A phase I dose escalation study of BIBW 2992, an irreversible dual inhibitor of epidermal growth factor receptor 1 (EGFR) and 2 (HER2) tyrosine kinase in a 2-week on, 2-week off schedule in patients with advanced solid tumours

Ganoderma microsporum immunomodulatory protein as an extracellular epidermal growth factor receptor (EGFR) degrader for suppressing EGFR-positive lung cancer cells

Epidermal growth factor receptor (EGFR) abnormalities relevant to tumor progression. A newly developed strategy for cancer therapy is induction of EGFR degradation. GMI, an immunomodulatory protein from the medicinal mushroom Ganoderma microsporum, exhibits anticancer activity. However, its role in the intracellular trafficking and degradation of EGFR remains unclear. In this study, we discovered that GMI inhibits the phosphorylation of multiple tyrosine kinases. Specifically, GMI was discovered to suppress lung cancer cells harboring both wild-type and mutant EGFR by inhibiting EGFR dimerization and eliminating EGFR-mediated signaling. Functional studies revealed that GMI binds to the extracellular segment of EGFR. GMI interacts with EGFR to induce phosphorylation of EGFR at tyrosine1045, which triggers clathrin-dependent endocytosis and degradation of EGFR. Furthermore, in the mouse models, GMI was discovered to suppress tumor growth. Knockdown of EGFR in lung cancer cells abolishes GMI's anticancer activity in vivo and in vitro. Our results reveal the interaction mechanisms through which GMI induces EGFR degradation and abolishes EGFR-mediated intracellular pathway. Our study indicates that GMI is an EGFR degrader for inhibiting EGFR-expressing tumor growth.

Targeting the Epidermal Growth Factor Receptor with Molecular Degraders: State-of-the-Art and Future Opportunities

Epidermal growth factor receptor (EGFR) is an oncogenic drug target and plays a critical role in several cellular functions including cancer cell growth, survival, proliferation, differentiation, and motility. Several small-molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) have been approved for targeting intracellular and extracellular domains of EGFR, respectively. However, cancer heterogeneity, mutations in the catalytic domain of EGFR, and persistent drug resistance limited their use. Different novel modalities are gaining a position in the limelight of anti-EGFR therapeutics to overcome such limitations. The current perspective reflects upon newer modalities, importantly the molecular degraders such as PROTACs, LYTACs, AUTECs, and ATTECs, etc., beginning with a snapshot of traditional and existing anti-EGFR therapies including small molecule inhibitors, mAbs, and antibody drug conjugates (ADCs). Further, a special emphasis has been made on the design, synthesis, successful applications, state-of-the-art, and emerging future opportunities of each discussed modality.

Pharmacokinetic and Safety Comparison of 2 Afatinib Dimaleate Tablets in Healthy Chinese Volunteers Under Fasted Conditions: A Randomized, Open-Label, 2-Period, Single-Dose Crossover Study

In this bioequivalence study, we aimed to evaluate the bioequivalence of test (T) and reference (R) afatinib dimaleate tablets in healthy Chinese subjects under fasted conditions. This was a randomized, open-label, 2-period, single-dose, crossover study. A total of 60 healthy subjects were included in the study according to the screening criteria, and the subjects were randomly divided into the T/R and R/T groups. All subjects were administrated a single 40-mg oral dose of the test or reference formulation, separated by a 14-day washout period in the crossover manner. The pharmacokinetic parameters, including maximum concentration (C_max ), area under the concentration-time curve (AUC) from time 0 to the last measurable concentration and AUC from time 0 to infinity were assessed for bioequivalence. The plasma concentrations of afatinib dimaleate were analyzed by liquid chromatography-tandem mass spectrometry. In addition, adverse events were monitored and recorded on the basis of patient interviews and physical examinations to assess the safety of the 2 formulations. There were 4 subjects who withdrew before the dosing of period 2. The 90%CIs of geometric mean ratios of C_max , AUC from time 0 to the last measurable concentration, and AUC from time 0 to infinity were 95.9% to 104.1%, 98.8 % to 104.1%, and 98.9% to 104.0%, respectively, all of which were within the bioequivalence range of 80.0% to 125.0%. This randomized study demonstrated that the test formulation of afatinib was bioequivalent to the reference formulation in healthy Chinese subjects under fasted conditions. Both formulations were well tolerated, and no serious adverse events were observed during the study.

Discovery of mobocertinib, a new irreversible tyrosine kinase inhibitor indicated for the treatment of non-small-cell lung cancer harboring EGFR exon 20 insertion mutations

Epidermal growth factor receptor (EGFR) is essential for normal cellular functions. Mutations of EGFR's kinase domain can cause dysregulation leading to non-small cell lung cancer (NSCLC). Exon 20 insertion (ex20ins) mutations in EGFR are one of the leading contributors to oncogenesis and confer insensitivity to most available therapeutics. Mobocertinib is a novel tyrosine kinase inhibitor (TKI) recently approved by the US FDA as a first-in-class small molecule therapeutic for EGFR ex20ins-positive NSCLC. When compared to osimertinib, a TKI indicated for the treatment of EGFR T790M-positive NSCLC, mobocertinib differs only by the presence of an additional C5-carboxylate isopropyl ester group on the middle pyrimidine core. Together with the acrylamide side chain that is responsible for irreversible inhibition, this additional C5-substituent affords mobocertinib high anticancer potency and specificity to EGFR ex20ins-positive lung cancer that is resistant to other EGFR TKIs. This review article provides an overview of the discovery of mobocertinib from osimertinib including their structure-activity relationships, mechanisms of action, preclinical pharmacology, pharmacokinetics, and clinical applications. The discovery and use of mobocertinib and other EGFR TKIs demonstrate the power of structure-based drug design and promising therapeutic outcomes of using precision medicine approaches in the management of molecularly defined tumors. Graphical abstract.

Metabolic complete tumor response in a patient with epidermal growth factor receptor mutant non-small cell lung cancer treated with a reduced dose of afatinib

Tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor (EGFR) are the first-line treatment for EGFR-mutant non-small cell lung cancer. Toxicities related to EGFR-TKIs include skin rash, paronychia, and diarrhea, which in some cases can lead to dose reductions or treatment interruptions. Herein, we report the case of a 51-year-old woman affected by advanced adenocarcinoma harboring an exon 19 deletion in the EGFR gene, who was treated with second-generation EGFR-TKI following a scheduled gradual dose reduction to better manage toxicities. Following prescription labeling, treatment was initiated at a dose of 40 mg daily. After a few months, the dose was reduced to 30 mg daily owing to grade 3 skin toxicity. A metabolic complete tumor response was observed after 1 year of treatment, then therapy was continued at 20 mg daily, enabling disease stabilization. In conclusion, low dose afatinib was effective in an EGFR-mutant non-small cell lung cancer patient who required dose reductions to better manage toxicities.

Simultaneous determination of dacomitinib and its major metabolite, O-desmethyl dacomitinib in human plasma by LC-MS/MS and its application to clinical testing in patients with non-small cell lung cancer

Dacomitinib, an irreversible pan-ErbB tyrosine kinase inhibitor targeting the human epidermal growth factor receptor, is used for the treatment of metastatic non-small cell lung cancer. To facilitate the investigations on its metabolism and other relevant studies, based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), a rapid and sensitive bioanalytical technique was established and fully validated for simultaneous quantification of dacomitinib and its main metabolite in human plasma. The plasma samples were treated with acetonitrile containing 0.1% formic acid and the liquid supernatant was collected, dried and dissolved in methanol-water-formic acid (200:800:1, v/v) before injection. The chromatographic separation was performed on an ACE Excel C₁₈ column (2.1 mm × 50.0 mm, i.d., 5 μm) by gradient elution with a mixture of buffer (5 mM ammonium acetate in 0.1% formic acid) and acetonitrile, serving as the mobile phase, with an overall run time of 4 min. Dacomitinib, O-desmethyl dacomitinib and IS were subsequently detected on an AB QTRAP 5500 mass spectrometer in positive ion and multiple reaction monitoring modes at the precursor-to-product transitions of m/z 470.4 → 385.0, m/z 456.0 → 370.9 and m/z 480.2 → 385.1, respectively. The accuracy and precision of determinations were guaranteed within the concentration ranges of 0.25-100 ng/mL for dacomitinib and 0.20-80 ng/mL for O-desmethyl dacomitinib. The intra- and inter-assay accuracy ranged from 92.00% to 104.50% and the intra- and inter-assay precision was less than 8.20% for each analyte. The method was validated and the relevant parameters, including selectivity, interference among analytes and internal standard, carry-over effect, dilution integrity, extraction recovery, matrix effect, and stability, all satisfied the requirements formulated by the US Food and Drug Administration and the European Medicines Agency. The clinical applicability of the fully-validated method was evaluated in medicated samples from patients on dacomitinib.

The synthesis and bioactivity of pyrrolo[2,3-d]pyrimidine derivatives as tyrosine kinase inhibitors for NSCLC cells with EGFR mutations

EGFR mutations are an ongoing challenge in the treatment of NSCLC, and demand continuous updating of EGFR TKI drug candidates. Pyrrolopyrimidines are one group of versatile scaffolds suitable for tailored drug development. However not many precedents of this type of pharmacophore have been investigated in the realm of third generation of covalent EGFR-TKIs. Herein, a series of pyrrolo[2,3-d]pyrimidine derivatives able to block mutant EGFR activity in a covalent manner were synthesized, through optimized Buchwald-Hartwig C-N cross coupling reactions. Their preliminary bioactivity and corresponding inhibitory mechanistic pathways were investigated at molecular and cellular levels. Several compounds exhibited increased biological activity and enhanced selectivity compared to the control compound. Notably, compound 12i selectively inhibits HCC827 cells harboring the EGFR activating mutation with up to 493-fold increased efficacy compared to in normal HBE cells. Augmented selectivity was also confirmed by kinase enzymatic assay, with the test compound selectively inhibiting the T790 M activating mutant EGFRs (IC₅₀ values of 0.21 nM) with up to 104-fold potency compared to the wild-type EGFR (IC₅₀ values of 22 nM). Theoretical simulations provide structural evidence of selective kinase inhibitory activity. Thus, this series of pyrrolo[2,3-d]pyrimidine derivatives could serve as a starting point for the development of new EGFR-TKIs.

Canine parvovirus induces G1/S cell cycle arrest that involves EGFR Tyr1086 phosphorylation

Canine parvovirus (CPV) has been used in cancer control as a drug delivery vehicle or anti-tumor reagent due to its multiple natural advantages. However, potential host cell cycle arrest induced by virus infection may impose a big challenge to CPV associated cancer control as it could prevent host cancer cells from undergoing cell lysis and foster them regain viability once the virotherapy was ceased. To explore CPV-induced cell cycle arrest and the underlying mechanism toward improved virotherapeutic design, we focus on epidermal growth factor receptor (EGFR), a cellular receptor interacting with TfR that mediates CPV-host interactions, and alterations on its tyrosine phosphorylation sites in response to CPV infection. We found that CPV could trigger host G1/S cell cycle arrest via the EGFR (Y1086)/p27 and EGFR (Y1068)/STAT3/cyclin D1 axes, and EGFR inhibitor could not reverse this process. Our results contribute to our understandings on the mechanism of CPV-induced host cellular response and can be used in the onco-therapeutic design utilizing CPV by preventing host cancer cells from entering cell cycle arrest.

Identification of Phospho-Tyrosine Targets as a Strategy for the Treatment of Esophageal Adenocarcinoma Cells

Introduction

Esophageal cancer (EC) is an aggressive cancer type that is increasing at a high rate in the US and worldwide. Extensive sequencing of EC specimens has shown that there are no consistent driver mutations that can impact treatment strategies. The goal of this study was to identify activated tyrosine kinase receptors (TKRs) in EC samples as potential targets in the treatment of EC.

Methods

Activated tyrosine kinase receptors were detected using a dot-blot array for human TK receptors. Human esophageal cancer cell lines were transplanted into immunocompromised mice, and tumor xenografts were subjected to tyrosine kinase inhibitors based on the dot-blot array data.

Results

Using the OE33 esophageal cancer cell line, we identified activated EGF receptor (EGFR), as well as ErbB2 and ErbB3. Treatment of this cell line with erlotinib, a specific inhibitor of EGFR, did not impact the growth of this tumor cell line. Treating the OE33 cell line with afatinib, a pan-EGFR family inhibitor resulted in the growth inhibition of OE33, indicating that the ErbB2 and ErbB3 receptors were contributing to tumor cell proliferation. Afatinib treatment of mice growing OE33 tumors inhibited growth of the OE33 tumor cells.

Discussion

Activated tyrosine kinase receptors were readily detected in both cancer cell lines and human esophageal cancer samples. By identifying the activated receptors and then using the appropriate tyrosine kinase inhibitors, we can block tumor growth in vitro and in animal xenografts. We propose that identifying and targeting activated TKRs can be used as a personalized EC tumor treatment strategy.

The pre-clinical discovery and development of osimertinib used to treat non-small cell lung cancer

Introduction: Osimertinib is currently the only FDA- and EMA-approved third-generation small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). It was initially indicated for second-line treatment of patients with metastatic EGFR T790M mutation-positive non-small cell lung cancer (NSCLC) and got approved for first-line treatment of EGFR activation mutation-positive metastatic NSCLC in 2018. Most recently, the FDA granted approval for the adjuvant treatment of patients with early-stage mutated EGFR NSCLC after tumor resection.Areas covered: This drug discovery case history focuses on the key studies that led to the preclinical discovery and development of osimertinib. The authors focus on published preclinical studies by scientists from AstraZeneca and highlight key events in the clinical development.Expert opinion: Although eventually compromised by the cellular plasticity of the tumor and the inevitable acquisition of drug resistance through the use of osimertinib, its key role in the treatment of NSCLC with specific EGFR mutations will be maintained in the near future. As the genome of EGFR is highly labile and since the rapid development of new mutants remains an issue, there is still room for improvement for the next generation of inhibitors.

HER2-positive breast cancer and tyrosine kinase inhibitors: the time is now

Human epidermal growth factor receptor 2 (HER2) positive breast cancer accounts for 20–25% of all breast cancers. Multiple HER2-targeted therapies have been developed over the last few years, including the tyrosine kinase inhibitors (TKI) lapatinib, neratinib, tucatinib, and pyrotinib. These drugs target HER2 and other receptors of the epidermal growth factor receptor family, therefore each has unique efficacy and adverse event profile. HER2-directed TKIs have been studied in the early stage and advanced settings and have shown promising responses. There is increasing interest in utilizing these drugs in combination with chemotherapy and /or other HER2-directed agents in patients with central nervous system involvement, TKIs have shown to be effective in this setting for which treatment options have been previously limited and the prognosis remains poor. The aim of this review is to summarize currently approved TKIs for HER2+ breast, key clinical trials, and their use in current clinical practice.

Absorption, metabolism, excretion, and safety of [14C]almonertinib in healthy Chinese subjects

Background

Almonertinib Mesilate Tablets (HS-10296, Hansoh Pharma, Shanghai, China) is a novel and selective third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). A phase I study of almonertinib in patients with non-small cell lung cancer (NSCLC) demonstrated a linear metabolic trend, a good tolerability/safety profile, and preliminary antitumor activity. However, the metabolism, excretion, and substance balance of almonertinib has not been clearly determined. Here, we investigated the pharmacokinetic characteristics and safety profile of almonertinib following a single oral dose (110 mg/50 µCi) in healthy Chinese male participants.

Methods

Total radioactivity (TRA) in whole blood, plasma, urine, and feces was measured by utilizing a liquid scintillation counter to obtain almonertinib substance balance data. The pharmacokinetic parameters of [¹⁴C]almonertinib and the parent drug almonertinib in whole blood and plasma were analyzed with noncompartmental analysis in the WinNonlin software (Pharsight Corp). The major metabolites in plasma, urine, and feces were analyzed by high-performance liquid chromatography (HPLC) coupled with an online or offline isotope detector. The safety of the drug was evaluated after administration.

Results

The safety and tolerability of a single oral dose of 110 mg/50 µCi [¹⁴C] almonertinib suspension were good in healthy Chinese male participants. There was no significant abnormality or special adverse reaction. TRA peaked quickly in plasma, with a T_max of 4.0 h; however, TRA was cleared slowly in vivo, with a mean terminal elimination phase (half-life, T_1/2) of up to 863 h. In addition to the parent drug, a total of 26 metabolites in blood, urine, and feces were analyzed. In plasma, parent drug was the major drug-related component, accounting for 69.97% of TRA, and M440 (almonertinib-M2 demethyl product) was the major metabolite, accounting for 5.08% of TRA; in urine, parent drug accounted for 0.48% of the dose administered and HAS-719 was the major metabolite, accounting for 1.20% of the administered dose; in feces, parent drug was about 8.61% of the dose administered and HAS-719 was the major metabolite, accounting for 12.33% of the administered dose, which was followed by M541a/M470a and M617/M575, accounting for 11.8% and 6.76% of the administered dose, respectively.

Conclusions

Almonertinib has a good safety profile, with parent drug as its main circulating component. almonertinib is extensively metabolized in vivo before excretion and is excreted as a parent drug and metabolites mainly via feces.

Trial registration

The trial registration number: CTR20192291.

ERK Inhibitor LY3214996-Based Treatment Strategies for RAS-Driven Lung Cancer

RAS gene mutations are the most frequent oncogenic event in lung cancer. They activate multiple RAS-centric signaling networks among them the MAPK, PI3K, and RB pathways. Within the MAPK pathway, ERK1/2 proteins exert a bottleneck function for transmitting mitogenic signals and activating cytoplasmic and nuclear targets. In view of disappointing antitumor activity and toxicity of continuously applied MEK inhibitors in patients with KRAS-mutant lung cancer, research has recently focused on ERK1/2 proteins as therapeutic targets and on ERK inhibitors for their ability to prevent bypass and feedback pathway activation. Here, we show that intermittent application of the novel and selective ATP-competitive ERK1/2 inhibitor LY3214996 exerts single-agent activity in patient-derived xenograft (PDX) models of RAS-mutant lung cancer. Combination treatments were well tolerated and resulted in synergistic (ERKi plus PI3K/mTORi LY3023414) and additive (ERKi plus CDK4/6i abemaciclib) tumor growth inhibition in PDX models. Future clinical trials are required to investigate if intermittent ERK inhibitor-based treatment schedules can overcome toxicities observed with continuous MEK inhibition and-equally important-to identify biomarkers for patient stratification.

Design, synthesis, and computational validation of novel compounds selectively targeting HER2-expressing breast cancer

Human epidermal growth factor receptor (HER) is a family of multidomain proteins that plays important role in the regulation of several biological functions. HER2 is a member of HER that is highly presented in breast cancer cells. Here, we designed and synthesized a series of diaryl urea/thiourea compounds. The compounds were tested on HER2⁺ breast cancer cells including MCF-7 and SkBr3, compared to HER2^- breast cancer cells including MDA-MB-231 and BT-549. Only compounds 12-14 at 10 µM showed selective anti-proliferative activity against MCF-7 and SkBr3 by 65-79%. Compounds 12-14 showed >80% inhibition of the intracellular kinase domain of HER2. The results obtained indicated that compounds 12-14 are selectively targeting HER2⁺ cells. The IC₅₀ of compound 13 against MCF-7 and SkBR3 were 1.3 ± 0.009 and 0.73 ± 0.03 µM, respectively. Molecular docking and MD simulations (50 ns) were carried out, and their binding free energies were calculated. Compounds 12-14 formed strong hydrogen bond and pi-pi stacking interactions with the key residues Thr862 and Phe864. 3DQSAR model confirmed the role of 3-bromo substituent of pyridine ring and 4-chloro substituent of phenyl ring in the activity of the compounds. In conclusion, novel compounds, particularly 13 were developed selectively against HER2-expressing/overexpressing breast cancer cells including MCF7 and SkBr3.

First-in-Human Phase 1 Study of ES-072, an Oral Mutant-Selective EGFR T790M Inhibitor, in Non-Small-Cell Lung Cancer

BACKGROUND

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are rapidly being developed for treatment of non-small-cell lung cancer (NSCLC) in patients harboring EGFR T790M mutations. This first-in-human phase 1 study evaluated the maximum tolerated dose, recommended phase 2 dose (RP2D), safety, tolerability, and pharmacokinetics (PK), and preliminarily determined the antitumor activity of ES-072 in NSCLC patients with EGFR T790M mutations.

PATIENTS AND METHODS

Dose escalation and expansion studies were performed using an accelerated titration method. Oral ES-072 doses (25-450 mg) were administrated once daily for single- and multiple-dose escalation trials. Characteristic PK parameters were assessed in the single-dose escalation phase and in the first cycle of the multiple-dose escalation phase. Tumor responses were assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 to evaluate ES-072 antitumor activity.

RESULTS

Nineteen patients were enrolled onto this study, 16 to the dose-escalation phase and 3 to the dose-expansion phase. The most common adverse events were QT interval prolongation (11/19, 57.9%), anemia (5/19, 26.3%), mouth ulceration (4/19, 21.1%), keratosis (4/19, 21.1%), and cough (4/19, 21.1%). Safety and tolerability evaluation of ES-072 showed an maximum tolerated dose of 300 mg, and the RP2D dose was therefore 300 mg once daily. PK analysis showed an ES-072 half-life of 24.5 hours and a T_max of approximately 4 hours. The total objective response rate and disease control rate were 46.2% and 76.9%, respectively.

CONCLUSION

ES-072 was safe and well tolerated in NSCLC patients harboring EGFR T790M mutations, and adverse events were controllable and reversible. A RP2D of 300 mg once daily was determined, and preliminary investigations showed promising antitumor activity.

In Vitro and In Vivo Efficacies of the EGFR/MEK/ERK Signaling Inhibitors in the Treatment of Alveolar Echinococcosis

Alveolar echinococcosis (AE), caused by the larval stage of the cestode Echinococcus multilocularis, is a lethal disease in humans. Novel therapeutic options are urgently needed since the current chemotherapy displays limited efficiency in AE treatment. In this study, we assessed the in vitro and in vivo effects of the epidermal growth factor receptor (EGFR)/MEK/extracellular signal-regulated kinase (ERK) signaling inhibitors, including BIBW2992, CI-1033, and U0126, on E. multilocularis.

Alveolar echinococcosis (AE), caused by the larval stage of the cestode Echinococcus multilocularis, is a lethal disease in humans. Novel therapeutic options are urgently needed since the current chemotherapy displays limited efficiency in AE treatment. In this study, we assessed the in vitro and in vivo effects of the epidermal growth factor receptor (EGFR)/MEK/extracellular signal-regulated kinase (ERK) signaling inhibitors, including BIBW2992, CI-1033, and U0126, on E. multilocularis. Our data showed that BIBW2992, CI-1033, and U0126 all displayed in vitro effects on the viability of the E. multilocularis metacestode. These inhibitors also showed protoscolicidal activities and caused severe ultrastructural alterations in the parasite. Moreover, BIBW2992 and CI-1033 exhibited potent proapoptotic effects on E. multilocularis metacestodes. Strikingly, a large portion of the apoptotic cells were found to be the germinative cells. In vivo studies showed that BIBW2992 and U0126 significantly reduced parasite burden, and the parasite obtained from BIBW2992-treated mice displayed impaired structural integrity of the germinal layer. In conclusion, these findings demonstrate the potential of EGFR-mediated signaling as a target for the development of novel anti-AE agents. The EGFR inhibitor BIBW2992 represents a promising drug candidate and/or a lead compound for anti-AE chemotherapy.

Afatinib for the treatment of EGFR mutation-positive NSCLC: A review of clinical findings

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors represent the standard of care in patients with EGFR mutation-positive (EGFRm+) non-small cell lung cancer (NSCLC). The availability of several EGFR tyrosine kinase inhibitors approved for use in the first-line or later settings in NSCLC warrants an in-depth understanding of the pharmacological properties of, and clinical data supporting, these agents. The second-generation, irreversible ErbB-family blocker, afatinib, has been extensively studied in the context of EGFRm+ NSCLC. Results from the LUX-Lung 3 and 6 studies showed that afatinib was more active and better tolerated than chemotherapy in patients with tumors harboring EGFR mutations. Subanalysis of these trials, along with real-world data, indicates that afatinib is active in patients with certain uncommon EGFR mutations (S768I/G719X/L861Q) as well as common mutations (Del19/L858R), and in patients with active brain metastases. In LUX-Lung 7, a head-to-head phase IIb trial, afatinib improved progression-free survival and time-to-treatment failure versus the first-generation reversible EGFR tyrosine kinase inhibitor, gefitinib, albeit with a higher incidence of serious treatment-related adverse events. Nevertheless, afatinib is generally well tolerated, and adverse events are manageable through supportive care and a well-defined tolerability-guided dose adjustment scheme. In this review, we provide a detailed overview of the pharmacology, efficacy, and safety of afatinib, discuss treatment sequencing strategies following emergence of different resistance mechanisms, and shed light on the economic impact of afatinib. We also provide a comparison of afatinib with the available EGFR tyrosine kinase inhibitors and discuss its position within treatment strategies for patients with EGFRm+ NSCLC.

Efficacy and safety of afatinib for non-small-cell lung cancer: state-of-the-art and future perspectives

INTRODUCTION

Afatinib is a second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, acting as an irreversible and multitarget blocker of ErbB family members. Afatinib is currently approved for advanced non-small-cell lung cancer (NSCLC) harboring common and uncommon sensitizing EGFR mutations and for squamous NSCLC patients progressing after first-line platinum-based chemotherapy.

AREAS COVERED

This review summarizes the efficacy and safety profile of afatinib compared with chemotherapy and other EGFR TKIs, in order to evaluate its characteristics and potential role in the increasingly complex treatment landscape of EGFR-mutant lung cancer. Future perspectives and innovative drug combinations are also discussed.

EXPERT OPINION

Afatinib has been demonstrated to improve efficacy and quality of life compared with chemotherapy with a managed toxicity profile. However, in recent years, the increasing availability of different treatment options for advanced EGFR-mutant NSCLC has made the current treatment scenario more complicated, with an increasing need of new and deeper scientific data. In this light, the identification and validation of potential clinicopathological and/or molecular predictors of benefit, as well as the clarification of resistance mechanisms, may help to clarify the most appropriate treatment strategies and sequences for EGFR-mutant patients.

Landscape of drug-resistance mutations in kinase regulatory hotspots

More than 48 kinase inhibitors (KIs) have been approved by Food and Drug Administration. However, drug-resistance (DR) eventually occurs, and secondary mutations have been found in the previously targeted primary-mutated cancer cells. Cancer and drug research communities recognize the importance of the kinase domain (KD) mutations for kinasopathies. So far, a systematic investigation of kinase mutations on DR hotspots has not been done yet. In this study, we systematically investigated four types of representative mutation hotspots (gatekeeper, G-loop, αC-helix and A-loop) associated with DR in 538 human protein kinases using large-scale cancer data sets (TCGA, ICGC, COSMIC and GDSC). Our results revealed 358 kinases harboring 3318 mutations that covered 702 drug resistance hotspot residues. Among them, 197 kinases had multiple genetic variants on each residue. We further computationally assessed and validated the epidermal growth factor receptor mutations on protein structure and drug-binding efficacy. This is the first study to provide a landscape view of DR-associated mutation hotspots in kinase's secondary structures, and its knowledge will help the development of effective next-generation KIs for better precision medicine.

Enhanced Efficacy of Gefitinib in Drug-Sensitive and Drug-Resistant Cancer Cell Lines after Arming with a Singlet Oxygen Releasing Moiety

Attractive results have been achieved with small-molecule target-based drugs in the anticancer field; however, enhancing their treatment effect and solving the problem of drug resistance remain key concerns worldwide. Inspired by the specific affinity of gefitinib for tumour cells and the strong oxidation capacity of singlet oxygen, we combined a chemically generated singlet oxygen moiety with the small-molecule targeted drug gefitinib to improve its anticancer effect. We designed and synthesised a novel compound (Y5-1), in which a small-molecule targeted therapy agent (gefitinib) and a singlet oxygen (provided by an in vitro photodynamic reaction) thermally controlled releasing moiety are covalently conjugated. We demonstrated that the introduction of the singlet oxygen thermally controlled releasing moiety enhanced the anticancer activities of gefitinib. The results of this study are expected to provide a novel strategy to enhance the effect of chemotherapy drugs on drug-resistant cell lines.

[Studies and Progress of EGFR exon 20 Insertion Mutation in Non-small Cell Lung Cancer]

Lung cancer has the highest morbidity and mortality among malignant tumors worldwidely. Targeted therapy related to non-small cell lung cancer (NSCLC) is the research hotspot in recent year. The emergence of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has brought a huge change in the treatment of patients with EGFR mutation. The patients with EGFR exon20 insertion are specific cohort in NSCLC. Reviewing the clinical researches to EGFR exon20 insertion mutation positive NSCLC, as well as summarizing character, testing methods and treatment, will provide a help for clinical application, bringing more benefits for patients at the same time.

FDA- and EMA-Approved Tyrosine Kinase Inhibitors in Advanced EGFR-Mutated Non-Small Cell Lung Cancer: Safety, Tolerability, Plasma Concentration Monitoring, and Management

Non-small-cell lung cancer (NSCLC) is the most common form of primary lung cancer. The discovery of several oncogenic driver mutations in patients with NSCLC has allowed the development of personalized treatments based on these specific molecular alterations, in particular in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene. Gefitinib, erlotinib, afatinib, and osimertinib are TK inhibitors (TKIs) that specifically target EGFR and are currently approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) as first line treatment for sensitive EGFR-mutant patients. However, these four drugs are associated with severe adverse events (AEs) that can significantly impact patient health-related quality of life and patient monitoring. EGFR-TKIs are commonly used together with other types of medication that can substantially interact. Here, we review approaches used for the management of TKI-AEs in patients with advanced NSCLC to promote the benefits of treatments and minimize the risk of TKI treatment discontinuation. We also consider potential TKI–drug interactions and discuss the usefulness of plasma concentration monitoring TKIs based on chromatographic and mass spectrometry approaches to guide clinical decision-making. Adjusting the most appropriate therapeutic strategies and drug doses may improve the performance therapy and prognosis of patients with advanced EGFR-mutated NSCLC.

The exosomal compartment protects epidermal growth factor receptor from small molecule inhibitors

Epidermal growth factor receptor (EGFR) plays a significant role in promoting breast cancer progression. However, targeting EGFR as a single treatment only resulted in moderate efficacy to the disease. The underlying mechanism of low responsiveness to EGFR inhibition remains largely unclear. Tumor-secreted extracellular vesicles (EVs) play a crucial role in mediating intercellular communication between tumor and stromal cells in local microenvironment and distant metastatic niche. Extracellular vesicles mediate cell-to-cell transfer of lipids, nucleic acids, and proteins. Although numerous recent studies have demonstrated exchanges of extracellular vesicles between cancer cells and the recipient cells contribute to tumor proliferation, invasion, and metastasis, yet little is known how the exosomal compartment responds to targeted therapies and their role in promoting drug resistance. In the current study we used a triple-negative breast cancer model to show that EV-encapsulated EGFR is protected from targeted inhibitors of EGFR and can trigger signaling pathway in recipient cancer cells, promoting proliferation and migration ability in vitro. Taken together, our study suggested a novel mechanism of drug resistance entailing the EV compartment, such as exosomes, as a target shelter which when released can signal for tumor promotion in the recipient cancer cells.

Safety and efficacy of afatinib as add-on to standard therapy of gemcitabine/cisplatin in chemotherapy-naive patients with advanced biliary tract cancer: an open-label, phase I trial with an extensive biomarker program

BACKGROUND

To date, the cornerstone of treatment in patients with advanced or metastatic cholangiocarcinoma (CCA) is systemic chemotherapy based on a combination of gemcitabine and a platinum derivative. Other therapeutic approaches including targeted agents and tyrosine kinase inhibitors (TKI) have demonstrated disappointing results, highlighting the complexity of CCA. Recently, drugs aiming at the inhibition of HER-receptors have shown first therapeutic benefit in patients with late stage disease. The aim of this phase I study was to test the dose level toxicities (DLTs), safety and efficacy of afatinib, a highly specific panErbB family receptor TKI, in chemotherapy naive patients with advanced CCA in conjunction with an extensive biomarker program.

METHODS

Afatinib was administered continuously p. o. as add-on in patients with advanced CCA who received conventional chemotherapy with gemcitabine/cisplatin. A classical 3 + 3 phase I study was employed, while the maximum tolerated dose (MTD) of oral afatinib was determined in a 2 step dose escalation. Safety, overall survival (OS) and progression free survival (PFS) were evaluated for all patients. Finally, a translational biomarker analysis was conducted for the EGFR and VEGF signalling cascades.

RESULTS

Overall, 9 patients were enrolled. Further recruitment was discontinued due to lack of efficacy results of the tested drug in other indications. 30 mg afatinib could be safely administered as add-on to 80% of standard dose gemcitabine/cisplatin. The mOS and mPFS were 7.7 and 6.0 months, respectively. Diarrhoea and haematological disorders were the most common observed AEs. Almost all patients overexpressed EGFR on their tumour tissues, whereas none of them expressed mutations in Exons 18, 19 and 21. Non-responders showed a higher variation of VEGF-C, -D, leptin and sEGFR in their sera.

CONCLUSIONS

Afatinib failed to show survival benefits in combination with gemcitabine/cisplatin in patients with advanced CCA. Mutational analysis of EGFR and pathways associated with VEGF-C, -D and leptin might show promising results in future studies.

CLINICAL TRIALS REGISTRATION

NCT01679405 August, 2012.

Treatment effectiveness and tolerability of afatinib at different doses in patients with EGFR-mutated lung adenocarcinoma: How low can we go?

INTRODUCTION

Afatinib is commonly used as the first-line treatment for EGFR-mutated lung adenocarcinoma. However, dose adjustments are frequently required. This study aimed to investigate the treatment effectiveness of afatinib administered at different doses to patients with EGFR-mutated lung adenocarcinoma.

METHODS

Treatment-naïve patients with advanced EGFR-mutated lung adenocarcinoma who received afatinib therapy between May 2014 and September 2016 were enrolled retrospectively. Collected clinical data included age, sex, smoking history, performance status, disease stages, EGFR mutation status, initial doses of afatinib, dose adjustments, treatment responses, progression-free survival and treatment-associated adverse events. The average daily dose was calculated by dividing the summation of all doses of prescribed tablets during the treatment period by the total days of afatinib use. The patients were classified into five treatment groups based on average daily doses: 40 mg, <40 and >30 mg, 30 mg, <30 and ≥ 20 mg and <20 mg.

RESULTS

A total of 254 patients were included. No significant differences were found among these five treatment groups with respect to response rates (69.3%, 68.3%, 70.5%, 77.8% and 66.7%, respectively, p = 0.920) and disease control rates (97.4%, 95.2%, 97.7%, 100% and 100%, respectively, p = 0.749). However, the treatment group with an average daily dose of <20 mg had a significant shorter progression-free survival as compared with the other groups (16.8, 12.4, 13.9, 17.0 and 5.3 months, respectively, p = 0.049).

CONCLUSIONS

Dose reduction may not affect the treatment effectiveness until the average daily dose is below 20 mg. Further prospective studies of afatinib therapy at different daily doses are warranted.

TAS6417, A Novel EGFR Inhibitor Targeting Exon 20 Insertion Mutations

Activating mutations in the EGFR gene are important targets in cancer therapy because they are key drivers of non-small cell lung cancer (NSCLC). Although almost all common EGFR mutations, such as exon 19 deletions and the L858R point mutation in exon 21, are sensitive to EGFR-tyrosine kinase inhibitor (TKI) therapies, NSCLC driven by EGFR exon 20 insertion mutations is associated with poor clinical outcomes due to dose-limiting toxicity, demonstrating the need for a novel therapy. TAS6417 is a novel EGFR inhibitor that targets EGFR exon 20 insertion mutations while sparing wild-type (WT) EGFR. In cell viability assays using Ba/F3 cells engineered to express human EGFR, TAS6417 inhibited EGFR with various exon 20 insertion mutations more potently than it inhibited the WT. Western blot analysis revealed that TAS6417 inhibited EGFR phosphorylation and downstream molecules in NSCLC cell lines expressing EGFR exon 20 insertions, resulting in caspase activation. These characteristics led to marked tumor regression in vivo in both a genetically engineered model and in a patient-derived xenograft model. Furthermore, TAS6417 provided a survival benefit with good tolerability in a lung orthotopic implantation mouse model. These findings support the clinical evaluation of TAS6417 as an efficacious drug candidate for patients with NSCLC harboring EGFR exon 20 insertion mutations. Mol Cancer Ther; 17(8); 1648-58. ©2018 AACR.

Tyrosine kinase inhibitors for brain metastases in HER2-positive breast cancer

Approximately 30-50% of advanced HER2-positive breast cancer patients will develop central nervous system (CNS) metastases, with an annual risk of around 10%, and a half of them will die from brain progression. An increased risk of brain metastases is also seen in patients with early HER2-positive breast cancer administered curative therapy. Brain metastases in HER2-positive breast cancer patients usually constitute the first site of recurrence. The administration of anti-HER2 monoclonal antibodies, trastuzumab and pertuzumab, considerably delays the onset of symptomatic brain disease: however, the limited penetration of these compounds into the CNS hinders their efficacy. The small-molecule tyrosine kinase inhibitors of epidermal growth factor receptors family have established activity in HER2-positive breast cancer in both advanced disease and neoadjuvant setting. Favorable physico-chemical properties of these compounds allow them for a more efficient penetration through the blood-brain barrier, and hold the promise for more effective prevention and treatment of brain metastases. In this article we review the role of currently available or investigational HER2 tyrosine kinase inhibitors: lapatinib, neratinib, afatinib and tucatinib in the treatment of brain metastases in HER2-positive breast cancer patients.

Sleeve lobectomy for lung adenocarcinoma treated with neoadjuvant afatinib

Afatinib, the second-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has been postulated to be associated with improved inhibition of EGFR-dependent tumor growth compared with first-generation EGFR-TKIs for advanced non-small cell lung cancer (NSCLC). We present a case of lung adenocarcinoma (cT3N0M0) treated with neoadjuvant afatinib and sleeve lobectomy. Because of the location of the tumor, reduced FEV1 value, and the presence of EGFR mutation, the patient was planned to be prescribed afatinib (30 mg daily) for 3 weeks as neoadjuvant therapy and underwent sleeve lobectomy to avoid pneumonectomy as much as possible. Although the patient presented with grade 3 diarrhea and dose reduction of afatinib to 20 mg daily was needed, several image findings showed a partial response of the tumor on Day 20. Oral administration of afatinib was discontinued on Day 22. A right upper sleeve lobectomy combined with partial resection of lower lobe was performed after oral administration of afatinib on Day 24. The patient's postoperative course was uneventful and she has been free of recurrence for 26 months. This strategy could reduce the risk of pneumonectomy with acceptable side effects. The treatment, clinical course and pathological findings of the patient are discussed.

Research progress in quinazoline derivatives as multi-target tyrosine kinase inhibitors

Receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR), are involved in multiple human tumors. Therefore, RTKs are attractive targets for various antitumor strategies. Two classes of tyrosine kinase antagonists were applied in the clinic for monoclonal antibodies and small-molecule tyrosine kinase inhibitors. A well-studied class of small-molecule inhibitors is represented by 4-anilinoquinazolines, exemplified by gefitinib and erlotinib as mono-targeted EGFR inhibitors, which were approved for the treatment of non-small-cell lung cancer. Mono-target drugs may result in drug resistance and the innovation of multi-target drugs has grown up to be an active field. Recent advances in research on antitumor bioactivity of 4-anilino(or phenoxy)quinazoline derivatives with multiple targets are reviewed in this paper. At the same time, synthetic methods of quinazolines were introduced from the point of building the ring skeleton and based on the types of reaction.

Clinical Pharmacokinetics and Pharmacodynamics of Afatinib

Afatinib is an oral, irreversible ErbB family blocker that covalently binds to the kinase domains of epidermal growth factor receptor (EGFR), human EGFRs (HER) 2, and HER4, resulting in irreversible inhibition of tyrosine kinase autophosphorylation. Studies in healthy volunteers and patients with advanced solid tumours have shown that once-daily afatinib has time-independent pharmacokinetic characteristics. Maximum plasma concentrations of afatinib are reached approximately 2–5 h after oral administration and thereafter decline, at least bi-exponentially. Food reduces total exposure to afatinib. Over the clinical dose range of 20–50 mg, afatinib exposure increases slightly more than dose proportional. Afatinib metabolism is minimal, with unchanged drug predominantly excreted in the faeces and approximately 5 % in urine. Apart from the parent drug afatinib, the major circulation species in human plasma are the covalently bound adducts to plasma protein. The effective elimination half-life is approximately 37 h, consistent with an accumulation of drug exposure by 2.5- to 3.4-fold based on area under the plasma concentration–time curve (AUC) after multiple dosing. The pharmacokinetic profile of afatinib is consistent across a range of patient populations. Age, ethnicity, smoking status and hepatic function had no influence on afatinib pharmacokinetics, while females and patients with low body weight had increased exposure to afatinib. Renal function is correlated with afatinib exposure, but, as for sex and body weight, the effect size for patients with severe renal impairment (approximately 50 % increase in AUC) is only mildly relative to the extent of unexplained interpatient variability in afatinib exposure. Afatinib has a low potential as a victim or perpetrator of drug–drug interactions, especially with cytochrome P450-modulating agents. However, concomitant treatment with potent inhibitors or inducers of the P-glycoprotein transporter can affect the pharmacokinetics of afatinib. At a dose of 50 mg, afatinib does not have proarrhythmic potential.

Phase 1 Studies of Poziotinib, an Irreversible Pan-HER Tyrosine Kinase Inhibitor in Patients with Advanced Solid Tumors

Purpose

Poziotinib, a pan-human epidermal growth factor receptor 2 (HER) tyrosine kinase inhibitor, has shown potent activity againstwild type of epidermal growth factorreceptor(EGFR) family kinases including EGFR, HER2, and HER4 and EGFR-mutant cells in vitro. Two phase I studies were conducted to determine the maximum tolerated dose (MTD), pharmacokinetics, safety, and antitumor activity against advanced solid tumors.

Materials and Methods

Standard 3+3 dose escalation scheme using two different dosing schedules were studied: once daily, 14-day on, and 7-day off (intermittent schedule); and once daily continuous dosing with food effect. Additional patients were enrolled in an expansion cohort.

Results

A total of 75 patients were enrolled in the two studies. The most common drug-related treatment-emergent adverse eventswere diarrhea,rash, stomatitis, pruritus, and anorexia. Dose-limiting toxicities were grade 3 diarrhea in the intermittent schedule and grade 3 anorexia and diarrhea in the continuous dosing schedule. The MTDs were determined as 24 mg/day in the intermittent dosing schedule and 18 mg/day in the continuous dosing schedule. Eight (16%) and 24 (47%) of 51 evaluable patients in the intermittent schedule achieved partial response (PR) and stable disease (SD), respectively. Four (21%) and six (32%) of 19 evaluable patients in continuous dosing schedule achieved PR and SD, respectively. Patients with PR (n=7) or SD ≥ 12 weeks (n=7) had HER2 amplification (n=7; breast cancer, 5; and stomach cancer, 2) and EGFR amplification (n=1, squamous cell lung cancer).

Conclusion

Poziotinib was safe and well tolerated in patients with advanced solid tumors. It showed an encouraging activity against EGFR-mutant and HER2-amplified cancers.

Real-world experience of afatinib as a first-line therapy for advanced EGFR mutation-positive lung adenocarcinoma

We evaluated the real-world efficacy and side effects of afatinib as a first-line therapy for advanced EGFR mutation-positive lung adenocarcinoma. The medical records of patients receiving afatinib as a first-line therapy after National Health Insurance reimbursement between May 2014 and January 2016 were reviewed, and information on patient characteristics and treatment courses were collected consecutively. Rebiopsy tissue was collected for EGFR mutation and MET amplification analyses. MET amplification was detected by fluorescence in situ hybridization and immunohistochemistry. In total, 140 patients were enrolled (median follow-up, 18.0 months). No significant differences in side effects, treatment responses, progression-free survival, or brain metastasis control were observed between patients receiving 40 mg versus < 40 mg of afatinib during the first 6 months. Patients with significant pretreatment weight loss (> 10.0% in 6 months) had a shorter median progression-free survival. Patients with brain metastases had a poorer Eastern Cooperative Oncology Group performance status and were associated with a shorter median progression-free survival. Nine patients (32.1%) had a p.T790M mutation and only 1 patient gained MET amplifications after disease progression. Afatinib is effective as a first-line therapy for advanced EGFR mutation-positive lung adenocarcinoma. Afatinib dosage does not affect clinical efficacy and drug-related side effects.

Treating EGFR mutation resistance in non-small cell lung cancer - role of osimertinib

The discovery of mutations in EGFR significantly changed the treatment paradigm of patients with EGFR-mutant non-small cell lung cancer (NSCLC), a particular group of patients with different clinical characteristics and outcome to EGFR-wild-type patients. In these patients, the treatment of choice as first-line therapy is first- or second-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, erlotinib, or afatinib. Inevitably, after the initial response, all patients become refractory to these drugs. The most common mechanism of acquired resistance to EGFR-TKIs is the development of a second mutation in exon 20 of EGFR (T790M). Osimertinib is a third-generation EGFR-TKI designed for overcoming T790M-mediated resistance. Based on the results of efficacy and tolerability of Phase II and Phase III studies, osimertinib has been approved for treatment of advanced EGFRT790M+ mutation NSCLC following progression on a prior EGFR-TKI. Occurrence of acquired resistance to osimertinib represents an urgent need for additional strategies including combination with other agents, such as other targeted therapies or checkpoint inhibitors, or development of new and more potent compounds.

Developments in pharmacotherapy for treating metastatic non-small cell lung cancer

INTRODUCTION

Most patients with non-small cell lung (NSCLC), including squamous cell carcinoma, adenocarcinoma and large cell carcinoma, have advanced disease at diagnosis and systemic therapy is the standard-of-care. About 20% of Caucasian patients are affected by an oncogene-addicted advanced NSCLC for which correspondent inhibitors are available. Areas covered: The main state-of-the-art synthetic anticancer drugs in the groups of chemotherapeutics, epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinase inhibitors for NSCLC treatment, are reviewed and discussed from phase III randomized practice-changing trials onwards. A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question was undertaken. Expert opinion: The survival of NSCLC patients is increasing, regardless of the presence or not of a specific target, due to the availability of new generation drugs. The continuous deep knowledge of the mechanisms of NSCLC development and the constant research into new drugs should lead to the discovery of new potential targets and the synthesis of corresponding inhibitors to improve the outcomes of each subgroup of patients in order to control the disease in a constantly growing percentage of patients.

Unravelling signal escape through maintained EGFR activation in advanced non-small cell lung cancer (NSCLC): new treatment options

The discovery of activating epidermal growth factor receptor (EGFR) mutations has opened up a new era in the development of more effective treatments for patients with non-small cell lung cancer (NSCLC). However, patients with EGFR-activating mutated NSCLC treated with EGFR tyrosine kinase inhibitors (TKIs) ultimately develop acquired resistance (AR). Among known cases of patients with AR, 70% of the mechanisms involved in the development of AR to EGFR TKI have been identified and may be categorised as either secondary EGFR mutations such as the T790M mutation, activation of bypass track signalling pathways such as MET amplification, or histologic transformation. EGFR-mutant NSCLC tumours maintain oncogenic addiction to the EGFR pathway beyond progression with EGFR TKI. Clinical strategies that can be implemented in daily clinical practice to potentially overcome this resistance and prolong the outcome in this subgroup of patients are presented.

Afatinib reverses multidrug resistance in ovarian cancer via dually inhibiting ATP binding cassette subfamily B member 1

ABCB1-mediated multidrug resistance (MDR) remains a major obstacle to successful chemotherapy in ovarian cancer. Herein, afatinib at nontoxic concentrations significantly reversed ABCB1-mediated MDR in ovarian cancer cells in vitro (p < 0.05). Combining paclitaxel and afatinib caused tumor regressions and tumor necrosis in A2780T xenografts in vivo. More interestingly, unlike reversible TKIs, afatinib had a distinctive dual-mode action. Afatinib not only inhibited the efflux function of ABCB1, but also attenuated its expression transcriptionally via down-regulation of PI3K/AKT and MAPK/p38-dependent activation of NF-κB. Furthermore, apart from a substrate binding domain, afatinib could also bind to an ATP binding domain of ABCB1 through forming hydrogen bonds with Gly533, Gly534, Lys536 and Ala560 sites. Importantly, mutations in these four binding sites of ABCB1 and the tyrosine kinase domain of EGFR were not correlated with the reversal activity of afatinib on MDR. Given that afatinib is a clinically approved drug, our results suggest combining afatinib with chemotherapeutic drugs in ovarian cancer. This study can facilitate the rediscovery of superior MDR reversal agents from molecular targeted drugs to provide a more effective and safer way of resensitizing MDR.

Preclinical and clinical studies on afatinib in monotherapy and in combination regimens: Potential impact in colorectal cancer

Targeting the epidermal growth factor receptor (EGFR) with monoclonal antibodies (mAbs) or tyrosine kinase inhibitors (TKI) has been an interesting therapeutic strategy because aberrant activation of this receptor plays an important role in the tumorgenesis of many cancer types, including colorectal cancer (CRC). After the initial promising results of EGFR-targeted therapies, therapeutic resistance is a major clinical problem. In order to overcome resistance to these EGFR-targeted therapies, new treatment options are necessary. In contrast to first generation EGFR inhibitors, afatinib (BIBW2992) is a second-generation irreversible ErbB family blocker that inhibits EGFR as well as HER2 and HER4. Consequently, treatment with afatinib may result in a distinct and more pronounced therapeutic benefit. Preclinical studies have reported promising results for afatinib in monotherapy as well as in combination with other drugs in CRC model systems. Furthermore, clinical studies examining afatinib as single agent and in combination therapy demonstrated manageable safety profile. Nevertheless, only limited antitumor activity has been observed in CRC patients. Although several combination treatments with afatinib have already been investigated, no optimal combination has been identified for CRC patients yet. As molecular tumor characteristics have gained increased importance in the choice of treatment, additional studies with biomarker-driven patient recruitment are required to further explore afatinib efficacy in CRC.

IKBKE Is a Substrate of EGFR and a Therapeutic Target in Non-Small Cell Lung Cancer with Activating Mutations of EGFR

Non-small cell lung cancers (NSCLC) marked by EGFR mutations tend to develop resistance to therapeutic EGFR inhibitors, often due to secondary mutation EGFR(T790M) but also other mechanisms. Here we report support for a rationale to target IKBKE, an IκB kinase family member that activates the AKT and NF-κB pathways, as one strategy to address NSCLC resistant to EGFR inhibitors. While wild-type and mutant EGFR directly interacted with IKBKE, only mutant EGFR phosphorylated IKBKE on residues Y153 and Y179. The unphosphorylatable mutant IKBKE-Y153F/Y179-F that lost kinase activity failed to activate AKT and inhibited EGFR signaling. In clinical specimens of NSCLC with activating mutations of EGFR, we observed elevated levels of phospho-Y153 IKBKE. IKBKE ablation with shRNA or small-molecule inhibitor amlexanox selectively inhibited the viability of NSCLC cells with EGFR mutations in vitro In parallel, we found that these treatments activated the MAPK pathway due to attenuation of an IKBKE feedback mechanism. In vivo studies revealed that combining amlexanox with MEK inhibitor AZD6244 significantly inhibited the xenograft tumor growth of NSCLC cells harboring activating EGFR mutations, including EGFR(T790M) Overall, our findings define IKBKE as a direct effector target of EGFR and provide a therapeutic rationale to target IKBKE as a strategy to eradicate EGFR-TKI-resistant NSCLC cells. Cancer Res; 76(15); 4418-29. ©2016 AACR.

Afatinib in squamous cell carcinoma of the head and neck

INTRODUCTION

Recently new data on the efficacy of afatinib in head and neck squamous cell carcinoma (HNSCC) have been published.

AREAS COVERED

We searched the literature for published and ongoing studies with afatinib in HNSCC. Phase I data and results of phase II and III studies of afatinib in HNSCC are discussed. The maximum tolerated dose (MTD) of afatinib monotherapy with continuous administration was determined at 40 or 50 mg/day, rash and diarrhea being the principal dose-limiting toxicities. The MTD was lower when combined with chemotherapy. Studies with afatinib have been conducted or are ongoing both in the recurrent or metastatic (R/M) and in the locoregionally advanced (LA) HNSCC disease setting.

EXPERT OPINION

Comparable disease control and tumor shrinkage rates were observed with cetuximab and afatinib in HNSCC progressing after platinum-containing chemotherapy. In patients with R/M- Squamous cell carcinoma of the head and neck (SCCHN) who had progressed on/after first-line platinum-based therapy, afatinib induced significantly higher disease control rate, longer progression-free survival and improved patient-reported outcome compared to methotrexate. Randomized phase III trials studying the role of adjuvant afatinib after definitive or postoperative chemoradiation in LA-HNSCC are ongoing.

HER-2 and HER-3 expression in liver metastases of patients with colorectal cancer

OBJECTIVE

In this study, we evaluate the frequency of HER-2 and HER-3 expression in liver metastases from patients with colorectal cancer (CRLM). We analyzed the potential of HER-2 and HER-3 as therapeutic targets and evaluated their prognostic value.

PATIENTS AND METHODS

Overall 208 patients with CRLM were enrolled. HER-2 and HER-3 expression were determined in metastatic tissue of diagnostic punch biopsies (n = 29) or resection specimens (n = 179). The results of immunohistochemistry (IHC) scoring and In-situ-hybridization (ISH)-amplification were correlated with clinical parameters and for the 179 resected patients with cancer-specific (CSS) and overall survival (OS). The mean follow-up time was 56.7 months.

RESULTS

Positivity of HER-2 status (IHC score 2+/ISH+ and IHC 3+) was found in 8.2% of CRLM. High expression of HER-3 (IHC score 2+ and IHC 3+) was detected in 75.0% of liver metastases. CSS after liver surgery was determined and was independent from the HER-2 status (p = 0.963); however HER-3 was prognostic with a favorable course for patients showing an overexpression of HER-3 (p = 0.037).

CONCLUSIONS

HER-2 overexpression occurs in only 8% of patients with CRLM but with 75% of cases HER-3 is frequently overexpressed in CRLM. Therefore, HER-2 and particularly HER-3 could serve as novel targets to be addressed within multimodal treatment approaches.

Discovery of 5-(methylthio)pyrimidine derivatives as L858R/T790M mutant selective epidermal growth factor receptor (EGFR) inhibitors

To overcome the drug-resistance of first generation EGFR inhibitors and the nonselective toxicities of second generation inhibitors among NSCLC patients, a series of 5-(methylthio)pyrimidine derivatives were discovered as novel EGFR inhibitors, which harbored not only potent enzymatic and antiproliferative activities against EGFR(L858R/T790M) mutants, but good selectivity over wide-type form of the receptor. This goal was achieved by employing structure-based drug design and traditional optimization strategies, based on WZ4002 and CO1686. These derivatives inhibited the enzymatic activity of EGFR(L858R/T790M) mutants with IC50 values in subnanomolar ranges, while exhibiting hundreds of fold less potency on EGFR(WT). These compounds also strongly inhibited the proliferation of H1975 non-small cell lung cancer cells bearing EGFR(L858R/T790M), while being significantly less toxic to A431 human epithelial carcinoma cells with overexpressed EGFR(WT). The EGFR kinase inhibitory and antiproliferative activities were further validated by Western blot analysis for activation of EGFR and the downstream signaling in cancer cells.