Current situation of Panitumumab, Matuzumab, Nimotuzumab and Zalutumumab

Evaluation of a cIEF Fractionation Workflow for Offline MS Analysis of Charge Variants of the Monoclonal Antibody Matuzumab

Biological drugs like monoclonal antibodies require careful analysis and characterization to ensure product quality, safety, and efficacy. Charge variants of the molecule are of key interest and are analyzed using imaged capillary isoelectric focusing (icIEF). However, deeper characterization of these variants poses challenges. Two workflows for their characterization exist: an ion-exchange chromatography method for variant collection before mass spectrometry (MS) analysis, which is labor-intensive, and direct coupling of CE to MS, which allows detailed structural characterization but has limitations, for example, due to incompatibilities with ES ionization using high BGE concentrations. This study evaluates a platform that fractionates charge variants for offline MS analysis. The suitability of a procedure in which analytical icIEF methods are converted into preparative cIEF fractionation methods by increasing the sample concentration and adding 20 mM arginine as a cathodic spacer was tested. After chemical mobilization and fraction collection, the identity of the fractions was determined by fluorescence measurement and reinjection of the protein-containing fractions, using the previously developed analytical icIEF method. MS was subsequently performed. The general suitability of the workflow was demonstrated using Matuzumab. Transferring the analytical method from a concentration of 0.2 to 1.2 mg/mL in fractionation yielded an identical number of peaks and visually comparable peak profiles. The preparative separation took 50 min, with an additional 25 min for mobilization and 45 s per fraction collection, totaling approximately 2.5 h. Verification of charge variant isolation was straightforward via analytical icIEF. Following fractionation, MS allowed for the identification of the main peaks. Preliminary results with other antibodies indicated that the concentration range for MS experiments needs further investigation. Future work will aim to optimize sensitivity, selectivity, analysis time, and reproducibility.

Nimotuzumab combined with radiotherapy+/- chemotherapy for definitive treatment of locally advanced squamous cell carcinoma of head and neck: a metanalysis of randomized controlled trials

Objectives

To assess the efficacy and safety of nimotuzumab in combination with radiotherapy or chemoradiotherapy for locally advanced head and neck squamous cell carcinoma.

Methods

Systematic searches were performed on PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biomedical Medicine, Wanfang, VIP databases. Seven eligible randomized controlled trials (n = 1012) were selected through rigorous inclusion and exclusion criteria.

Results

A total of 1012 cases were included. including 508 (50.2%) in the nimotuzumab combination treatment group; There were 504 cases (49.8%) in the control group. The results of meta-analysis showed that the overall survival (Hazard Ratio [HR]=0.75, 95% Confidence Interval [CI]: 0.62-0.90, P<0.05), progression-free survival (HR=0.69, 95% CI: 0.54-0.87, P<0.05), complete response rate (Risk Ratio [RR]=1.52, 95% CI: 1.24-1.86, P<0.05), and objective response rate (RR=1.32, 95% CI: 1.17-1.48, P<0.05) were significantly improved in the nimotuzumab combination treatment group compared with the control group. In terms of the incidence of adverse effects, only the incidence of rash was the nimotuzumab combination group higher than in the treatment alone group, and there was no significant difference between the remaining adverse reactions (neutropenia, anemia, nausea/vomiting, mucositis, dermatitis, dysphagia).

Conclusion

Nimotuzumab combined with radiotherapy or chemoradiotherapy is more effective than radiotherapy alone or chemoradiotherapy in locally advanced squamous cell carcinoma of the head and neck, and the safety profile is controllable. Therefore, the addition of nimotuzumab to treatment is expected to be an effective treatment option for this disease. However, more prospective randomized controlled trials are needed to fully explore the effectiveness of this treatment in patients with locally advanced head and neck squamous cell carcinoma.

Systematic Review Registration

identifier PROSPERO (CRD: 42022383313).

Repurposing EGFR Inhibitors for Oral Cancer Pain and Opioid Tolerance

Oral cancer pain remains a significant public health concern. Despite the development of improved treatments, pain continues to be a debilitating clinical feature of the disease, leading to reduced oral mobility and diminished quality of life. Opioids are the gold standard treatment for moderate-to-severe oral cancer pain; however, chronic opioid administration leads to hyperalgesia, tolerance, and dependence. The aim of this review is to present accumulating evidence that epidermal growth factor receptor (EGFR) signaling, often dysregulated in cancer, is also an emerging signaling pathway critically involved in pain and opioid tolerance. We presented preclinical and clinical data to demonstrate how repurposing EGFR inhibitors typically used for cancer treatment could be an effective pharmacological strategy to treat oral cancer pain and to prevent or delay the development of opioid tolerance. We also propose that EGFR interaction with the µ-opioid receptor and glutamate N-methyl-D-aspartate receptor could be two novel downstream mechanisms contributing to pain and morphine tolerance. Most data presented here support that repurposing EGFR inhibitors as non-opioid analgesics in oral cancer pain is promising and warrants further research.

Current and Emerging Molecular Therapies for Head and Neck Squamous Cell Carcinoma

Head and neck cancer affects nearly 750,000 patients, with more than 300,000 deaths annually. Advances in first line surgical treatment have improved survival rates marginally particularly in developed countries, however survival rates for aggressive locally advanced head and neck cancer are still poor. Recurrent and metastatic disease remains a significant problem for patients and the health system. As our knowledge of the genomic landscape of the head and neck cancers continues to expand, there are promising developments occurring in molecular therapies available for advanced or recalcitrant disease. The concept of precision medicine is underpinned by our ability to accurately sequence tumour samples to best understand individual patient genomic variations and to tailor targeted therapy for them based on such molecular profiling. Not only is their purported response to therapy a factor of their genomic variation, but so is their inclusion in biomarker-driven personalised medicine therapeutic trials. With the ever-expanding number of molecular druggable targets explored through advances in next generation sequencing, the number of clinical trials assessing these targets has significantly increased over recent years. Although some trials are focussed on first-line therapeutic approaches, a greater majority are focussed on locally advanced, recurrent or metastatic disease. Similarly, although single agent monotherapy has been found effective in some cases, it is the combination of drugs targeting different signalling pathways that seem to be more beneficial to patients. This paper outlines current and emerging molecular therapies for head and neck cancer, and updates readers on outcomes of the most pertinent clinical trials in this area while also summarising ongoing efforts to bring more molecular therapies into clinical practice.

EGFR targeting for cancer therapy: Pharmacology and immunoconjugates with drugs and nanoparticles

The epidermal growth factor receptor (EGFR) belongs to the tyrosine kinase receptors family and is present in the epithelial cell membrane. Its endogenous activation occurs through the binding of different endogenous ligands, including the epidermal growth factor (EGF), leading to signaling cascades able to maintain normal cellular functions. Although involved in the development and maintenance of tissues in normal conditions, when EGFR is overexpressed, it stimulates the growth and progression of tumors, resulting in angiogenesis, invasion and metastasis, through some main cascades such as Ras/Raf/MAPK, PIK-3/AKT, PLC-PKC and STAT. Besides, considering the limitations of conventional chemotherapy that result in high toxicity and low tumor specificity, EGFR is currently considered an important target. As a result, several monoclonal antibodies are currently approved for use in cancer treatment, such as cetuximab (CTX), panitumumab, nimotuzumab, necitumumab and others are in clinical trials. Aiming to combine the chemotherapeutic agent toxicity and specific targeting to EGFR overexpressing tumor tissues, two main strategies will be discussed in this review: antibody-drug conjugates (ADCs) and antibody-nanoparticle conjugates (ANCs). Briefly, ADCs consist of antibodies covalently linked through a spacer to the cytotoxic drug. Upon administration, binding to EGFR and endocytosis, ADCs suffer chemical and enzymatic reactions leading to the release and accumulation of the drug. Instead, ANCs consist of nanotechnology-based formulations, such as lipid, polymeric and inorganic nanoparticles able to protect the drug against inactivation, allowing controlled release and also passive accumulation in tumor tissues by the enhanced permeability and retention effect (EPR). Furthermore, ANCs undergo active targeting through EGFR receptor-mediated endocytosis, leading to the formation of lysosomes and drug release into the cytosol. Herein, we will present and discuss some important aspects regarding EGFR structure, its role on internal signaling pathways and downregulation aspects. Then, considering that EGFR is a potential therapeutic target for cancer therapy, the monoclonal antibodies able to target this receptor will be presented and discussed. Finally, ADCs and ANCs state of the art will be reviewed and recent studies and clinical progresses will be highlighted. To the best of our knowledge, this is the first review paper to address specifically the EGFR target and its application on ADCs and ANCs.

Induction of different cellular arrest and molecular responses in low EGFR expressing A549 and high EGFR expressing A431 tumor cells treated with various doses of 177Lu-Nimotuzumab

INTRODUCTION

Radioimmunotherapy (RIT) is a major anti-cancer therapy in cancer management multimodalities. ¹⁷⁷Lu-Nimotuzumab has been in the use for radioimmunotherapy of EGFR expressing tumors. This study focuses on understanding the differential cellular and molecular mechanisms of anti-tumor effects of ¹⁷⁷Lu-Nimotuzumab on low EGFR expressing A549 and high EGFR expressing A431 tumor cells.

MATERIALS AND METHODS

Nimotuzumab labeled with ¹⁷⁷Lu was characterized by SE-HPLC. Specificity of ¹⁷⁷Lu-Nimotuzumab to EGFR expressed on A549 and A431 cells was confirmed by competitive assay using increasing amounts of unlabeled Nimotuzumab. Cellular responses of A549 (low EGFR) and A431 (high EGFR) in response to different doses of ¹⁷⁷Lu-Nimotuzumab were determined by Viable count assay for cellular viability, cell-cycle analysis by DNA staining, apoptotic assay for cell death, and CFSE dilution assay for cellular proliferation capacity. The number of DNA DSBs formed was determined using γ-H2AX assay with PI staining. Transcription of genes involved in DNA damage response and repair (DRR) pathways was monitored by RT-qPCR.

RESULTS

¹⁷⁷Lu-Nimotuzumab characterized by SE-HPLC exhibited a radiochemical purity of 99.1 ± 0.6%. Cell binding competition studies with ¹⁷⁷Lu-Nimotuzumab showed specific binding of 34.3 ± 1.7% with A431 cells and 18.4 ± 1.9% with A549 cells which decreased when co-incubated with unlabeled Nimotuzumab. Cytotoxicity and DNA damage (DNA DSBs) increased with an increase in the dose of ¹⁷⁷Lu-Nimotuzumab. A549 displayed G2/M arrest while A431 showed G1 arrest. Apoptotic death was determined to be one of the modes of death of arrested A549 and A431 cells which increases with the increase in the dose of ¹⁷⁷Lu-Nimotuzumab. Loss of proliferation capacity was higher in A431 showed by CFSE staining at different doses of ¹⁷⁷Lu-Nimotuzumab. Transcription profile of most DRR genes in A431 and A549 showed a decrease in the transcription at 4 h followed by recovery at 16 h post-treatment. The degree of transcription of most DRR genes was similar, irrespective of ¹⁷⁷Lu-Nimotuzumab dose.

CONCLUSION

¹⁷⁷Lu-Nimotuzumab induces different cellular arrest and molecular responses in low EGFR expressing A549 and high EGFR expressing A431 tumor cells. This study would enable the development of integrative novel treatment strategies for radioimmunotherapy in low and high EGFR expressing tumors by ¹⁷⁷Lu-Nimotuzumab with therapeutic gains.

EGFR exon 19-deletion aberrantly regulate ERCC1 expression that may partly impaired DNA damage repair ability in non-small cell lung cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) activating mutations are usually associated with DNA damage repair (DDR) deficiency. However, the precise mechanism has remained elusive. In this study, we aimed to investigate whether EGFR exon 19 deletion mutation downstream signals contributed to DDR deficiency by downregulation of excision repair cross-complementation group-1 (ERCC1), a key factor in DDR, expression and function.

METHODS

We first measured cell survival, DNA damage (γ-H2AX foci formation) and damage repair (ERCC1 and RAD51 foci formation) ability in response to DNA cross-linking drug in EGFR exon 19 deletion and EGFR wild-type cells separately. We then investigated the involvement of EGFR downstream signals in regulating ERCC1 expression and function in EGFR exon 19 deletion cells as compared with EGFR wild-type ones.

RESULTS

We observed increased γ-H2AX, but impaired ERCC1 and RAD51 nuclear foci formation in EGFR exon 19 deletion cells as compared with EGFR wild-type ones treated with DNA cross-linker. In addition, we identified that inhibition of EGFR exon 19 deletion signals increased ERCC1 expression, whereas blocked wild-type EGFR signals decreased ERCC1 expression, on both mRNA and protein levels. Furthermore, EGFR exon 19 deletion downstream signals not only inhibited ERCC1 expression but also influenced ERCC1 foci formation in response to DNA cross-linker.

CONCLUSION

Our findings indicated that the aberrant EGFR exon 19 deletion signals were not only associated with decreased expression of ERCC1 but were also involved in impaired ERCC1 recruitment in response to DNA cross-link damage, thereby providing us with more evidence for exploring the mechanism of DDR deficiency in EGFR mutant NSCLC.

Targeted and novel therapy in advanced gastric cancer

The systemic treatment options for advanced gastric cancer (GC) have evolved rapidly in recent years. We have reviewed the recent data of clinical trial incorporating targeted agents, including inhibitors of angiogenesis, human epidermal growth factor receptor 2 (HER2), mesenchymal-epithelial transition, epidermal growth factor receptor, mammalian target of rapamycin, claudin-18.2, programmed death-1 and DNA. Addition of trastuzumab to platinum-based chemotherapy has become standard of care as front-line therapy in advanced GC overexpressing HER2. In the second-line setting, ramucirumab with paclitaxel significantly improves overall survival compared to paclitaxel alone. For patients with refractory disease, apatinib, nivolumab, ramucirumab and TAS-102 have demonstrated single-agent activity with improved overall survival compared to placebo alone. Pembrolizumab has demonstrated more than 50% response rate in microsatellite instability-high tumors, 15% response rate in tumors expressing programmed death ligand 1, and non-inferior outcome in first-line treatment compared to chemotherapy. This review summarizes the current state and progress of research on targeted therapy for advanced GC.

New Therapies in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy with high rates of mortality and morbidity. Beginning with cetuximab, investigators continue to optimize antibody technology to target cell-surface receptors that promote HNSCC growth. Small molecules and oligonucleotides have also emerged as therapeutic inhibitors of key receptor-mediated signaling pathways. Although many such therapies have been disappointing in clinical trials as single agents, they continue to be studied in combination with standard therapies. Approvals of pembrolizumab and nivolumab opened a new era of immunotherapy that aims to stimulate antitumor immunity in the tumor microenvironment. Immunotherapies are being intensively investigated in new HNSCC clinical trials, with the goal of optimizing the therapeutic potential of this new class of anticancer agent.

Monoclonal antibody-based therapeutics, targeting the epidermal growth factor receptor family: from herceptin to Pan HER

Objectives

Monoclonal antibody-based of cancer therapy has been considered as one of the most successful therapeutic strategies for both haematologic malignancies and solid tumours in the last two decades. Epidermal growth factor receptor (EGFR) family signalling pathways play a key role in the regulation of cell proliferation, survival and differentiation. Hence, anti-EGFR family mAbs is one of the most promising approaches in cancer therapy.

Key findings

Here, recent advances in anti-EGFR mAb including approved or successfully tested in preclinical and clinical studies have been reviewed. Although we focus on monoclonal antibodies against the EGF receptor, but the mechanisms underlying the effects of EGFR-specific mAb in cancer therapy, to some extend the resistance to existing anti-EGFR therapies and some therapeutic strategies to overcome resistance such as combination of mAbs on different pathways are briefly discussed as well.

Summary

The EGFR family receptors, is considered as an attractive target for mAb development to inhibit their consecutive activities in tumour growth and resistance. However, due to resistance mechanisms, the combination therapies may become a good candidate for targeting EGFR family receptors.

Epidermal growth factor receptor inhibitors trigger a type I interferon response in human skin

The Epidermal Growth Factor Receptor (EGFR) is centrally involved in the regulation of key processes of the epithelia, including cell proliferation, survival, differentiation, and also tumorigenesis. Humanized antibodies and small-molecule inhibitors targeting EGFR were developed to disrupt these functions in cancer cells and are currently used in the treatment of diverse metastatic epithelial cancers. By contrast, these drugs possess significant skin-specific toxic effects, comprising the establishment of a persistent inflammatory milieu. So far, the molecular mechanisms underlying these epiphenomena have been investigated rather poorly. Here we showed that keratinocytes respond to anti-EGFR drugs with the development of a type I interferon molecular signature. Upregulation of the transcription factor IRF1 is early implicated in the enhanced expression of interferon-kappa, leading to persistent activation of STAT1 and further amplification of downstream interferon-induced genes, including anti-viral effectors and chemokines. When anti-EGFR drugs are associated to TNF-α, whose expression is enhanced by the drugs themselves, all these molecular events undergo a dramatic enhancement by synergy mechanisms. Finally, high levels of interferon-kappa can be observed in epidermal keratinocytes and also in leukocytes infiltrating the upper dermis of cetuximab-driven skin lesions. Our data suggest that dysregulated activation of type I interferon innate immunity is implicated in the molecular processes triggered by anti-EGFR drugs and leading to persistent skin inflammation.

Extreme Phenotype of Epidermal Growth Factor Receptor Inhibitor-induced Destructive Folliculitis

Due to the increasingly widespread use and side effect profile of epidermal growth factor receptor inhibitors (EGFRIs), cutaneous side effects of these drugs are frequently encountered. The EGFR is expressed on keratinocytes and fibroblasts. Inhibition of EGFR can produce a range of cutaneous adverse effects, the most frequent being a characteristic acneiform skin eruption. As the latter is associated with good anti-neoplastic responses, the onset of EGFRI-induced acneiform skin eruption is typically viewed as a positive sign by patients and physicians. It can usually be treated well with standard acne drugs, but in rare cases, the skin eruption can be so severe that systemic therapy and/or interruption of EGFRI treatment are required. One of the severest forms of EGFRI-induced skin eruption occurring on the head and neck area resembles folliculitis decalvans. Here, we discuss the management of such a case seen in our department. In addition, we present an analysis of tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-17A expression based on immunohistochemical stains and qPCR.

What is the best strategy for targeting EGF receptors in non-small-cell lung cancer?

EGF receptors (EGFRs) are often overexpressed or constitutively activated in non-small-cell lung cancer, and are an important therapeutic target. EGFR signaling can be blocked with tyrosine kinase inhibitors (TKIs) and anti-EGFR antibodies. Three EGFR-TKIs are approved as initial monotherapies in patients with EGFR-activating mutations, and erlotinib has a role as maintenance and second-line therapy. Investigational anti-EGFR monoclonal antibodies plus standard first-line therapy improve survival in patients with advanced non-small-cell lung cancer, especially in tumors with high EGFR expression. Anti-EGFR antibodies inhibit EGFR signaling and have the potential to stimulate antibody-dependent cell-mediated cytotoxicity. Multikinase TKIs are investigational as first- and second-line therapies, as monotherapies and in combination with chemotherapy. This article summarizes the available clinical data for EGFR-targeted therapies.

Enhanced dimerization drives ligand-independent activity of mutant epidermal growth factor receptor in lung cancer

Epidermal growth factor receptor kinase mutations drive oncogenesis, but the molecular mechanism of pathological signal initiation is poorly understood. Using high-resolution microscopy methods, the authors reveal that these kinase mutations induce structural changes in the receptor ectodomain that lead to enhanced, ligand-independent dimerization.

Mutations within the epidermal growth factor receptor (EGFR/erbB1/Her1) are often associated with tumorigenesis. In particular, a number of EGFR mutants that demonstrate ligand-independent signaling are common in non–small cell lung cancer (NSCLC), including kinase domain mutations L858R (also called L834R) and exon 19 deletions (e.g., ΔL747-P753insS), which collectively make up nearly 90% of mutations in NSCLC. The molecular mechanisms by which these mutations confer constitutive activity remain unresolved. Using multiple subdiffraction-limit imaging modalities, we reveal the altered receptor structure and interaction kinetics of NSCLC-associated EGFR mutants. We applied two-color single quantum dot tracking to quantify receptor dimerization kinetics on living cells and show that, in contrast to wild-type EGFR, mutants are capable of forming stable, ligand-independent dimers. Two-color superresolution localization microscopy confirmed ligand-independent aggregation of EGFR mutants. Live-cell Förster resonance energy transfer measurements revealed that the L858R kinase mutation alters ectodomain structure such that unliganded mutant EGFR adopts an extended, dimerization-competent conformation. Finally, mutation of the putative dimerization arm confirmed a critical role for ectodomain engagement in ligand-independent signaling. These data support a model in which dysregulated activity of NSCLC-associated kinase mutants is driven by coordinated interactions involving both the kinase and extracellular domains that lead to enhanced dimerization.

Anti-EGFR monoclonal antibodies for treatment of colorectal cancers: development of cetuximab and panitumumab

Over the last decade, anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) have been firmly established as essential drugs for the treatment of metastatic colorectal cancer (CRC). Cetuximab and panitumumab have been approved by American and European drug agencies. This review aims at exploring the main outcomes of clinical studies performed during their clinical development, from phase I to III trials, and hence at giving a comprehensive review of the scientific rational and up-to-date evidence sustaining the use of these drugs. Many areas are still under active investigation such as administration schedules, their efficacy in comparison with bevacizumab, their role in adjuvant therapy, molecular predictors, and management of side effects.

Nimotuzumab enhances radiation sensitivity of NSCLC H292 cells in vitro by blocking epidermal growth factor receptor nuclear translocation and inhibiting radiation-induced DNA damage repair

Background

The epidermal growth factor receptor (EGFR) signaling pathway plays a significant role in radiation resistance. There is evidence that EGFR nuclear translocation is associated with DNA double-strand breaks (DSB) repair. Nimotuzumab has shown the effect of radiosensitization in various cancer cells, but little is known about the relationship between nimotuzumab and EGFR nuclear translocation in non-small cell lung cancer (NSCLC) cell lines. In this study, we selected two NSCLC cell lines, namely, H292 (with high EGFR expression) and H1975 (with low EGFR expression) and explored the mechanisms underlying radiation sensitivity.

Methods

MTT assay, clonogenic survival assay, and flow cytometry were performed separately to test cell viability, radiation sensitivity, cell cycle distribution, and apoptosis. Protein γ-H2AX, DNA-PK/p-DNA-PK, and EGFR/p-EGFR expression were further compared both in the cytoplasm and the nucleus with the western blot.

Results

Nimotuzumab reduced the viability of H292 cells and sensitized H292 cells to ionizing radiation. The radiation sensitivity enhancement ratio (SER) was 1.304 and 1.092 for H292 and H1975 cells, respectively. H292 cells after nimotuzumab administration were arrested at the G0/G1 phase in response to radiation. Apoptosis was without statistical significance in both cell lines. γ-H2AX formation in the combination group (nimotuzumab and radiation) increased both in the cytoplasm and the nucleus along with the decreased expression of nuclear EGFR/p-EGFR and p-DNA-PK in H292 cells (P<0.05) that was more significant than that in H1975 cells.

Conclusion

Our research revealed a possible mechanism to explain the radiosensitivity in H292 cells. Nimotuzumab decreased the radiation-induced activation of DNA-PK by blocking EGFR nuclear translocation and impairing DNA DSB repair, thus enhancing radiosensitivity in H292 cells. Because these results represent early research, the matters of how γ-H2AX and DNA-PK dynamically change simultaneously with nuclear EGFR and the best time to administer nimotuzumab will require further exploration.

Semimechanistic model to characterize nonlinear pharmacokinetics of nimotuzumab in patients with advanced breast cancer

This study aimed (1) to develop a semimechanistic pharmacokinetic (PK) model for nimotuzumab in patients with advanced breast cancer and (2) to identify demographic, biochemical, and clinical predictive factors of the PK variability. Data from a phase 1 study were analyzed using the nonlinear mixed-effects approach (NONMEM). A target-mediated disposition model that included 2 open PK compartments, the monoclonal antibody (mAb)-target binding, and target and mAb-target complex turnovers best described the linear and nonlinear PK. Covariates had no influence on the PK parameters. The final parameter estimates were 19.93 L (steady-state volume), 0.0045-0.0172 L/h (range of total clearance values), 6.96 μg/mL (steady-state binding constant), 5.50 h(-1) (target degradation rate constant), 1.43 (μg/mL) · h(-1) (complex formation rate), and 0.148 h(-1) (complex internalization rate constant). The model described the effect of the mAb-target binding, and target and mAb-target complex turnovers on nimotuzumab PK. Simulations showed that doses above 200 mg maintained the 50% target occupancy during all of the treatment. This model can be very useful for knowing the dosing schedules required for efficacy and supports further investigation of the pharmacokinetic/pharmacodynamic relationships of nimotuzumab to improve its therapeutic use.

Immunobiology and immunotherapeutic targeting of glioma stem cells

For decades human brain tumors have confounded our efforts to effectively manage and treat patients. In adults, glioblastoma multiforme is the most common malignant brain tumor with a patient survival of just over 14 months. In children, brain tumors are the leading cause of solid tumor cancer death and gliomas account for one-fifth of all childhood cancers. Despite advances in conventional treatments such as surgical resection, radiotherapy, and systemic chemotherapy, the incidence and mortality rates for gliomas have essentially stayed the same. Furthermore, research efforts into novel therapeutics that initially appeared promising have yet to show a marked benefit. A shocking and somewhat disturbing view is that investigators and clinicians may have been targeting the wrong cells, resulting in the appearance of the removal or eradication of patient gliomas only to have brain cancer recurrence. Here we review research progress in immunotherapy as it pertains to glioma treatment and how it can and is being adapted to target glioma stem cells (GSCs) as a means of dealing with this potential paradigm.

Molecularly targeting the PI3K-Akt-mTOR pathway can sensitize cancer cells to radiotherapy and chemotherapy

Radiotherapy and chemotherapeutic agents that damage DNA are the current major non-surgical means of treating cancer. However, many patients develop resistances to chemotherapy drugs in their later lives. The PI3K and Ras signaling pathways are deregulated in most cancers, so molecularly targeting PI3K-Akt or Ras-MAPK signaling sensitizes many cancer types to radiotherapy and chemotherapy, but the underlying molecular mechanisms have yet to be determined. During the multi-step processes of tumorigenesis, cancer cells gain the capability to disrupt the cell cycle checkpoint and increase the activity of CDK4/6 by disrupting the PI3K, Ras, p53, and Rb signaling circuits. Recent advances have demonstrated that PI3K-Akt-mTOR signaling controls FANCD2 and ribonucleotide reductase (RNR). FANCD2 plays an important role in the resistance of cells to DNA damage agents and the activation of DNA damage checkpoints, while RNR is critical for the completion of DNA replication and repair in response to DNA damage and replication stress. Regulation of FANCD2 and RNR suggests that cancer cells depend on PI3K-Akt-mTOR signaling for survival in response to DNA damage, indicating that the PI3K-AktmTOR pathway promotes resistance to chemotherapy and radiotherapy by enhancing DNA damage repair.

Epidermal growth factor receptor signalling in keratinocyte biology: implications for skin toxicity of tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) and its ligands have been long recognized as centrally involved in the growth and repair process of epithelia, as well as in carcinogenesis. In addition, the EGFR has been demonstrated to be importantly involved in the control of inflammatory responses. During this last decade, a number of highly specific agents targeting this system have become an integral component of pharmacologic strategies against many solid malignancies. These drugs have led to increased patient survival and made therapy more tolerant when compared to conventional cytotoxic drugs. Nonetheless, their use is associated with a constellation of toxic effects on the skin, including follicular pustules, persistent inflammation, xerosis and pruritus, and enhanced susceptibility to infections. This dramatic impairment of skin homoeostasis underscores the centrality of the EGFR-ligand system in the whole skin immune system. So far, no mechanism-based approaches are available to specifically counteract the adverse effects of anti-EGFR drugs or any other class of tyrosine kinase inhibitors. Only the knowledge of the cellular and molecular events underlying these adverse effects in humans, combined with in vitro/in vivo models able to mimic these toxic responses, may guide the development of mechanism-based treatment or prevention strategies.

Three-dimensional histologic validation of high-resolution SPECT of antibody distributions within xenografts

Longitudinal imaging of intratumoral distributions of antibodies in vivo in mouse cancer models is of great importance for developing cancer therapies. In this study, multipinhole SPECT with sub-half-millimeter resolution was tested for exploring intratumoral distributions of radiolabeled antibodies directed toward the epidermal growth factor receptor (EGFr) and compared with full 3-dimensional target expression assessed by immunohistochemistry.

METHODS

(111)In-labeled zalutumumab, a human monoclonal human EGFr-targeting antibody, was administered at a nonsaturating dose to 3 mice with xenografted A431 tumors exhibiting high EGFr expression. Total-body and focused in vivo tumor SPECT was performed at 0 and 48 h after injection and compared both visually and quantitatively with full 3-dimensional immunohistochemical staining for EGFr target expression.

RESULTS

SPECT at 48 h after injection showed that activity was predominantly concentrated in the tumor (10.5% ± 1.3% of the total-body activity; average concentration, 30.1% ± 4.6% of the injected dose per cubic centimeter). (111)In-labeled EGFr-targeting antibodies were distributed heterogeneously throughout the tumor. Some hot spots were observed near the tumor rim. Immunohistochemistry indicated that the antibody distributions obtained by SPECT were morphologically similar to those obtained for ex vivo EGFr target expression. Regions showing low SPECT activity were necrotic or virtually negative for EGFr target expression. A good correlation (r = 0.86, P < 0.0001) was found between the percentage of regions showing low activity on SPECT and the percentage of necrotic tissue on immunohistochemistry.

CONCLUSION

Multipinhole SPECT enables high-resolution visualization and quantification of the heterogeneity of (111)In-zalutumumab concentrations in vivo.

Efficacy of nimotuzumab plus gemcitabine usage as first-line treatment in patients with advanced pancreatic cancer

Advanced pancreatic cancer patients have poor prognosis and scarcely respond to conventional therapies. Clinical trials support the use of molecular-targeted therapy against epidermal growth factor receptor (EGFR) signaling. The objective of the current study was to evaluate the contribution of a monoclonal antibody against EGFR, nimotuzumab, to standard gemcitabine therapy. Patients with unresectable locally advanced or metastatic pancreatic adenocarcinoma were assigned to receive gemcitabine plus nimotuzumab. The primary end point was overall survival, whereas the secondary end points included progression-free survival, objective response, and adverse side effects. A total of 18 eligible patients were accrued between December 2007 and July 2010. The disease control rate, calculated as the sum of complete response, partial response, and stable disease, was 55.6%. The median overall survival time was 9.29 months (95% CI, 5.499 to 13.072). The median progression-free survival was 3.71 months (95% CI, 2.526 to 4.902), and the 1-year survival rate was 38.9%. Of all the patients, 88.8% had at least one adverse side effect; however, no grade 4 adverse side effect was reported. Nimotuzumab as a high-purity humanized monoclonal antibody with favorable safety profile, its value in the treatment of pancreatic cancer along with gemcitabine, particularly in the comprehensive treatment of advanced pancreatic cancer, is appealing for further prospective randomized large-scale clinical trials.

A phase I, pharmacokinetic and pharmacodynamic study of nimotuzumab in Japanese patients with advanced solid tumors

PURPOSE

Nimotuzumab is a humanized IgG₁ monoclonal antibody to the epidermal growth factor receptor (EGFR) and has demonstrated the absence of severe dermatological toxicity commonly caused by other EGFR-targeting antibodies. We conducted a phase I study to assess toxicities, pharmacokinetics, pharmacodynamics, and predictive biomarkers of nimotuzumab administered in Japanese patients with advanced solid tumors.

METHODS

Three dose levels, 100, 200, and 400 mg, of weekly i.v. nimotuzumab were given until disease progression or drug intolerability. Four patients with solid tumors were enrolled in each dose level. The expression and gene copy number of EGFR or its downstream transducers were investigated using skin biopsy samples and tumor specimens.

RESULTS

Planned dose escalation was completed without dose-limiting toxicity, and maximum tolerated dose was not reached. No allergic reaction and hypomagnesaemia were observed, and grade 3 or 4 toxicity did not occur. The common toxicity was skin rash (58 %); however, all of them were grade 1 or 2. In skin biopsies, no correlation was shown between doses and the phosphorylation of EGFR or its downstream signal transducers. Of 11 evaluable patients, no objective response was obtained, while 8 patients had stable disease (73 %). Patients with a higher-EGFR gene copy number level measured by FISH showed a longer time to progression.

CONCLUSIONS

Nimotuzumab administered weekly was feasible and well tolerated up to 400 mg in Japanese patients. A low dermatological toxicity could be a notable advantage as anti-EGFR mAb, and further evaluation is warranted.

Which is false: oxaliplatin or fluoropyrimidine? An analysis of patients with KRAS wild-type metastatic colorectal cancer treated with first-line epidermal growth factor receptor monoclonal antibody

This meta-analysis was performed to determine whether the addition of monoclonal antibodies (mAbs) of epidermal growth factor receptor (EGFR) to oxaliplatin-based chemotherapy treatment improves efficacy in KRAS wild-type metastatic colorectal cancer (mCRC), and whether infusional 5-fluorouracil (5-FU) and oxaliplatin is a preferred combination for EGFR mAbs. Oxaliplatin (including treatment), EGFR mAbs, first-line treatment, KRAS wild-type, and mCRC were used as key words. The PRIME, OPUS, COIN, and NORDIC VII trials were identified by two independent authors. Time-to-event outcomes of overall survival (OS) and progression-free survival (PFS) were analyzed using HRs (hazard ratios) with fixed effect, and response rate (RR) using odd ratios (OR) with fixed effect. A total of 1767 patients who were KRAS wild-type were included in this meta-analysis, with 866 patients in the mAbs and chemotherapy combination group and 901 patients in the chemotherapy alone group. The addition of mAbs to oxaliplatin-based chemotherapy in patients with KRAS wild-type mCRC as first-line treatment resulted in significant improvements in PFS (HR = 0.88; 95% confidence interval (CI), 0.79-0.99; P = 0.03) and response rate (RR) (OR = 1.38; 95% CI, 1.14-1.66; P = 0.009) compared with chemotherapy alone, but the difference in OS was not significant (HR = 0.96; 95% CI, 0.85-1.08; P = 0.48). However, the differences in OS and PFS were not significant when mAbs were added to bolus 5-FU or capecitabine-based regimens compared with chemotherapy alone, whereas PFS improved with an infusional 5-FU and oxaliplatin combination (P = 0.06; PFS, HR = 0.76; 95% CI, 0.65-0.86; P = 0.0002), and even OS was marginally significant, which was consistent with the subgroup analysis of cetuximab and panitumumab. EGFR mAbs combined with oxaliplatin and an infusional 5-FU regimen was associated with significantly improved RR, PFS and OS as first-line treatment in KRAS wild-type mCRC.

Radiotherapy plus nimotuzumab or placebo in the treatment of high grade glioma patients: results from a randomized, double blind trial

Background

The prognosis of patients bearing high grade glioma remains dismal. Epidermal Growth Factor Receptor (EGFR) is well validated as a primary contributor of glioma initiation and progression. Nimotuzumab is a humanized monoclonal antibody that recognizes the EGFR extracellular domain and reaches Central Nervous System tumors, in nonclinical and clinical setting. While it has similar activity when compared to other anti-EGFR antibodies, it does not induce skin toxicity or hypomagnesemia.

Methods

A randomized, double blind, multicentric clinical trial was conducted in high grade glioma patients (41 anaplastic astrocytoma and 29 glioblastoma multiforme) that received radiotherapy plus nimotuzumab or placebo. Treatment and placebo groups were well-balanced for the most important prognostic variables. Patients received 6 weekly doses of 200 mg nimotuzumab or placebo together with irradiation as induction therapy. Maintenance treatment was given for 1 year with subsequent doses administered every 3 weeks. The objectives of this study were to assess the comparative overall survival, progression free survival, response rate, immunogenicity and safety.

Results

The median cumulative dose was 3200 mg of nimotuzumab given over a median number of 16 doses. The combination of nimotuzumab and RT was well-tolerated. The most prevalent related adverse reactions included nausea, fever, tremors, anorexia and hepatic test alteration. No anti-idiotypic response was detected, confirming the antibody low immunogenicity. The mean and median survival time for subjects treated with nimotuzumab was 31.06 and 17.76 vs. 21.07 and 12.63 months for the control group.

Conclusions

In this randomized trial, nimotuzumab showed an excellent safety profile and significant survival benefit in combination with irradiation.

Trial registration

Cuban National Register for clinical trials (No. 1745) (http://registroclinico.sld.cu/ensayos).

Nimotuzumab treatment of malignant gliomas

INTRODUCTION

In spite of new alkylating medication and recently accumulated knowledge about genomics, the prognosis of malignant gliomas remains poor. The introduction of single substances interfering with tumour proliferation dynamics has been disappointing and the lessons learned indicate that a complicated network of proliferation needs time consuming, in-depth analysis in order to more specifically treat now distinguishable subgroups of a disease, which too long was thought of as a uniform entity.

AREAS COVERED

The clinical trials using the EGFR antibody nimotuzumab in the treatment of malignant gliomas are reviewed. Pending conformation in future studies the antibody might be part of the treatment of MGMT-negative, EGFR-amplified, not completely resected gliomas of adulthood and juvenile DIPG (pontine gliomas). Upcoming genomic results of the different tumour entities may suggest certain combination partners of the antibody. Recent studies of nimotuzumab indicate the reason for the lack of toxicity, which is the most attractive argument for its clinical use besides modest efficacy.

EXPERT OPINION

We await the final results on the use of the antibody together with vinorelbine and radiation therapy for the therapy of DIPG. Adult patients with MGMT-negative, EGFR amplified, not totally resected GBM may also profit from this combination therapy. TK-inhibitors combined with the antibody and irradiation may be an option for a therapeutic trial in paediatric patients.

Targeting proliferation and survival pathways in head and neck cancer for therapeutic benefit

Head and neck squamous cell carcinomas (HNSCC) are common human malignancies with poor clinical outcomes. The 5-year survival rates for patients with advanced stage HNSCC have not changed appreciably in the past few decades, underscoring a dire need for improved therapeutic options. Recent studies have elucidated a key signaling axis, the EGFR-STAT3-Bcl-XL signaling axis, that is aberrantly activated in a majority of HNSCC and contributes to the proliferation and survival of malignant cells. Considerable effort is being placed on developing highly specific inhibitors of different components of this pathway. This review highlights the progress that is being made towards achieving potent inhibition of the EGFR-STAT3-Bcl-XL signaling axis in HNSCC and the promising therapeutic strategies that are currently under development for this disease.

Landscape of EGFR signaling network in human cancers: biology and therapeutic response in relation to receptor subcellular locations

The epidermal growth factor receptor (EGFR) pathway is one of the most dysregulated molecular pathways in human cancers. Despite its well-established importance in tumor growth, progression and drug-resistant phenotype over the past several decades, targeted therapy designed to circumvent EGFR has yielded only modest clinical success in cancer patients, except those with non-small cell lung cancer (NSCLC) carrying EGFR activation mutations. However, almost all of these NSCLC patients eventually developed resistance to small molecule EGFR kinase inhibitors. These disappointing outcomes are, in part, due to the high complexity and the interactive nature of the EGFR signaling network. More recent compelling evidence further indicates that EGFR functionality can be dependent on its subcellular location. In this regard, EGFR undergoes translocation into different organelles where it elicits distinctly different functions than its best known activity as a plasma membrane-bound receptor tyrosine kinase. EGFR can be shuttled into the cell nucleus and mitochondrion upon ligand binding, radiation, EGFR-targeted therapy and other stimuli. Nuclear EGFR behaves as transcriptional regulator, tyrosine kinase, and mediator of other physiological processes. The role of mitochondrial EGFR remains poorly understood but it appears to regulate apoptosis and autophagy. While studies using patient tumors have shown nuclear EGFR to be an indicator for poor clinical outcomes in cancer patients, the impact of mitochondrial EGFR on tumor behavior and patient prognosis remains to be defined. Most recently, several lines of evidence suggest that mislocated EGFR may regulate tumor response to therapy and that plasma membrane-bound EGFR elicits survival signals independent of its kinase activity. In light of these recent progresses and discoveries, we will outline in this minireview an emerging line of research that uncovers and functionally characterizes several novel modes of EGFR signaling that take center stage in the cell nucleus, mitochondrion and other subcellular compartments. We will also discuss the clinical implications of these findings in the rationale design for therapeutic strategy that overcomes tumor drug resistance.

Targeting Ras-RAF-ERK and its interactive pathways as a novel therapy for malignant gliomas

Malignant gliomas are the most common and the deadliest brain malignancies in adults. Despite the lack of a complete understanding of the biology of these tumors, significant advances have been made in the past decades. One of the key discoveries made in the area of malignant gliomas is that these tumors can be induced and maintained by aberrant signaling networks. In this context, the Ras pathway has been extensively exploited, from both basic and translational perspectives. Although somatic oncogenic mutations of Ras genes are frequent in several cancer types, early investigations on gliomas revealed disappointing facts that the Ras mutations are nearly absent in malignant gliomas and that the BRAF mutations are present in a very small percentage of gliomas. Therefore, the observed deregulation of the Ras-RAF-ERK signaling pathway in gliomas is attributed to its upstream positive regulators, including, EGFR and PDGFR known to be highly active in the majority of malignant gliomas. In contrast to the initial negative results on the somatic mutations of H-Ras, K-Ras and BRAF, recent breakthrough studies on pediatric low-grade astrocytomas uncovered genetic alterations of the BRAF gene involving copy number gains and rearrangements. The 7q34 rearrangements result in a novel in-frame KIAA1549:BRAF fusion gene that possesses constitutive BRAF kinase activity resembling oncogenic BRAF (V600E). In light of the earlier findings and recent breakthroughs, this review summarizes our current understanding of the Ras-RAF-ERK signaling pathway in gliomas and the outcome of preclinical and clinical studies that evaluated the efficacy of Ras-targeted therapy in malignant gliomas.

Pharmacokinetic and pharmacodynamic perspectives on the clinical drug development of panitumumab

Panitumumab is a recombinant, fully human IgG2 monoclonal antibody directed against the epidermal growth factor receptor (EGFR). It is indicated for use as monotherapy in the treatment of patients with EGFR-expressing metastatic colorectal cancer after disease progression with standard chemotherapy. The currently indicated dose is 6 mg/kg given every 2 weeks. Panitumumab is mainly distributed into the vascular space and exhibits nonlinear pharmacokinetics that are consistent with target-mediated drug disposition, involving saturable binding to EGFR and subsequent internalization and degradation inside the cells. Panitumumab is also cleared in a linear fashion by the reticuloendothelial system, similarly to other endogenous immunoglobulins. After single-dose administration of panitumumab as a 1-hour intravenous infusion, the area under the serum concentration-time curve increases in a greater-than-dose-proportional manner as the dose increases from 0.75 to 5 mg/kg; however, at doses above 2 mg/kg, the exposure to panitumumab increases in a dose-proportional manner. Panitumumab pharmacokinetics are not meaningfully affected by the tumour type, EGFR membrane expression, tumour KRAS mutation, sex, age, race or renal or hepatic dysfunction. In addition, irinotecan-containing and paclitaxel/carboplatin-containing chemotherapeutic regimens do not appear to affect panitumumab pharmacokinetics. The results of population pharmacokinetic analyses have shown that bodyweight is the most influential covariate on panitumumab exposure, supporting the current use of bodyweight-adjusted doses (mg/kg). The relationship between the weekly dose of panitumumab and skin rash, an on-target pharmacodynamic effect of EGFR inhibition, reaches a plateau at 2.5 mg/kg, indicating that this is the optimal weekly dose. Two less-frequent dosing regimens (6 mg/kg given every 2 weeks and 9 mg/kg given every 3 weeks) achieve steady-state serum trough concentrations similar to those achieved by 2.5 mg/kg given every week, ensuring maximal EGFR coverage. Anti-panitumumab antibody production is uncommon and does not appear to have an impact on the pharmacokinetics of panitumumab.

Antibodies in oncology

Monoclonal antibodies (mAbs) have become one of the largest classes of new therapeutic agents approved for use in oncology, and have revolutionised the treatment of many human malignancies. Clinically useful mAbs can function through several different mechanisms, including inhibition of tumour-related signalling, induction of apoptosis, inhibition of angiogenesis, enhancing host immune response against cancer and targeted delivery of payloads (such as toxins, cytotoxic agents or radioisotopes) to the tumour site. The increasing knowledge of key molecules and cellular pathways involved in tumour induction and progression has led to a rise in the proportion of therapeutic mAbs entering clinical trials. These mAbs consist of various conventional or recombinant, murine, humanised, chimeric or fully human and fusion constructs. In this review, we provide an overview of mAbs approved for use in clinical oncology and those currently in clinical development. We also discuss the mechanisms of action of anti-cancer mAbs, as well as the antigen targets recognised by these antibodies.

Phase II study of nimotuzumab, a humanized monoclonal anti-epidermal growth factor receptor (EGFR) antibody, in patients with locally advanced or metastatic pancreatic cancer

INTRODUCTION

Nimotuzumab is a humanized monoclonal antibody that binds to the EGFR. Based on phase I data, the recommended dose has been established at 200 mg weekly. This study was aimed at evaluating the safety and efficacy of nimotuzumab monotherapy in patients (pts) with locally advanced or metastatic pancreatic cancer.

METHODS

Pts who failed first line standard chemotherapy for advanced disease and had at least one measurable lesion were eligible for the study. Nimotuzumab was given intravenously at 200 mg once weekly for 6 weeks (wks). Follow up by CT scan was performed after 8 weeks. Pts continued receiving treatment 3-weekly until disease progression or unacceptable toxicity occurred. Endpoints included tumor response (RECIST), progression-free survival (PFS), and safety.

RESULTS

A total of 56 pts were enrolled for treatment (ECOG status of 1 [n = 41] or 0 [n = 15]), the majority (47 pts) had metastatic disease. Nearly half of the pts [n = 26] received ≥2 regimens. Pts evaluable for response: n = 36; CR: 0; PR: 0; SD: 6 pts. Median PFS for pts with SD was 19.2 weeks, for all pts 6.7 weeks (95% CI: 6.43-7.14 weeks). PFS after 1 year was 10.3% with a median overall survival of 18.1 weeks. Treatment-related adverse events were generally mild including rash grade 1 in 5 pts. After a single dose of 200 mg, the t(1/2) was calculated to 45 h.

CONCLUSION

These data confirm that nimotuzumab is safe and very well tolerated. To improve efficacy, a randomized, placebo-controlled trial with Gem has been initiated.

Nimotuzumab for pediatric diffuse intrinsic pontine gliomas

INTRODUCTION

Diffuse intrinsic pontine gliomas (DIPG) have a poor prognosis: the median survival rate is less than one year. Radiotherapy is the only effective treatment affording an overall survival of 6 - 9 months. So far, no improvement has been achieved with the addition of single/poly-chemotherapy regimens. An urgent need is to advance in this field, from both the biological and the clinical points of view.

AREAS COVERED

Among the few studies providing biological information on DIPG, Gilbertson's group demonstrated a significant increase in EGFR expression. The activity of nimotuzumab, a humanized anti-EGFR monoclonal antibody, was therefore studied within a Phase II trial in 47 relapsing pediatric patients with DIPG and high-grade gliomas, showing an interesting, persistent response, especially in the first group treated. A multicenter exploratory study combining nimotuzumab and radiotherapy showed disease control and an overall patient survival similar to previous experiences along with an improvement in the quality of patient survival and no severe side effects.

EXPERT OPINION

We recommend considering this combination in the armamentarium against DIPG. It might be improved by adding other target drugs/low-toxicity chemotherapy regimens with a synergistic effect with the anti-EGFR component.

Emerging drugs to treat squamous cell carcinomas of the head and neck

IMPORTANCE OF THE FIELD

Head and neck squamous cell carcinoma (HNSCC) is the eighth leading cause of cancer death worldwide. Despite advances in surgery and chemoradiation therapy, there has been little improvement in survival rates over the past 4 decades. Additionally, surgery and chemoradiotherapy have serious side effects. The development of agents with greater efficacy and tolerability is needed.

AREAS COVERED IN THIS REVIEW

EGFR is the only proven molecular target for HNSCC therapy. Cetuximab, the sole FDA-approved molecular targeted HNSCC therapy, and other potential targeted therapies are being evaluated in preclinical, clinical and post-marketing studies. Here, we review the emerging targets for biological agents in HNSCC and the rationale for their selection.

WHAT THE READER WILL GAIN

Key information in the development of new drug targets and the emergence of new biomarkers are discussed. Readers will gain insight regarding the limitations of current therapies, the impact of recently approved targeted therapies and the influence that predictive biomarkers will have on drug development.

TAKE HOME MESSAGE

The head and neck cancer drug market is rapidly evolving. Coordination between drug and biomarker development efforts may soon yield targeted therapies that can achieve the promise of personalized cancer medicine.

EGFR-targeted therapy in malignant glioma: novel aspects and mechanisms of drug resistance

Glioblastoma, GBM, is the most frequent brain malignancy in adults. Patients with these tumors survive only, approximately, one year after diagnosis and rarely survive beyond two years. This poor prognosis is, in part, due to our insufficient understanding of the complex aggressive nature of these tumors and the lack of effective therapy. In GBM, over-expression of EGFR and/or its constitutively activated variant EGFRvIII is a major characteristic and is associated with tumorigenesis and more aggressive phenotypes, such as, invasiveness and therapeutic resistance. Consequently, both have been major targets for GBM therapy, however, clinical trials of EGFR- and EGFRvIII-targeted therapies have yielded unsatisfactory results and the molecular basis for the poor results is still unclear. Thus, in this review, we will summarize results of recent clinical trials and recent advances made in the understanding of the EGFR/EGFRvIII pathways with a key focus on those associated with intrinsic resistance of GBM to EGFR-targeted therapy. For example, emerging evidence indicates an important role that PTEN plays in predicting GBM response to EGFR-targeted therapy. Aberrant Akt/mTOR pathway has been shown to contribute to the resistant phenotype. Also, several studies have reported that EGFR/EGFRvIII's cross-talk with the oncogenic transcription factorSTAT3 and receptor tyrosine kinases, (c-Met and PDGFR) potentially lead to GBM resistance to anti-EGFR therapy. Other emerging mechanisms, including one involving HMG-CoA reductase, will also be discussed in this mini-review. These recent findings have provided new insight into the highly complex and interactive nature of the EGFR pathway and generated rationales for novel combinational targeted therapies for these tumors.

A dose-escalation phase I trial of nimotuzumab, an antibody against the epidermal growth factor receptor, in patients with advanced solid malignancies

PURPOSE

Nimotuzumab is a humanized monoclonal antibody which inhibits the ligand-dependent activation of epidermal growth factor receptor (EGFR). We conducted a phase I trial to assess the pharmacodynamic (PD) effects of escalating doses of nimotuzumab administered alone in patients with advanced solid cancers patients.

EXPERIMENTAL DESIGN

Patients were treated with escalating doses of weekly intravenous nimotuzumab at doses ranging between 100 and 800 mg. Tumor and skin biopsies were done before start of treatment and repeated 3 weeks after to assess immunohistochemical expression of EGFR and its downstream components.

RESULTS

Seventeen patients were enrolled, including 1 patient never treated. Although 1 dose-limiting-toxicity (DLT) was observed at 100 mg (grade 3 fatigue), nimotuzumab dose was escalated to 800 mg with no other DLT. No grade 4 toxicity was observed. Only 3 patients developed a grade 1 acneiform rash (18.7%). One patient achieved a partial response (6.2%) and 8 patients had stable disease (50.0%). The median TTP was 2.4 months. No significant changes in EGFR, AKT, ERK and Ki67 immuno-stainings were observed between pre- and on-treatment tumor or skin biopsies.

CONCLUSION

Nimotuzumab could be safety administered up to 800 mg with manageable toxicity. No relationships were found between pharmacodynamic effects on EGFR downstream signaling pathways and drug efficacy or toxicity.

Pharmacodynamic trial of nimotuzumab in unresectable squamous cell carcinoma of the head and neck: a SENDO Foundation study

PURPOSE

To assess the pharmacodynamic effects of nimotuzumab, an anti-epidermal growth factor receptor (EGFR) monoclonal antibody with intermediate affinity for the receptor, in skin and tumor tissues from head and neck cancer patients.

EXPERIMENTAL DESIGN

Pharmacodynamic study in patients with advanced squamous cell carcinoma of the head and neck, unsuitable for chemoradiotherapy, enrolled in a single-center trial. Patients received 8 weekly infusions of nimotuzumab. The first nimotuzumab infusion was administered 1 week before starting radiation, whereas the remaining doses were administered concomitantly with irradiation. Paired biopsies were taken from skin and primary tumors, before (pretherapy) and 1 week (on single-agent therapy) after first infusion. Immunohistochemistry was conducted to assay the effects of nimotuzumab on total and phosphorylated EGFR, phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), p-AKT, and proliferation (Ki-67).

RESULTS

Nimotuzumab was well tolerated and there was no evidence of skin rash. Objective response was achieved in 9 of 10 patients. The pharmacodynamic assays showed inhibition of p-EGFR in both skin and tumor (P = 0.042 in skin and P = 0.034 in tumor). No significant changes in p-ERK1/2, p-AKT, or Ki-67 were detected in skin. In addition, lymphocytic infiltrates, folliculitis, or perifolliculitis were not observed. In tumor samples, there was an upregulation of p-AKT (P = 0.043), a reduction in proliferation index (P = 0.012), and a nonsignificant trend toward a decrease of p-ERK1/2 (P = 0.091).

CONCLUSIONS

The pharmacodynamic data confirmed the ability of nimotuzumab to decrease EGFR phosphorylation. Downstream effects were observed in tumor cells but not in skin, a finding that may help to explain the lack of skin rash in patients treated with nimotuzumab.

Nimotuzumab in pediatric glioma

High-grade gliomas and diffuse brainstem gliomas carry a very poor prognosis despite current therapies, and account together for the largest number of deaths in children with brain tumors. Many of these tumors have been found to overexpress the EGF receptor (EGFR). Nimotuzumab (h-R3) is a humanized monoclonal antibody against the EGFR, and consequently inhibits tyrosine kinase activation. In vitro and in vivo studies have supported the antiproliferative, antiangiogenic, pro-apoptotic and radiosensitizing activities of nimotuzumab. Emerging trials suggest a promising role for nimotuzumab as a therapeutic agent in patients with high-grade gliomas. This review attempts to provide a context for the evolving interest and evidence for nimotuzumab in pediatric glioma.

Sym004: a novel synergistic anti-epidermal growth factor receptor antibody mixture with superior anticancer efficacy

Epidermal growth factor receptor (EGFR) is a validated therapeutic target in cancer and EGFR antagonists with greater effectiveness than existing clinical agents remain of interest. Here, we report a novel approach based on Sym004, a mixture of two anti-EGFR monoclonal antibodies directed against distinct nonoverlapping epitopes in EGFR extracellular domain III. Like anti-EGFR monoclonal antibodies in current clinical use, Sym004 inhibits cancer cell growth and survival by blocking ligand-binding receptor activation and phosphorylation and downstream receptor signaling. However, unlike the other antibodies, Sym004 induces rapid and efficient removal of the receptor from the cancer cell surface by triggering EGFR internalization and degradation. Compared with reference anti-EGFR monoclonal antibodies, Sym004 exhibited more pronounced growth inhibition in vitro and superior efficacy in vivo. Together, these findings illustrate a strategy to target EGFR more effectively than existing clinical antibodies.

Current status and problems in development of molecular target agents for gastrointestinal malignancy in Japan

Since late 1990s, many molecular target agents have been introduced to clinical trials for various kinds of tumors, and some of them showing significant benefits have been approved. However, these global trials were mainly conducted outside Japan, and the 'drag lag' has been a serious problem in Japan recently. Nowadays, Japanese institutions have been participating in some global trials, and the drug lags are getting shorter. For colorectal cancer, molecular target agents such as bevacizumab and cetuximab have been approved in Japan, resulting in improved clinical outcomes. For gastric cancer, Japanese institutions not only contribute to the global Phase III trials of trastuzumab and bevacizumab but also show leadership in the early development of other new agents. For pancreatic cancer, only erlotinib has shown a survival benefit in these 10 years. Worldwide approach including Japan is warranted to achieve better clinical outcomes. For liver cancer, although Japanese institutions did not participate even in the Asian trial of sorafenib, it has been approved in Japan. For esophageal cancer, because there has been no new molecular target agents developed by pharmaceutical companies, investigator-initiated registration trial will play an important role. For all gastrointestinal malignancies, molecular target agents have made a progress in their treatments. In the near future, Japanese institutions will participate in more and more global trials and should play a specific role in worldwide drug development. Furthermore, the optimal use of these new drugs, molecular target agents, based on the daily practice should also be explored in Japan.

Targeting the epidermal growth factor receptor in epithelial ovarian cancer: current knowledge and future challenges

The epidermal growth factor receptor is overexpressed in up to 60% of ovarian epithelial malignancies. EGFR regulates complex cellular events due to the large number of ligands, dimerization partners, and diverse signaling pathways engaged. In ovarian cancer, EGFR activation is associated with increased malignant tumor phenotype and poorer patient outcome. However, unlike some other EGFR-positive solid tumors, treatment of ovarian tumors with anti-EGFR agents has induced minimal response. While the amount of information regarding EGFR-mediated signaling is considerable, current data provides little insight for the lack of efficacy of anti-EGFR agents in ovarian cancer. More comprehensive, systematic, and well-defined approaches are needed to dissect the roles that EGFR plays in the complex signaling processes in ovarian cancer as well as to identify biomarkers that can accurately predict sensitivity toward EGFR-targeted therapeutic agents. This new knowledge could facilitate the development of rational combinatorial therapies to sensitize tumor cells toward EGFR-targeted therapies.

Somatic EGFR mutation and gene copy gain as predictive biomarkers for response to tyrosine kinase inhibitors in non-small cell lung cancer

PURPOSE

The aim of this systematic review and meta-analysis was to characterize common EGFR molecular aberrations as potential predictive biomarkers for response to monotherapy with tyrosine kinase inhibitors (TKI) in non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

We systematically identified articles investigating EGFR status [somatic mutational and gene copy aberrations (copy number)] in patients with NSCLC treated with TKIs. Eligible studies had to report complete and partial response rates stratified by EGFR status. We used random effects models for bivariable meta-analysis of sensitivity and specificity; positive and negative likelihood ratios (+LR and -LR, respectively) were also calculated and were considered as secondary end points.

RESULTS

Among 222 retrieved articles, 59 were considered eligible for the somatic EGFR mutation meta-analysis (1,020 mutations among 3,101 patients) and 21 were considered eligible for the EGFR gene copy number meta-analysis (542 gene gain among 1,539 patients). EGFR mutations were predictive of response to single-agent TKIs [sensitivity, 0.78; 95% confidence interval (95% CI), 0.74-0.82; specificity, 0.86; 95% CI, 0.82-0.89; +LR, 5.6; -LR, 0.25]. EGFR gene gain was also associated with response to TKIs, albeit with lower sensitivity and specificity. In subgroup analysis, the only recognized trend was for a higher predictive value in Whites compared with East Asians for both mutation and gene copy number.

CONCLUSION

This analysis provides empirical evidence that EGFR mutations are sensitive and specific predictors of response to single-agent epidermal growth factor receptor TKIs in advanced NSCLC. The diagnostic performance of mutations seems better than that of EGFR gene gain.

Nimotuzumab: a novel anti-EGFR monoclonal antibody that retains anti-EGFR activity while minimizing skin toxicity

Due to the broad importance of EGFR to tumorogenesis, targeted therapy against it has rapidly developed into a novel paradigm for cancer treatment. Two promising classes of drugs are now in use and undergoing development that target this receptor: tyrosine kinase inhibitors (TKIs) and mAbs that inhibit EGFR's extracellular domain. Nimotuzumab, a humanized murine mAb created in Cuba, has demonstrated antitumor activity similar to that of other anti-EGFR mAbs and shows promise as a single agent and as an adjunct to radiation in Phase I and II clinical trials. Surprisingly, the typical severe dermatological toxicities thus far associated with anti-EGFR therapy have not been described with nimotuzumab. Here we summarize the background, development and characteristics of this new drug while reviewing the latest preclinical and clinical trial data that underpin its gradual adoption into clinical practice.

Fluorophore-quencher based activatable targeted optical probes for detecting in vivo cancer metastases

In vivo molecularly targeted fluorescence imaging of tumors has been proposed as a strategy for improving cancer detection and management. Activatable fluorophores, which increased their fluorescence by 10-fold after binding tumor cells, result in much higher target to background ratios than conventional fluorophores. We developed an in vivo targeted activatable optical imaging probe based on a fluorophore-quencher pair, bound to a targeting moiety. With this system, fluorescence is quenched by the fluorophore-quencher interaction outside cancer cells, but is activated within the target cells by dissociation of the fluorophore-quencher pair. We selected the TAMRA (fluorophore)-QSY7 (quencher) pair and conjugated it to either avidin (targeting the D-galactose receptor) or trastuzumab (a monoclonal antibody against the human epithelial growth factor receptor type2 (HER2/neu)) and evaluated their performance in mouse models of cancer. Two probes, TAMRA-QSY7 conjugated avidin (Av-TM-Q7) and trastuzumab (Traz-TM-Q7) were synthesized. Both demonstrated better than similar self-quenching probes. In vitro fluorescence microscopic studies of SHIN3 and NIH/3T3/HER2+ cells demonstrated that Av-TM-Q7 and Traz-TM-Q7 produced high intracellular fluorescent signal. In vivo imaging with Av-TM-Q7 and Traz-TM-Q7 in mice enabled the detection of small tumors. This molecular imaging probe, based on a fluorophore-quencher pair conjugated to a targeting ligand, successfully detected tumors in vivo due to its high activation ratio and low background signal. Thus, these activatable probes, based on the fluorophore-quencher system, hold promise clinically for "see and treat" strategies of cancer management.

Somatic EGFR mutations and efficacy of tyrosine kinase inhibitors in NSCLC

Early clinical studies of tyrosine kinase inhibitors (TKIs) that target the EGFR in patients with advanced non-small-cell lung cancer (NSCLC) showed that some patients experienced rapid, durable, complete or partial responses. These data were the basis for attempts to identify specific subgroups of patients who would further benefit from these agents. The discovery of somatic mutations in EGFR that correlated with sensitivity to TKIs identified a plausible explanation for these observations. Clinical and pathological factors such as female sex, never having smoked, Asian origin and adenocarcinoma histology correlate with the presence of EGFR mutations and objective responses to TKIs in patients with NSCLC. Recent studies in metastatic colorectal cancer highlighted that somatic mutations in KRAS represent a negative predictor of response to anti-EGFR monoclonal antibodies; KRAS mutations also represent an important mechanism of resistance to TKIs in NSCLC. Many large clinical studies are currently investigating the predictive and prognostic value of EGFR mutational status and other candidate biomarkers. We summarize the literature and present an overview of the field of anti-EGFR therapy in NSCLC, focusing on the influence of somatic EGFR mutations on selection of patients for TKI therapy and the influence of EGFR pathway regulation.