Abivertinib in patients with T790M-positive advanced NSCLC and its subsequent treatment with osimertinib

Synthetic Routes and Clinical Application of Representative Small-Molecule EGFR Inhibitors for Cancer Therapy

The epidermal growth factor receptor (EGFR) plays a pivotal role in cancer therapeutics, with small-molecule EGFR inhibitors emerging as significant agents in combating this disease. This review explores the synthesis and clinical utilization of EGFR inhibitors, starting with the indispensable role of EGFR in oncogenesis and emphasizing the intricate molecular aspects of the EGFR-signaling pathway. It subsequently provides information on the structural characteristics of representative small-molecule EGFR inhibitors in the clinic. The synthetic methods and associated challenges pertaining to these compounds are thoroughly examined, along with innovative strategies to overcome these obstacles. Furthermore, the review discusses the clinical applications of FDA-approved EGFR inhibitors such as erlotinib, gefitinib, afatinib, and osimertinib across various cancer types and their corresponding clinical outcomes. Additionally, it addresses the emergence of resistance mechanisms and potential counterstrategies. Taken together, this review aims to provide valuable insights for researchers, clinicians, and pharmaceutical scientists interested in comprehending the current landscape of small-molecule EGFR inhibitors.

An assessment of EGFR and HER2 inhibitors with structure activity relationship of fused pyrimidine derivatives for breast cancer: a brief review

Epidermal growth factor receptor (EGFR) and its subtype human epidermal growth factor receptor 2 (HER2) gets activated when its endogenous ligand(s) bind to its ATP binding site of target receptors. In breast cancer (BC), EGFR and HER2 are two proteins are overexpressed which leads to overexpression of cells proliferation and decreases cell death/apoptosis. Pyrimidine is one of the most widely studied heterocyclic scaffolds for EGFR as well as HER2 inhibition. We gather some remarkable results for fused-pyrimidine derivatives on various cancerous cell lines (in-vitro) and animal (in-vivo) evaluation to highlight their potency. The heterocyclic (five, six-membered, etc.) moieties which are coupled with pyrimidine moiety are potent against EGFR and HER2 inhibitions. Hence structure-activity relationship (SAR) plays important role in study of heterocyclic moiety along pyrimidine and effects of substituents, groups for increase or decrease in the cancerous activity and toxicity. By thoughtful of fused pyrimidines SAR study, it facilitates in receiving excellent overview of the compounds by concerning of efficacy and potential summary for future EGFR inhibitors. Furthermore, we studied the in-silico interactions of synthesized compounds to evaluate binding affinity towards the key amino acids..Communicated by Ramaswamy H. Sarma.

Targeting the EGFR/RAS/RAF signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023)

INTRODUCTION

Recent years have seen significant strides in drug developmenttargeting the EGFR/RAS/RAF signaling pathway which is critical forcell growth and proliferation. Protein-protein interaction networksamong EGFR, RAS, and RAF proteins offer insights for drug discovery. This review discusses the drug design and development efforts ofinhibitors targeting these proteins over the past 3 years, detailingtheir structures, selectivity, efficacy, and combination therapy.Strategies to combat drug resistance and minimize toxicities areexplored, along with future research directions.

AREA COVERED

This review encompasses clinical trials and patents on EGFR, KRAS,and BRAF inhibitors from 2020 to 2023, including advancements indesign and synthesis of proteolysis targeting chimeras (PROTACs) forprotein degradation.

EXPERT OPINION

To tackle drug resistance, designing allosteric fourth-generationEGFR inhibitors is vital. Covalent, allosteric, or combinationaltherapies, along with PROTAC degraders, are key methods to addressresistance and toxicity in KRAS and BRAF inhibitors.

Overview of the multifaceted resistances toward EGFR-TKIs and new chemotherapeutic strategies in non-small cell lung cancer

The role of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) has been vastly studied over the last decade. This has led to the rapid development of many generations of EGFR tyrosine kinase inhibitors (EGFR-TKIs). However, patients treated with third-generation TKIs (osimertinib, avitinib and rociletinib) targeting the EGFR T790M mutation have shown emerging resistances and relapses. Therefore, further molecular understanding of NSCLC mutations, bypass signalling, tumour microenvironment and the existence of cancer stem cells to overcome such resistances is warranted. This will pave the way for designing novel and effective chemotherapies to improve patients' overall survival. In this review, we provide an overview of the multifaceted mechanism of resistances towards EGFR-TKIs, as well as the challenges and perspectives that should be addressed in strategising chemotherapeutic treatments to overcome the ever evolving and adaptive nature of NSCLC.

A Review on Fused Pyrimidine Systems as EGFR Inhibitors and Their Structure–Activity Relationship

Epidermal growth factor receptor (EGFR) belongs to the family of tyrosine kinase that is activated when a specific ligand binds to it. The EGFR plays a vital role in the cellular proliferation process, differentiation, and apoptosis. In the case of cancer, EGFR undergoes uncontrolled auto-phosphorylation that results in increased cellular proliferation and decreased apoptosis, causing cancer promotion. From the literature, it shows that pyrimidine is one of the most commonly studied heterocycles for its antiproliferative activity against EGFR inhibition. The authors have collated some interesting results in the heterocycle-fused pyrimidines that have been studied using different cell lines (sensitive and mutational) and in animal models to determine their activity and potency. It is quite clear that the fused systems are highly effective in inhibiting EGFR activity in cancer cells. Therefore, the structure–activity relationship (SAR) comes into play in determining the nature of the heterocycle and the substituents that are responsible for the increased activity and toxicity. Understanding the SAR of heterocycle-fused pyrimidines will help in getting a better overview of the molecules concerning their activity and potency profile as future EGFR inhibitors.

Bim- and Bax-mediated mitochondrial pathway dominates abivertinib-induced apoptosis and ferroptosis

Abivertinib (AC) is a novel epidermal growth factor receptor tyrosine kinase inhibitor with highly efficient antitumor activity. Here, we report the capacity of AC to induce both reactive oxygen species (ROS)-dependent apoptosis and ferroptosis in tumor cells. Our data showed that AC induced iron- and ROS-dependent cytotoxicity in MCF7, HeLa, and A549 cell lines. Flow cytometry analyses showed that AC increased ferrous ions and ROS and induced ferroptosis in MCF-7 cells. This was confirmed by the findings that AC not only decreased solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) expression but also induced iron- and ROS-dependent aggrandized lipid ROS accumulation and plasma membrane damage. Meanwhile, AC induced nuclear condensation and increased ROS-dependent phosphatidylserine (PS) eversion, caspase-3 activation, and cleaved-PARP expression, suggesting that AC also induced ROS-dependent apoptosis. In addition, mitochondrial depletion significantly inhibited AC-induced cytotoxicity, including ferroptosis and apoptosis, indicating the key role of mitochondria in AC-induced ferroptosis and apoptosis. Moreover, knockout of Bim or Bax not only remarkably inhibited AC-induced apoptosis, but also markedly inhibited AC-triggered downregulation of SLC711 and GPX4, accumulation of lipid ROS, and damage to the plasma membrane. This suggests that Bim and Bax act upstream of SLC7A11 and GPX4 to mediate AC-induced ferroptosis. Collectively, AC induces ferroptosis and apoptosis, in which the Bim- and Bax-mediated mitochondrial pathways play a dominant role.

LS-106, a novel EGFR inhibitor targeting C797S, exhibits antitumor activities both in vitro and in vivo

With the wide clinical use of the third-generation epidermal growth factor receptor (EGFR) inhibitor osimertinib for the treatment of EGFR-mutated non-small cell lung cancer (NSCLC), acquired resistance caused by EGFR C797S tertiary mutation has become a concern. Therefore, fourth-generation EGFR inhibitors that could overcome this mutation have gained increasing attention in recent years. Here, we identified LS-106 as a novel EGFR inhibitor against C797S mutation and evaluated its antitumor activity both in vitro and in vivo. In cell-free assay, LS-106 potently inhibited the kinase activities of EGFR19del/T790M/C797S and EGFRL858R/T790M/C797S with IC50 values of 2.4 nmol/L and 3.1 nmol/L, respectively, which was more potent than osimertinib. Meanwhile, LS-106 exhibited comparable kinase inhibitory effect to osimertinib on EGFRL858R/T790M and wild-type EGFR. Results from cellular experiments demonstrated that LS-106 potently blocked the phosphorylation of EGFR C797S triple mutations in the constructed BaF3 cells that highly expressed EGFR19del/T790M/C797S or EGFRL858R/T790M/C797S , and thus inhibited the proliferation of these cells. We also constructed tumor cells harboring EGFR19del/T790M/C797S (named PC-9-OR cells) using the CRISPR/Cas9 system and found that LS-106 markedly suppressed the activation of EGFR19del/T790M/C797S and the proliferation of PC-9-OR cells. Moreover, cells harboring EGFR19del/T790M/C797S underwent remarkable apoptosis upon LS-106 treatment. In vivo experiments further demonstrated that oral administration of LS-106 caused significant tumor regression in a PC-9-OR xenograft model, with a tumor growth inhibition rate (TGI) of 83.5% and 136.6% at doses of 30 and 60 mg/kg, respectively. Taken together, we identified LS-106 as a novel fourth-generation EGFR inhibitor against C797S mutation and confirmed its preclinical antitumor effects in C797S-triple-mutant tumor models.

Mechanisms and management of 3rd‑generation EGFR‑TKI resistance in advanced non‑small cell lung cancer (Review)

Targeted therapy with epidermal growth factor receptor (EGFR)‑tyrosine kinase inhibitors (TKIs) is a standard modality of the 1st‑line treatments for patients with advanced EGFR‑mutated non‑small cell lung cancer (NSCLC), and substantially improves their prognosis. However, EGFR T790M mutation is the primary mechanism of 1st‑ and 2nd‑generation EGFR‑TKI resistance. Osimertinib is a representative of the 3rd‑generation EGFR‑TKIs that target T790M mutation, and has satisfactory efficacy in the treatment of T790M‑positive NSCLC with disease progression following use of 1st‑ or 2nd‑generation EGFR‑TKIs. Other 3rd‑generation EGFR‑TKIs, such as abivertinib, rociletinib, nazartinib, olmutinib and alflutinib, are also at various stages of development. However, the occurrence of acquired resistance is inevitable, and the mechanisms of 3rd‑generation EGFR‑TKI resistance are complex and incompletely understood. Genomic studies in tissue and liquid biopsies of resistant patients reveal multiple candidate pathways. The present review summarizes the recent findings in mechanisms of resistance to 3rd‑generation EGFR‑TKIs in advanced NSCLC, and provides possible strategies to overcome this resistance. The mechanisms of acquired resistance mainly include an altered EGFR signaling pathway (EGFR tertiary mutations and amplification), activation of aberrant bypassing pathways (hepatocyte growth factor receptor amplification, human epidermal growth factor receptor 2 amplification and aberrant insulin‑like growth factor 1 receptor activation), downstream pathway activation (RAS/RAF/MEK/ERK and PI3K/AKT/mTOR) and histological/phenotypic transformations (SCLC transformation and epithelial‑mesenchymal transition). The combination of targeted therapies is a promising strategy to treat osimertinib‑resistant patients, and multiple clinical studies on novel combined therapies are ongoing.

Effectiveness and Safety of EGFR-TKI Rechallenge Treatment in Elderly Patients with Advanced Non-Small-Cell Lung Cancer Harboring Drug-Sensitive EGFR Mutations

Background and Objectives: Epidermal growth factor receptor–tyrosine kinase inhibitors (EGFR-TKIs) are effective first-line chemotherapeutic agents for patients with advanced non-small-cell lung cancer (NSCLC) harboring drug-sensitive EGFR mutations. However, the effectiveness of EGFR-TKI rechallenge after first-line EGFR-TKI treatment is not sufficient in elderly patients (over 75 years of age) harboring drug-sensitive EGFR mutations. Therefore, we investigated the effectiveness and safety of EGFR-TKI rechallenge after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations. Materials and Methods: Between April 2008 and December 2015, we analyzed 78 elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations with first-line EGFR-TKI treatment at four Japanese institutions. We retrospectively evaluated the clinical effectiveness and safety profiles of EGFR-TKI rechallenge after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations (exon 19 deletion/exon 21 L858R mutation). Results: Twenty-two patients in the cohort were rechallenged with EGFR-TKI. The median age was 79.5 years (range 75–87 years). Despite the fact that it was a retrospective analysis, even with EGFR-TKI rechallenge treatment the response rate was 23%, progression-free survival was 5.3 months, and overall survival was 14.4 months. Common adverse events included rash acneiform, paronychia, diarrhea, and anorexia. There were no treatment-related deaths. Due to the occurrence of adverse events of grade 2 or more, dose reduction was performed in 15 (68.2%) of 22 cases. Conclusions: EGFR-TKI rechallenge treatment after first-line EGFR-TKI treatment in elderly patients with advanced NSCLC harboring drug-sensitive EGFR mutations was one of the limited, safe and effective treatment options for elderly EGFR-positive lung cancer patients.

Effects of Avitinib on CYP450 Enzyme Activity in vitro and in vivo in Rats

Purpose

Avitinib is the first third-generation epithelial growth factor receptor (EGFR) inhibitor independently developed in China and is mainly used for treating non-small cell lung cancer. However, pharmacokinetic details are limited. This study explored the in vivo and in vitro effects of avitinib on cytochrome CYP450 enzymes metabolic activity.

Methods

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determining six probe substrates and their metabolites. Avitinib influence on activity levels of CYP isozymes was examined in vitro using human and rat liver microsomes (HLMs/RLMs). For in vivo studies, rats were pretreated with 30 mg/kg avitinib once daily for 7 days (avitinib multiple-doses group), 30 mg/kg avitinib on day 7 (avitinib single-dose group), or an equivalent amount of CMC-Na once daily for 7 days (control group), followed by intragastrical administration of the probe substrates (1 mg/kg tolbutamide and 10 mg/kg phenacetin, bupropion, chlorzoxazone, dextromethorphan, and midazolam). Plasma pharmacokinetics and IC₅₀ values of the probe substrates were then compared. Pharmacokinetic parameters were determined using non-compartmental analysis implemented in a pharmacokinetic program.

Results

In vitro experiments revealed different inhibitory effects of avitinib on the six probe substrates with various IC₅₀ values (bupropion, 6.39/22.64 μM; phenacetin, 15.79/48.36 μM; chlorzoxazone, 23.15/57.09 μM; midazolam, 27.64/59.6 μM; tolbutamide, 42.18/6.91 μM; dextromethorphan, 44.39/56.57 μM, in RLMs and HLMs respectively). In vivo analysis revealed significant differences (P <0.05) in distinct pharmacokinetic parameters (AUC_(0-t), AUC _(0-∞), C_max, MRT_(0-t), MRT _(0-∞), and CLz/F) for the six probe substrates after avitinib pretreatment.

Conclusion

A sensitive and reliable UPLC-MS/MS method was established to determine the concentration of six probe substrates in rat plasma. Avitinib had inhibitory effects on CYP450 enzymes, especially cyp2b1, cyp1a2 in RLMs, CYP2C9 in HLMs, and cyp1a2, cyp2b1, cyp2d1, and cyp2e1 in vivo. Our data recommend caution when avitinib was taken simultaneously with drugs metabolized by CYP450 enzymes.

Flavonoids as an effective sensitizer for anti-cancer therapy: insights into multi-faceted mechanisms and applicability towards individualized patient profiles

Cost-efficacy of currently applied treatments is an issue in overall cancer management challenging healthcare and causing tremendous economic burden to societies around the world. Consequently, complex treatment models presenting concepts of predictive diagnostics followed by targeted prevention and treatments tailored to the personal patient profiles earn global appreciation as benefiting the patient, healthcare economy, and the society at large. In this context, application of flavonoids as a spectrum of compounds and their nano-technologically created derivatives is extensively under consideration, due to their multi-faceted anti-cancer effects applicable to the overall cost-effective cancer management, primary, secondary, and even tertiary prevention. This article analyzes most recently updated data focused on the potent capacity of flavonoids to promote anti-cancer therapeutic effects and interprets all the collected research achievements in the frame-work of predictive, preventive, and personalized (3P) medicine. Main pillars considered are: - Predictable anti-neoplastic, immune-modulating, drug-sensitizing effects; - Targeted molecular pathways to improve therapeutic outcomes by increasing sensitivity of cancer cells and reversing their resistance towards currently applied therapeutic modalities.

Repurposing approved drugs for cancer therapy

BACKGROUND

Many drugs approved for other indications can control the growth of tumor cells and limit adverse events (AE).

DATA SOURCES

Literature searches with keywords 'repurposing and cancer' books, websites: https://clinicaltrials.gov/, for drug structures: https://pubchem.ncbi.nlm.nih.gov/.

AREAS OF AGREEMENT

Introducing approved drugs, such as those developed to treat diabetes (Metformin) or inflammation (Thalidomide), identified to have cytostatic activity, can enhance chemotherapy or even replace more cytotoxic drugs. Also, anti-inflammatory compounds, cytokines and inhibitors of proteolysis can be used to control the side effects of chemo- and immuno-therapies or as second-line treatments for tumors resistant to kinase inhibitors (KI). Drugs specifically developed for cancer therapy, such as interferons (IFN), the tyrosine KI abivertinib TKI (tyrosine kinase inhibitor) and interleukin-6 (IL-6) receptor inhibitors, may help control symptoms of Covid-19.

AREAS OF CONTROVERSY

Better knowledge of mechanisms of drug activities is essential for repurposing. Chemotherapies induce ER stress and enhance mutation rates and chromosome alterations, leading to resistance that cannot always be related to mutations in the target gene. Metformin, thalidomide and cytokines (IFN, tumor necrosis factor (TNF), interleukin-2 (IL-2) and others) have pleiomorphic activities, some of which can enhance tumorigenesis. The small and fragile patient pools available for clinical trials can cloud the data on the usefulness of cotreatments.

GROWING POINTS

Better understanding of drug metabolism and mechanisms should aid in repurposing drugs for primary, adjuvant and adjunct treatments.

AREAS TIMELY FOR DEVELOPING RESEARCH

Optimizing drug combinations, reducing cytotoxicity of chemotherapeutics and controlling associated inflammation.

Effects of avitinib on the pharmacokinetics of osimertinib in vitro and in vivo in rats

BACKGROUND

Avitinib is one type of the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for the treatment of non-small cell lung cancer (NSCLC) with EGFR mutations. The purpose of this study was to investigate the effect of avitinib on the pharmacokinetics of osimertinib, one FDA approved third-generation TIKI, both in vitro and in vivo.

METHODS

The in vitro metabolic stability and inhibitory effect of avitinib on osimertinib were assessed with rat liver microsomes (RLM) to determine its IC₅₀ values. For the in vivo study, 18 Sprague-Dawley rats were randomly divided into three groups: the avitinib multiple dose group (30 mg/kg avitinib once daily for seven days), the avitinib single dose group (PEG200 once daily for six days and a dose of 30 mg/kg avitinib in PEG200 on day 7) and the control group (equal amounts of PEG200 once daily for seven days). Next, all rats were given osimertinib at a dosage of 10 mg/kg. UPLC/MS-MS was used for the determination of the concentration of osimertinib in plasma.

RESULTS

In vitro analysis revealed that the IC₅₀ value of osimertinib in rat liver microsomes was 27.6 μM. When rats were pretreated with avitinib, the values of AUC and MRT of the osimertinib were increased, and its C_max and T_max were significantly extended, whereas the values of CLz/F were significantly decreased (P < 0.05).

CONCLUSIONS

Both in vitro and in vivo results demonstrated that a drug-drug interaction between avitinib and osimertinib occurred and more attention should be paid when avitinib and osimertinib are synchronously administered in clinic.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: Osimertinib is the only market available third-generation EGFR-TKI and it has been reported that some drugs could have drug-drug interactions with it.

WHAT THIS STUDY ADDS

For the first time, we systematically investigated the effect of avitinib, one newly developed third-generation EGFR-TKI, on the pharmacokinetics of osimertinib both in vitro and in vivo using a rat model.

Abivertinib synergistically strengthens the anti-leukemia activity of venetoclax in acute myeloid leukemia in a BTK-dependent manner

B‐cell lymphoma 2 (BCL‐2), a crucial member of the anti‐apoptotic BCL‐2 family, is frequently dysregulated in cancer and plays an important role in acute myeloid leukemia (AML). Venetoclax is a highly selective BCL‐2 inhibitor that has been approved by the FDA for treating elderly AML patients. However, the emergence of resistance after long‐term treatment emphasizes the need for a deeper understanding of the potential mechanisms of resistance and effective rescue methods. By using RNA‐seq analysis in two human AML cohorts made up of three patients with complete remission and three patients without remission after venetoclax treatment, we identified that upregulation of BTK enabled AML blast resistance to venetoclax. Interestingly, we found that abivertinib, an oral BTK inhibitor, could synergize with venetoclax to inhibit the proliferation of primary AML cells and cell lines. It is worth noting that the combination of the two effectively enhanced the sensitivity of two AML patients (AML#3 and AML#12) to venetoclax. In this study, we demonstrated that combined use of the two drugs can synergistically inhibit the colony‐forming capacity of AML cells, arrest the AML cell cycle in the G0/G1 phase, and inhibit the BCL‐2 anti‐apoptotic family protein, activating the caspase family to induce apoptosis. Mechanistically, knockdown of BTK in AML cell lines impaired the synergistic effect of the two drugs. In vivo study showed similar results as those seen in vitro. Abivertinib in combination with venetoclax could significantly prolong the survival time and reduce the tumor burden of MV4‐11‐NSG mice compared with those of control and single‐agent groups. Our in vitro and in vivo studies have shown that the combination of abivertinib and venetoclax may benefit AML patients, especially in patients resistant to venetoclax or those that relapse. New clinical trials will be planned.