Clinical efficacy and drug resistance of anti-epidermal growth factor receptor therapy in colorectal cancer

Colorectal cancer(CRC) ranked third in cancer related death and its incidence has been increasing worldwide. In recent decades important therapeutic advances have been developed in treatment of metastatic CRC(mCRC), such as monoclonal antibodies against epidermal growth factor receptor(anti-EGFR), which provided additional clinical benefits in mCRC. However, anti-EGFR therapies have limited usage due to approximately 95% of patients with KRAS mutated mCRC do not response to anti-EGFR treatment. Thus, KRAS mutation is predictive of nonresponse to anti-EGFR therapies but it alone is not a sufficient basis to decide who should not be received such therapies because; approximately fifty percent(40%-60%) of CRC patients with wild-type KRAS mutation also have poor response to anti-EGFR based treatment. This fact leads us to suspect that there must be other molecular determinants of response to anti-EGFR therapies which have not been identified yet. Current article summarizes the clinical efficacy of anti-EGFR therapies and also evaluates its resistance mechanisms.

Emerging role of liquid biopsy in rat sarcoma virus mutated metastatic colorectal cancer:A case report

BACKGROUND In patients with metastatic colorectal cancer(mCRC),the treatment options are limited and have been proved to be affected by rat sarcoma virus(RAS)mutational status.In RAS wild-type(wt)patients,the combination of antiepidermal growth factor receptor(EGFR)monoclonal antibodies with chemotherapy(CT)is more effective than CT alone.On the other hand,RAS-mutated patients are not eligible for treatment with anti-EGFR antibodies.CASE SUMMARY Eleven patients with initially RAS-mutated mCRC were followed from diagnosis to May 2022.At the time of cell-free DNA determination,five patients had undergone one CT line,five patients had undergone two CT lines,and one patient had undergone three CT lines(all in combination with bevacizumab).At the second and third treatment lines[second line(2L),third line(3L)],patients with neo-RAS wt received a combination of CT and cetuximab.In neo-RAS wt patients treated with anti-EGFR,our findings indicated an increase in progression-free survival for both 2L and 3L(14.5 mo,P=0.119 and 3.9 mo,P=0.882,respectively).Regarding 2L overall survival,we registered a slight increase in neo-RAS wt patients treated with anti-EGFR(33.6 mo vs 32.4 mo,P=0.385).At data cut-off,two patients were still alive:A RAS-mutated patient undergoing 3L treatment and a neo-RAS wt patient who received 2L treatment with anti-EGFR(ongoing).CONCLUSION Our case series demonstrated that monitoring RAS mutations in mCRC by liquid biopsy may provide an additional treatment line for neo-RAS wt patients.

Successful cetuximab rechallenge in metastatic colorectal cancer:A case report

BACKGROUND Metastatic colorectal cancer(mCRC)treatment has been evolving and increasingly driven by tumor biology and gene expression analysis.Rechallenge with epidermal growth factor receptor(EGFR)inhibitors(anti-EGFR)represents a promising strategy for patients with RAS wild-type(RAS-wt)mCRC and circulating tumor DNA has emerged as a potential selection strategy.Herein,we report the case of a RAS-wt mCRC patient who had a successful response to cetuximab rechallenge.CASE SUMMARY Our patient was diagnosed with stage IV RAS-wt,microsatellite-stable rectosigmoid junction adenocarcinoma.He was started on first-line treatment with FOLFIRI and cetuximab and achieved partial response,allowing for a left hepatectomy(R0),followed by post-operative chemotherapy and an anterior resection;progression-free survival(PFS)of 16 months was obtained.Due to hepatic and nodal relapse,second-line treatment with FOLFOX and bevacizumab was started with partial response;metastasectomy was performed(R0),achieving a PFS of 11 months.After a 15 months anti-EGFR-free interval,FOLFIRI and cetuximab were reintroduced upon disease progression,again with partial response and a PFS of 16 months.Following extensive hepatic relapse,cetuximab was reintroduced and a marked clinical and analytical improvement was seen,after only one cycle.RASwt status was confirmed on circulating tumor DNA.The patient’s overall survival exceeded 5 years.CONCLUSION Our case provides real-world data to support cetuximab rechallenge in later lines of RAS-wt mCRC treatment.

Prognostic and predictive biomarkers in metastatic colorectal cancer anti-EGFR therapy

AIM: To reviewing genetic and epigenetic make-up of metastatic colorectal cancers (mCRCs) addicted to epidermal growth factor receptor (EGFR) signalling.METHODS: The present study summarizes the potential value of prognostic and predictive biomarkers in selecting mCRC patients treated with anti-EGFR therapy. A meta-analysis was performed using a systematic search of PubMed, Medline and Web of Science to identify eligible papers until March 21st, 2016 using these following terms: ‘‘colorectal cancer’’, “predictive biomarkers’’, “anti-EGFR therapy”, “KRAS”, “NRAS’’, “PIK3CA”, “TP53”, “PTEN”, ‘‘EGFR”, “MET”, “HER2”, “epiregulin”, “amphiregulin”, “prognostic biomarkers”, “BRAF”, “miRNA” and “antibody-dependent cell-mediated cytotoxicity (ADCC) activity”. Two investigators independently evaluated and extracted data from each identified studies based on selected criteria of inclusion and exclusion.RESULTS: The introduction of agents targeting EGFR such as cetuximab and panitumumab increased overall survival of mCRCs. Nevertheless, it has firstly became evident that response rates to cetuximab regimens in unselected patient populations were typically lower than 30%. Clinical data confirmed the predictive value of RAS mutations for resistance to cetuximab and panitumumab leading to the license of these monoclonal antibodies exclusively for the management of patients with RAS-wild type colorectal cancers. So far the identification of predictive biomarkers have generated interesting, though preliminary and, at times, conflicting data on the importance of tumour mRNA levels of EGFR ligands, of activating mutations in other genes such as NRAS and PIK3CA. The prognostic value of selected microRNAs level and ADCC activity is under investigation, while the prognostic impact of BRAF status remains controversial.CONCLUSION: This review focuses on the personalized treatment of mCRC and discusses the potential of new prognostic and predictive biomarkers in selecting patients treated with anti-EGFR therapy.

Tumor budding predicts response to anti-EGFR therapies in metastatic colorectal cancer patients

AIM:To investigate whether the evaluation of tumor budding can complement K-RAS analysis to improve the individualized prediction of response to anti-epidermal growth factor receptor based therapies in metastatic colorectal cancer (mCRC) patients. METHODS:Forty-three patients with mCRC treated with cetuximab or panitumumab were entered into this study. According to the Response Evaluation Criteria in Solid Tumors criteria, 30 patients had stable or progressive disease (non-responsive), while 13 patients had a partial response. Tumor buds were evaluated from whole tissue sections stained for pan-cytokeratin, evaluated in the densest region using a 40 × objective and "high-grade" tumor budding was defi ned as 15 buds/high-power f ield.RESULTS: Tumor buds and K-RAS mutation both correctly classif ied 68% of patients. All patients with K-RAS mutation (n=7) or high-grade tumor budding (n=11) were non-responsive, of which 4 patients had both features. All 13 partial responders were K-RAS wild-type with low-grade tumor budding. Combined, the predictive value of K-RAS and tumor budding was 80%. Additionally, high-grade tumor budding was significantly related to worse progression-free survival [HR (95% CI): 2.8 (1.3-6.0, P=0.008)].CONCLUSION: If confirmed in larger cohorts, the addition of tumor budding to K-RAS analysis may represent an effective approach for individualized patient management in the metastatic setting.

Beyond KRAS:Predictive factors of the efficacy of anti-EGFR monoclonal antibodies in the treatment of metastatic colorectal cancer

Systematic analysis of the epidermal growth factor receptor(EGFR)pathway revealed that biomarkers could be used to predict the response to and outcome of antiEGFR therapies in patients affected by metastatic colorectal cancer.We have conducted a review on the most recent findings and advances on this topic.To this aim,we searched the PubMed database for articles devoted to predictive and prognostic biomarkers for patients administered cetuximab-and panitumumab-based therapies.Here we review the state of the art and the controversies about the molecular factors known to be predictors of the efficacy of anti-EGFR therapy,namely,KRAS,BRAF,NRAS,PI3KCA and PTEN,and we discuss their prognostic value in colorectal cancer patients.

Dual HER2 inhibition strategies in the management of treatment-refractory metastatic colorectal cancer:History and status

Human epidermal growth factor receptor 2(HER2) signaling pathway activation has been identified as a contributor to de novo or acquired resistance to epidermal growth factor receptor(EGFR) inhibitors in a small subset of patients with metastatic colorectal cancer(mCRC). Dual anti-HER2-targeted treatment exhibits strong antitumor activity in preclinical models of HER2-positive mCRC, supporting its testing in clinical trials. The HERACLES trial at four Italian academic cancer centers has confirmed the effectiveness of dual blockage of HER2 with trastuzumab plus lapatinib in patients with heavily pretreated HER2-positive mCRC, refractory to the anti-EGFR antibodies cetuximab or panitumumab. Here, we reviewed the preclinical studies exploring the role of HER2 signaling in the development of anti-EGFR therapy resistance and discussed the status of clinical trials assessing the activity of HER2 inhibitors in this setting.

Molecular testing for colorectal cancer:Clinical applications

Molecular genetic analysis is an integral part of colorectal cancer(CRC)management.The choice of systemic therapy for CRC is largely based on the results of tumor molecular testing.Evaluation of the KRAS and NRAS gene status is mandatory for consideration of anti-epidermal growth factor receptor(EGFR)therapy.Tumors with the BRAF V600E substitution are characterized by aggressive behaviour,may require intensified cytotoxic regimens and benefit from combined BRAF and EGFR inhibition.The inactivation of DNA mismatch repair(MMR),or MUTYH gene,or DNA polymerase epsilon results in excessive tumor mutational burden;these CRCs are highly antigenic and therefore sensitive to immune checkpoint inhibitors.Some CRCs are characterized by overexpression of the HER2 oncogene and respond to the appropriate targeted therapy.There are CRCs with clinical signs of hereditary predisposition to this disease,which require germline genetic testing.Liquid biopsy is an emerging technology that has the potential to assist CRC screening,control the efficacy of surgical intervention and guide disease monitoring.The landscape of CRC molecular diagnosis is currently undergoing profound changes due to the increasing use of next generation sequencing.

Nimotuzumab with Concurrent Chemo-Radiotherapy in Patients with Locally Advanced Squamous Cell Carcinoma of Head and Neck (LASCCHN)

Background: Head and neck cancers (HNCs) constitute 5% of all cancers globally and are the most common cancers in India. Chemotherapy and radiotherapy have not been proved to be effective in advanced cases and the prognosis remains dismal. This underscores the need for newer treatment options in these cases. Nimotuzumab, an anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, was safer when combined with chemo- or radio-therapy. Aim: To evaluate the safety and efficacy of concurrently administered nimotuzumab with chemo-radiotherapy in patients with advanced inoperable squamous cell carcinomas of head and neck (LASCCHN). Methods:?This was an open-label, single arm study evaluating 57 patients with histologically confirmed inoperable LASCCHN (stages III and IV) and eastern co-operative oncology group (ECOG) performance status < 2. Informed consent was obtained from all patients. The patients were administered IV cisplatin 30 mg/m2?and IV nimotuzumab 200 mg weekly for 6 weeks, along with radiotherapy of 6600 cGy over 33 fractions. Patients were evaluated over response evaluation criteria in solid tumors (RECIST) criteria 24 weeks after the last cycle of chemotherapy. Results: Mean age of patient was 50 years old (29 - 79 years old). The most common site of cancer was oral cavity (56.1%). Forty six patients (80.7%) completed 6 cycles of therapy. Objective response rate (ORR) was 80.7%, with 34 patients (59.6%) achieving complete response (CR), and 12 (21%) achieving partial response (PR). Stable disease (SD) was noted in 8 (14%) patients and progressive disease in 3 (5.2%) patients. Conclusion: Addition of nimotuzumab is a safe and efficacious option in patients with inoperable LASCCHN. Our observations confirm the available Phase II data. The long term survival benefits based on this encouraging response rate need to be further evaluated in this subset of cancer patients.