The safety of monoclonal antibodies for treatment of colorectal cancer

Colorectal Cancer Liver Metastases: Genomics and Biomarkers with Focus on Local Therapies

Molecular cancer biomarkers help personalize treatment, predict oncologic outcomes, and identify patients who can benefit from specific targeted therapies. Colorectal cancer (CRC) is the third-most common cancer, with the liver being the most frequent visceral metastatic site. KRAS, NRAS, BRAF V600E Mutations, DNA Mismatch Repair Deficiency/Microsatellite Instability Status, HER2 Amplification, and NTRK Fusions are NCCN approved and actionable molecular biomarkers for colorectal cancer. Additional biomarkers are also described and can be helpful in different image-guided hepatic directed therapies specifically for CRLM. For example, tumors maintaining the Ki-67 proliferation marker after thermal ablation was shown to be particularly resilient to ablation. Ablation margin was also shown to be an important factor in predicting local recurrence, with a ≥10 mm minimal ablation margin being required to attain local tumor control, especially for patients with mutant KRAS CRLM.

Biomarkers in Metastatic Colorectal Cancer: Status Quo and Future Perspective

Colorectal cancer (CRC) is the third most frequent cancer worldwide, and its incidence is steadily increasing. During the last two decades, a tremendous improvement in outcome has been achieved, mainly due to the introduction of novel drugs, targeted treatment, immune checkpoint inhibitors (CPIs) and biomarker-driven patient selection. Moreover, progress in molecular diagnostics but also improvement in surgical techniques and local ablative treatments significantly contributed to this success. However, novel therapeutic approaches are needed to further improve outcome in patients diagnosed with metastatic CRC. Besides the established biomarkers for mCRC, such as microsatellite instability (MSI) or mismatch repair deficiency (dMMR), RAS/BRAF, sidedness and HER2 amplification, new biomarkers have to be identified to better select patients who derive the most benefit from a specific treatment. In this review, we provide an overview about therapeutic relevant and established biomarkers but also shed light on potential promising markers that may help us to better tailor therapy to the individual mCRC patient in the near future.

Methyl Gallate Suppresses Tumor Development by Increasing Activation of Caspase3 and Disrupting Tumor Angiogenesis in Melanoma

Methyl gallate is a phenolic compound mainly found in medicinal plants. It has been reported to its anticancer activity in various tumors. In this study, we aimed to demonstrate the antitumor effect of methyl gallate in the melanoma mouse model and B16F10 cells. Our results showed that methyl gallate decreased cell viability and induced apoptosis by increasing the expression of cleaved caspase3 in B16F10 cells and prevented cell migration and tube formation in human umbilical vein endothelial cells. In B16F10 cell-inoculated mice, methyl gallate not only decreased tumor volume by 30% but also significantly reduced tumor vessel density and pericyte coverage. Moreover, methyl gallate diminished by close to 50% the expression of cytokeratin and LYVE-1 in mouse right inguinal lymph nodes, indicating that methyl gallate could suppress metastasis. In conclusion, this study suggests that methyl gallate inhibits tumor development by inducing apoptosis and blocking tumor angiogenesis and metastasis and might be considered a therapeutic agent for melanoma.

Immunotherapy for Colorectal Cancer: Mechanisms and Predictive Biomarkers

Simple Summary

Late-stage colorectal cancer treatment often involves chemotherapy and radiation that can cause dose-limiting toxicity, and therefore there is great interest in developing targeted therapies for this disease. Immunotherapy is a targeted therapy that uses peptides, cells, antibodies, viruses, or small molecules to engage or train the immune system to kill cancer. Here, we discuss the preclinical and clinical development of immunotherapy for treatment of colorectal cancer and provide an overview of predictive biomarkers for such treatments. We also consider open questions including optimal combination treatments and sensitization of colorectal cancer patients with proficient mismatch repair enzymes.

Abstract

Though early-stage colorectal cancer has a high 5 year survival rate of 65–92% depending on the specific stage, this probability drops to 13% after the cancer metastasizes. Frontline treatments for colorectal cancer such as chemotherapy and radiation often produce dose-limiting toxicities in patients and acquired resistance in cancer cells. Additional targeted treatments are needed to improve patient outcomes and quality of life. Immunotherapy involves treatment with peptides, cells, antibodies, viruses, or small molecules to engage or train the immune system to kill cancer cells. Preclinical and clinical investigations of immunotherapy for treatment of colorectal cancer including immune checkpoint blockade, adoptive cell therapy, monoclonal antibodies, oncolytic viruses, anti-cancer vaccines, and immune system modulators have been promising, but demonstrate limitations for patients with proficient mismatch repair enzymes. In this review, we discuss preclinical and clinical studies investigating immunotherapy for treatment of colorectal cancer and predictive biomarkers for response to these treatments. We also consider open questions including optimal combination treatments to maximize efficacy, minimize toxicity, and prevent acquired resistance and approaches to sensitize mismatch repair-proficient patients to immunotherapy.

HB-EGF Activates the EGFR/HIF-1α Pathway to Induce Proliferation of Arsenic-Transformed Cells and Tumor Growth

Arsenic was recently identified as a pollutant that is a major cause of lung cancer. Since heparin-binding EGF-like growth factor (HB-EGF) was reported to be a promising therapeutic target for lung cancer, we investigated the role and mechanism of HB-EGF during arsenic-induced carcinogenesis and development of lung cancer. HB-EGF expression were upregulated in As-T cells, lung cancer cell lines, and in most lung cancer tissue samples; and HB-EGF activated the EGFR/p-ERK/HIF-1α pathway and induced VEGF by regulating HIF-1α transcription. HIF-1α transcriptional stimulation by HB-EGF was facilitated by PKM2 and played an important role in HB-EGF's effect on cells. An HB-EGF inhibitor(CRM197, cross-reacting material 197) slowed cell proliferation and inhibited migration of As-T and A549 cells, and inhibited tumor growth. PKM2 also played an important role in the proliferation and migration in As-T cells. The positive staining ratios of EGFR phosphorylation (Y1068) and PKM2 were significantly higher in most cases of lung cancer than in paired normal tumor-adjacent lung tissues; and HB-EGF expression levels strongly correlated with p-EGFR expression levels. Thus, HB-EGF drives arsenic-induced carcinogenesis, tumor growth, and lung cancer development via the EGFR/PKM2/HIF-1α pathway.

Nimotuzumab for Patients With Inoperable Cancer of the Head and Neck

EGFR activation induces cell proliferation, neoformation of blood vessels, survival, and metastasis of the cancer cells. Nimotuzumab is an engineered, intermediate affinity anti-EGFR antibody, that apart from other drugs in its class, is very safe and does not cause hypomagnesemia or grade 3–4 cutaneous rash. The antibody inhibits cell proliferation and angiogenesis, activates natural killer cells, stimulates dendritic cell maturation, and induces cytotoxic T cells. Nimotuzumab restores MHC-I expression on tumor cells, hindering one of the EGFR immune-escape ways. The antibody has been extensively studied in 7 clinical trials, concurrently with irradiation or irradiation plus chemotherapy in subjects with inoperable head and neck tumors. Nimotuzumab was safe and efficacious in unfit patients receiving irradiation alone and in subjects treated with cisplatin and radiotherapy. In patients with locally advanced squamous cell carcinomas of the head and neck, nimotuzumab in combination with low dose cisplatin and radiotherapy was superior to cisplatin and radiotherapy in progression free survival, disease free survival, and locoregional tumor control.

A polymorphism within the R-spondin 2 gene predicts outcome in metastatic colorectal cancer patients treated with FOLFIRI/bevacizumab: data from FIRE-3 and TRIBE trials

BACKGROUND

Through enhancement of the Wnt signalling pathway, R-spondins are oncogenic drivers in colorectal cancer. Experimental data suggest that the R-spondin/Wnt axis stimulates vascular endothelial growth factor (VEGF)-dependent angiogenesis. We therefore hypothesise that variations within R-spondin genes predict outcome in patients with metastatic colorectal cancer (mCRC) treated with upfront FOLFIRI and bevacizumab.

PATIENTS AND METHODS

773 patients with mCRC enrolled in the randomised phase III FIRE-3 and TRIBE trials and receiving either FOLFIRI/bevacizumab (training and validation cohorts) or FOLFIRI/cetuximab (control group) were involved in this study. The impact of six functional single-nucleotide polymorphisms (SNPs) within the R-spondin 1-3 genes on outcome was evaluated.

RESULTS

RAS and KRAS wild-type patients harbouring any G allele of the RSPO2 rs555008 SNP had a longer overall survival compared with those having a TT genotype in both the training (FIRE-3) and validation (TRIBE) cohorts (29.0 vs 23.6 months, P = 0.009 and 37.8 vs 19.4 months, P = 0.021 for RAS wild-type patients and 28.4 vs 22.3 months, P = 0.011 and 36.0 vs 23.3 months, P = 0.046 for KRAS wild-type patients). Conversely, any G allele carriers with KRAS and RAS mutant tumours exhibited a shorter progression-free survival compared with TT genotype carriers, whereas the results were clinically more evident for KRAS mutant patients in both the training and validation cohorts (8.1 vs 11.2 months, P = 0.023 and 8.7 vs 10.3 months, P = 0.009).

CONCLUSION

Genotyping of the RSPO2 rs555008 polymorphism may help to select patients who will derive the most benefit from FOLFIRI/bevacizumab dependent on (K)RAS mutational status.

Single Nucleotide Polymorphisms in 25-Hydroxyvitamin D3 1-Alpha-Hydroxylase (CYP27B1) Gene: The Risk of Malignant Tumors and Other Chronic Diseases

: Vitamin D is widely known for its roles in the promotion of apoptosis and differentiation, with simultaneous inhibition of proliferation, inflammation, angiogenesis, invasion, and metastasis. Modern literature lacks complete information on polymorphisms in CYP27B1, the only enzyme capable of vitamin D activation. This review presents gathered data that relate to genetic variants in CYP27B1 gene in correlation to multiple diseases, mostly concerning colorectal, prostate, breast, lung, and pancreatic cancers, as well as on other pathologies, such as non-Hodgkin's lymphoma, oral lichen planus, or multiple sclerosis.

Anti-VEGF/VEGFR2 Monoclonal Antibodies and their Combinations with PD-1/PD-L1 Inhibitors in Clinic

The vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) signaling pathway is one of the most important pathways responsible for tumor angiogenesis. Currently, two monoclonal antibodies, anti-VEGF-A antibody Bevacizumab and anti-VEGFR2 antibody Ramucizumab, have been approved for the treatment of solid tumors. At the same time, VEGF/VEGFR2 signaling is involved in the regulation of immune responses. It is reported that the inhibition of this pathway has the capability to promote vascular normalization, increase the intra-tumor infiltration of lymphocytes, and decrease the number and function of inhibitory immune cell phenotypes, including Myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and M2 macrophages. On this basis, a number of clinical studies have been performed to investigate the therapeutic potential of VEGF/VEGFR2-targeting antibodies plus programmed cell death protein 1 (PD-1)/ programmed cell death ligand 1 (PD-L1) inhibitors in various solid tumor types. In this context, VEGF/VEGFR2- targeting antibodies, Bevacizumab and Ramucizumab are briefly introduced, with a description of the differences between them, and the clinical studies involved in the combination of Bevacizumab/ Ramucizumab and PD-1/PD-L1 inhibitors are summarized. We hope this review article will provide some valuable clues for further clinical studies and usages.

Stromal PD-1/PD-L1 Expression Predicts Outcome in Colon Cancer Patients

INTRODUCTION

The programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis plays an important role in controlling immune suppression by down-regulating T effector cell activities, enabling tumor cells to escape from the host's antitumor immunsurveillance. While only a small part of colon cancer cells express PD-L1, we sought to evaluate the differential impact of stromal and epithelial PD-L1 expression of primary tumors and liver metastasis on overall survival (OS) in colon cancer patients.

PATIENTS AND METHODS

Using a next-generation tissue microarray approach, we assessed both epithelial and stromal PD-L1 expression levels in primary tumors (n = 279) and corresponding liver metastases (n = 14) of colon cancer patients. PD-L1 positivity was graded according to the percentage (0.1%-1%, > 1%, > 5%, > 50%) of tumor cells with membranous PD-L1 expression or as the percentage of positive stroma cells and associated inflammatory infiltrates. We also assessed the interplay between stromal PD-1/PD-L1 and both intratumoral and stromal CD8 count and their impact on outcome. The primary end point was OS.

RESULTS

Stromal PD-L1 and PD-1 expression were both associated with less aggressive tumor behavior in colon cancer patients, which translated into better OS and disease-free survival, respectively. Conversely, PD-L1 staining in the tumor cells was less frequent than stromal staining and was associated with features of aggressive tumor biology, although without impact on outcome. Interestingly, the PD-L1 staining pattern remained similar between primary tumors and corresponding liver metastases. Stromal PD-1 expression correlated significantly with stromal PD-L1 staining and both intratumoral and stromal CD8 expression.

CONCLUSION

Stromal PD-1/PD-L1 expression might serve as a prognostic marker in colon cancer patients.

Targeted therapies and adverse drug reactions in oncology: the role of clinical pharmacist in pharmacovigilance

Background The majority of adverse drug reactions (ADRs) reported in the summary of product characteristics (SPCs) are based on pivotal clinical trials, performed under controlled conditions and with selected patients. Objectives (1) to observe ADRs in the real-world setting and to evaluate if the supervision of the pharmacist impacts on the management of ADRs and on the satisfaction of patients; (2) to sensitise health professionals and patients on the need to increase the reporting of ADRs, in compliance with Pharmacovigilance. Setting CRO Aviano, Italian National Cancer Institute. Method From February 2013 to April 2015, we conducted an observational study enrolling 154 patients (≥ 18 years) undergoing treatment with at least one of ten targeted-therapies included in the study. Main outcome ADR reporting in the real-world setting. Patient satisfaction with clinical pharmacist support. Results Reported ADRs in the real setting do not always correspond with data described in the respective SPCs. Unknown ADRs were also identified such as hyperglycaemia with lenalidomide and sorafenib; and hypomagnesaemia with bevacizumab. We also observed a 124.3% increase in spontaneous reports. Conclusion This study shows the high value of active pharmacovigilance programs, and our results might be a starting point for developing a randomised trial which should aim to demonstrate the impact of the pharmacist on improving patient’s adherence and in measuring the difference in ADRs reports in the different arms followed or not by the pharmacist.

A Polymorphism within the Vitamin D Transporter Gene Predicts Outcome in Metastatic Colorectal Cancer Patients Treated with FOLFIRI/Bevacizumab or FOLFIRI/Cetuximab

Purpose: Vitamin D exerts its inhibitory influence on colon cancer growth by inhibiting Wnt signaling and angiogenesis. We hypothesized that SNPs in genes involved in vitamin D transport, metabolism, and signaling are associated with outcome in metastatic colorectal cancer (mCRC) patients treated with first-line FOLFIRI and bevacizumab.Experimental Design: 522 mCRC patients enrolled in the FIRE-3 (discovery cohort) and TRIBE (validation set) trials treated with FOLFIRI/bevacizumab were included in this study. 278 patients receiving FOLFIRI and cetuximab (FIRE-3) served as a control cohort. Six SNPs in 6 genes (GC, CYP24A1, CYP27B1, VDR, DKK1, CST5) were analyzed.Results: In the discovery cohort, AA carriers of the GC rs4588 SNP encoding for the vitamin D-binding protein, and treated with FOLFIRI/bevacizumab had a shorter overall survival (OS) than those harboring any C allele (15.9 vs. 25.1 months) in both univariable (P = 0.001) and multivariable analyses (P = 0.047). This association was confirmed in the validation cohort in multivariable analysis (OS 18.1 vs. 26.2 months, HR, 1.83; P = 0.037). Interestingly, AA carriers in the control set exhibited a longer OS (48.0 vs. 25.2 months, HR, 0.50; P = 0.021). This association was further confirmed in a second validation cohort comprising refractory mCRC patients treated with cetuximab ± irinotecan (PFS 8.7 vs. 3.7 months) in univariable (P = 0.033) and multivariable analyses (P = 0.046).Conclusions:GC rs4588 SNP might serve as a predictive marker in mCRC patients treated with FOLFIRI/bevacizumab or FOLFIRI/cetuximab. Whereas AA carriers derive a survival benefit with FOLFIRI/cetuximab, treatment with FOLFIRI/bevacizumab is associated with a worse outcome. Clin Cancer Res; 24(4); 784-93. ©2017 AACR.

Impact of genetic variations in the MAPK signaling pathway on outcome in metastatic colorectal cancer patients treated with first-line FOLFIRI and bevacizumab: data from FIRE-3 and TRIBE trials

BACKGROUND

The MAPK-interacting kinase 1 (MKNK1) is localized downstream of the RAS/RAF/ERK and the MAP3K1/MKK/p38 signaling pathway. Through phosphorylation MKNK1 regulates the function of eukaryotic translation initiation factor 4E, a key player in translational control, whose expression is often upregulated in metastatic colorectal cancer patients (mCRC). Preclinical data suggest that MKNK1 increases angiogenesis by upregulating angiogenic factors. We therefore hypothesize that variations in the MKNK1 gene predict outcome in mCRC patients treated with first-line FOLFIRI and bevacizumab (bev).

PATIENTS AND METHODS

A total of 567 patients with KRAS wild-type mCRC in the randomized phase III FIRE-3 and TRIBE trials treated with first-line FOLFIRI/bev (discovery and validation cohorts) or FOLFIRI and cetuximab (cet) (control cohort) were included in this study. Five single-nucleotide polymorphisms in the MAPK signaling pathway were analyzed.

RESULTS

AA genotype carriers of the MKNK1 rs8602 single-nucleotide polymorphism treated with FOLFIRI/bev in the discovery cohort (FIRE-3) had a shorter progression-free survival (PFS) than those harboring any C (7.9 versus 10.3 months, Hazard ratio (HR) 1.73, P = 0.038). This association could be confirmed in the validation cohort (TRIBE) in multivariable analysis (PFS 9.0 versus 11.0 months, HR 3.04, P = 0.029). Furthermore, AA carriers in the validation cohort had a decreased overall response rate (25% versus 66%, P = 0.049). Conversely, AA genotype carriers in the control group receiving FOLFIRI/cet did not show a shorter PFS. By combining both FOLFIRI/bev cohorts the worse outcome among AA carriers became more significant (PFS 9.0 versus 10.5 months) in univariable (HR 1.74, P = 0.015) and multivariable analysis (HR 1.76, P = 0.022). Accordingly, AA carriers did also exhibit an inferior overall response rate compared with those harboring any C (36% versus 65%, P = 0.005).

CONCLUSION

MKNK1 polymorphism rs8602 might serve as a predictive marker in KRAS wild-type mCRC patients treated with FOLFIRI/bev in the first-line setting. Additionally, MKNK1 might be a promising target for drug development.

A Novel Fully Human Agonistic Single Chain Fragment Variable Antibody Targeting Death Receptor 5 with Potent Antitumor Activity In Vitro and In Vivo

Agonistic antibodies, which bind specifically to death receptor 5 (DR5), can trigger apoptosis in tumor cells through the extrinsic pathway. In this present study, we describe the use of a phage display to isolate a novel fully human agonistic single chain fragment variable (scFv) antibody, which targets DR5. After five rounds of panning a large (1.2 × 10⁸ clones) phage display library on DR5, a total of over 4000 scFv clones were screened by the phage ELISA. After screening for agonism in a cell-viability assay in vitro, a novel DR5-specific scFv antibody TR2-3 was isolated, which inhibited COLO205 and MDA-MB-231 tumor cell growth without any cross-linking agents. The activity of TR2-3 in inducing apoptosis in cancer cells was evaluated by using an Annexin V-PE apoptosis detection kit in combination with flow cytometry and the Hoechst 33342 and propidium iodide double staining analysis. In addition, the activation of caspase-dependent apoptosis was evaluated by Western blot assays. The results indicated that TR2-3 induced robust apoptosis of the COLO205 and MDA-MB-231 cells in a dose-dependent and time-dependent manner, while it remarkably upregulated the cleavage of caspase-3 and caspase-8. Furthermore, TR2-3 suppressed the tumor growth significantly in the xenograft model. Taken together, these data suggest that TR2-3 exhibited potent antitumor activity both in vitro and in vivo. This work provides a novel human antibody, which might be a promising candidate for cancer therapy by targeting DR5.

Management of adverse events during treatment of gastrointestinal cancers with epidermal growth factor inhibitors

The epidermal growth factor receptor (EGFR) is involved in development and progression of some gastrointestinal cancers, and is targeted by monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs) used to treat these conditions. Targeted agents are generally better tolerated than conventional chemotherapy, but have characteristic toxicities that can affect adherence, dosing, and outcomes. Skin conditions are the most common toxicities associated with EGFR inhibitors, particularly papulopustular rash. Other common toxicities include mucosal toxicity, electrolyte imbalances (notably hypomagnesaemia), and diarrhoea, while the chimaeric mAb cetuximab is also associated with increased risk of infusion reactions. With appropriate prophylaxis, the incidence and severity of these events can be reduced, while management strategies tailored to the patient and the degree of toxicity can help to ensure continuation of anti-cancer therapy. Here, we review the main toxicities associated with EGFR-inhibiting mAbs and TKIs in patients with gastrointestinal cancers, and provide recommendations for prophylaxis and treatment.

Autophagy-related polymorphisms predict hypertension in patients with metastatic colorectal cancer treated with FOLFIRI and bevacizumab: Results from TRIBE and FIRE-3 trials

PURPOSE

The most frequent bevacizumab-related side-effects are hypertension, proteinuria, bleeding and thromboembolism. To date, there is no biomarker that predicts anti-VEGF-associated toxicity. As autophagy inhibits angiogenesis, we hypothesised that single-nucleotide polymorphisms (SNPs) within autophagy-related genes may predict bevacizumab-mediated toxicity in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

Patients with mCRC treated with first-line FOLFIRI and bevacizumab in two phase III randomised trials, namely the TRIBE trial (n = 219, discovery cohort) and the FIRE-3 trial (n = 234, validation cohort) were included in this study. Patients receiving treatment with FOLFIRI and cetuximab (FIRE-3, n = 204) served as a negative control. 12 SNPs in eight autophagy-related genes (ATG3/5/8/13, beclin 1, FIP200, unc-51-like kinase 1, UVRAG) were analysed by PCR-based direct sequencing.

RESULTS

The FIP200 rs1129660 variant showed significant associations with hypertension in the TRIBE cohort. Patients harbouring any G allele of the FIP200 rs1129660 SNP showed a significantly lower rate of grade 2-3 hypertension compared with the A/A genotype (3% versus 15%, odds ratio [OR] 0.17; 95% confidence interval [CI], 0.02-0.73; P = 0.009). Similarly, G allele carriers of the FIP200 rs1129660 SNP were less likely to develop grade 2-3 hypertension than patients with an A/A genotype in the FIRE-3 validation cohort (9% versus 20%, OR 0.43; 95% CI, 0.14-1.11; P = 0.077), whereas this association could not be observed in the control cohort (12% versus 9%, OR 1.40; 95% CI, 0.45-4.04; P = 0.60).

CONCLUSION

This is the first report demonstrating that polymorphisms in the autophagy-related FIP200 gene may predict hypertension in patients with mCRC treated with FOLFIRI and bevacizumab.

Panitumumab-Associated Encephalopathy after Accidental Intra-arterial Application through Dislocated Central Venous Access Device

Acute central nervous system (CNS) toxicity and immune-related side effects are increasingly recognized with the use of monoclonal antibodies for cancer therapy. Here, we report a patient who developed of acute-onset encephalopathy and coma, which began shortly after administration of panitumumab for the treatment of metastatic colorectal cancer. Echocardiography revealed that the drug had been infused into the left cardiac ventricle via a dislocated central venous line. Diffusion-weighted magnetic resonance imaging disclosed multiple cortical hyperintensities, which were preferentially located in the frontal lobes. While the neurological condition improved within a few days, the patient died 4 weeks later. It seems likely that the administration of the antibody via the intra-arterial route contributed to the development of this condition. Toxic encephalopathy may be a hitherto unrecognized complication of panitumumab treatment and should be taken into consideration in patients developing CNS symptoms undergoing this therapy.

Efficacy and safety of anti-epidermal growth factor receptor therapy compared with anti-vascular endothelial growth factor therapy for metastatic colorectal cancer in first-line and second-line therapies: a meta-analysis

Aim

This study aimed to compare anti-epidermal growth factor receptor (anti-EGFR) therapy and anti-vascular endothelial growth factor therapy as first-line and second-line therapies in patients with KRAS exon 2 codon 12/13 wild-type (KRAS-WT) metastatic colorectal cancer (mCRC).

Methods

Major databases were systematically searched. The hazard ratio (HR), odds ratio (OR), and 95% confidence intervals (95% CIs) were used to estimate the effect measures. Review Manager software version 5.3 was used for statistical analysis.

Results

Seven trials including ten articles were eligible in the meta-analysis. The patients treated with anti-EGFR as first-line therapy showed a longer overall survival (OS) for KRAS-WT and all RAS wild-type (RAS-WT) mCRC (HR =0.81, 95% CI: 0.72–0.92, P<0.01, n=5; HR =0.78, 95% CI: 0.66–0.93, P<0.01, n=3, respectively). The objective response rate (ORR) was better with the anti-EGFR therapy for KRAS-WT and all RAS-WT mCRC (OR =1.32, 95% CI: 1.11–1.56, P<0.01, n=5; OR =1.55, 95% CI: 1.21–2.00, P<0.01, n=3, respectively). There was no difference in progression-free survival (PFS) for KRAS-WT mCRC and all RAS-WT mCRC between the two groups (HR =1.00; 95% CI: 0.92–1.09, P=0.99, n=4; HR =0.92, 95% CI: 0.71–1.19, P=0.52, n=3, respectively). In addition, two trials provided data on the second-line therapy; there was no significant difference in OS and PFS for the second-line therapy, but a significant improvement in ORR was found in the anti-EGFR group (OR =1.91, 95% CI: 1.16–3.16, P=0.01, n=2). No difference in the conversion therapy (OR =1.34; 95% CI: 0.91–1.99; P=0.14, n=4) was observed between the two therapies.

Conclusion

Our results indicate that anti-EGFR therapy is superior to anti-vascular endothelial growth factor therapy for OS and ORR as a first-line therapy for KRAS-WT mCRC. In the second-line therapy, there was no significant difference in the survival outcomes on the basis of OS and PFS between the two groups. However, ORR improved significantly in the anti-EGFR group.