriately selected patients who have an ECOG performance status of 0 or 1, with no more than mild hepatic impairment or mild-to-moderate renal impairment, and who are capable of adhering to oral therapy safely. Appropriate dosing, monitoring for adverse events and effective management of side effects are essential.

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).

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.

Circulating Tumor DNA as a Novel Biomarker Optimizing Chemotherapy for Colorectal Cancer

Liquid biopsy is a minimally invasive method for detecting soluble factors, including circulating tumor DNA (ctDNA), in body fluids. ctDNA carrying tumor-specific genetic or epigenetic alterations is released into circulation from tumor cells. ctDNA in the plasma contains somatic mutations that have occurred in the tumor, and reflects tumor progression and therapeutic effects promptly and accurately. Furthermore, ctDNA is useful for early detection of recurrence and estimation of prognosis and may be utilized for diagnosis and personalized medicine for treatment selection. Thus, in the near future, it will be possible to select the most appropriate treatment based on real-time genetic information using ctDNA.

[Personalized systemic treatment of metastatic colorectal cancer]

This article deals with the treatment of metastatic colorectal cancer (stage IV). The treatment goals and approaches are determined by the resectability status of the metastases: resectable liver and lung metastases are primarily resected and perioperative chemotherapy appears to be dispensable. In potentially resectable metastases, a conversion therapy is attempted to enable a potentially curative resection. In the case of nonresectability the treatment goal is palliative. Induction and maintenance therapy as well as drug holidays are suggested in an attempt to achieve extended survival while maintaining the quality of life, beginning with the best possible individual treatment. For some patients with stage IV, molecular targeted therapies are available. The study situation and approval status are dealt with in detail. With improved molecular characterization of tumors the treatment can be further individualized.