Next-Generation Covalent Irreversible Kinase Inhibitors in NSCLC: Focus on Afatinib

Advancing non-small cell lung cancer treatment: the power of combination immunotherapies

Non-small cell lung cancer (NSCLC) remains an unsolved challenge in oncology, signifying a substantial global health burden. While considerable progress has been made in recent years through the emergence of immunotherapy modalities, such as immune checkpoint inhibitors (ICIs), monotherapies often yield limited clinical outcomes. The rationale behind combining various immunotherapeutic or other anticancer agents, the mechanistic underpinnings, and the clinical evidence supporting their utilization is crucial in NSCLC therapy. Regarding the synergistic potential of combination immunotherapies, this study aims to provide insights to help the landscape of NSCLC treatment and improve clinical outcomes. In addition, this review article discusses the challenges and considerations of combination regimens, including toxicity management and patient selection.

Chemical Scaffolds for the Clinical Development of Mutant-Selective and Reversible Fourth-Generation EGFR-TKIs in NSCLC

In nonsmall cell lung cancer (NSCLC), as well as in other tumors, the targeted therapy is mainly represented by tyrosine kinase inhibitors (TKIs), small molecules able to target oncogenic driver alterations affecting the gene encoding the epidermal growth factor receptor (EGFR). Up to now, several different TKIs have been developed. However, cancer cells showed an incredible adaptive tumor response to the inhibition of the sequentially mutated EGFR (EGFRM+), triggering the need to explore novel pharmacochemical strategies. This Review summarizes the recent efforts in the development of new reversible next-generation EGFR TKIs to fight the resistance against T790M and C797S mutations. Specifically, after giving an overview of the role of the EGFR's signaling pathways in cancer progression, we are going to discuss the most relevant approved drugs and drug candidates in terms of chemical structure, binding modalities, and their potency and selectivity against the mutated EGFR over the wild-type form. This could provide important guidelines and rationale for the discovery and iterative development of new drugs.

Immune modulation in malignant pleural effusion: from microenvironment to therapeutic implications

Immune microenvironment and immunotherapy have become the focus and frontier of tumor research, and the immune checkpoint inhibitors has provided novel strategies for tumor treatment. Malignant pleural effusion (MPE) is a common end-stage manifestation of lung cancer, malignant pleural mesothelioma and other thoracic malignancies, which is invasive and often accompanied by poor prognosis, affecting the quality of life of affected patients. Currently, clinical therapy for MPE is limited to pleural puncture, pleural fixation, catheter drainage, and other palliative therapies. Immunization is a new direction for rehabilitation and treatment of MPE. The effusion caused by cancer cells establishes its own immune microenvironment during its formation. Immune cells, cytokines, signal pathways of microenvironment affect the MPE progress and prognosis of patients. The interaction between them have been proved. The relevant studies were obtained through a systematic search of PubMed database according to keywords search method. Then through screening and sorting and reading full-text, 300 literatures were screened out. Exclude irrelevant and poor quality articles, 238 literatures were cited in the references. In this study, the mechanism of immune microenvironment affecting malignant pleural effusion was discussed from the perspectives of adaptive immune cells, innate immune cells, cytokines and molecular targets. Meanwhile, this study focused on the clinical value of microenvironmental components in the immunotherapy and prognosis of malignant pleural effusion.

Six-Membered Aromatic Nitrogen Heterocyclic Anti-Tumor Agents: Synthesis and Applications

Cancer stands as a serious malady, posing substantial risks to human well-being and survival. This underscores the paramount necessity to explore and investigate novel antitumor medications. Nitrogen-containing compounds, especially those derived from natural sources, form a highly significant category of antitumor agents. Among these, antitumor agents with six-membered aromatic nitrogen heterocycles have consistently attracted the attention of chemists and pharmacologists. Accordingly, we present a comprehensive summary of synthetic strategies and clinical implications of these compounds in this review. This entails an in-depth analysis of synthesis pathways for pyridine, quinoline, pyrimidine, and quinazoline. Additionally, we explore the historical progression, targets, mechanisms of action, and clinical effectiveness of small molecule inhibitors possessing these structural features.

Redrawing Urokinase Receptor (uPAR) Signaling with Cancer Driver Genes for Exploring Possible Anti-Cancer Targets and Drugs

During tumorigenesis, urokinase (uPA) and uPA receptor (uPAR) play essential roles in mediating pathological progression in many cancers. To understand the crosstalk between the uPA/uPAR signaling and cancer, as well as to decipher their cellular pathways, we proposed to use cancer driver genes to map out the uPAR signaling. In the study, an integrated pharmaceutical bioinformatics approach that combined modulator identification, driver gene ontology networking, protein targets prediction and networking, pathway analysis and uPAR modulator screening platform construction was employed to uncover druggable targets in uPAR signaling for developing a novel anti-cancer modality. Through these works, we found that uPAR signaling interacted with 10 of 21 KEGG cancer pathways, indicating the important role of uPAR in mediating intracellular cancerous signaling. Furthermore, we verified that receptor tyrosine kinases (RTKs) and ribosomal S6 kinases (RSKs) could serve as signal hubs to relay uPAR-mediated cellular functions on cancer hallmarks such as angiogenesis, proliferation, migration and metastasis. Moreover, we established an in silico virtual screening platform and a uPAR-driver gene pair rule for identifying potential uPAR modulators to combat cancer. Altogether, our results not only elucidated the complex networking between uPAR modulation and cancer but also provided a paved way for developing new chemical entities and/or re-positioning clinically used drugs against cancer.

Rare T263P epidermal growth factor receptor extracellular domain mutation of advanced non-small cell lung cancer in a Vietnamese male patient

T263P mutation is one of the rare EGFR mutations located on chromosome 7p11.2, which is a change in amino acid residue at position 263 of the epidermal growth factor receptor protein, where L-threonine has been replaced by L-proline. This missense mutation in the extracellular EGFR domain is not well-known in lung cancer. In this study, we first report a patient with advanced lung adenocarcinoma harbouring only a rare T263P EGFR mutation who benefited from first-line afatinib therapy in Vietnam. The patient achieved a partial response with a time-to-treatment failure of 5 months. The patient subsequently received several chemotherapy regimens as the disease progressed, with overall survival of 17 months. Non-small cell lung cancer with a rare T263P EGFR mutation responds to afatinib but has a poor prognosis. Further studies are needed to determine the efficacy of targeted therapies in this specific population.

Efficacy of erlotinib in NSCLC harboring rare EGFR extracellular domain mutation (T263P) and common mutations: Case report and literature review

The epidermal growth factor receptor (EGFR) typically contains an extracellular domain (ECD), a transmembrane (TM) domain, and an intracellular kinase (KD) domain. ECD mutations of EGFR in NSCLC may affect its normal function and intrinsic resistance to tyrosine kinase inhibitors (TKIs) and the effectiveness of drugs for these patients is unsatisfactory. Recently, we found an EGFR T263P mutation located at the ECD, which has never been reported in Chinese non-small cell lung cancer (NSCLC). Hence, we reported that a patient with advanced lung adenocarcinoma harboring the EGFR T263P mutation, L858R mutation and MET amplification was resistant to osimertinib but significantly benefited from erlotinib and capmatinib treatment. This patient achieved a partial response and had progression-free survival (PFS) for more than 19 months. In summary, we are the first researchers to report in detail on a Chinese patient carrying the T263P mutation and summarize all the ECD mutations in NSCLC. We believe this finding will enlighten us to treat patients with EGFR ECD mutations and more patients deserve further study.

Utility and Drawbacks of Chimeric Antigen Receptor T Cell (CAR-T) Therapy in Lung Cancer

The present treatments for lung cancer include surgical resection, radiation, chemotherapy, targeted therapy, and immunotherapy. Despite advances in therapies, the prognosis of lung cancer has not been substantially improved in recent years. Chimeric antigen receptor (CAR)-T cell immunotherapy has attracted growing interest in the treatment of various malignancies. Despite CAR-T cell therapy emerging as a novel potential therapeutic option with promising results in refractory and relapsed leukemia, many challenges limit its therapeutic efficacy in solid tumors including lung cancer. In this landscape, studies have identified several obstacles to the effective use of CAR-T cell therapy including antigen heterogeneity, the immunosuppressive tumor microenvironment, and tumor penetration by CAR-T cells. Here, we review CAR-T cell design; present the results of CAR-T cell therapies in preclinical and clinical studies in lung cancer; describe existing challenges and toxicities; and discuss strategies to improve therapeutic efficacy of CAR-T cells.

Biodegradable Carbonate Apatite Nanoparticle as a Delivery System to Promote Afatinib Delivery for Non-Small Cell Lung Cancer Treatment

Nanomedicine-based drug-delivery systems have significant interest in cancer treatment, such as improving the stabilities and biocompatibilities, precise targeting, and reducing toxicities for non-cancerous cells. Herein, this study presents the synthesis and characterisation of carbonate apatite nanoparticles (nCA) and encapsulated afatinib (AFA) as promising drug delivery candidates for lung cancer treatment. nCA/AFA was synthesised and physicochemically characterised, then the encapsulation capacity, drug loading, and cumulative drug release profile were evaluated. Powder X-ray diffraction (PXRD) confirmed that the synthesised nCA is apatite. Fourier-transform infrared spectroscopy (FTIR) results confirmed the drug loading into the nanoparticles. High-resolution transmission electron microscopy (HR-TEM) determined the morphology of nCA and nCA/AFA and the diameters of 47.36 ± 3.16 and 42.97 ± 2.78 nm, respectively, without an unaltered nCA phase. Encapsulation efficiency (%) and drug loading (%) were 55.08% ± 1.68% and 8.19% ± 0.52%. Brunauer-Emmett-Teller (BET) and dynamic light-scattering (DLS) results revealed that the synthesised nCA is mesoporous, with a surface area of 55.53 m2/g, and is negatively charged. Atomic force microscopy (AFM) showed increasing roughness of nCA/AFA compared to nCA. The drug release from the nano-formulation nCA/AFA demonstrated slow and sustained release compared to the pure drug. Accordingly, nCA/AFA represents a promising drug delivery system for NSCLC treatment.

Molecular target therapeutics of EGF-TKI and downstream signaling pathways in non-small cell lung cancers

Lung carcinoma (LC) is the third most common cancer diagnosis and accounted for the most cancer-related mortality worldwide in 2018. Based on the type of cells from which it originates, LC is commonly classified into non-small cell lung cancers (NSCLC) and small cell lung cancers (SCLC). NSCLC account for the majority of LC and can be further categories into adenocarcinoma, large cell carcinoma, and squamous cell carcinoma. Accurate classification of LC is critical for its adequate treatment and therapeutic outcome. Since NSCLC express more epidermal growth factor receptor (EGFR) with activation mutations, targeted therapy EGFR-tyrosine kinase inhibitors (TKIs) have been considered as primary option of NSCLC patients with activation EGFR mutation. In this review, we present the genetic alterations, reported mutations in EGFR, and TKIs treatment in NSCLC patients with an emphasis on the downstream signaling pathways in NSCLC progression. Among the signaling pathways identified, mitogen activation protein kinase (MAPK), known also as extracellular signal-regulated protein kinase (Erk) pathway, is the most investigated among the related pathways. EGFR activation leads to the autophosphorylation of its kinase domain and subsequent activation of Ras, phosphorylation of Raf and MEK1/2, and the activation of ERK1/2. Phosphatidylinositol 3-kinase (PI3K)/Akt is another signal pathway that regulates cell cycle and has been linked to NSCLC progression. Currently, three generations of EGFR TKIs have been developed as a first-line treatment of NSCLC patients with EGFR activation and mutation in which these treatment options will be further discussed in this review. The Supplementary Appendix for this article is available at http://links.lww.com/JCMA/A138.

Mechanism-Based and Computational-Driven Covalent Drug Design

Covalent drugs offer higher efficacy and longer duration of action than their noncovalent counterparts. Significant advances in computational methods for modeling covalent drugs are poised to shift the paradigm of small molecule therapeutics within the next decade. This viewpoint discusses the advantages of a two-state model for ranking reversible and irreversible covalent ligands and of more complex models for dissecting reaction mechanisms. The relation between these models highlights the complexity and diversity of covalent drug binding and provides opportunities for mechanism-based rational design.

Evaluation of the pharmacokinetic effects of itraconazole on alflutinib (AST2818): an open-label, single-center, single-sequence, two-period randomized study in healthy volunteers

Alflutinib (AST2818) is a newly developed third-generation EGFR tyrosine kinase inhibitor for the treatment of lung cancer patients with T790M-resistant mutations. It is metabolized mainly by the CYP3A4 enzyme. At the same time, it has the potential to induce CYP3A4. In this study, we aimed to estimate the effect of itraconazole (a strong inhibitor of CYP3A4) on the pharmacokinetics of alflutinib. For this aim, a single-center, open-label, single-sequence, two-period trial was designed. The pharmacokinetic parameters of AST2818 and its active metabolite AST5902 were established from blood concentration measurements, and adverse events (AEs) of two periods of treatment were documented. For AST2818, the C_max, AUC_0-t, and AUC_0-∞ in period II (coadministration of itraconazole) increased by 6.5 ng/mL, 1263.0 h*ng/mL, and 1067.0 h*ng/mL, respectively. And the corresponding 90% CIs were 1.23 (1.14-1.32), 2.41 (2.29-2.54), and 2.22 (2.11-2.34), respectively. The C_max, AUC_0-t, and AUC_0-∞ of AST5902 in period II decreased by 4.849 ng/mL, 415.60 h*ng/mL, and 391.4 h*ng/mL, respectively. Moreover, the corresponding 90% CIs were 0.09 (0.08-0.10), 0.18 (0.17-0.19), and 0.14 (0.13-0.15), respectively. Nonetheless, in period II, plasma concentrations of total active components (AST2818 and AST5902) changed marginally. The AUC_0-∞ of total active components increased 60%, and the corresponding C_max increased 8%. Possible treatment-related AEs assessed by investigators were fewer in period II (23.3% vs 36.7%). In conclusion, the total exposure of AST2818 and active metabolite AST5902 increased following the coadministration of itraconazole, but it was still safe and well-tolerated.

Lipid polymeric nanoparticles modified with tight junction-modulating peptides promote afatinib delivery across a blood–brain barrier model

Background

Brain metastases from non-small cell lung cancer (NSCLC) remain one of the most challenging malignancies. Afatinib (Afa) is an orally administered irreversible ErbB family blocker approved for epidermal growth factor receptor (EGFR)-mutated NSCLC. However, the incidence of brain metastases in patients with NSCLC and EGFR mutation is high. One of the major obstacles in the treatment of brain metastases is to transport drugs across the blood–brain barrier (BBB). A lipid polymeric nanoparticle (LPN) modified with a tight junction-modulating peptide is a potential formulation to deliver therapeutics across the BBB. FD7 and CCD are short peptides that perturb the tight junctions (TJs) of the BBB. In this study, the use of LPN modified with FD7 or CCD as a delivery platform was explored to enhance Afa delivery across the BBB model of mouse brain-derived endothelial bEnd.3 cells.

Results

Our findings revealed that Afa/LPN-FD7 and Afa/LPN-CCD exhibited a homogeneous shape, a uniform nano-scaled particle size, and a sustained-release profile. FD7, CCD, Afa/LPN-FD7, and Afa/LPN-CCD did not cause a significant cytotoxic effect on bEnd.3 cells. Afa/LPN-FD7 and Afa/LPN-CCD across the bEnd.3 cells enhanced the cytotoxicity of Afa on human lung adenocarcinoma PC9 cells. FD7 and CCD-modulated TJ proteins, such as claudin 5 and ZO-1, reduced transendothelial electrical resistance, and increased the permeability of paracellular markers across the bEnd.3 cells. Afa/LPN-FD7 and Afa/LPN-CCD were also partially transported through clathrin- and caveolae-mediated transcytosis, revealing the effective activation of paracellular and transcellular pathways to facilitate Afa delivery across the BBB and cytotoxicity of Afa on PC9 cells.

Conclusion

TJ-modulating peptide-modified LPN could be a prospective platform for the delivery of chemotherapeutics across the BBB to the brain for the potential treatment of the BM of NSCLC.

Fibroblast growth factor receptor facilitates recurrence of minimal residual disease following trastuzumab emtansine therapy

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) that efficiently delivers a highly potent microtubule inhibitor to HER2 overexpressing cells. Herein, we utilize HER2 transformed human mammary epithelial cells (HME2) to demonstrate in vitro and in vivo response and recurrence upon T-DM1 treatment. Continuous in vitro dosing of HME2 cells with T-DM1 failed to produce a spontaneously resistant cell line. However, induction of epithelial-mesenchymal transition (EMT) via pretreatment with TGF-β1 was capable of promoting emergence of T-DM1-resistant (TDM1R) cells. Flow cytometric analyses indicated that induction of EMT decreased trastuzumab binding, prior to overt loss of HER2 expression in TDM1R cells. Kinome analyses of TDM1R cells indicated increased phosphorylation of ErbB1, ErbB4, and FGFR1. TDM1R cells failed to respond to the ErbB kinase inhibitors lapatinib and afatinib, but they acquired sensitivity to FIIN4, a covalent FGFR kinase inhibitor. In vivo, minimal residual disease (MRD) remained detectable via bioluminescent imaging following T-DM1-induced tumor regression. Upon cessation of the ADC, relapse occurred and secondary tumors were resistant to additional rounds of T-DM1. These recurrent tumors could be inhibited by FIIN4. Moreover, ectopic overexpression of FGFR1 was sufficient to enhance tumor growth, diminish trastuzumab binding, and promote recurrence following T-DM1-induced MRD. Finally, patient-derived xenografts from a HER2+ breast cancer patient who had progressed on trastuzumab failed to respond to T-DM1, but tumor growth was significantly inhibited by FIIN4. Overall, our studies strongly support therapeutic combination of TDM1 with FGFR-targeted agents in HER2+ breast cancer.

Afatinib in EGFR TKI-naïve patients with locally advanced or metastatic EGFR mutation-positive non-small cell lung cancer: Interim analysis of a Phase 3b study

OBJECTIVES

Randomized controlled trials have demonstrated that afatinib is a suitable treatment option for patients with epidermal growth factor receptor mutation-positive (EGFRm +) non-small cell lung cancer (NSCLC). However, such studies often exclude patients treated in routine clinical practice. We report interim results from a Phase 3b, open-label, multicenter, single-arm, exploratory trial, in which afatinib was investigated in a real-world setting.

MATERIALS AND METHODS

Patients with EGFRm + tyrosine kinase inhibitor (TKI)-naïve NSCLC received afatinib 40 mg orally, once-daily, until disease progression, or voluntary withdrawal. Primary objective was safety.

RESULTS

Overall, 479 patients received afatinib: median age 65 years, 8 % of patients had an ECOG performance status ≥ 2, 17 % had brain metastases, and 13 % had tumors containing uncommon mutations only. All but one patient (99.8 %) had an adverse event (AE). Treatment-related AEs (TRAEs; any/grade ≥ 3) occurred in 97 %/44 % of patients; most common were diarrhea (87 %/16 %) and rash (51 %/11 %). AEs leading to afatinib dose-reduction were reported in 258 patients (54 %), and 37 patients (8 %) discontinued treatment due to a TRAE. Objective response rate was 45.5 %, median duration of response was 14.1 months (95 % CI: 12.2-16.4). Overall median time to symptomatic progression and progression-free survival were 14.9 months (95 % CI: 13.8-17.6) and 13.4 months (95 % CI: 11.8-14.5), respectively, in the overall population and 19.3 months (95 % CI: 15.6-21.8) and 15.9 months (95 % CI: 13.9-19.1) in patients with EGFR exon 19 deletions.

CONCLUSIONS

Afatinib administration in routine clinical practice was well tolerated with no new safety signals and demonstrated promising efficacy in patients with EGFRm + NSCLC. TRAEs were generally manageable with tolerability-guided dose reductions. Overall, these data independently support findings from randomized controlled trials of afatinib in EGFRm + NSCLC.

Selective inhibition of stemness through EGFR/FOXA2/SOX9 axis reduces pancreatic cancer metastasis

Pancreatic cancer (PC) is difficult to defeat due to mechanism (s) driving metastasis and drug resistance. Cancer stemness is a major challenging phenomenon associated with PC metastasis and limiting therapy efficacy. In this study, we evaluated the pre-clinical and clinical significance of eradicating pancreatic cancer stem cells (PCSC) and its components using a pan-EGFR inhibitor afatinib in combination with gemcitabine. Afatinib in combination with gemcitabine, significantly reduced Kras^G12D/+; Pdx-1 Cre (KC) (P<0.01) and Kras^G12D/+; p53^R172H/+; Pdx-1 Cre (KPC) (P<0.05) derived mouse tumoroids and KPC-derived murine syngeneic cell line growth compared to gemcitabine/afatinib alone treatment. The drug combination also reduced PC xenograft tumor burden (P<0.05) and the incidence of metastasis by affecting key stemness markers, as confirmed by co-localization studies. Moreover, the drug combination significantly decreases the growth of various PC patient-derived organoids (P<0.001). We found that SOX9 is significantly overexpressed in high-grade PC tumors (P<0.05) and in chemotherapy-treated patients compared to chemo-naïve patients (P<0.05). These results were further validated using publicly available datasets. Moreover, afatinib alone or in combination with gemcitabine decreased stemness and tumorspheres by reducing phosphorylation of EGFR family proteins, ERK, FAK, and CSC markers. Mechanistically, afatinib treatment decreased CSC markers by downregulating SOX9 via FOXA2. Indeed, EGFR and FOXA2 depletion reduced SOX9 expression in PCSCs. Taken together, pan EGFR inhibition by afatinib impedes PCSCs growth and metastasis via the EGFR/ERK/FOXA2/SOX9 axis. This novel mechanism of panEGFR inhibitor and its ability to eradicate CSC may serve as a tailor-made approach to enhance chemotherapeutic benefits in other cancer types.

Chimeric antigen receptor (CAR)-T-cell therapy in non-small-cell lung cancer (NSCLC): current status and future perspectives

There has been a rapid progress in developing genetically engineered T cells in recent years both in basic and clinical cancer studies. Chimeric antigen receptor (CAR)-T cells exert an immune response against various cancers, including the non-small-cell lung cancer (NSCLC). As novel agents of immunotherapy, CAR-T cells show great promise for NSCLC. However, targeting specific antigens in NSCLC with engineered CAR-T cells is complicated because of a lack of tumor-specific antigens, the immunosuppressive tumor microenvironment, low levels of infiltration of CAR-T cells into tumor tissue, and tumor antigen escape. Meanwhile, the clinical application of CAR-T cells remains limited due to the cases of on-target/off-tumor and neurological toxicity, as well as cytokine release syndrome. Hence, optimal CAR-T-cell design against NSCLC is urgently needed. In this review, we describe the basic structure and generation of CAR-T cells and summarize the common tumor-associated antigens targeted in clinical trials on CAR-T-cell therapy for NSCLC, as well as point out current challenges and novel strategies. Although many obstacles remain, the new/next generation of CARs show much promise. Taken together, research on CAR-T cells for the treatment of NSCLC is underway and has yielded promising preliminary results both in basic and pre-clinical medicine. More pre-clinical experiments and clinical trials are, therefore, warranted.

Antiviral Activity of Compound L3 against Dengue and Zika Viruses In Vitro and In Vivo

Dengue virus (DENV) and Zika virus (ZIKV) are mosquito-borne flaviviruses that cause severe illness after infection. Currently, there are no specific or effective treatments against DENV and ZIKV. Previous studies have shown that tyrosine kinase activities and signal transduction are involved in flavivirus replication, suggesting a potential therapeutic strategy for DENV and ZIKV. In this study, we found that compound L3 can significantly reduce viral protein expression and viral titers in HEK-293, MCF-7, HepG2, and Huh-7 cells and exhibits superior therapeutic efficacy against flaviviral infection compared to other tyrosine kinase inhibitors. In addition, compound L3 can decrease endogenous HER2 activation and inhibit the phosphorylation of the HER2 downstream signaling molecules Src and ERK1/2, the levels of which have been associated with viral protein expression in MCF-7 cells. Moreover, silencing HER2 diminished DENV-2 and ZIKV expression in MCF-7 cells, which suggests that HER2 activity is involved in flavivirus replication. Furthermore, in DENV-2-infected AG129 mice, treatment with compound L3 increased the survival rates and reduced the viremia levels. Overall, compound L3 demonstrates therapeutic efficacy both in vitro and in vivo and could be developed as a promising antiviral drug against emerging flaviviruses or for concurrent DENV and ZIKV outbreaks.

Tyrosine Kinase Inhibitors for the Treatment of EGFR Mutation-Positive Non-Small-Cell Lung Cancer: A Clash of the Generations

The availability of 3 generations of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) with different pharmacologic characteristics and clinical profiles has provided oncologists with a potentially confusing choice for the treatment of EGFR mutation-positive non-small-cell lung cancer. Although recent head-to-head clinical trials have demonstrated improved efficacy with second-generation (ie, afatinib, dacomitinib) and third-generation (ie, osimertinib) TKIs compared with the first-generation TKIs (eg, erlotinib, gefitinib), acquired resistance has been inevitable, regardless of which agent has been chosen as first-line therapy. Thus, the potential availability of subsequent treatment options is an important consideration. Recent data have demonstrated that osimertinib confers an overall survival benefit compared with first-generation EGFR TKIs, and dacomitinib has shown an overall survival benefit compared with gefitinib in an exploratory analysis. However, the relative benefits of different sequential EGFR-TKI regimens, especially those involving second- and third-generation agents, have remained uncertain and require prospective evaluation. Few such data currently exist to inform treatment choices. In the present review, we examined the pharmacologic characteristics and current clinical data for EGFR TKIs, including emerging information on the molecular mechanisms of resistance across the different generations of TKIs. Given the uncertainties regarding the optimal treatment choice, we have focused on the factors that might help determine the treatment decisions, such as efficacy and safety in patient subgroups. We also discussed the emerging real-world data, which have provided some insights into the benefits of sequential regimens in everyday clinical practice.

Toward Atomistic Modeling of Irreversible Covalent Inhibitor Binding Kinetics

Covalent inhibitors have emerged as an important drug class in recent years, largely due to their many unique advantages as compared to noncovalent inhibitors, including longer duration of action, lower prolonged systemic exposure, higher potency, and selectivity. However, the potential off-target toxicity of covalent inhibitors, particularly of irreversible covalent inhibitors, represents a great challenge in covalent drug development. Therefore, accurate calculation of protein covalent inhibitor reaction kinetics to guide the design of selective inhibitors would greatly benefit covalent drug discovery efforts. In the present paper, we present a computational method to calculate the relative reaction kinetics between congeneric irreversible covalent inhibitors and their protein receptors. The method combines density functional theory calculations of the transition state barrier height of the rate-limiting step for reaction between the warhead of the inhibitor and a single protein residue, and molecular-mechanics-based free energy calculations to account for the interactions between the ligand in the transition state and the protein environment. The method was tested on four pharmaceutically interesting irreversible covalent binding systems involving 28 ligands; the mean unsigned error (MUE) of the relative reaction rate for all pairs of ligands between the predictions and experimental results for these tested systems is 0.79 log unit. This is to our knowledge the first time where the reaction kinetics of protein irreversible covalent inhibition have been directly calculated with physics-based free energy calculation methods and transition state theory. We anticipate the outstanding accuracy demonstrated here across a broad range of target classes will have a strong impact on the design of selective covalent inhibitors.

Improving the anticancer effect of afatinib and microRNA by using lipid polymeric nanoparticles conjugated with dual pH-responsive and targeting peptides

Background

The emergence of resistance to chemotherapy or target therapy, tumor metastasis, and systemic toxicity caused by available anticancer drugs hamper the successful colorectal cancer (CRC) treatment. The rise in epidermal growth factor receptor (EGFR; human epidermal growth factor receptor 1; HER1) expression and enhanced phosphorylation of HER2 and HER3 are associated with tumor resistance, metastasis and invasion, thus resulting in poor outcome of anti-CRC therapy. The use of afatinib, a pan-HER inhibitor, is a potential therapeutic approach for resistant CRC. Additionally, miR-139 has been reported to be negatively correlated with chemoresistance, metastasis, and epithelial–mesenchymal transition (EMT) of CRC. Hence, we develop a nanoparticle formulation consisting of a polymer core to carry afatinib or miR-139, which is surrounded by lipids modified with a targeting ligand and a pH-sensitive penetrating peptide to improve the anticancer effect of cargos against CRC cells.

Results

Our findings show that this formulation displays a spherical shape with core/shell structure, homogeneous particle size distribution and negative zeta potential. The prepared formulations demonstrate a pH-sensitive release profile and an enhanced uptake of cargos into human colorectal adenocarcinoma Caco-2 cells in response to the acidic pH. This nanoparticle formulation incorporating afatinib and miR-139 exhibits low toxicity to normal cells but shows a better inhibitory effect on Caco-2 cells than other formulations. Moreover, the encapsulation of afatinib and miR-139 in peptide-modified nanoparticles remarkably induces apoptosis and inhibits migration and resistance of Caco-2 cells via suppression of pan-HER tyrosine kinase/multidrug resistance/metastasis pathways.

Conclusion

This study proposes a multifunctional nanoparticle formulation for targeted modulation of apoptosis/EGFR/HER/EMT/resistance/progression pathways to increase the sensitivity of colon cancer cells to afatinib.

Electronic supplementary material

The online version of this article (10.1186/s12951-019-0519-6) contains supplementary material, which is available to authorized users.

Comparative review of drug-drug interactions with epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small-cell lung cancer

The development of small-molecule tyrosine kinase inhibitors (TKIs) that target the epidermal growth factor receptor (EGFR) has revolutionized the management of non-small-cell lung cancer (NSCLC). Because these drugs are commonly used in combination with other types of medication, the risk of clinically significant drug–drug interactions (DDIs) is an important consideration, especially for patients using multiple drugs for coexisting medical conditions. Clinicians need to be aware of the potential for clinically important DDIs when considering therapeutic options for individual patients. In this article, we describe the main mechanisms underlying DDIs with the EGFR-TKIs that are currently approved for the treatment of NSCLC, and, specifically, the potential for interactions mediated via effects on gastrointestinal pH, cytochrome P450-dependent metabolism, uridine diphosphate-glucuronosyltransferase, and transporter proteins. We review evidence of such DDIs with the currently approved EGFR-TKIs (gefitinib, erlotinib, afatinib, osimertinib, and icotinib) and discuss several information sources that are available online to aid clinical decision-making. We conclude by summarizing the most clinically relevant DDIs with these EFGR-TKIs and provide recommendations for managing, minimizing, or avoiding DDIs with the different agents.

Comparison of T790M Acquisition Between Patients Treated with Afatinib and Gefitinib as First-Line Therapy: Retrospective Propensity Score Matching Analysis

Afatinib, a second-generation, irreversible pan-HER inhibitor, shows better suppression of T790M-positive lung cancer cells than gefitinib in preclinical studies. However, whether the effect of afatinib on T790M acquisition differs from that of gefitinib when used clinically as first-line therapy remains unclear. To reaffirm the preclinical efficacy of afatinib on T790M-positive lung cancer cells, H1975 cells and established PC-9 cells resistant to gefitinib and erlotinib by T790M were used. In total, 398 patients with second biopsy at progression with stage IIIB/IV non–small cell lung cancer with EGFR mutation, treated with afatinib or gefitinib as first-line therapy, were retrospectively reviewed. Propensity score matching was used to balance covariates. Afatinib inhibited the growth of lung cancer cells with low T790M allele frequencies, which are resistant to gefitinib, but not those with high T790M allele frequencies. Afatinib and gefitinib showed similar efficacy in terms of progression-free survival (PFS) (11.5 vs 13.4 months, P = .08) and overall survival (OS) (29.3 vs 28.5 months, P = .76). T790M patients had better PFS and OS than those without T790M. There was no significant difference in the cumulative T790M acquisition ratio over time between afatinib and gefitinib (48.8% vs 59.3%, P = .317). The median time to acquire T790M was 12.9 months for afatinib and 15.7 months for gefitinib (P = .342). Although afatinib inhibited the growth of lung cancer cells with low T790M allele frequencies in preclinical studies, this could not be translated into clinical efficacy in terms of lowering the rate or delaying the time of T790M acquisition.

The Impact of Afatinib on Survival in Advanced Non-Small Cell Lung Cancer: A Meta-Analysis of Randomized Controlled Trials

Background: Afatinib is a second-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) that has been approved by the Food and Drug Administration for the treatment of advanced non-small cell lung cancer (NSCLC) harboring EGFR mutations. We performed a meta-analysis to assess the efficacy and safety of afatinib in advanced NSCLC.

Methods: We searched PubMed, PMC database, EMBASE, Cochrane Library and Web of Science to obtain the relevant literature. The efficacy and safety of afatinib was assessed based on progression-free survival (PFS), overall survival (OS), overall response rate (ORR), primary grade 3/4 adverse events and fatal adverse events (FAEs). A subgroup analysis was performed according to control type for all end-points.

Results: Seven randomized controlled trials were included, with a total of 3093 patients. The meta-analysis showed that afatinib treatment significantly prolonged PFS in patients compared with control groups (HR = 0.57, 95% CI: 0.42-0.76; P = 0.00), increased OS (HR = 0.91, 95% CI: 0.83-0.99; P = 0.04) and ORR (RR = 1.82, 95% CI: 1.13-2.93; P = 0.01). In terms of safety, afatinib significantly increased the incidence of diarrhea (RR = 8.9, 95% CI: 5.33-14.93; P = 0.00), rash (RR = 7.31, 95% CI: 1.56-34.12; P = 0.01) and stomatitis (RR = 6.45, 95% CI: 1.27-32.78; P = 0.03), compared with the control group. However, there was no significant difference in FAEs (RR = 0.75, 95% CI: 0.38-1.49; P = 0.41).

Conclusions: This meta-analysis confirmed that afatinib extended survival, improved response rates and did not increase the risk of treatment-related mortality in advanced NSCLC. As a novel EGFR-TKI, afitinib has significant potential for clinical application.

Ginsenoside Rg3 promotes the antitumor activity of gefitinib in lung cancer cell lines

Lung cancer is one of the most common types of cancer with one of the highest incidence and mortality rates. Gefitinib is widely used for the treatment of non-small cell lung cancer (NSCLC). However, issues regarding drug resistance, toxicity and limited applicability have been associated with gefitinib. The aim of the present study was to investigate whether ginsenoside Rg3 enhances the anticancer activity of gefitinib in NSCLC cells. MTT assay demonstrated that ginsenoside Rg3 increased the cytotoxic effect of gefitinib in NSCLC cell lines in a dose- and time-dependent manner. In addition, flow cytometric analysis revealed that the combined treatment with gefitinib and ginsenoside Rg3 significantly increased apoptosis in NSCLC cell lines. Transwell migration assays demonstrated that the combined treatment with gefitinib and ginsenoside Rg3 significantly decreased NSCLC cell migration compared with gefitinib or ginsenoside Rg3 treatment alone. Furthermore, western blot analysis revealed that in NSCLC cell lines, the combined treatment with gefitinib and ginsenoside Rg3 increased protein expression levels of pro-apoptotic proteins Bax and cleaved-caspase-3, whilst the expression level of anti-apoptotic protein Bcl-2 decreased. In addition, western blot analysis revealed that, in NSCLC cell lines, the combined treatment with gefitinib and ginsenoside Rg3 decreased the protein expression levels of pro-migration factors SNAIL and SLUG, whilst the expression level of anti-migration protein E-cadherin increased. In conclusion, ginsenoside Rg3 may be able to enhance the anticancer activity of gefitinib, making NSCLC cells more sensitive to gefitinib.

An Update on Predictive Biomarkers for Treatment Selection in Non-Small Cell Lung Cancer

It is now widely established that management of lung cancer is much more complex and cannot be centered on the binary classification of small-cell versus non-small cell lung cancer (NSCLC). Lung cancer is now recognized as a highly heterogeneous disease that develops from genetic mutations and gene expression patterns, which initiate uncontrolled cellular growth, proliferation and progression, as well as immune evasion. Accurate biomarker assessment to determine the mutational status of driver mutations such as EGFR, ALK and ROS1, which can be targeted by specific tyrosine kinase inhibitors, is now essential for treatment decision making in advanced stage NSCLC and has shifted the treatment paradigm of NSCLC to more individualized therapy. Rapid advancements in immunotherapeutic approaches to NSCLC treatment have been paralleled by development of a range of potential predictive biomarkers that can enrich for patient response, including PD-L1 expression and tumor mutational burden. Here, we review the key biomarkers that help predict response to treatment options in NSCLC patients.

Irreversible tyrosine kinase inhibition of epidermal growth factor receptor with afatinib in EGFR activating mutation-positive advanced non-small-cell lung cancer

Despite recent advances in the systemic therapy of non-small-cell lung cancer (nsclc), the prognosis for stage iv disease remains poor. The discovery of targetable mutations has led to new treatment options. The most common mutations, the EGFR activating mutations, are present in about 50% of Asian patients and up to 15% of white patients. First-generation reversible epidermal growth factor receptor (egfr) tyrosine kinase inhibitors (tkis) have led to improved survival in patients positive for EGFR activating mutations, but resistance eventually leads to disease progression. The irreversible egfr tki afatinib was developed to counter such resistance. The clinical efficacy of afatinib has been shown in first-line studies comparing it with both cytotoxic chemotherapy and first-generation egfr tkis. Afatinib has also shown continued benefit beyond progression while a patient is taking an egfr inhibitor. Furthermore, its toxicity profile is both predictable and manageable. The results of the principal clinical trials assessing afatinib are reviewed here.

Afatinib

Afatinib (BIBW 2992, US: Gilotrif^TM, other countries: Giotrif©) is an irreversible blocker of the ErbB family, acting at the tyrosine kinases of these proteins. In 2013, it was approved by the FDA and the EMA for the treatment of adults with advanced, EGFR mutation-positive non-small-cell lung cancer. Further investigations for the treatment of many other tumors with afatinib, e.g., HNSCC and breast cancer, are ongoing.

Role of afatinib in the treatment of advanced lung squamous cell carcinoma

Lung cancer treatment has considerably changed over the last few years: the identification of druggable oncogenic alterations and innovative immunotherapic approaches granted lung cancer patients the possibility of more efficient and less toxic therapeutic options than chemotherapy. Nowadays, lung squamous cell carcinomas (SqCCs) patients have the chance to benefit from novel treatment alternatives, including immune checkpoint blockade and anti-angiogenic agents and, given positive trial results, from afatinib, a second generation tyrosine kinase inhibitor (TKI) that irreversibly antagonizes ErbB family tyrosine kinase receptors. Considering the role of the ErbB-signaling cascade in lung SqCC, it is relevant to note that ErbB1 (epidermal growth factor receptor [EGFR]) is overexpressed in 85% of non-small-cell lung carcinomas (NSCLCs), particularly in patients with squamous histology, and is associated with poor prognosis. For this reason, EGFR activity has been investigated as a therapeutic strategy in lung SqCC. Even taking into account statistically positive trial results, anti-EGFR approach still remains controversial in unselected/wild-type EGFR lung SqCC patients, as well as the optimal timing and sequencing of all available targeted therapies considering the approval of immunotherapeutic agents. This review analyzes current data about EGFR inhibition in lung SqCC with a specific focus on afatinib in order to elucidate available clinical evidence supporting EGFR targeting in this setting as well as a future management of advanced lung SqCCs in the context of new emerging immunotherapeutic drugs.

Evaluating the cost-effectiveness of afatinib after platinum-based therapy for the treatment of squamous non-small-cell lung cancer in France

Background and aims

Lung cancer has the highest mortality rate of all cancers worldwide. Non-small-cell lung cancer (NSCLC) accounts for 85% of all lung cancers and has an extremely poor prognosis. Afatinib is an irreversible ErbB family blocker designed to suppress cellular signaling and inhibit cellular growth and is approved in Europe after platinum-based therapy for squamous NSCLC. The objective of the present analysis was to evaluate the cost-effectiveness of afatinib after platinum-based therapy for squamous NSCLC in France.

Methods

The study population was based on the LUX-Lung 8 trial that compared afatinib with erlotinib in patients with squamous NSCLC. The analysis was performed from the perspective of all health care funders and affected patients. A partitioned survival model was developed to evaluate cost-effectiveness based on progression-free survival and overall survival in the trial. Life expectancy, quality-adjusted life expectancy and direct costs were evaluated over a 10-year time horizon. Future costs and clinical benefits were discounted at 4% annually. Deterministic and probabilistic sensitivity analyses were performed.

Results

Model projections indicated that afatinib was associated with greater life expectancy (0.16 years) and quality-adjusted life expectancy (0.094 quality-adjusted life years [QALYs]) than that projected for erlotinib. The total cost of treatment over a 10-year time horizon was higher for afatinib than erlotinib, EUR12,364 versus EUR9,510, leading to an incremental cost-effectiveness ratio of EUR30,277 per QALY gained for afatinib versus erlotinib. Sensitivity analyses showed that the base case findings were stable under variation of a range of model inputs.

Conclusion

Based on data from the LUX-Lung 8 trial, afatinib was projected to improve clinical outcomes versus erlotinib, with a 97% probability of being cost-effective assuming a willingness to pay of EUR70,000 per QALY gained, after platinum-based therapy in patients with squamous NSCLC in France.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Polyphyllin VII increases sensitivity to gefitinib by modulating the elevation of P21 in acquired gefitinib resistant non-small cell lung cancer

Blockade of EGFR with reversible EGFR tyrosine kinase inhibitors (TKIs) is considered the frontline strategy for advanced NSCLC with EGFR mutations. However, acquired resistance to EGFR-TKI has been observed, resulting in disease progression and limited clinical benefit. Polyphyllin VII is the main member of polyphyllin family, which has been demonstrated to show strong anticancer activity against carcinomas. The sensitizing effect and underlying mechanism of Polyphyllin VII against acquired EGFR-TKI resistant NSCLC are still unexplored. In the present study, we aim to examined the sensitizing effect of Polyphyllin VII to gefitinib by modulating P21 signaling pathway in gefitinib acquired resistant NSCLC in vitro and in vivo. Gefitinib sensitive PC-9 cells and gefitinib acquired resistant H1975 cells were used. Cell proliferation and Clonogenic assay, Cell cycle analysis, Western blotting analysis and xenograft treatment were carried out. Polyphyllin VII enhanced the anti-proliferative effects of gefitinib and gefitinib-induced G1 phase arrest by modulation of P21 signaling pathway in acquired gefitinib resistant cells in vitro and in vivo. Polyphyllin VII elevated sensitization of gefitinib acquired resistant NSCLC cells to gefitinib through G1 phase arrest and modulation of P21 signaling pathway. It provides a potential new strategy to overcome gefitinib acquired resistance for EGFR-TKI resistant NSCLC.

The efficacy of 40 mg versus dose de-escalation to less than 40 mg of afatinib (Giotrif) as the first-line therapy for patients with primary lung adenocarcinoma harboring favorable epidermal growth factor mutations

The choice of a first-line therapy for lung cancer is a crucial decision that can impact the survival as well as the quality of life of a patient. Inhibitors of epidermal growth factor receptor (EGFR) such as afatinib, erlotinib, and gefitinib have previously been used to treat non-small cell lung cancer harboring favorable EGFR mutations. Although afatinib has greater efficacy than other EGFR inhibitors, adverse events related to its use can result in the discontinuation of the therapy. In this study, we compared the therapeutic efficacy in lung cancer patients of a regimen of 40 mg/day of afatinib with that of a lower dose regimen of <40 mg/day resulting either from a lower starting dose of 30 mg/day or dose adjustment. Seventy-nine patients were treated with 40 mg/day and 67 received de-escalated doses of <40 mg/day. There was no significant difference in the clinical characteristics of the two groups except that the proportion of patients with a body weight of 50 kg or more was greater in the 40 mg/day group. Otherwise, there were no significant differences between the two groups in the average time to treatment failure (TTF), the rates at which the administration of a second-line therapy was necessary, or the frequency and severity of adverse events. Overall, these results suggest that it is possible to calibrate the dosage of afatinib to suit individual patient parameters such as low body weight, and that such calibration can be advised based on the given patient's individual experience of the drug.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Treatment of Metastatic Non-Small Cell Lung Cancer, with a Focus on Afatinib

Somatic epidermal growth factor receptor (EGFR) mutations are present in around 50% of Asian patients and in 10–15% of Caucasian patients with metastatic non-small cell lung cancer (NSCLC) of adenocarcinoma histology. The first-generation EGFR-tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib have demonstrated improved progression-free survival (PFS) and response rates but not overall survival (OS) benefit in randomized phase III trials when compared with platinum-doublet chemotherapy. All patients treated with EGFR-TKIs will eventually develop acquired resistance to these agents. Afatinib, an irreversible ErbB family blocker, has shown in two randomly controlled trials in patients with EGFR-activating mutations, a significant improvement in PFS and health-related quality of life when compared to platinum-based chemotherapy. Afatinib improved OS in patients with Del19 mutations. In patients having progressed on first-generation EGFR-TKIs, afatinib did lead to a clinical benefit. A randomly controlled trial showed that PFS was significantly superior with afatinib vs. erlotinib in patients with squamous NSCLC in the second-line setting. A phase IIb trial comparing afatinib and gefitinib in first-line EGFR positive NSCLC showed significantly improved PFS with afatinib but OS was not significantly improved.

New developments in the treatment of advanced squamous cell lung cancer: focus on afatinib

Until recently, few treatment options existed for the treatment of squamous cell carcinoma (SqCC) of the lung, especially in the second-line setting following platinum-based chemotherapy. Accordingly, outcomes in this subtype of non-small-cell lung cancer (NSCLC) were generally poor. In this context, the recent availability of the checkpoint inhibitors nivolumab and pembrolizumab, the anti-VEGFR2 antibody ramucirumab (combined with docetaxel), and the ErbB-family blocker afatinib for the treatment of relapsed/refractory SqCC of the lung represent major advances. However, the rapid expansion of the treatment armamentarium invites many questions regarding optimal treatment choice and sequence in individual patients. This review focuses on the biologic rationale and clinical evidence to support the use of afatinib in this treatment setting, highlighting the prominent role of the ErbB-signaling cascade in SqCC tumors. The seminal Phase III LUX-Lung 8 study, on which the approval of afatinib is based, is discussed and contextualized with the emergence of immunotherapies. Finally, criteria are explored that might drive physicians’ treatment decisions when considering the use of afatinib based on individual patient characteristics. Other ongoing developments in the treatment of SqCC of the lung that will lead to further options and welcome improvements in the management of this difficult-to-treat disease are summarized.

Capilliposide from Lysimachia capillipes inhibits AKT activation and restores gefitinib sensitivity in human non-small cell lung cancer cells with acquired gefitinib resistance

Most gefitinib-treated patients with non-small cell lung cancer (NSCLC) would eventually develop resistance. Lysimachia capillipes (LC) capilliposide extracts from LC Hemsl. show both in vitro and in vivo anti-cancer effects. In this study we investigated whether LC capilliposide in combination with gefitinib could overcome the resistance of NSCLC cells to gefitinib and identified the signaling pathways involved. Treatment with LC capilliposide alone inhibited the growth of a panel of NSCLC cell lines (PC-9, H460, H1975, H1299 and PC-9-GR) sensitive or resistant to gefitinib with IC₅₀ values in the range of μg/mL. In the gefitinib-resistant PC-9-GR cells (which have a T790M EGFR mutation), LC capilliposide (at the IC30, i.e.1.2 μg/mL) markedly enhanced the inhibitory effects of gefitinib with its IC50 value being decreased from 6.80±1.00 to 0.77±0.12 μmol/L. By using the median effect analysis we showed that combination treatment of LC capilliposide and gefitinib could restore gefitinib sensitivity in PC-9-GR cells. Furthermore, LC capilliposide (1.2 μg/mL) significantly increased the apoptotic responses to gefitinib (0.77 μmol/L) in PC-9-GR cells, but did not affect gefitinib-induced G₀/G₁ arrest. Moreover, LC capilliposide (1.2 μg/mL) in combination with gefitinib (0.77, 1.0 μmol/L) markedly decreased the phosphorylation of the EGFR downstream signaling molecule AKT, which neither LC capilliposide nor gefitinib alone affected. In PC-9-GR cells with siRNA knockdown of AKT, addition of LC capilliposide was unable to increase gefitinib sensitivity. In a PC-9-GR xenograft mouse model, combination treatment with LC capilliposide (15 mg·kg^-1·d^-1, ip) and gefitinib (50 mg·kg^-1·d^-1, ip) dramatically enhanced tumor growth suppression (with a TGI of 109.3%), compared with TGIs of 22.6% and 56.6%, respectively, in mice were treated with LC capilliposide or gefitinib alone. LC capilliposide can restore the cells' sensitivity to gefitinib through modulation of pAKT levels, suggesting that a combination of LC capilliposide and gefitinib may be a promising therapeutic strategy to overcome gefitinib resistance in NSCLCs with a T790M mutation.

Advanced non-small cell lung cancer (NSCLC) with activating EGFR mutations: first-line treatment with afatinib and other EGFR TKIs

INTRODUCTION

Based on the results of several randomised controlled trials, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have now replaced platinum-based chemotherapy as first-line therapy for advanced non-small cell lung cancer (NSCLC) harboring an activating EGFR mutation. Areas covered: This review describes the EGFR pathway and its abnormalities in NSCLC and discusses the differential molecular and clinical activity of first and next-generation EGFR TKIs in the first-line treatment of tumors with an activating EGFR mutation, with a special focus on the second-generation agent afatinib. A comprehensive literature search was conducted to identify all relevant clinical trials including abstracts from most recent meetings to provide up-to-date information on this topic. Expert commentary: While the first-generation EGFR TKIs erlotinib and gefitinib exhibited good tolerability and improved progression-free survival compared with a platinum doublet, they failed to improve overall survival (OS). In contrast, clinical trials of afatinib (LUX-Lung 3 and 6) demonstrated a significant OS advantage over a platinum doublet, particularly in patients whose tumors harbored the Del19 mutation. Moreover, in a head-to-head comparison afatinib improved efficacy versus gefitinib in patients with common EGFR mutations across a range of clinically relevant endpoints. Afatinib is therefore a promising first-line option in these patients.

The safety of afatinib for the treatment of non-small cell lung cancer

INTRODUCTION

Lung cancer tumors present EGFR mutations associated with an increased response rate to tyrosine kinase inhibitors (TKIs). Afatinib acts as an irreversible pan-ErbB-TKI. Areas covered: This review summarizes the results of clinical trials in NSCLC regarding its safety and efficacy. Expert opinion: Afatinib in 40 mg doses is highly effective in patients with NSCLC and EGFR mutations, improving progression-free survival and disease-related symptoms compared to chemotherapy. Additionally, afatinib has a better response rate and shows a small benefit in progression free survival compared to first-generation TKIs, and patients with exon 19 deletion could represent a subgroup with better prognosis and overall survival. Diarrhea, mucositis and rash are frequent adverse events induced by afatinib, these can impair quality of life and sometimes afatinib discontinuation is necessary. Management of adverse events, including early antidiarrheal treatment and prophylactic or early antibiotic management can reduce the gastrointestinal and cutaneous adverse events, respectively. Different risk factors, including malnourishment, sarcopenia, and low body surface might be associated with a higher toxicity risk, and these groups of patients could begin treatment with a low dose of afatinib followed by a close evaluation on tolerability and toxicity in order to slowly increase the dosage of afatinib.

Next-generation EGFR/HER tyrosine kinase inhibitors for the treatment of patients with non-small-cell lung cancer harboring EGFR mutations: a review of the evidence

Tyrosine kinase inhibitors (TKIs) against human epidermal growth factor receptor (EGFR/HER) family have been introduced into the clinic to treat cancers, particularly non-small-cell lung cancer (NSCLC). There have been three generations of the EGFR/HER-TKIs. First-generation EGFR/HER-TKIs, binding competitively and reversibly to the ATP-binding site of the EGFR TK domain, show a significant breakthrough treatment in selected NSCLC patients with activating EGFR mutations (actEGFRm) EGFR (L858R) and EGFR (Del19), in terms of safety, efficacy, and quality of life. However, all those responders inevitably develop acquired resistance within 12 months, because of the EGFR (T790M) mutation, which prevents TKI binding to ATP-pocket of EGFR by steric hindrance. The second-generation EGFR/HER-TKIs were developed to prolong and maintain more potent response as well as overcome the resistance to the first-generation EGFR/HER-TKIs. They are different from the first-generation EGFR/HER-TKIs by covalently binding to the ATP-binding site, irreversibly blocking enzymatic activation, and targeting EGFR/HER family members, including EGFR, HER2, and HER4. Preclinically, these compounds inhibit the enzymatic activation for actEGFRm, EGFR (T790M), and wtEGFR. The second-generation EGFR/HER-TKIs improve overall survival in cancer patients with actEGFRm in a modest way. However, they are not clinically active in overcoming EGFR (T790M) resistance, mainly because of dose-limiting toxicity due to simultaneous inhibition against wtEGFR. The third-generation EGFR/HER-TKIs selectively and irreversibly target EGFR (T790M) and actEGFRm while sparing wtEGFR. They yield promising efficacy in NSCLC patients with actEGFRm as well as EGFR (T790M) resistant to the first- and second-generation EGFR-TKIs. They also appear to have a lower incidence of toxicity due to the reduced inhibitory effect on wtEGFR. Currently, the first-generation EGFR/HER-TKIs gefitinib and erlotinib and second-generation EGFR/HER-TKI afatinib have been approved for use as the first-line treatment of metastatic NSCLC with actEGFRm. This review will summarize and evaluate a broad range of evidence of recent development of EGFR/HER-TKIs, with a focus on the second- and third-generation EGFR/HER-TKIs, in the treatment of patients with NSCLC harboring EGFR mutations.

The Under-Appreciated Promiscuity of the Epidermal Growth Factor Receptor Family

Each member of the epidermal growth factor receptor (EGFR) family plays a key role in normal development, homeostasis, and a variety of pathophysiological conditions, most notably in cancer. According to the prevailing dogma, these four receptor tyrosine kinases (RTKs; EGFR, ERBB2, ERBB3, and ERBB4) function exclusively through the formation of homodimers and heterodimers within the EGFR family. These combinatorial receptor interactions are known to generate increased interactome diversity and therefore influence signaling output, subcellular localization and function of the heterodimer. This molecular plasticity is also thought to play a role in the development of resistance toward targeted cancer therapies aimed at these known oncogenes. Interestingly, many studies now challenge this dogma and suggest that the potential for EGFR family receptors to interact with more distantly related RTKs is much greater than currently appreciated. Here we discuss how the promiscuity of these oncogenic receptors may lead to the formation of many unexpected receptor pairings and the significant implications for the efficiency of many targeted cancer therapies.

Covalent Targeting of Fibroblast Growth Factor Receptor Inhibits Metastatic Breast Cancer

Therapeutic targeting of late-stage breast cancer is limited by an inadequate understanding of how tumor cell signaling evolves during metastatic progression and by the currently available small molecule inhibitors capable of targeting these processes. Herein, we demonstrate that both β3 integrin and fibroblast growth factor receptor-1 (FGFR1) are part of an epithelial-mesenchymal transition (EMT) program that is required to facilitate metastatic outgrowth in response to fibroblast growth factor-2 (FGF2). Mechanistically, β3 integrin physically disrupts an interaction between FGFR1 and E-cadherin, leading to a dramatic redistribution of FGFR1 subcellular localization, enhanced FGF2 signaling and increased three-dimensional (3D) outgrowth of metastatic breast cancer cells. This ability of β3 integrin to drive FGFR signaling requires the enzymatic activity of focal adhesion kinase (FAK). Consistent with these mechanistic data, we demonstrate that FGFR, β3 integrin, and FAK constitute a molecular signature capable of predicting decreased survival of patients with the basal-like subtype of breast cancer. Importantly, covalent targeting of a conserved cysteine in the P-loop of FGFR1-4 with our newly developed small molecule, FIIN-4, more effectively blocks 3D metastatic outgrowth as compared with currently available FGFR inhibitors. In vivo application of FIIN-4 potently inhibited the growth of metastatic, patient-derived breast cancer xenografts and murine-derived metastases growing within the pulmonary microenvironment. Overall, the current studies demonstrate that FGFR1 works in concert with other EMT effector molecules to drive aberrant downstream signaling, and that these events can be effectively targeted using our novel therapeutics for the treatment of the most aggressive forms of breast cancer. Mol Cancer Ther; 15(9); 2096-106. ©2016 AACR.

Covalent EGFR Inhibitors: Binding Mechanisms, Synthetic Approaches, and Clinical Profiles

Being overexpressed in several types of cancer, the epidermal growth factor receptor (EGFR) is considered one of the key therapeutic targets in oncology. Although many first-generation EGFR inhibitors had been FDA approved for the treatment of certain types of cancer, patients soon developed resistance to these reversible ATP competitive inhibitors via mutations in the kinase domain of EGFR. A new trend was adopted to design covalent irreversible inhibitors, that is, second- and third-generation inhibitors. Second-generation inhibitors can inhibit the mutant forms but, unfortunately, they had dose limiting side effects due to wild-type EGFR inhibition. Third-generation inhibitors emerged shortly, which were capable of inhibiting the mutant forms exclusively while sparing the wild type. Many other strategies have also been developed to reduce the risk of covalent interactions with off-targets, thus improving the pharmacokinetic and/or pharmacodynamic profile of the antiproliferative agents. In this review, we focused mainly on second- and third-generation EGFR inhibitors, their binding mechanisms (either docking studies or co-crystallized structures), their synthetic approaches, clinical profiles, and limitations.

Challenges and Perspectives on the Development of Small-Molecule EGFR Inhibitors against T790M-Mediated Resistance in Non-Small-Cell Lung Cancer

Because of the development of drug-resistance mutations, particularly the "gatekeeper" threonine(790)-to-methionine(790) (T790M) mutation in the ATP-binding pocket of the epidermal growth factor receptor (EGFR), the current generation of EGFR tyrosine kinase inhibitors lost their clinical efficacy. Recently, a large number of small-molecule inhibitors with striking inhibitory potency against EGFR mutants with the T790M change have been identified. In particular, the inhibitors rociletinib and osimertinib, which can selectively target both sensitizing mutations and the T790M resistance while sparing the wild-type (WT) form of the receptor, have been designated as breakthrough therapies in the treatment of mutant non-small-cell lung cancer (NSCLC) by the U.S. FDA in 2014. We hope that this review on the small-molecule EGFR T790M inhibitors, along with their discovery strategies, will assist in the design of future T790M-containing EGFR inhibitors with high levels of selectivity over WT EGFR, broad kinase selectivity, and desirable physicochemical properties.