Randomized phase III trial results of panitumumab, a fully human anti-epidermal growth factor receptor monoclonal antibody, in metastatic colorectal cancer

Results of the Phase I/II Study and Preliminary B-cell Gene Signature of Combined Inhibition of Glutamine Metabolism and EGFR in Colorectal Cancer

PURPOSE

EGFR-targeting mAbs are essential for managing rat sarcoma virus wild-type metastatic colorectal cancer (mCRC), but their limited efficacy necessitates exploring immunologic and metabolic factors influencing response. This study evaluated glutamine metabolism targeting with EGFR inhibition to identify response biomarkers in patients with prior anti-EGFR treatment progression.

PATIENTS AND METHODS

We conducted a phase I/II trial in patients with KRAS wild-type mCRC, combining panitumumab (6 mg/kg) and CB-839 (600 mg/kg or 800 mg/kg), hypothesizing that the dual inhibition of glutamine metabolism and MAPK signaling would enhance outcomes. As study correlatives, we investigated the B-cell activation signature "B-score" and glutamine PET as potential treatment response biomarkers.

RESULTS

The combination of panitumumab and CB-839 was tolerable with manageable side effects, including grade 4 hypomagnesemia in four patients, a known panitumumab-related event. Two patients achieved partial response, and five had stable disease, with a 41% disease control rate. Median progression-free survival and overall survival were 1.84 and 8.87 months, respectively. A positive correlation between "B-score" and lesion size reduction suggested its association with clinical benefit (partial response and stable disease). Lower "B-score" correlated with greater tumor avidity for glutamine by PET, indicating B-cell activation sensitivity to glutamine depletion.

CONCLUSIONS

The combination of CB-839 and panitumumab showed safety and promising preliminary responses, but the study closed early due to CB-839 development termination. The B-cell activation signature "B-score" emerged as a potential biomarker for EGFR and glutaminase inhibition in mCRC, warranting further studies. These findings suggest opportunities to improve immune response and therapies in glutaminolysis-dependent tumors.

A Comprehensive Review of the Mechanisms and Clinical Development of Monoclonal Antibodies in Cancer Therapy

Cancer is still the disease that ranks first in human mortality in the twenty-first century. In the last 20 years, the concept of molecular targeted therapy has come to the fore with the use of small molecule agents or signal transduction inhibitors that show anticancer effects for certain types of cancer. Monoclonal antibodies, which have a therapeutic effect, especially by providing signal transduction inhibition, are used clinically as first-line treatment in various types of cancer. Molecular targeted therapies are critical for eliminating the adverse effects and drug resistance problems that occur in traditional cancer treatments. This review summarizes current information on various targeted therapeutic agents, including the structure and classification of monoclonal antibodies, their production methods and mechanisms of action, the monoclonal antibodies used in clinical trials, the complement system mechanism and cancer relationship, and the relationship between complement-dependent cytotoxicity and monoclonal antibodies.

Therapeutic antibodies in oncology: an immunopharmacological overview

The biotechnological development of monoclonal antibodies and their immunotherapeutic use in oncology have grown exponentially in the last decade, becoming the first-line therapy for some types of cancer. Their mechanism of action is based on the ability to regulate the immune system or by interacting with targets that are either overexpressed in tumor cells, released into the extracellular milieu or involved in processes that favor tumor growth. In addition, the intrinsic characteristics of each subclass of antibodies provide specific effector functions against the tumor by activating antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, among other mechanisms. The rational design and engineering of monoclonal antibodies have improved their pharmacokinetic and pharmacodynamic features, thus optimizing the therapeutic regimens administered to cancer patients and improving their clinical outcomes. The selection of the immunoglobulin G subclass, modifications to its crystallizable region (Fc), and conjugation of radioactive substances or antineoplastic drugs may all improve the antitumor effects of therapeutic antibodies. This review aims to provide insights into the immunological and pharmacological aspects of therapeutic antibodies used in oncology, with a rational approach at molecular modifications that can be introduced into these biological tools, improving their efficacy in the treatment of cancer.

Incidence and associated factors of cetuximab-induced hypersensitivity infusion reactions in 1392 cancer patients treated in four French areas: a possible association with Lyme disease?

BACKGROUND

Previous studies have observed an increased incidence of Cetuximab-induced hypersensitivity infusion reactions (CI-IRs) in the southeastern states of the USA. Tick's bites were suspected of generating cross-reactions between cetuximab and alpha-gal. This study aims was to describe the incidence and associated risk factors of CI-IRs, in the French areas chosen according to their Lyme disease incidence.

PATIENTS AND METHODS

A retrospective chart review was conducted on patients that received cetuximab infusion from January 2010 to June 2019 in 4 French areas with different Lyme disease incidence rates.

RESULTS

Of 1392 patients, 117 (8.4%) experienced a CI-IR, including 68 severe (grade 3 or 4) reactions (4.9%). This CI-IR incidence was significantly higher in the Lyme disease high-risk area than in the other areas (13.2% versus 7.1%, 8.1% and 6.4%; P = 0.016). Sex (P = 0.53), premedication (P = 0.91), primary cancer location (P = 0.46) and chemotherapy regimen type (P = 0.78) had no impact on CI-IR incidence in the overall population. In the head and neck squamous cell carcinoma (HNSCC) patient subgroup, CI-IRs were significantly more frequent in the high-risk area (16.4% versus 6.7%, 7.1% and 7.0%; P = 0.0015).

CONCLUSION

This study suggests that patients treated in the French area with the highest incidence of Lyme disease are at a higher risk of CI-IRs.

Development of therapeutic antibodies for the treatment of diseases

Since the first monoclonal antibody drug, muromonab-CD3, was approved for marketing in 1986, 165 antibody drugs have been approved or are under regulatory review worldwide. With the approval of new drugs for treating a wide range of diseases, including cancer and autoimmune and metabolic disorders, the therapeutic antibody drug market has experienced explosive growth. Monoclonal antibodies have been sought after by many biopharmaceutical companies and scientific research institutes due to their high specificity, strong targeting abilities, low toxicity, side effects, and high development success rate. The related industries and markets are growing rapidly, and therapeutic antibodies are one of the most important research and development areas in the field of biology and medicine. In recent years, great progress has been made in the key technologies and theoretical innovations provided by therapeutic antibodies, including antibody-drug conjugates, antibody-conjugated nuclides, bispecific antibodies, nanobodies, and other antibody analogs. Additionally, therapeutic antibodies can be combined with technologies used in other fields to create new cross-fields, such as chimeric antigen receptor T cells (CAR-T), CAR-natural killer cells (CAR-NK), and other cell therapy. This review summarizes the latest approved or in regulatory review therapeutic antibodies that have been approved or that are under regulatory review worldwide, as well as clinical research on these approaches and their development, and outlines antibody discovery strategies that have emerged during the development of therapeutic antibodies, such as hybridoma technology, phage display, preparation of fully human antibody from transgenic mice, single B-cell antibody technology, and artificial intelligence-assisted antibody discovery.

The mosaic puzzle of the therapeutic monoclonal antibodies and antibody fragments - A modular transition from full-length immunoglobulins to antibody mimetics

The use of monoclonal antibodies represents an important and efficient diagnostic and therapeutic tool in disease management and modern science but remains limited by several factors including the uneven distribution in diseased tissues as well as undesired activation of side immune reactions. Major scientific advancements including Recombinant DNA Technology, Hybridoma Technology, and Polymerase Chain Reaction have considerably impacted the use of monoclonal antibodies providing technical and effective solutions to overcome the shortcomings encountered with conventional antibodies. Initially, the introduction of antibody fragments allowed a more uniform and deeper penetration of the targeted tissue and reduced unwanted activation of Fc-mediated immune reactions. On another level, the immunogenicity of murine-derived antibodies was overcome by humanizing their encoding genes with specific sequences of human origin andtransgenic mice able to synthesize fully human antibodies were successfully created. Moreover, the advancement of genetic engineering techniques supported by the modular structure of antibody coding genes paved the way for the development of a new generation of antibody fragments with a wide spectrum of monospecific and bispecific agents. These later could be monovalent, bivalent, or multivalent, and either expressed as a single chain, assembled in multimeric forms or stringed in tandem. This has conferred improved affinity, stability, and solubility to antibody targetting. Lately, a new array of monoclonal antibody fragments was introduced with the engineering of nanobody and antibody mimetics as non-immunoglobulin-derived fragments with promising diagnostic and therapeutic applications. In this review, we decipher the molecular basis of monoclonal antibody engineering with a detailed screening of the antibody derivatives that provides new perspectives to expand the use of monoclonal fragments into previously unexplored fields.

Current innovative engineered antibodies

Antibody engineering has developed very intensively since the invention of the hybridoma technology in 1975, and it now can generate therapeutic agents with high specificity and reduced adverse effects. Indeed, antibodies have become one of the most innovative therapeutic agents in recent years, with some landing in the top 10 bestselling pharmaceutical drugs. New antibodies are being approved every year, in different formats and for treating various illnesses, including cancer, autoimmune inflammatory diseases, metabolic diseases and infectious diseases. In this review, I summarize current progress in innovative engineered antibodies. Overall, this progress has led to the approval by regulatory authorities of more than 100 antibody-based molecules, with many others at various stages of clinical development, indicating the high growth potential of the field.

Cinobufagin Is a Selective Anti-Cancer Agent against Tumors with EGFR Amplification and PTEN Deletion

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor, and almost half of the patients carrying EGFR-driven tumor with PTEN deficiency are resistant to EGFR-targeted therapy. EGFR amplification and/or mutation is reported in various epithelial tumors. This series of studies aimed to identify a potent compound against EGFR-driven tumor. We screened a chemical library containing over 600 individual compounds purified from Traditional Chinese Medicine against GBM cells with EGFR amplification and found that cinobufagin, the major active ingredient of Chansu, inhibited the proliferation of EGFR amplified GBM cells and PTEN deficiency enhanced its anti-proliferation effects. Cinobufagin also strongly inhibited the proliferation of carcinoma cell lines with wild-type or mutant EGFR expression. In contrast, the compound only weakly inhibited the proliferation of cancer cells with low or without EGFR expression. Cinobufagin blocked EGFR phosphorylation and its downstream signaling, which additionally induced apoptosis and cytotoxicity in EGFR amplified cancer cells. In vivo, cinobufagin blocked EGFR signaling, inhibited cell proliferation, and elicited apoptosis, thereby suppressing tumor growth in both subcutaneous and intracranial U87MG-EGFR xenograft mouse models and increasing the median survival of nude mice bearing intracranial U87MG-EGFR tumors. Cinobufagin is a potential therapeutic agent for treating malignant glioma and other human cancers expressing EGFR.

Modifications of Plasma Membrane Organization in Cancer Cells for Targeted Therapy

Modifications of the composition or organization of the cancer cell membrane seem to be a promising targeted therapy. This approach can significantly enhance drug uptake or intensify the response of cancer cells to chemotherapeutics. There are several methods enabling lipid bilayer modifications, e.g., pharmacological, physical, and mechanical. It is crucial to keep in mind the significance of drug resistance phenomenon, ion channel and specific receptor impact, and lipid bilayer organization in planning the cell membrane-targeted treatment. In this review, strategies based on cell membrane modulation or reorganization are presented as an alternative tool for future therapeutic protocols.

Trial Watch: Tumor-targeting monoclonal antibodies in cancer therapy

In 1997, for the first time in history, a monoclonal antibody (mAb), i.e., the chimeric anti-CD20 molecule rituximab, was approved by the US Food and Drug Administration for use in cancer patients. Since then, the panel of mAbs that are approved by international regulatory agencies for the treatment of hematopoietic and solid malignancies has not stopped to expand, nowadays encompassing a stunning amount of 15 distinct molecules. This therapeutic armamentarium includes mAbs that target tumor-associated antigens, as well as molecules that interfere with tumor-stroma interactions or exert direct immunostimulatory effects. These three classes of mAbs exert antineoplastic activity via distinct mechanisms, which may or may not involve immune effectors other than the mAbs themselves. In previous issues of OncoImmunology, we provided a brief scientific background to the use of mAbs, all types confounded, in cancer therapy, and discussed the results of recent clinical trials investigating the safety and efficacy of this approach. Here, we focus on mAbs that primarily target malignant cells or their interactions with stromal components, as opposed to mAbs that mediate antineoplastic effects by activating the immune system. In particular, we discuss relevant clinical findings that have been published during the last 13 months as well as clinical trials that have been launched in the same period to investigate the therapeutic profile of hitherto investigational tumor-targeting mAbs.

Successful rechallenge with cetuximab after an infusion related reaction to panitumumab in a patient with locally advanced rectal cancer

Incidence of infusion related reaction (IR) is more common with cetuximab (Cmab) than with panitumumab (Pmab). Although little is known about rechallenge IR with monoclonal antibodies, we experienced a successful rechallenge to Cmab after IR to Pmab. A 67-year-old female patient was scheduled for chemotherapy with mFOLFOX6 plus Pmab against unresectable advanced rectal cancer in the hope of tumor shrinkage. On the first administration of Pmab, she complained of dyspnea with shortness of breath and wheezing, even after premedication with steroids and antihistamines. Her reaction was judged as Grade 2 IR to Pmab. For the next course, we tried Cmab. No IRs were observed. Since then, she has undergone seven further courses of treatment, followed by surgical resection. The patient benefited from administration of Cmab after experiencing IR to Pmab, suggesting this treatment to be an option for patients of this type who experience IR to Pmab.

A phase 1b study of the MET inhibitor capmatinib combined with cetuximab in patients with MET-positive colorectal cancer who had progressed following anti-EGFR monoclonal antibody treatment

Background Overcoming resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) in patients with KRAS wildtype (WT) metastatic colorectal cancer (mCRC) could help meet the needs of patients with limited treatment options. Methods In this phase 1b study, patients with N/KRAS WT, MET-positive mCRC who had progressed following anti-EGFR mAb treatment received escalating oral doses of capmatinib (150, 300, and 400 mg) twice daily plus weekly intravenous cetuximab (at the approved dose). The primary objective was to establish a recommended dose for expansion (RDE) of capmatinib in combination with cetuximab. Safety, preliminary activity, pharmacokinetics, and pharmacodynamics were also explored. Results Thirteen patients were enrolled. No patients experienced a dose-limiting toxicity at investigated doses; the RDE was established as capmatinib 400 mg twice daily plus cetuximab. All patients experienced adverse events (AEs) suspected to be related to the study treatment. Five patients (38.5%) reported study-drug-related AEs of grade 3/4 in severity. No patients achieved a complete or partial response according to RECIST v1.1; however, tumor shrinkage of 29-44% was observed in 4 patients. Conclusions Capmatinib plus cetuximab was well tolerated. Preliminary signs of activity were observed. Further investigation is warranted to obtain efficacy data and refine predictive biomarkers of response. Clinical trial registration NCT02205398.

Nanobodies in cancer

For treatment and diagnosis of cancer, antibodies have proven their value and now serve as a first line of therapy for certain cancers. A unique class of antibody fragments called nanobodies, derived from camelid heavy chain-only antibodies, are gaining increasing acceptance as diagnostic tools and are considered also as building blocks for chimeric antigen receptors as well as for targeted drug delivery. The small size of nanobodies (∼15 kDa), their stability, ease of manufacture and modification for diverse formats, short circulatory half-life, and high tissue penetration, coupled with excellent specificity and affinity, account for their attractiveness. Here we review applications of nanobodies in the sphere of tumor biology.

The Latest Battles Between EGFR Monoclonal Antibodies and Resistant Tumor Cells

Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor involved in homeostatic regulation of normal cells and carcinogenesis of epithelial malignancies. With rapid development of the precision medicine era, a series of new therapies targeting EGFR are underway. Four EGFR monoclonal antibody drugs (cetuximab, panitumumab, nimotuzumab, and necitumumab) are already on the market, and a dozen other EGFR monoclonal antibodies are in clinical trials. Here, we comprehensively review the newly identified biological properties and anti-tumor mechanisms of EGFR monoclonal antibodies. We summarize recently completed and ongoing clinical trials of the classic and new EGFR monoclonal antibodies. More importantly, according to our new standard, we re-classify the complex evolving tumor cell resistance mechanisms, including those involving exosomes, non-coding RNA and the tumor microenvironment, against EGFR monoclonal antibodies. Finally, we analyzed the limitations of EGFR monoclonal antibody therapy, and discussed the current strategies overcoming EGFR related drug resistance. This review will help us better understand the latest battles between EGFR monoclonal antibodies and resistant tumor cells, and the future directions to develop anti-tumor EGFR monoclonal antibodies with durable effects.

Molecular Interaction Characterization Strategies for the Development of New Biotherapeutic Antibody Modalities

The characterization of target binding interactions is critical at each stage of antibody therapeutic development. During early development, it is important to design fit-for-purpose in vitro molecular interaction characterization (MIC) assays that accurately determine the binding kinetics and the affinity of therapeutic antibodies for their targets. Such information enables PK/PD (pharmacokinetics/pharmacodynamics) modeling, estimation of dosing regimens, and assessment of potency. While binding kinetics and affinities seem to be readily obtained, there is little discussion in the literature on how the information should be generated and used in a systematic manner along with other approaches to enable key drug development decisions. The introduction of new antibody modalities poses unique challenges to the development of MIC assays and further increases the need to discuss the impact of developing context-appropriate MIC assays to enable key decision making for these programs. In this paper, we discuss for the first time the challenges encountered when developing MIC assays supporting new antibody modalities. Additionally, through the presentation of several real case studies, we provide strategies to overcome these challenges to enable investigational new drug (IND) filings.

Epidermal growth factor receptor (EGFR) involvement in epithelial-derived cancers and its current antibody-based immunotherapies

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein that is part of the family of tyrosine kinase receptors. The binding of EGFR to its cognate ligands leads to its autophosphorylation and subsequent activation of the signal transduction pathways involved in regulating cellular proliferation, differentiation, and survival. Accordingly, this receptor carries out both redundant and restricted functions in the germline development of mammals and in the maintenance of various adult tissues. Correspondingly, the loss of EGFR regulation results in many human diseases, with the most notable cancer. This receptor is overexpressed and/or mutated in multiple epithelial-derived tumors, and associated with poor prognosis and survival in cancer patients. Here, we discuss in detail the role of EGFR in specific epithelial-derived cancer pathologies; these include lung cancer, colorectal cancer, and squamous cell carcinomas. The development of multiple anticancer agents against EGFR diminished the progression and metastasis of tumors. Some of the most versatile therapeutic anti-EGFR agents include the monoclonal antibodies (mAbs), demonstrating success in clinical settings when used in combination with cytotoxic treatments, such as chemotherapy and/or radiation. We thus discuss the development and application of two of the most notable therapeutic mAbs, cetuximab, and panitumumab, currently utilized in various EGFR-related epithelial cancers.

Development of therapeutic antibodies for the treatment of diseases

It has been more than three decades since the first monoclonal antibody was approved by the United States Food and Drug Administration (US FDA) in 1986, and during this time, antibody engineering has dramatically evolved. Current antibody drugs have increasingly fewer adverse effects due to their high specificity. As a result, therapeutic antibodies have become the predominant class of new drugs developed in recent years. Over the past five years, antibodies have become the best-selling drugs in the pharmaceutical market, and in 2018, eight of the top ten bestselling drugs worldwide were biologics. The global therapeutic monoclonal antibody market was valued at approximately US$115.2 billion in 2018 and is expected to generate revenue of $150 billion by the end of 2019 and $300 billion by 2025. Thus, the market for therapeutic antibody drugs has experienced explosive growth as new drugs have been approved for treating various human diseases, including many cancers, autoimmune, metabolic and infectious diseases. As of December 2019, 79 therapeutic mAbs have been approved by the US FDA, but there is still significant growth potential. This review summarizes the latest market trends and outlines the preeminent antibody engineering technologies used in the development of therapeutic antibody drugs, such as humanization of monoclonal antibodies, phage display, the human antibody mouse, single B cell antibody technology, and affinity maturation. Finally, future applications and perspectives are also discussed.

Cisplatin and 5-fluorouracil with or without epidermal growth factor receptor inhibition panitumumab for patients with non-resectable, advanced or metastatic oesophageal squamous cell cancer: a prospective, open-label, randomised phase III AIO/EORTC trial (POWER)

BACKGROUND

Palliative chemotherapy of advanced oesophageal squamous cell cancer (ESCC) consists of cisplatin/5-fluorouracil (CF) to target epidermal growth factor receptor (EGFR) with panitumumab (P); chemotherapy enhanced overall survival (OS) in advanced colorectal or squamous cell head and neck cancers. With prospective serum and tumour biomarkers, we tested if P added to CF (CFP) improved OS in advanced ESCC.

PATIENTS AND METHODS

Eligible patients with confirmed ESCC that was not curatively resectable or did not qualify for definitive radiochemotherapy, were randomised 1 : 1 to receive CF [cisplatin (C) 100 mg/m² i.v., day 1; 5-fluorouracil (F) 1000 mg/m² i.v., days 1-4] or CF plus P (9 mg/kg, i.v., day 1, each q3-week cycle) until progressive disease or unacceptable toxicity. Safety was reviewed by the Data Safety Monitoring Board after 40, 70 and 100 patients who completed at least one cycle. After 53 enrolled patients, cisplatin was reduced from 100 mg/m² to 80 mg/m².

RESULTS

The trial was stopped early based on interim efficacy results triggered by the third safety analysis: median OS (mOS) favoured CF over CFP, regardless of cisplatin dose [hazard ratio (HR) 1.77, 95% confidence interval (CI) 1.06-2.98; P = 0.028]. In the final analysis, mOS was 10.2 versus 9.4 months for CF versus CFP, respectively (HR 1.17, 95% CI 0.79-1.75; P = 0.43). One hundred (70.4%) of 142 patients in the safety population died, 51 (51.0%) with CFP. Most deaths were related to disease progression [44/49 (90%) deaths in CF versus 34/51 (67%) deaths in CFP]; objective responses [27/73 (37.0%)] were identical. The most common serious adverse events were kidney injury [3 (4.3%) versus 7 (9.7%)], general health deterioration [5 (7.1%) versus 5 (6.9%)] and dysphagia [4 (5.7%) versus 4 (5.6%)] in CF versus CFP, respectively. There were three (4.3%) and 17 (23.6%) common terminology criteria for adverse events (CTCAE) grade 5 events in CF versus CFP, respectively. Low soluble (s)EGFR levels were associated with better progression-free survival; sEGFR was induced under CFP.

CONCLUSION

EGFR inhibition added to CF did not improve survival in unselected advanced ESCC patients. The results support further liquid biopsy studies.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01627379) and EudraCT (2010-020606-15).

Bucillamine Prevents Afatinib-Mediated Inhibition of Epidermal Growth Factor Receptor Signaling

Molecular targeting therapies often cause characteristic adverse effects, such as skin rash during anti-epidermal growth factor receptor (EGFR) therapies, making treatment continuation difficult. In contrast, skin symptoms induced by EGFR inhibition are strongly correlated with the overall survival of the therapies. Therefore, controlling adverse effects not only facilitates treatment continuation but also increases clinical benefits. In this study, we proposed a novel strategy for reducing EGFR–tyrosine kinase inhibitor (TKI)-induced adverse effects in nontumorous organs by repositioning approved medicines using a zebrafish model. We developed a model system for evaluating chemical quenchers of afatinib, a clinically available irreversible EGFR-TKI, by scoring the inhibition of afatinib-induced hyperformation of lateral line neuromasts in zebrafish larvae. Bucillamine, an antirheumatic drug, was identified as an afatinib quencher in the zebrafish system and inhibited TKI activity in vitro. In addition, bucillamine restored EGFR autophosphorylation and downstream signaling in afatinib-treated A431 cells. Thus, topical bucillamine is a potential reliever of irreversible EGFR-TKI-induced skin rash. The zebrafish model can be applied to a screening for quenchers of other anti-EGFR-targeting therapies, including reversible TKIs and biologics.

Immunotherapies and Targeted Therapies in the Treatment of Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer deaths, and while mortality has largely improved in the developed world, five-year survival for metastatic disease remains dismally low at only 15%. Fortunately, nearly a dozen targeted therapies and immunotherapies have been FDA approved in the past decade for certain patient profiles with metastatic CRC (mCRC), and many others are under development. Checkpoint inhibitors such as pembrolizumab have proven effective at extending survival for mismatch repair (MMR)-deficient and high microsatellite instability (MSI) mCRC patients. In combination with chemotherapy in first- and second-line treatment, antiangiogenic (anti-vascular endothelial growth factor (anti-VGEF)) agent bevacizumab has been shown to increase mCRC survival. Anti-epidermal growth factor receptor (anti-EGFR) agents panitumumab and cetuximab, in combination with chemotherapy, have also prolonged survival among KRAS and all RAS wild-type mCRC patients. Among these patients, anti-EGFR therapy has been found to be more efficacious than bevacizumab. Improved selectivity has allowed small-molecule receptor tyrosine kinase (RTK) inhibitors to target VEGF and EGFR with greater efficacy and tolerability. Combinations of immunotherapies, RTKs, monoclonal antibodies, and cytotoxic drugs are being investigated to provide broad-spectrum protection against relapse by simultaneously targeting many cancer hallmarks. Lastly, human epidermal growth factor receptor 2 (HER2) therapy has shown promise for HER2-positive mCRC patients, though larger clinical trials are required to secure FDA approval.

High expression of ALDOA and DDX5 are associated with poor prognosis in human colorectal cancer

Purpose

The identification of prognostic markers for colorectal cancer (CRC) is needed for clinical practice. Fructose-bisphosphate aldolase A (ALDOA) and DEAD box p68 RNA helicase (DDX5) are commonly overexpressed in cancer and correlate with tumorigenesis. However, association between expression of ALDOA and DDX5, and CRC outcome has not been reported.

Patients and methods

We used 141 formalin-fixed paraffin-embedded (FFPE) specimens collected from 105 patients with CRC treated at the Affiliated Hospital of Guilin Medical University and the People’s Hospital of Liuzhou. We performed tissue microarray based immunohistochemistry to explore expression features and prognostic value (overall survival, OS; disease-free survival, [DFS]) of ALDOA and DDX5 in CRC tissues. The prognostic values were evaluated using Kaplan–Meier analysis, and Cox regression analyses.

Results

ALDOA and DDX5 were highly expressed in CRC tissues and liver metastatic CRC tissues compared with normal glandular epithelium tissues (all p<0.05). Interestingly, primary CRC tissues highly expressing ALDOA or DDX5 had poor outcome (p<0.0001 for both OS and DFS for ALDOA; p=0.001 for OS; and p=0.011 for DFS for DDX5) compared with patients who had low expression of those proteins. Furthermore, multivariate Cox analysis showed that ALDOA/DDX5 combination was an independent risk factor for OS and ALDOA was an independent risk factor for DFS.

Conclusion

High levels of ALDOA and DDX5 contribute to the aggressiveness and poor prognosis of CRC. ALDOA/DDX5 expression could be a biomarkers for the prognosis of CRC.

Downregulation of TRIM58 expression is associated with a poor patient outcome and enhances colorectal cancer cell invasion

TRIM58 is a member of the tripartite motif protein (TRIM) family of E3 ubiquitin ligases. Aberrant gene methylation of TRIM58 has been reported in liver and lung cancer and indicates a poor patient prognosis. However, the expression level and functional role of TRIM58 in colorectal cancer (CRC) have yet to be elucidated. In the present study, we found that TRIM58 expression was significantly suppressed in human CRC and was inversely correlated with CRC progression. Additionally, overall survival was significantly reduced in patients with low TRIM58 expression in CRC tumors. In vitro studies demonstrated that ectopic TRIM58 overexpression strongly inhibited CRC cell invasion but had minimal effects on cell proliferation, colonization and migration. Furthermore, TRIM58 suppression enhanced the expression of epithelial-to-mesenchymal transition (EMT) and matrix metalloproteinase (MMP) genes. Thus, our findings suggest that TRIM58 is a potential prognostic marker of CRC and functions as a tumor-suppressor gene via inhibition of cancer cell invasion through EMT and MMP activation.

BRAF Inhibitors for BRAF V600E Mutant Colorectal Cancers: Literature Survey and Case Report

The main method of fighting against colon cancer is targeted treatment. BRAF inhibitors, which are accepted as standard treatment for V600E mutant malign melanomas, are the newest approach for targeted treatment of V600E mutant colorectal cancers. In this case report, we share our experience about the use of BRAF inhibitor vemurafenib on a V600E mutant metastatic right colon adenocarcinoma patient. A 59-year-old male with only lung multiple metastatic V600E mutant right colon cancer presented to our clinic. The patient was evaluated and FOLFOX + bevacizumab treatment was initiated, which was then continued with vemurafenib. A remarkable response was achieved with vemurafenib treatment in which the drug resistance occurred approximately in the sixth month. Even though the patient benefited majorly from vemurafenib, he died on the 20th month of the diagnosis. The expected overall survival for metastatic V600E mutant colon adenocarcinoma patients is 4.7 months. BRAF inhibitors provide new treatment alternatives for V600E mutant colorectal cancers, with prolonged overall survival. BRAF inhibitors in combination with MEK inhibitors are reported as feasible treatment to overcome BRAF inhibitor drug resistance on which phase studies are still in progress. To conclude, BRAF inhibitors alone or in combination with other drugs provide a chance for curing BRAF V600E mutant colorectal cancer patients.

Mechanisms of receptor tyrosine kinase activation in cancer

Receptor tyrosine kinases (RTKs) play an important role in a variety of cellular processes including growth, motility, differentiation, and metabolism. As such, dysregulation of RTK signaling leads to an assortment of human diseases, most notably, cancers. Recent large-scale genomic studies have revealed the presence of various alterations in the genes encoding RTKs such as EGFR, HER2/ErbB2, and MET, amongst many others. Abnormal RTK activation in human cancers is mediated by four principal mechanisms: gain-of-function mutations, genomic amplification, chromosomal rearrangements, and / or autocrine activation. In this manuscript, we review the processes whereby RTKs are activated under normal physiological conditions and discuss several mechanisms whereby RTKs can be aberrantly activated in human cancers. Understanding of these mechanisms has important implications for selection of anti-cancer therapies.

Pharmacology of Epidermal Growth Factor Inhibitors

Research into the molecular bases of malignant diseases has yielded the development of many novel agents with potential antitumor activity. Evidence for a causative role for the epidermal growth factor receptor (EGFR), which is now regarded as an excellent target for cancer chemotherapy in human cancer, leads to the development of EGFR inhibitors. Two classes of anti-EGFR agents are currently in clinical use: monoclonal antibodies directed at the extracellular domain of the receptor, and the low-molecular-weight receptor tyrosine kinase inhibitors acting intracellularly by competing with adenosine triphosphate for binding to the tyrosine kinase portion of the EGFR. The effect on the receptor interferes with key biological functions including cell cycle arrest, potentiation of apoptosis, inhibition of angiogenesis and cell invasion and metastasis. Cetuximab, a monoclonal antibody, and the receptor tyrosine kinase inhibitors gefitinib and erlotinib are currently approved for the treatment of patients with cancer. New agents with clinical activity are entering the clinic, and new combinatorial approaches are being explored with the aim of improving the potency and pharmacokinetics of EGFR inhibition, to increase the synergistic activity in combination with chemotherapy and overcome resistance to the EGFR inhibitors.

Exposure-response relationship of ramucirumab in patients with advanced second-line colorectal cancer: exploratory analysis of the RAISE trial

PURPOSE

To characterize ramucirumab exposure-response relationships for efficacy and safety in patients with metastatic colorectal cancer (mCRC) using data from the RAISE study.

METHODS

Sparse pharmacokinetic samples were collected; a population pharmacokinetic analysis was conducted. Univariate and multivariate Cox proportional hazards models analyzed the relationship between predicted ramucirumab minimum trough concentration at steady state (C min,ss) and survival. Kaplan-Meier analysis was used to evaluate survival from patients in the ramucirumab plus folinic acid, 5-fluorouracil, and irinotecan (FOLFIRI) treatment arm stratified by C min,ss quartiles (Q). An ordered categorical model analyzed the relationship between C min,ss and safety outcomes.

RESULTS

Pharmacokinetic samples from 906 patients were included in exposure-efficacy analyses; samples from 905 patients were included in exposure-safety analyses. A significant association was identified between C min,ss and overall survival (OS) and progression-free survival (PFS) (p < 0.0001 for both). This association remained significant after adjusting for baseline factors associated with OS or PFS (p < 0.0001 for both). Median OS was 11.5, 12.9, 16.4, and 16.7, and 12.4 months for ramucirumab C min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. Median PFS was 5.4, 4.6, 6.8, 8.5, and 5.2 months for ramucirumab C min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. The risk of Grade ≥3 neutropenia was associated with an increase in ramucirumab exposure.

CONCLUSIONS

Exploratory exposure-response analyses suggested a positive relationship between efficacy and ramucirumab exposure with manageable toxicities in patients from the RAISE study with mCRC over the ranges of exposures achieved by a dose of 8 mg/kg every 2 weeks in combination with FOLFIRI.

Nimotuzumab Combined with Chemotherapy is a Promising Treatment for Locally Advanced and Metastatic Esophageal Cancer

Background

Nimotuzumab is an anti-EGFR monoclonal antibody which has been widely used in cancer treatment. However, the safety and efficacy of nimotuzumab combined with chemotherapy in locally advanced or metastatic esophageal cancer patients remain unclear.

Material/Methods

To address this open question, we collected a total data of 21 patients diagnosed with locally advanced or metastatic esophageal cancer between 2012 and 2016 in a, retrospective study. The patient characteristics, efficacy safety, and toxicity were evaluated in our study.

Results

We observed 1 (4.8%) patient with complete response, 7 (33.3%) patients with partial response, 9 (42.9%) patients with stable response and 4 (19%) patients with progression response. The objective response rate was 38.1% and disease control rate was 81%. The mean progression-free-survival was 7 months and the 18-month overall survival (OS) was 10%. The incidence rate of anemia and leukopenia was 71.4% and 81%, respectively. Two patients showed the serious adverse event of myelosuppression, with nausea, fatigue, and anorexia. No long-term drug-related toxicity was observed during the follow-up.

Conclusions

Nimotuzumab combined with chemotherapy can achieve promising clinical outcomes in locally advanced or metastatic esophageal cancer, without accumulation of toxicity and was well-tolerated.

Polarization of macrophages in the tumor microenvironment is influenced by EGFR signaling within colon cancer cells

Epidermal growth factor receptor (EGFR) is a target of colon cancer therapy, but the effects of this therapy on the tumor microenvironment remain poorly understood. Our in vivo studies showed that cetuximab, an anti-EGFR monoclonal antibody, effectively inhibited AOM/DSS-induced, colitis-associated tumorigenesis, downregulated M2-related markers, and decreased F4/80+/CD206+ macrophage populations. Treatment with conditioned medium of colon cancer cells increased macrophage expression of the M2-related markers arginase-1 (Arg1), CCL17, CCL22, IL-10 and IL-4. By contrast, conditioned medium of EGFR knockout colon cancer cells inhibited expression of these M2-related markers and induced macrophage expression of the M1-related markers inducible nitric oxide synthase (iNOS), IL-12, TNF-α and CCR7. EGFR knockout in colon cancer cells inhibited macrophage-induced promotion of xenograft tumor growth. Moreover, colon cancer-derived insulin-like growth factor-1 (IGF-1) increased Arg1 expression, and treatment with the IGF1R inhibitor AG1024 inhibited that increase. These results suggest that inhibition of EGFR signaling in colon cancer cells modulates cytokine secretion (e.g. IGF-1) and prevents M1-to-M2 macrophage polarization, thereby inhibiting cancer cell growth.

Identification of gene expression profiling associated with erlotinib-related skin toxicity in pancreatic adenocarcinoma patients

Erlotinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that showed activity against pancreatic ductal adenocarcinoma (PDAC). The drug's most frequently reported side effect as a result of EGFR inhibition is skin rash (SR), a symptom which has been associated with a better therapeutic response to the drug. Gene expression profiling can be used as a tool to predict which patients will develop this important cutaneous manifestation. The aim of the present study was to identify which genes may influence the appearance of SR in PDAC patients. The study included 34 PDAC patients treated with erlotinib: 21 patients developed any grade of SR, while 13 patients did not (controls). Before administering any chemotherapy regimen and the development of SR, we collected RNA from peripheral blood samples of all patients and studied the differential gene expression pattern using the Illumina microarray platform HumanHT-12 v4 Expression BeadChip. Seven genes (FAM46C, IFITM3, GMPR, DENND6B, SELENBP1, NOL10, and SIAH2), involved in different pathways including regulatory, migratory, and signalling processes, were downregulated in PDAC patients with SR. Our results suggest the existence of a gene expression profiling significantly correlated with erlotinib-induced SR in PDAC that could be used as prognostic indicator in this patients.

A variety of human monoclonal antibodies against epidermal growth factor receptor isolated from a phage antibody library

When the technology for constructing human antibody (Ab) libraries using a phage-display system was developed, many researchers in Ab-related fields anticipated that it would be widely applied to the development of pharmaceutical drugs against various diseases, including cancers. However, successful examples of such applications are very limited. Moreover, researchers who utilize phage-display technology now show divergent ways of thinking about phage Ab libraries. For example, there is debate about what should be the source of V_H and V_L genes for the construction of libraries to cover the whole repertoire of Abs present in the human body. In the immune system, the introduction of mutations into V genes followed by selection based on binding activity, termed Ab maturation, is required for the production of Abs exhibiting high affinity to the antigen (Ag). Therefore, introduction of mutations and selection are required for isolation of Abs with high affinity after isolation of clones from phage Ab libraries. We constructed a large human Ab library termed AIMS, developed a screening method termed ICOS, and succeeded in isolating many human monoclonal Abs (mAbs) that specifically and strongly bind to various tumor-associated Ags. Eight anti-EGFR mAbs were included, which we characterized. These mAbs showed various different activities against EGFR-expressing cancer cells. In this paper, we describe these data and discuss the possibility and necessity that the mAbs isolated from the AIMS library might be developed as therapeutic drugs against cancers without introduction of mutations.

CpG island methylator phenotype is associated with the efficacy of sequential oxaliplatin- and irinotecan-based chemotherapy and EGFR-related gene mutation in Japanese patients with metastatic colorectal cancer

BACKGROUND

The CpG island methylator phenotype (CIMP) with multiple promoter methylated loci has been observed in a subset of human colorectal cancer (CRC) cases. CIMP status, which is closely associated with specific clinicopathological and molecular characteristics, is considered a potential predictive biomarker for efficacy of cancer treatment. However, the relationship between the effect of standard chemotherapy, including cytotoxic drugs and anti-epidermal growth factor receptor (EGFR) antibodies, and CIMP status has not been elucidated.

METHODS

In 125 metastatic colorectal cancer (mCRC) patients, we investigated how clinical outcome of chemotherapy was related to CIMP status as detected by methylation-specific PCR (MSP) and to genetic status in five EGFR-related genes (KRAS, BRAF, PIK3CA, NRAS, and AKT1) as detected by direct sequencing.

RESULTS

CIMP-positive status was significantly associated with proximal tumor location and peritoneum metastasis (all P values <0.05). The progression-free survival of patients with CIMP-positive tumors receiving sequential therapy with FOLFOX as the first-line treatment followed by irinotecan-based therapy as the second-line treatment (median = 6.6 months) was inferior to that of such patients receiving the reverse sequence (median = 15.2 months; P = 0.043). Furthermore, CIMP-positive tumors showed higher mutation frequencies for the five EGFR-related genes (74.1 %) than the CIMP-negative tumors did (50.0 %). Among the KRAS wild-type tumors, CIMP-positive tumors were associated with a worse clinical outcome than CIMP-negative tumors following anti-EGFR antibody therapy.

CONCLUSION

Sequential FOLFOX followed by an irinotecan-based regimen is unfavorable in patients with CIMP-positive tumors. High frequencies of mutation in EGFR-related genes in CIMP-positive tumors may cause the lower response to anti-EGFR antibody therapy seen in patients with wild-type KRAS and CIMP-positive tumors.

Tumor evolution and intratumor heterogeneity in colorectal carcinoma: insights from comparative genomic profiling of primary tumors and matched metastases

Metastatic colorectal cancer (CRC) is one of the leading causes of cancer-related mortality among men and women worldwide. Over the past few decades, advances in our understanding of the genetic and epigenetic underpinnings of CRC have led to important insights into the pathogenesis of invasive tumors and have identified different molecular subgroups. Nonetheless, the events that might facilitate dissemination of tumor cells to distant sites giving rise to metastatic disease are not well characterized. Furthermore, in contrast to intertumor heterogeneity the extent of intratumor heterogeneity in different types of CRC has not been fully defined. In this paper, we review studies that have compared the genetic profile of primary invasive carcinomas to that of matched metastases and discuss the implications of their findings for our understanding of tumor evolution and for the clinical management of patients with advanced CRC.

Uracil/tegafur as a possible salvage therapy in chemo-refractory colorectal cancer patients: a single institutional retrospective study

AIM OF THE STUDY

Our aim was to determine the activity and toxicity of uracil/tegafur and leucovorin combination in metastatic colorectal cancer (mCRC) patients who have progressed with all currently active agents.

MATERIAL AND METHODS

This study was a retrospective analysis of 50 mCRC patients who had previously failed to respond to all available chemotherapeutics and who received subsequent treatment with uracil/tegafur 250 mg/m(2) d1-5 in combination with leucovorin 90 mg/day, d1-5 followed by two days' rest.

RESULTS

The median age of the patients was 60 years. Most of them (60%) were male. Bevacizumab was used in 65% and cetuximab in 55% of the patients. Thirty-nine patients (78%) were treated with uracil/tegafur in the fourth line setting. The median treatment duration was 4.2 months (range, 2-24 months). The objective response rate and the disease control rate were 4% and 34%, respectively. Median progression-free survival was 4.1 months (95% CI, 3.6-4.6 months) and overall survival was 6.6 months (95% CI, 4.5-8.6 months). Grade 3 or 4 toxicity was seen in 20% (n = 10) of the patients while 60% (n = 6) of them required dose reductions.

CONCLUSIONS

This retrospective data show that uracil/tegafur may be considered in heavily pretreated mCRC patients because of its activity, lower toxicity, and feasibility.

Hypersensitivity and tumor lysis syndrome associated with cetuximab treatment: should we be afraid?

The majority of the chemotherapy agents in use today cause various infusion reactions, from mild flushing to life-threatening events. The frequency of the reported hypersensitivity reactions induced by cetuximab varies between 3% and 22%. It is recommended in the literature to stop the infusion and replace cetuximab with panitumumab in case of hypersensitivity reactions observed during the treatment of colon cancer. Tumor lysis syndrome (TLS) may occur in colorectal cancers with heavy tumor load. Tumor lysis syndrome may be life-threatening. In our patient with widespread bone and liver metastases, treatment continued with cetuximab as a combination therapy with irinotecan in spite of the hypersensitivity and TLS led to a complete treatment response. The complete response observed after 3 months through continued therapy in our patient may present an example supporting treatment with cetuximab in spite of severe reactions.

Current practices and challenges of adjuvant chemotherapy in patients with colorectal cancer

Colorectal cancer is one of the most commonly diagnosed cancers in men and women in the developed world. Although surgery is the foundation of curative treatment, adjuvant chemotherapy also improves overall and disease-free survival in high-risk stage II and all stage III patients. Research strongly suggests that the timing from surgery to adjuvant chemotherapy is critical, because delays to the start of treatment significantly affect patient outcomes. Both clinical and systemic barriers, such as postoperative complications and institutional wait times, challenge the timely administration of adjuvant chemotherapy. Further research investigating solutions to overcome these barriers is needed.

The combination of FOLFOX4 and bevacizumab may enable salvage surgery of unresectable liver metastases in colon cancer

Colorectal cancer treatment has experienced important advances in the last 5 years. New targeted therapies have been included in the classical regimens based on 5-fluorouracil, oxaliplatin, or irinotecan. This new approach has brought great revolution in the treatment of this type of cancer. Bevacizumab (Avastin), a new antivascular endothelial growth factor drug, has been shown to improve overall survival in combination with chemotherapy in first-line and second-line settings as compared with standard chemotherapy regimens alone. This case report demonstrates our experience with bevacizumab in a colon cancer patient with liver, lung, and regional lymph node metastases who had a relapse in the liver after adjuvant treatment with capecitabine (Xeloda). The addition of bevacizumab to the FOLFOX4 regimen resulted in a partial response that provided an opportunity for salvage hepatic surgery.

Precise and in situ genetic humanization of 6 Mb of mouse immunoglobulin genes

Genetic humanization, which involves replacing mouse genes with their human counterparts, can create powerful animal models for the study of human genes and diseases. One important example of genetic humanization involves mice humanized for their Ig genes, allowing for human antibody responses within a mouse background (HumAb mice) and also providing a valuable platform for the generation of fully human antibodies as therapeutics. However, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which they were genetically humanized. Heretofore, most genetic humanizations have involved disruption of the endogenous mouse gene with simultaneous introduction of a human transgene at a new and random location (so-called KO-plus-transgenic humanization). More recent efforts have attempted to replace mouse genes with their human counterparts at the same genetic location (in situ humanization), but such efforts involved laborious procedures and were limited in size and precision. We describe a general and efficient method for very large, in situ, and precise genetic humanization using large compound bacterial artificial chromosome-based targeting vectors introduced into mouse ES cells. We applied this method to genetically humanize 3-Mb segments of both the mouse heavy and κ light chain Ig loci, by far the largest genetic humanizations ever described. This paper provides a detailed description of our genetic humanization approach, and the companion paper reports that the humoral immune systems of mice bearing these genetically humanized loci function as efficiently as those of WT mice.

Cytohesins/ARNO: the function in colorectal cancer cells

Epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) are critical regulators of cell differentiation, survival, proliferation, and migration in cancers. This study found that ARNO (cytohesin-2), an activator of the EGF and IGF-I pathways, was more highly expressed in colorectal cancer tissue than in benign adjacent colorectal tissue. When ARNO-siRNA or the chemical inhibitor SecinH3 blocked ARNO, the downstream of the EGF and IGF-I pathways decreased in colorectal cell lines HT29 and HCT116. This blocking also weakened cell proliferation, invasion, and migration in vitro. Furthermore, EGF receptor (EGFR)-dependent colorectal tumor xenografts in nude mouse exerted anti-proliferative and growth suppression effects by injecting secineH3. These data suggested that inhibiting cytohesins or ARNO as cytoplasmic activators of EGFR and IGF-I in colorectal cancer resulted in anti-proliferation, reduced invasion, decreased migration, and suppressed growth in vivo and in vitro. Therefore, cytohesins or ARNO may be a potential therapy target for some colorectal cancer.

Predicting response to epidermal growth factor receptor-targeted therapy in colorectal cancer

The discovery over 20 years ago by the Nobel Laureate Stanley Cohen of epidermal growth factor and its receptor, followed by the recognition that this receptor is overexpressed in multiple cancer types, has been of phenomenal significance. From these events the 'Holy Grail' of targeted therapy has looked increasingly realistic. Over the last 5 years this work has come of age with the licensing of multiple agents targeting this important mitogenic pathway in multiple tumor types. However, these agents and the technology behind them, while impressive, have resulted in lower clinical response rates than anticipated. In this review we will focus on the epidermal growth factor receptor-targeted therapies in colorectal cancer, why our expectations from these therapies have not yet been fulfilled and how we may predict those cancers that are likely to respond or be resistant to these therapies through a greater appreciation of the intricacy, diversity and dynamism of cellular signaling mechanisms.

Phase II open-label study to assess efficacy and safety of lenalidomide in combination with cetuximab in KRAS-mutant metastatic colorectal cancer

This study aimed to assess the efficacy and safety of combination treatment with lenalidomide and cetuximab in KRAS-mutant metastatic colorectal cancer patients. This was a phase II multicenter, open-label trial comprising a safety lead-in phase (phase IIa) to determine the maximum tolerated dose, and a randomized proof of concept phase (phase IIb) to determine the response rate of lenalidomide plus cetuximab combination therapy. Phase IIa treatment comprised oral lenalidomide (starting dose 25 mg/day) and intravenous cetuximab (400 mg/m² followed by weekly 250 mg/m²) in 28-day cycles. In phase IIb patients were randomized to either the phase IIa treatment schedule of lenalidomide plus cetuximab combination therapy or lenalidomide 25 mg/day monotherapy. Eight patients were enrolled into phase IIa. One patient developed a dose-limiting toxicity and the maximum tolerated dose of lenalidomide was determined at 25 mg/day. Forty-three patients were enrolled into phase IIb proof of concept. Best response was stable disease in 9 patients and study enrollment was terminated prematurely due to lack of efficacy in both treatment arms and failure to achieve the planned response objective. The majority of adverse events were grade 1 and 2. In both phases, the adverse events most commonly attributed to any study drugs were fatigue, rash and other skin disorders, diarrhea, nausea, and stomatitis. Thirty-nine deaths occurred; none was related to study drug. The combination of lenalidomide and cetuximab appeared to be well tolerated but did not have clinically meaningful activity in KRAS-mutant metastatic colorectal cancer patients.

Trial Registration

Clinicaltrials.gov NCT01032291

From bench to bedside: lessons learned in translating preclinical studies in cancer drug development

The development of targeted agents in oncology has rapidly expanded over the past 2 decades and has led to clinically significant improvements in the treatment of numerous cancers. Unfortunately, not all success at the bench in preclinical experiments has translated to success at the bedside. As preclinical studies shift toward defining proof of mechanism, patient selection, and rational drug combinations, it is critical to understand the lessons learned from prior translational studies to gain an understanding of prior drug development successes and failures. By learning from prior drug development, future translational studies will provide more clinically relevant data, and the underlying hope is that the clinical success rate will improve and the treatment of patients with ineffective targeted therapy will be limited.

Epidermal growth factor receptor targeting in cancer: a review of trends and strategies

The epidermal growth factor receptor (EGFR) is a cell-surface receptor belonging to ErbB family of tyrosine kinase and it plays a vital role in the regulation of cell proliferation, survival and differentiation. However; EGFR is aberrantly activated by various mechanisms like receptor overexpression, mutation, ligand-dependent receptor dimerization, ligand-independent activation and is associated with development of variety of tumors. Therefore, specific EGFR inhibition is one of the key targets for cancer therapy. Two major approaches have been developed and demonstrated benefits in clinical trials for targeting EGFR; monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs). EGFR inhibitors like, cetuximab, panitumumab, etc. (mAbs) and gefitinib, erlotinib, lapatinib, etc. (TKIs) are now commercially available for treatment of variety of cancers. Recently, many other agents like peptides, nanobodies, affibodies and antisense oligonucleotide have also shown better efficacy in targeting and inhibiting EGFR. Now a days, efforts are being focused to identify molecular markers that can predict patients more likely to respond to anti-EGFR therapy; to find out combinatorial approaches with EGFR inhibitors and to bring new therapeutic agents with clinical efficacy. In this review we have outlined the role of EGFR in cancer, different types of EGFR inhibitors, preclinical and clinical status of EGFR inhibitors as well as summarized the recent efforts made in the field of molecular EGFR targeting.

Colorectal cancer defeating? Challenge accepted!

Colorectal tumours are actually considered as aberrant organs, within it is possible to notice a different stage of cell growth and differentiation. Their origin is reported to arise from a subpopulation of tumour cells endowed with, just like the healthy stem cells, self-renewal and aberrant multi-lineage differentiation capacity likely to be called colorectal cancer stem cells (CCSCs). Cancer stem cells (CSCs) fate, since their origin, reflects the influences from their microenvironment (or niche) both in the maintenance of stemness, in promoting their differentiation, and in inducing epithelial-mesenchymal transition, responsible of CSCs dissemination and subsequent formation of metastatic lesions. The tumour cells heterogeneity and their immuno-response resistance nowadays probably responsible of the failure of the conventional therapies, make this research field an open issue. Even more importantly, our increasing understanding of the cellular and molecular mechanisms that regulate CSC quiescence and cell cycle regulation, self-renewal, chemotaxis and resistance to cytotoxic agents, is expected to eventually result in tailor-made therapies with a significant impact on the morbidity and overall survival of colorectal cancer patients.

Mutation analysis of KRAS in primary colorectal cancer and matched metastases by means of highly sensitivity molecular assay

Mutation analysis of KRAS is needed before starting treatment with anti-EGFR monoclonal antibodies in patients with metastatic colorectal cancer (CRC). In most of the cases, testing is performed on primary tumors, assuming that KRAS mutation status does not change in metastasis although correlation studies gave conflicting results. We evaluated the KRAS status concordance rate between primary tumors and related metastasis using a highly sensitive molecular assay. Forty-five primary tumors and related metastases from patients with CRC (28/45 male-62.2% and 17/45 female-37.8%; mean age 66.4 years) were analyzed by using TheraScreen: KRAS mutational kit. Metastatic samples were collected from lymph nodes (8/45-17.8%) and visceral sites (37/45-82.2%); 23 were synchronous (49%) and 22 were metachronous (51%), obtained after a mean of 30.8 months after the first diagnosis of CRC. Twenty-eight patients had KRAS mutations in both primary CRC and related metastases (62.2%). No differences in type and frequency of mutations were identified, despite different metastatic sites and time of onset of metastatic disease. Our results indicate that the mutation status of KRAS is the same in primary CRC and metastasis, suggesting that in clinical practice, KRAS testing can be performed on both tumor tissues when using a highly sensitive molecular assay.

Bevacizumab use and risk of cardiovascular adverse events among elderly patients with colorectal cancer receiving chemotherapy: a population-based study

BACKGROUND

Cardiovascular risk attributable to bevacizumab (Avastin(®), BEV) for treatment of metastatic colorectal cancer (CRC) remains unclear. We conducted a population-based cohort study to assess the safety of BEV use among patients aged ≥ 65.

PATIENTS AND METHODS

We identified CRC patients diagnosed from 2005 to 2007 who received chemotherapy and were followed until 31 December 2009. Outcomes were 3-year risk of arterial thromboembolic events (ATEs), cardiomyopathy or congestive heart failure (CM/CHF), and cardiac death (CD) after chemotherapy initiation. We fitted Cox-proportional hazards (PHs) models with inverse-probability-of-treatment-weights and calculated hazard ratios (HRs) for the risk of adverse events.

RESULTS

We identified 6803 CRC patients (median age: 73 years). Those with cardiac comorbidity were less likely to receive BEV (P < 0.0001). BEV is associated with an elevated risk of ATEs (HR = 1.82, 95% CI = 1.20-2.76, P < 0.001; rate difference: 3.5 additional cases/1000 person-years). We observed no association between BEV and CD or CM/CHF.

CONCLUSIONS

In general practice, the cardiovascular risk of BEV in elderly CRC is modest. The observed ATEs risk is lower than reported in clinical trials, which may be due to careful patient selection. Our findings may facilitate clinical decision-making of BEV use in elderly patients.

Targeted therapies in colorectal cancer-an integrative view by PPPM

In developed countries, colorectal cancer (CRC) is the third most common malignancy, but it is the second most frequent cause of cancer-related death. Clinicians are still faced with numerous challenges in the treatment of this disease, and future approaches which target the molecular features of the disorder will be critical for success in this disease setting. Genetic analyses of many solid tumours have shown that up to 100 protein-encoding genes are mutated. Within CRC, numerous genetic alterations have been identified in a number of pathways. Therefore, understanding the molecular pathology of CRC may present information on potential routes for treatment and may also provide valuable prognostic information. This will be particularly pertinent for molecularly targeted treatments, such as anti-vascular endothelial growth factor therapies and anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapy. KRAS and BRAF mutations have been shown to predict response to anti-EGFR therapy. As EGFR can also signal via the phosphatidylinositol 3-kinase (PI3K) kinase pathway, there is considerable interest in the potential roles of members of this pathway (such as PI3K and PTEN) in predicting treatment response. Therefore, a combined approach of new techniques that allow identification of these biomarkers alongside interdisciplinary approaches to the treatment of advanced CRC will aid in the treatment decision-making process and may also serve to guide future therapeutic approaches.

Optimizing treatment of metastatic colorectal cancer patients with anti-EGFR antibodies: overcoming the mechanisms of cancer cell resistance

INTRODUCTION

A number of anti-EGFR monoclonal antibodies (mAbs) have been recently developed for the treatment of refractory metastatic colorectal cancer (mCRC). These mAbs, blocking ligand/receptor interactions, exert their biological activity via multiple mechanisms, including inhibition of cell cycle progression, potentiation of cell apoptosis, inhibition of angiogenesis, tumor cell invasion and metastasis and, potentially, induction of immunological effector mechanisms.

AREAS COVERED

Cetuximab is an anti-EGFR mAb currently used in mCRC treatment. Despite the evidence of efficacy of cetuximab in the treatment of mCRC patients, the observation of low response rates was the proof of concept of resistance to anti-EGFR mAbs treatment. An increasing number of molecular alterations have been more recently hypothesized to be involved in resistance to anti-EGFR mAbs in CRC: mutations in BRAF, NRAS and PIK3CA, loss of expression of PTEN and, now, activation of HER2 signaling through HER2 gene amplification and/or increased heregulin stimulation.

EXPERT OPINION

This review focuses on the development of new strategies such as combination with other agents blocking alternative escape pathways, cancer cell prioritization hyperactivating EGFR pathway, combination with immune system, development of nanotech devices to increase efficacy of antibody-based therapy and overcome the mechanisms of cancer cell resistance.

Can knowledge of germline markers of toxicity optimize dosing and efficacy of cancer therapy?

The systemic treatment of cancer with traditional cytotoxic chemotherapeutic agents and more targeted agents is often complicated by the onset of adverse drug reactions. Pharmacogenetic prediction of adverse drug reactions might have consequences for dosing and efficacy. This review discusses relevant examples where the germline variant-toxicity relationship has been validated as an initial step in developing clinically useful pharmacogenetic markers and provides examples where germline variants have influenced dosing strategies and/or survival or other outcomes of efficacy. This review will also provide insight into the reasons why more pharmacogenetic markers have not been routinely integrated into clinical practice.