Neratinib, an irreversible ErbB receptor tyrosine kinase inhibitor, in patients with advanced ErbB2-positive breast cancer

Cardiotoxicity of small-molecule kinase inhibitors in cancer therapy

Cancer is one of the leading causes of death worldwide. Recent advances in precision oncology have enabled many specific cancer patient populations to respond well and achieve longer survival with small-molecule kinase inhibitors, which have become a new therapeutic strategy for tumors. Since 2001, the Food and Drug Administration has approved 108 and 63 new anticancer drugs for treating solid tumors and hematological malignancies, respectively, 89 of which belong to the large group of small-molecule kinase inhibitors (SMKIs). Compared to conventional chemotherapeutic agents such as cyclophosphamide, doxorubicin, and 5-FU, SMKIs offer better efficacy with fewer toxic side effects. Nevertheless, with the development of more novel SMKIs and their wider clinical application to a larger population of cancer patients, variable degrees of cardiotoxic adverse events have emerged for some SMKIs during cancer therapy. This review comprehensively summarizes the most updated progress in the cardiotoxicity of SMKIs in cancer therapy and discusses the new findings and mechanisms, which will provide emerging strategies for the prevention of cardiotoxicity caused by small molecule targeted drugs and the design of the next generation of low cardiotoxicity targeted drugs.

Emerging importance of HER3 in tumorigenesis and cancer therapy

HER3 is a member of the HER/ErbB family of receptor tyrosine kinases, together with EGFR (HER1), HER2 and HER4. Despite having only weak intrinsic kinase activity, HER3 can contribute to oncogenic signalling via ligand-induced heterodimerization with other HER family members. Evidence indicates that HER3 is altered or aberrantly expressed across a variety of tumour types and can be associated with poor clinical outcomes. Whereas anticancer agents targeting EGFR and HER2 have been approved for decades, no drug targeting HER3 had been approved until very recently. Initial targeting of HER3 with monoclonal antibodies as single agents or in combination with other therapeutics produced disappointing clinical results. Subsequently, efforts have been made to target HER3 with novel agents such as antibody-drug conjugates and bispecific antibodies, with promising efficacy observed in several trials encompassing various tumour types. In December 2024, the HER3 × HER2 bispecific antibody zenocutuzumab was granted FDA Accelerated Approval for the treatment of non-small-cell lung cancers or pancreatic cancers harbouring fusions involving NRG1, the gene encoding the high-affinity HER3 ligand neuregulin 1. In this Review, we provide an essential guide to HER3 signalling and oncogenesis, HER3 expression in cancer and its prognostic implications, oncogenic HER3 somatic mutations as well as rare NRG1 fusions that might depend on HER3 signalling, and the roles of HER3 in resistance to cancer therapies. We also highlight efforts to target HER3 with diverse therapeutic strategies and the potential interplay between HER3 and the antitumour immune response.

A Structural Insight Into Two Important ErbB Receptors (EGFR and HER2) and Their Relevance to Non-Small Cell Lung Cancer

The epidermal growth factor receptor (EGFR) family, comprising receptor tyrosine kinases (RTK) such as EGFR and HER2, plays a critical role in various signaling pathways related to cell proliferation, differentiation, and growth. EGFR overactivation due to aberrant signaling can lead to various cancers, including non-small cell lung cancer (NSCLC). To develop treatment for EGFR-related NSCLC, several tyrosine kinase inhibitors (TKIs) were designed: gefitinib, erlotinib, as first-generation; neratinib, dacomitinib as second-generation; osimertinib, lazertinib as third-generation, as examples. However, due to the acquired resistance by the mutations such as EGFRT790M and EGFRC797S together with the exon 20 insertion mutations, these drugs do not provide promising results for NSCLC patients. The development of fourth-generation inhibitors like EAI045 and further innovative drugs to overcome this resistance problem is a must to cure EGFR-related NSCLC. Among these, pyrazoline-thiazole scaffolds are found effective as EGFR-HER2 inhibitors against NSCLC, making them promising drug candidates. Although structures obtained so far for the EGFR family provide meaningful insights into the mechanisms, the quality and the quantity of the EGFR family structures are insufficient to elucidate the complete structures and functions to overcome NSCLC. This review evaluates the structures of EGFR-HER2 and investigates their relation to NSCLC.

Investigation of Prevalence, Survival, and Molecular Type of Breast Cancer Patients with Brain Metastases

Background

This study aims to investigate the factors associated with breast cancer brain metastasis (BCBM) in individuals suffering from breast cancer (BC).

Materials and Methods

This cross-sectional study conducted on 200 patients with metastatic breast cancer (MBC) including 52 brain and 148 other organ metastases. The demographic, medical, clinical, laboratory, and therapeutic approach characteristics were compared between the groups.

Results

Headache (61.5%), weakness and lethargy (26.9%), dizziness (15.4%), blurred vision/blindness (15.4%), and convulsions (15.4%) were the major initial symptoms of BCBM. Radiotherapy (71.2%), injectable (34.6%), and oral chemotherapy (26.9%) were the major applied therapeutic strategies to manage brain metastasis (BM). The overall survival of the patients from cancer diagnosis to death accounted for 33 months (95%CI: 27.52-38.47), while this period after BM diagnosis was limited to 6 months (95%CI: 5.15-6.84). The rate of hormone therapy was remarkably higher among the metastasis in other organs than the brain (P value = 0.005), while targeted therapy was performed in higher rates for BM (P value = 0.001). The evaluation of BC-related tumor markers revealed that human epidermal growth factor 2 (HER2) (P value < 0.001) positivity was remarkably higher among BCBM, while positive estrogen receptor (ER) (P value = 0.004) and progesterone receptor (PR) (P value = 0.013) were statistically more in the other group.

Conclusion

Based on the findings of this study, the BC patients with BM had a remarkable short survival, had a higher rate of perineural invasion, and were mostly positive for HER2. Radiotherapy, chemotherapy, and surgery were the most common approaches to these patients.

Strategies to Overcome Resistance to Osimertinib in EGFR-Mutated Lung Cancer

Non-small-cell lung cancer (NSCLC) represents the most common type of lung cancer. The majority of patients with lung cancer characterized by activating mutations in the epidermal growth factor receptor (EGFR), benefit from therapies entailing tyrosine kinase inhibitors (TKIs). In this regard, osimertinib, a third-generation EGFR TKI, has greatly improved the outcome for patients with EGFR-mutated lung cancer. The AURA and FLAURA trials displayed the superiority of the third-generation TKI in both first- and second-line settings, making it the drug of choice for treating patients with EGFR-mutated lung cancer. Unfortunately, the onset of resistance is almost inevitable. On-target mechanisms of resistance include new mutations (e.g., C797S) in the kinase domain of EGFR, while among the off-target mechanisms, amplification of MET or HER2, mutations in downstream signaling molecules, oncogenic fusions, and phenotypic changes (e.g., EMT) have been described. This review focuses on the strategies that are currently being investigated, in preclinical and clinical settings, to overcome resistance to osimertinib, including the use of fourth-generation TKIs, PROTACs, bispecific antibodies, and ADCs, as monotherapy and as part of combination therapies.

Phase I trial of the combination of the pan-ErbB inhibitor neratinib and mTOR inhibitor everolimus in advanced cancer patients with ErbB family gene alterations

BACKGROUND

The ErbB family of receptor tyrosine kinases are key targets for antitumor therapy. Although neratinib, a pan-ErbB kinase inhibitor, is approved in ErbB2-positive breast cancer, drug resistance is common. Preclinical data suggest that combining neratinib with the mTOR inhibitor everolimus may overcome such resistance.

PATIENTS AND METHODS

Our trial evaluated this combination's safety and efficacy in advanced cancers with ErbB alterations. We conducted a phase I dose-escalation trial of neratinib and everolimus. Primary objectives were to assess safety, tolerability, and dose-limiting toxicities (DLTs) and establish the maximum tolerated dose (MTD). Secondary objectives included objective response by RECIST v1.1 and pharmacokinetic analyses.

RESULTS

Twenty-two patients (median age 61, median of four prior therapies) with ErbB alterations (mutations 63.6%, amplification 36.3%, or ErbB2-overexpressed by immunohistochemistry 9.1%) were enrolled. Common tumor types included breast (31.8%), colorectal (18.2%), cervical (9.1%), and endometrial (9.1%) cancers. Frequent grade (G) 3 treatment-related adverse events were diarrhea (18.2%), anemia (9.1%), mucositis (9.1%), and acute kidney injury (9.1%). DLTs included G3 mucositis and diarrhea at dose level (DL) 5, and G3 increased creatinine at DL4. The MTD was DL4: neratinib 240 mg with everolimus 7.5 mg. The objective response rate was 19% with partial response in four patients. Stable disease ≥16 weeks was seen in two patients (9.5%), resulting in a clinical benefit rate of 28.6%.

CONCLUSION

Pharmacokinetic data indicated reduced neratinib clearance possibly due to CYP3A4 pathway saturation by everolimus. Combination therapy with neratinib and everolimus has a tolerable safety profile and clinical activity in ErbB-altered patients. ErbB family receptors and the PI3K pathway are commonly implicated in oncogenesis. This clinical study of neratinib and everolimus demonstrated favorable clinical activity and tolerability.

A review on tyrosine kinase inhibitors for targeted breast cancer therapy

Breast cancer is a heterogeneous disease with complex molecular pathogenesis. Overexpression of several tyrosine kinase receptors is associated with poor prognosis, therefore, they can be key targets in breast cancer therapy. Tyrosine kinase inhibitors (TKIs) have emerged as leading agents in targeted cancer therapy due to their effectiveness in disrupting key molecular pathways involved in tumor growth. TKIs target various tyrosine kinases, including the human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), Vascular endothelial growth factor receptor (VEGFR), anaplastic lymphoma kinase (ALK), vascular endothelial growth factor receptor (VEGFR)-associated multi-targets, rearranged during transfection (RET), fibroblast growth factor receptor (FGFR), receptor tyrosine kinase-like orphan signal 1 (ROS1), Mitogen-activated protein kinase (MAPK), and tropomyosin receptor kinase (TRK). These drugs target the tyrosine kinase domain of receptor tyrosine kinases and play a vital role in proliferation and migration of breast cancer cells. Several TKIs, including lapatinib, neratinib, and tucatinib, have been developed and are currently used in clinical settings, often in combination with chemotherapy, endocrine therapy, or other targeted agents. TKIs have demonstrated remarkable benefits in enhancing progression-free and overall survival in patients with breast cancer and have become a standard of care for this population. This review provides an overview of TKIs currently being examined in preclinical studies and clinical trials, especially in combination with drugs approved for breast cancer treatment. TKIs have emerged as a promising therapeutic option for patients with breast cancer and hold potential for treating other breast cancer subtypes. The development of new TKIs and their integration into personalized treatment strategies will continue to shape the future of breast cancer therapy.

EGFR-Targeted Therapies: A Literature Review

Lung cancer remains the leading cause of cancer death in the United States, underscoring the critical need to optimize treatment strategies. Compared to conventional treatments such as surgical resection, radiotherapy, chemotherapy, and immunotherapy, targeted therapy stands out for its higher selectivity and minimal adverse effects. Among these, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the most widely used in targeted therapy for non-small-cell lung cancer (NSCLC). In our paper, we will conduct a comprehensive review of current literature on EGFR TKIs to contribute to advancements in molecular genomics and the treatment of lung cancer.

Synthetic routes and clinical application of Small-Molecule HER2 inhibitors for cancer therapy

This comprehensive review undertakes a meticulous scrutiny of the synthesis and clinical applications pertaining to small-molecule tyrosine kinase inhibitors (TKIs) directed towards the human epidermal growth factor receptor 2 (HER2), a pivotal protagonist in the pathogenesis of cancer. Focused on compounds like lapatinib, neratinib, and tucatinib, the review delves into the intricate synthesis strategies, emphasizing the challenges associated with their structural complexity. The clinical utilization of HER2 TKIs underscores noteworthy strides in the therapeutic landscape for HER2-positive breast and gastric malignancies. Lapatinib, a dual HER2/ epidermal growth factor receptor (EGFR) inhibitor, has demonstrated efficacy in combination therapies, addressing the need for overcoming resistance mechanisms. Neratinib, an irreversible HER2 inhibitor, presents a promising avenue for patients with refractory tumors. Tucatinib, strategically engineered to traverse the blood-brain barrier, epitomizes a groundbreaking advancement in the management of metastatic HER2-positive breast cancer manifesting cerebral involvement. Despite their success, challenges such as resistance mechanisms and off-target effects persist, urging continuous research for the development of next-generation HER2 TKIs. This comprehensive review serves as a valuable resource for pharmaceutical scientists, offering insights into the synthetic intricacies and clinical impact of small-molecule TKIs targeting HER2.

Mechanisms of acquired resistance to HER2-Positive breast cancer therapies induced by HER3: A comprehensive review

Receptor tyrosine kinases (RTKs) are cell surface receptors with kinase activity that play a crucial role in diverse cellular processes. Among the RTK family members, Human epidermal growth factor receptor 2 (HER2) and HER3 are particularly relevant to breast cancer. The review delves into the complexities of receptor tyrosine kinase interactions, resistance mechanisms, and the potential of anti-HER3 drugs, offering valuable insights into the clinical implications and future directions in this field of study. It assesses the potential of anti-HER3 drugs, such as pertuzumab, in overcoming resistance observed in HER2-positive breast cancer therapies. The review also explores the resistance mechanisms associated with various drugs, including trastuzumab, lapatinib, and PI3K inhibitors, providing insights into the intricate molecular processes underlying resistance development. The review concludes by emphasizing the necessity for further clinical trials to assess the efficacy of HER3 inhibitors and the potential of developing safe and effective anti-HER3 treatments to improve treatment outcomes for patients with HER2-positive breast cancer.

Promoting reactive oxygen species accumulation to overcome tyrosine kinase inhibitor resistance in cancer

BACKGROUND

In tumor treatment, protein tyrosine kinase inhibitors (TKIs) have been extensively utilized. However, the efficacy of TKI is significantly compromised by drug resistance. Consequently, finding an effective solution to overcome TKI resistance becomes crucial. Reactive oxygen species (ROS) are a group of highly active molecules that play important roles in targeted cancer therapy including TKI targeted therapy. In this review, we concentrate on the ROS-associated mechanisms of TKI lethality in tumors and strategies for regulating ROS to reverse TKI resistance in cancer.

MAIN BODY

Elevated ROS levels often manifest during TKI therapy in cancers, potentially causing organelle damage and cell death, which are critical to the success of TKIs in eradicating cancer cells. However, it is noteworthy that cancer cells might initiate resistance pathways to shield themselves from ROS-induced damage, leading to TKI resistance. Addressing this challenge involves blocking these resistance pathways, for instance, the NRF2-KEAP1 axis and protective autophagy, to promote ROS accumulation in cells, thereby resensitizing drug-resistant cancer cells to TKIs. Additional effective approaches inducing ROS generation within drug-resistant cells and providing exogenous ROS stimulation.

CONCLUSION

ROS play pivotal roles in the eradication of tumor cells by TKI. Harnessing the accumulation of ROS to overcome TKI resistance is an effective and widely applicable approach.

Combined inhibition of HER2 and VEGFR synergistically improves therapeutic efficacy via PI3K-AKT pathway in advanced ovarian cancer

BACKGROUND

Ovarian cancer (OC) is a prevalent malignancy in the female reproductive system, and developing effective targeted therapies for this disease remains challenging. The aim of this study was to use clinically-relevant OC models to evaluate the therapeutic effectiveness of RC48, an antibody-drug conjugate (ADC) targeting HER2, either alone or in combination with the VEGFR inhibitor Cediranib Maleate (CM), for the treatment of advanced OC.

METHODS

OC tumor specimens and cell lines were analyzed to determine HER2 and VEGFR expression by Western blot, immunocytochemistry and immunofluorescence. Moreover, the OC cell lines, cell-derived xenograft (CDX) and patient-derived xenograft (PDX) models were treated with RC48 and/or CM and then subjected to cell proliferation, viability, apoptosis, and tumor growth analyses to evaluate the feasibility of combination therapy for OC both in vitro and in vivo. Additionally, RNA-Seq was performed to investigate the critical mechanism underlying the combination therapy of RC48 and CM.

RESULTS

Our results demonstrated that RC48 alone effectively targeted and inhibited the growth of HER2-positive OC tumors in both cell lines and PDX models. Furthermore, the combination of RC48 and CM synergistically induced tumor regression in human OC cell lines, as well as CDX and PDX models. Mechanistically, we observed that the combination treatment inhibited the growth of OC cells involved inducing apoptosis and suppressing cell motility. RNA-seq analysis provided further mechanistic insights and revealed that co-administration of RC48 and CM downregulated multiple cancer-related pathways, including the AKT/mTOR pathway, cell cycle, and cell proliferation. Notably, our data further confirmed that the PI3K-AKT pathway played a key role in the inhibition of proliferation triggered by combinational treatment of RC48 and CM in OC cells.

CONCLUSIONS

These findings provide a preclinical framework supporting the potential of dual targeting HER2 and VEGFR as a promising therapeutic strategy to improve outcomes in patients with OC.

Development of a Validated UPLC-MS/MS Method for Simultaneous Estimation of Neratinib and Curcumin in Human Plasma: Application to Greenness Assessment and Routine Quantification

A validated ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the first-ever simultaneous analysis of neratinib, curcumin and internal standard (imatinib) using acetonitrile as the liquid-liquid extraction medium. On a BEH C18 (100 mm × 2.1 mm, 1.7 μm) column, the analytes were separated isocratically using acetonitrile (0.1% formic acid):0.002M ammonium acetate. The flow rate was set at 0.5 mL.min-1. The authors utilized multiple reaction monitoring-based transitions for the precursor-to-product ion with m/z 557.099 → 111.928 for neratinib, m/z 369.231 → 176.969 curcumin and m/z 494.526 → 394.141 for imatinib during the study. Validation of the method as per United States Food and Drug Administration requirements for linearity (5-40 ng mL-1), accuracy and precision, stability, matrix effect, etc. were investigated and were observed to be acceptable. Afterward, we evaluated the method for establishing its greenness profile by using two greenness assessment tools and found it green. Overall, a reliable green UPLC-MS/MS method was devised and used to estimate neratinib and curcumin in human plasma simultaneously.

Targeted Inhibitors of EGFR: Structure, Biology, Biomarkers, and Clinical Applications

Members of the EGFR family of tyrosine kinase receptors are major regulators of cellular proliferation, differentiation, and survival. In humans, abnormal activation of EGFR is associated with the development and progression of many cancer types, which makes it an attractive target for molecular-guided therapy. Two classes of EGFR-targeted cancer therapeutics include monoclonal antibodies (mAbs), which bind to the extracellular domain of EGFR, and tyrosine kinase inhibitors (TKIs), which mostly target the intracellular part of EGFR and inhibit its activity in molecular signaling. While EGFR-specific mAbs and three generations of TKIs have demonstrated clinical efficacy in various settings, molecular evolution of tumors leads to apparent and sometimes inevitable resistance to current therapeutics, which highlights the need for deeper research in this field. Here, we tried to provide a comprehensive and systematic overview of the rationale, molecular mechanisms, and clinical significance of the current EGFR-targeting drugs, highlighting potential candidate molecules in development. We summarized the underlying mechanisms of resistance and available personalized predictive approaches that may lead to improved efficacy of EGFR-targeted therapies. We also discuss recent developments and the use of specific therapeutic strategies, such as multi-targeting agents and combination therapies, for overcoming cancer resistance to EGFR-specific drugs.

Circulating tumour DNA testing in metastatic breast cancer: Integration with tissue testing

Breast cancer biomarker profiling predominantly relies on tissue testing (surgical and/or biopsy samples). However, the field of liquid biopsy, particularly the analysis of circulating tumour DNA (ctDNA), has witnessed remarkable progress and continues to evolve rapidly. The incorporation of ctDNA-based testing into clinical practice is creating new opportunities for patients with metastatic breast cancer (MBC). ctDNA offers advantages over conventional tissue analyses, as it reflects tumour heterogeneity and enables multiple serial biopsies in a minimally invasive manner. Thus, it serves as a valuable complement to standard tumour tissues and, in certain instances, may even present a potential alternative approach. In the context of MBC, ctDNA testing proves highly informative in the detection of disease progression, monitoring treatment response, assessing actionable biomarkers, and identifying mechanisms of resistance. Nevertheless, ctDNA does exhibit inherent limitations, including its generally low abundance, necessitating timely blood samplings and rigorous management of the pre-analytical phase. The development of highly sensitive assays and robust bioinformatic tools has paved the way for reliable ctDNA analyses. The time has now come to establish how ctDNA and tissue analyses can be effectively integrated into the diagnostic workflow of MBC to provide patients with the most comprehensive and accurate profiling. In this manuscript, we comprehensively analyse the current methodologies employed in ctDNA analysis and explore the potential benefits arising from the integration of tissue and ctDNA testing for patients diagnosed with MBC.

20 years since the approval of first EGFR-TKI, gefitinib: Insight and foresight

Epidermal growth factor receptor (EGFR) actively involves in modulation of various cancer progression related mechanisms including angiogenesis, differentiation and migration. Therefore, targeting EGFR has surfaced as a prominent approach for the treatment of several types of cancers, including non-small cell lung cancer (NSCLC), pancreatic cancer, glioblastoma. Various first, second and third generation of EGFR tyrosine kinase inhibitors (EGFR-TKIs) have demonstrated effectiveness as an anti-cancer therapeutics. However, rapid development of drug resistance and mutations still remains a major challenge for the EGFR-TKIs therapy. Overcoming from intrinsic and acquired resistance caused by EGFR mutations warrants the further exploration of alternative strategies and discovery of novel inhibitors. In this review, we delve into the breakthrough discoveries have been made in previous 20 years, and discuss the currently ongoing efforts aimed to circumvent the chemo-resistance. We also highlight the new challenges, limitations and future directions for the development of improved therapeutic approaches such as fourth-generation EGFR-TKIs, peptides, nanobodies, PROTACs etc.

Neratinib for HER2-positive breast cancer with an overlooked option

Positive human epidermal growth factor receptor 2 (HER2) expression is associated with an increased risk of metastases especially those to the brain in patients with advanced breast cancer (BC). Neratinib as a tyrosine kinase inhibitor can prevent the transduction of HER1, HER2 and HER4 signaling pathways thus playing an anticancer effect. Moreover, neratinib has a certain efficacy to reverse drug resistance in patients with BC with previous HER2 monoclonal antibody or targeted drug resistance. Neratinib, as monotherapy and in combination with other therapies, has been tested in the neoadjuvant, adjuvant, and metastatic settings. Neratinib with high anticancer activity is indicated for the prolonged adjuvant treatment of HER2-positive early BC, or in combination with other drugs including trastuzumab, capecitabine, and paclitaxel for the treatment of advanced HER2-positive BC especially cancers with central nervous system (CNS) metastasis to reduce the risk of BC recurrence. This article reviewed the pharmacological profiles, efficacy, safety, tolerability, and current clinical trials pertaining to neratinib, with a particular focus on the use of neratinib in patients with metastatic breast cancer (MBC) involving the CNS. We further discussed the use of neratinib for HER2-negative and HER2-mutant breast cancers, and mechanisms of resistance to neratinib. The current evidence suggests that neratinib has promising efficacy in patients with BC which is at least non-inferior compared to previous therapeutic regimens. The most common AE was diarrhea, and the incidence, severity and duration of neratinib-related grade 3 diarrhea can be reduced with loperamide. Of note, neratinib has the potential to effectively control and prevent brain metastasis in patients with advanced BC, providing a therapeutic strategy for HER2-positive BC.

Crofelemer for the Management of Neratinib-Associated Diarrhea in Patients With HER2+ Early-Stage Breast Cancer

BACKGROUND

To evaluate the efficacy of crofelemer, a first in class anti-secretory anti-diarrheal agent, to manage neratinib-induced diarrhea in patients with early-stage breast cancer taking adjuvant neratinib.

PATIENTS AND METHODS

This single center, open label trial enrolled patients with Stage 2 to 3 HER2+ breast cancer taking adjuvant neratinib. One cohort took prophylactic crofelemer 125 mg bid and loperamide in the first 2 cycles, and as needed in subsequent cycles. The second cohort took dose-escalated neratinib with loperamide as needed (DE cohort). The primary endpoint was incidence of grade ≥ 3 diarrhea in the first 2 cycles.

RESULTS

Seven patients in the crofelemer cohort and 4 in the DE cohort were enrolled. In the first 2 cycles, 2 patients (29%) in the crofelemer cohort and 2 patients (50%) in the DE cohort experienced grade 3 diarrhea lasting 1 day on average. After cycle 2, no additional patients in either cohort had grade 3 diarrhea. Five of 7 patients controlled diarrhea with crofelemer alone. There were no grade 4 diarrhea events in either cohort. Three patients in the crofelemer cohort dose-reduced neratinib due to diarrhea in the first 2 cycles. Patients in the crofelemer cohort had an average of 0.58 diarrhea episodes/day. 82% experienced constipation, all grade 1.

CONCLUSIONS

This is the first study to investigate crofelemer for neratinib-induced diarrhea and demonstrates crofelemer activity in this setting. Further investigation of crofelemer for diarrhea secondary to cancer treatment is needed.

Neratinib as adjuvant therapy in patients with HER2 positive breast cancer: expert opinion

Neratinib is a tyrosine kinase receptor inhibitor used in the extended adjuvant therapy of early-stage breast cancer. After adjuvant trastuzumab therapy, neratinib reduces the risk of recurrence and, if taken within 1 year from trastuzumab, significantly improves the invasive disease-free survival of patients with early-stage human epidermal growth factor receptor-2 positive (HER2+) breast cancer with no increased risk of long-term toxicity. Diarrhea, the most common adverse event associated with neratinib use, deters some clinicians from prescribing this drug. However, neratinib-related toxicity is predictable, short-lived, mostly limited to the first month of treatment and can be managed with dose-escalation and prophylactic strategies. Thus, close surveillance and prompt management, relying on supportive care and administration schedule modification, allows discontinuation of treatment to be avoided.

Preclinical and clinical activity of DZD1516, a full blood-brain barrier-penetrant, highly selective HER2 inhibitor

BACKGROUND

Patients with HER2-positive metastatic breast cancer (MBC) are at high risk of developing central nervous system (CNS) metastases. A potent and selective HER2 inhibitor with good blood-brain barrier (BBB) penetration is highly desirable.

METHODS

The design and structure-activity relationship of DZD1516 was described. The potency and selectivity of DZD1516 were determined by enzymatic and cellular assays. The antitumor activity of DZD1516 monotherapy or in combination with HER2 antibody-drug conjugate was assessed in CNS and subcutaneous xenograft mouse models. A phase 1 first-in-human study evaluated the safety, tolerability, pharmacokinetics, and preliminary antitumor activity of DZD1516 in patients with HER2+ MBC who relapsed from standard of care.

RESULTS

DZD1516 showed good selectivity against HER2 over wild-type EGFR in vitro and potent antitumor activity in vivo. Twenty-three patients were enrolled and received DZD1516 monotherapy treatment across six dose levels (25-300 mg, twice daily). Dose-limiting toxicities were reported at 300 mg, and thus 250 mg was defined as the maximum tolerated dose. The most common adverse events included headache, vomiting, and hemoglobin decreased. No diarrhea or skin rash was observed at ≤ 250 mg. The mean Kp,uu,CSF was 2.1 for DZD1516 and 0.76 for its active metabolite DZ2678. With median seven lines of prior systemic therapy, the best antitumor efficacy in intracranial, extracranial and overall lesions was stable disease.

CONCLUSIONS

DZD1516 provides positive proof of concept for an optimal HER2 inhibitor with high BBB penetration and HER2 selectivity. Further clinical evaluation of DZD1516 is warranted, with the RP2D being 250 mg BID.

CLINICALTRIALS

gov identifier NCT04509596. Registered on August 12, 2020; Chinadrugtrial: CTR20202424 Registered on December 18, 2020.

HER2 inhibition increases non-muscle myosin IIA to promote tumorigenesis in HER2+ breast cancers

HER2 is over-expressed in around 15% to 20% of breast cancers. HER3 plays a critical role in HER2 mediated tumorigenesis. Increased HER3 transcription and protein levels occur upon inhibition of HER2. We aimed to identify proteins that bound to HER3 upon inhibition of the HER family with the pan-HER inhibitor neratinib in HER2+ breast cancer cells. Immunoprecipitation of HER3 followed by mass spectrometry experiments found non-muscle myosin IIA (NMIIA) increased upon neratinib treatment relative to vehicle DMSO treatment. MYH9 is the gene that encodes for the heavy chain of NMIIA. Breast cancer patients with high MYH9 were significantly associated with a shorter disease specific survival compared to patients with low MYH9 expression from the METABRIC cohort of patients. In addition, high MYH9 expression was associated with HER2+ tumors from this cohort. Immunoblots of whole cell lysates of BT474 and MDA-MB-453 HER2+ breast cancer cells demonstrated elevated HER3 and NMIIA protein levels upon neratinib treatment for 24 hours. To examine the role of NMIIA in HER2+ breast cancer, we modulated NMIIA levels in BT474 and MDA-MB-453 cells using doxycycline inducible shRNA targeting MYH9. MYH9 knockdown reduces HER3 protein levels and concomitant reduction in downstream P-Akt. In addition, loss of MYH9 suppresses cell growth, proliferation, migration, and invasion. Our data reveals that NMIIA regulates HER3 and loss of NMIIA reduces HER2+ breast cancer growth.

UPLC-MS/MS Method for Simultaneous Estimation of Neratinib and Naringenin in Rat Plasma: Greenness Assessment and Application to Therapeutic Drug Monitoring

Tyrosine kinase inhibitors have often been reported to treat early-stage hormone-receptor-positive breast cancers. In particular, neratinib has shown positive responses in stage I and II cases in women with HER2-positive breast cancers with trastuzumab. In order to augment the biopharmaceutical attributes of the drug, the work designed endeavors to explore the therapeutic benefits of neratinib in combination with naringenin, a phytoconstituent with reported uses in breast cancer. A UPLC-MS/MS method was developed for the simultaneous estimation of neratinib and naringenin in rat plasma, while imatinib was selected as the internal standard (IS). Acetonitrile was used as the liquid extractant. The reversed-phase separation was achieved on a C18 column (100 mm × 2.1 mm, 1.7 µm) with the isocratic flow of mobile phase-containing acetonitrile (0.1% formic acid) and 0.002 M ammonium acetate (50:50, % v/v) at flow rate 0.5 mL·min−1. The mass spectra were recorded by multiple reaction monitoring of the precursor-to-product ion transitions for neratinib (m/z 557.138→111.927), naringenin (m/z 273.115→152.954), and the IS (m/z 494.24→394.11). The method was validated for selectivity, trueness, precision, matrix effect, recovery, and stability over a concentration range of 10–1280 ng·mL−1 for both targets and was acceptable. The method was also assessed for greenness profile by an integrative qualitative and quantitative approach; the results corroborated the eco-friendly nature of the method. Therefore, the developed method has implications for its applicability in clinical sample analysis from pharmacokinetic studies in human studies to support the therapeutic drug monitoring (TDM) of combination drugs.

Resistance to Antibody-Drug Conjugates Targeting HER2 in Breast Cancer: Molecular Landscape and Future Challenges

The treatment of HER2-positive metastatic breast cancer (mBC) with Trastuzumab emtansine (T-DM1) and Trastuzumab deruxtecan (T-DXd), two antibody-drug conjugates (ADCs) targeting HER2, is burdened by progression of disease related to the acquisition of mechanisms of resistance. Resistance to T-DM1 is caused by the decrease of HER2 expression, the alteration of intracellular trafficking, the impairment of lysosome functions, the drug expulsion through efflux pumps and the activation of alternative signal pathways. Instead, the decrease of HER2 expression and SLX4 loss of function mutations represent the first evidences of mechanisms of resistance to T-DXd, according to the results of DAISY trial. Several strategies are under evaluation to overcome resistances to anti-HER2 ADCs and improve clinical outcomes in patients progressing on these agents: combinations with tyrosine kinase inhibitors, statins, immune checkpoint inhibitors and synthetic DNA-damaging agents are emerging as promising approaches. Furthermore, novel anti-HER2 ADCs with innovative structures and mechanisms of action are in development, in the attempt to further improve the activity and tolerability of currently available agents.

Improvement of the Chemical Reactivity of Michael Acceptor of Ethacrynic Acid Correlates with Antiproliferative Activities

The present study aims to report the design, synthesis, and biological activity of new ethacrynic acid (EA) analogs (6-10) obtained by the double modulation of the carboxylic acid moiety and the aromatic ring with the aim to increase the chemical reactivity of Michael acceptor of EA. All obtained compounds were characterized by ¹H and ¹³C NMR, IR, and high-resolution mass spectrometry. The antiproliferative activity was evaluated in vitro using MMT test, in a first step, against HL60 cell line and in a second step, on a panel of human cancer cell lines such as HCT116, A549, MCF7, PC3, U87-MG, and SKOV3, and normal cell line MRC5 in comparison with positive control doxorubicin. Among all the tested compounds, the product 8 containing a propargyl and a hydroxyl groups, allowing an intramolecular hydrogen bond with the keto group of EA, exhibited a pronounced and selective activity in a nanomolar range against HL60, A549, PC3, and MCF7 with IC₅₀ values of 15, 41.2, 68.7, and 61.5 nM, respectively. Compound 8 also showed a good selectivity index (SI) against HL60 and moderate SI against the other three human cancer cells (A549, PC3, and MCF7). The study of the structure-activity relationship showed that both modifications of the carboxylic group and the introduction of an intramolecular hydrogen bond are highly required to improve the antiproliferative activities. The molecular modeling studies of compound 8 revealed that it favorably binds to the glutathione S-transferase active site, which may explain its interesting anticancer activity. These new compounds have potential to be developed as novel therapeutic agents against various cancer types.

New Concepts in Cardio-Oncology

Cancer and cardiovascular disease are the two major causes of morbidity and mortality in worldwide. Discovering new therapeutic agents for the management of breast cancer (BC) has increased the numbers of cancer survivors but with the risk of cardiovascular adverse events (CV-AEs). All drugs can potentially damage the cardiovascular system, with different types of clinical manifestations from ischemic myocardial disease to vasculitis, thrombosis or pericarditis. An early detection of CV-AEs guarantees an earlier treatment, which is associated with better outcomes. Cardio-oncology field enlarged its studies to improve prevention, monitoring and treatment of all cardiotoxic manifestations related to old or modern oncological agents. A multidisciplinary approach with a close partnership between oncologists and cardiologists is essential for an optimal management and therapeutic decision-making. The aim of this chapter is to review all types of cardiotoxic manifestations related to novel and old agents approved for treatment of BC patients including chemotherapy, anti-HER2 agents, cyclin-dependent kinase 4/6 inhibitors, PolyADP-ribose polymerase (PARP) inhibitors, antiangiogenic drugs and immunotherapy. We also focused our discussion on prevention, monitoring, treatment, and management of CV-AEs.

Systemic Therapy for HER2-Positive Metastatic Breast Cancer: Current and Future Trends

Approximately 20% of breast cancers (BC) overexpress human epidermal growth factor receptor 2 (HER2). This subtype of BC is a clinically and biologically heterogeneous disease that was associated with an increased risk for the development of systemic and brain metastases and poor overall survival before anti-HER2 therapies were developed. The standard of care was dual blockade with trastuzumab and pertuzumab as first-line followed by TDM-1 as second-line. However, with the advent of new HER2-targeted monoclonal antibodies, tyrosine kinase inhibitors and antibody- drug conjugates, the clinical outcomes of patients with HER2-positive BC have changed dramatically in recent years, leading to a paradigm shift in the treatment of the disease. Notably, the development of new-generation ADCs has led to unprecedented results compared with T-DM1, currently establishing trastuzumab deruxtecan as a new standard of care in second-line. Despite the widespread availability of HER2-targeted therapies, patients with HER2-positive BC continue to face the challenges of disease progression, treatment resistance, and brain metastases. Response rate and overall life expectancy decrease with each additional line of treatment, and tumor heterogeneity remains an issue. In this review, we update the new-targeted therapeutic options for HER2-positive BC and highlight the future perspectives of treatment in this setting.

A Review of Margetuximab-Based Therapies in Patients with HER2-Positive Metastatic Breast Cancer

Breast cancer (BC) is the most commonly diagnosed cancer globally, with high mortality rates. Targeted drug therapies have revolutionized cancer treatment. For example, treatment with human epidermal receptor 2 (HER2) antagonists has markedly improved the prognosis of patients with HER2-positive BC (HER2 + BC). However, HER2+ metastatic BC (MBC) remains prevalent owing to its resistance to conventional anti-HER2 drugs. Therefore, novel agents are needed to overcome the limitations of existing cancer treatments and to enhance the progression-free and overall survival rates. Progress has been made by optimizing the fragment crystallizable (Fc) domain of trastuzumab, an IgG1 monoclonal, chimeric anti-HER2 antibody, to develop margetuximab. The modified Fc domain of margetuximab enhances its binding affinity to CD16A and decreases its binding affinity to CD32B, thereby promoting its antitumor activity. This review summarizes studies on the efficacy of margetuximab, discusses its utility as an anti-HER2 monoclonal antibody drug for the treatment of HER2 + BC, and presents the latest advances in the treatment of BC. This review provides insights into the clinical implication of margetuximab in HER2 + MBC treatment.

Antibody-Drug Conjugates for the Treatment of HER2-Positive Breast Cancer

Human epidermal growth factor receptor 2 (HER2) receptor tyrosine kinase is overexpressed in 20-30% of breast cancers and is associated with poor prognosis and worse overall patient survival. Most women with HER2-positive breast cancer receive neoadjuvant chemotherapy plus HER2-targeted therapies. The development of HER2-directed therapeutics is an important advancement in targeting invasive breast cancer. Despite the efficacy of anti-HER2 monoclonal antibodies, they are still being combined with adjuvant chemotherapy to improve overall patient outcomes. Recently, significant progress has been made towards the development of a class of therapeutics known as antibody-drug conjugates (ADCs), which leverage the high specificity of HER2-targeted monoclonal antibodies with the potent cytotoxic effects of various small molecules, such as tubulin inhibitors and topoisomerase inhibitors. To date, two HER2-targeting ADCs have been approved by the FDA for the treatment of HER2-positive breast cancer: Ado-trastuzumab emtansine (T-DM1; Kadcyla®) and fam-trastuzumab deruxtecan-nxki (T-Dxd; Enhertu®). Kadcyla and Enhertu are approved for use as a second-line treatment after trastuzumab-taxane-based therapy in patients with HER2-positive breast cancer. The success of ADCs in the treatment of HER2-positive breast cancer provides novel therapeutic advancements in the management of the disease. In this review, we discuss the basic biology of HER2, its downstream signaling pathways, currently available anti-HER2 therapeutic modalities and their mechanisms of action, and the latest clinical and safety characteristics of ADCs used for the treatment of HER2-positive breast cancer.

Advances in the Management of Central Nervous System Metastases from Breast Cancer

Central nervous system (CNS) metastases are common in breast cancer (BC) patients and are particularly relevant as new treatments for BC are prolonging survival. Here, we review advances in the treatment of CNS metastases from BC, including radiotherapy, systemic therapies, and the evolving role of immunotherapy. The use of radiotherapy and chemotherapy is the cornerstone of treatment for CNS metastases. However, new targeted therapies have recently been developed, including anti-HER2 agents and antibody-drug conjugates that have presented promising results for the treatment of these patients.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Neratinib in advanced HER2-positive breast cancer: experience from the royal Marsden hospital

PURPOSE

To describe the tolerability and efficacy of neratinib as a monotherapy and in combination with capecitabine in advanced HER2-positive breast cancer in a real-world setting.

METHODS

Patients who received neratinib for advanced HER2-positive at the Royal Marsden Hospital NHS Trust between August 2016 and May 2020 were identified from electronic patient records and baseline characteristics, previous treatment and response to treatment were recorded. The primary endpoint of the study was progression-free survival (PFS). Secondary endpoints included overall survival (OS) and safety.

RESULTS

Seventy-two patients were eligible for the analysis. Forty-five patients received neratinib in combination with capecitabine and 27 patients received monotherapy. After a median duration of follow-up of 38.5 months, the median PFS for all patients was 5.9 months (95% confidence interval (CI) 4.9-7.4 months) and median OS was 15.0 months (95% Cl 10.4-22.2 months). Amongst the 52.7% (38/72) patients with confirmed brain metastases at baseline, median PFS was 5.7 months (95% CI 2.9-7.4 months) and median OS was 12.5 months (95% CI 7.7-21.4 months). Despite anti-diarrhoeal prophylaxis, diarrhoea was the most frequent adverse event, reported in 64% of patients which was grade 3 in 10%. There were no grade 4 or 5 toxicities. Seven patients discontinued neratinib due to toxicity.

CONCLUSIONS

Neratinib monotherapy or in combination with capecitabine is a useful treatment for patients with and without brain metastases. PFS and OS were found to be similar as previous trial data. Routine anti-diarrhoeal prophylaxis allows this combination to be safely delivered to patients in a real-world setting.

Decoding kinase-adverse event associations for small molecule kinase inhibitors

Small molecule kinase inhibitors (SMKIs) are being approved at a fast pace under expedited programs for anticancer treatment. In this study, we construct a multi-domain dataset from a total of 4638 patients in the registrational trials of 16 FDA-approved SMKIs and employ a machine-learning model to examine the relationships between kinase targets and adverse events (AEs). Internal and external (datasets from two independent SMKIs) validations have been conducted to verify the usefulness of the established model. We systematically evaluate the potential associations between 442 kinases with 2145 AEs and made publicly accessible an interactive web application “Identification of Kinase-Specific Signal” (https://gongj.shinyapps.io/ml4ki). The developed model (1) provides a platform for experimentalists to identify and verify undiscovered KI-AE pairs, (2) serves as a precision-medicine tool to mitigate individual patient safety risks by forecasting clinical safety signals and (3) can function as a modern drug development tool to screen and compare SMKI target therapies from the safety perspective.

Small molecule kinase inhibitors (SMKIs) are being approved at a fast pace under expedited programs for anticancer treatment. Here, the authors employ a machine-learning model to examine the relationships between kinase targets and adverse events in the trials of 16 FDA-approved SMKIs.

Discovery of potent and selective HER2 inhibitors with efficacy against HER2 exon 20 insertion-driven tumors, which preserve wild-type EGFR signaling

Oncogenic alterations in human epidermal growth factor receptor 2 (HER2) occur in approximately 2% of patients with non-small cell lung cancer and predominantly affect the tyrosine kinase domain and cluster in exon 20 of the ERBB2 gene. Most clinical-grade tyrosine kinase inhibitors are limited by either insufficient selectivity against wild-type (WT) epidermal growth factor receptor (EGFR), which is a major cause of dose-limiting toxicity or by potency against HER2 exon 20 mutant variants. Here we report the discovery of covalent tyrosine kinase inhibitors that potently inhibit HER2 exon 20 mutants while sparing WT EGFR, which reduce tumor cell survival and proliferation in vitro and result in regressions in preclinical xenograft models of HER2 exon 20 mutant non-small cell lung cancer, concomitant with inhibition of downstream HER2 signaling. Our results suggest that HER2 exon 20 insertion-driven tumors can be effectively treated by a potent and highly selective HER2 inhibitor while sparing WT EGFR, paving the way for clinical translation.

Perioperative HER2 targeted treatment in early stage HER2-positive breast cancer

Although human epidermal growth factor receptor 2 (HER2)-positive breast cancer was associated with poor prognosis, it has been changed after the development of trastuzumab. There has been great progress in perioperative HER2-targeting treatment, and investigations of several novel drugs and their combinations are ongoing. Adjuvant trastuzumab with or without pertuzumab for 1 year in combination with concomitant chemotherapy has become a standard treatment in high-risk node-negative tumors or node-positive HER2-positive early breast cancer patients without residual disease or who have not received neoadjuvant treatment. For low-risk HER2-positive early breast cancer patients, adjuvant paclitaxel and 1-year trastuzumab are possible alternatives. For residual disease after neoadjuvant treatment, adjuvant trastuzumab emtansine (T-DM1) for 14 cycles is a standard treatment. Non-anthracycline chemotherapy with dual anti-HER2 targeting of trastuzumab and pertuzumab represents one of the preferred neoadjuvant regimens to achieve higher pathologic complete response (pCR) rates and better clinical outcomes. Further research is needed to develop and validate potential biomarkers to predict pCR, which could help escalate or de-escalate anti-HER2 therapy. Trials incorporating novel agents such as T-DM1, trastuzumab deruxtecan (T-DXd), and immune checkpoint inhibitors and trying to de-escalate treatments in neoadjuvant setting are ongoing. In the future, tailored treatments such as no adjuvant therapy, various HER2-directed therapies alone with chemotherapy, combinations of various HER2-directed therapies and chemotherapy, addition of immune checkpoint inhibitors, and omission of surgery will be individualized in HER2-positive early breast cancer patients.

Cross-Resistance Among Sequential Cancer Therapeutics: An Emerging Issue

Over the past two decades, cancer treatment has benefited from having a significant increase in the number of targeted drugs approved by the United States Food and Drug Administration. With the introduction of targeted therapy, a great shift towards a new era has taken place that is characterized by reduced cytotoxicity and improved clinical outcomes compared to traditional chemotherapeutic drugs. At present, targeted therapies and other systemic anti-cancer therapies available (immunotherapy, cytotoxic, endocrine therapies and others) are used alone or in combination in different settings (neoadjuvant, adjuvant, and metastatic). As a result, it is not uncommon for patients affected by an advanced malignancy to receive subsequent anti-cancer therapies. In this challenging complexity of cancer treatment, the clinical pathways of real-life patients are often not as direct as predicted by standard guidelines and clinical trials, and cross-resistance among sequential anti-cancer therapies represents an emerging issue. In this review, we summarize the main cross-resistance events described in the diverse tumor types and provide insight into the molecular mechanisms involved in this process. We also discuss the current challenges and provide perspectives for the research and development of strategies to overcome cross-resistance and proceed towards a personalized approach.

Inactivating amplified HER2: challenges, dilemmas, and future directions

The pharmaceutical inactivation of driver oncogenes has revolutionized the treatment of cancer replacing cytotoxic chemotherapeutic approaches with kinase inhibitor therapies for many types of cancers. This approach has not yet been realized for the treatment of HER2-amplified cancers. The monotherapy activities associated with HER2-targeting antibodies and kinase inhibitors are modest, and their clinical use has been in combination with, and not in replacement of cytotoxic chemotherapies. This stands in sharp contrast to achievements in the treatment of many other oncogene-driven cancers. The mechanism-based treatment hypothesis regarding the inactivation of HER2 justifies expectations far beyond what is currently realized. Overcoming this barrier requires mechanistic insights that can fuel new directions for pursuit, but scientific investigation of this treatment hypothesis, particularly with regards to trastuzumab, has been complicated by conflicting and confusing data sets, ironclad dogma, and mechanistic conclusions that have repeatedly failed to translate clinically. We are now approaching a point of convergence regarding the challenges and resiliency in this tumor driver, and I will provide here a review and opinion to inform where we currently stand with this treatment hypothesis and where the future potential lies.

Natural History and Characteristics of ERBB2-mutated Hormone Receptor-positive Metastatic Breast Cancer: A Multi-institutional Retrospective Case-control Study from AACR Project GENIE

PURPOSE

We wanted to determine the prognosis and the phenotypic characteristics of hormone receptor-positive advanced breast cancer tumors harboring an ERBB2 mutation in the absence of a HER2 amplification.

EXPERIMENTAL DESIGN

We retrospectively collected information from the American Association of Cancer Research-Genomics Evidence Neoplasia Information Exchange registry database from patients with hormone receptor-positive, HER2-negative, ERBB2-mutated advanced breast cancer. Phenotypic and co-mutational features, as well as response to treatment and outcome were compared with matched control cases ERBB2 wild type.

RESULTS

A total of 45 ERBB2-mutant cases were identified for 90 matched controls. The presence of an ERBB2 mutation was not associated with worse outcome determined by overall survival (OS) from first metastatic relapse. No significant differences were observed in phenotypic characteristics apart from higher lobular infiltrating subtype in the ERBB2-mutated group. ERBB2 mutation did not seem to have an impact in response to treatment or time-to-progression (TTP) to endocrine therapy compared with ERBB2 wild type. In the co-mutational analyses, CDH1 mutation was more frequent in the ERBB2-mutated group (FDR < 1). Although not significant, fewer co-occurring ESR1 mutations and more KRAS mutations were identified in the ERBB2-mutated group.

CONCLUSIONS

ERBB2-activating mutation was not associated with a worse OS from time of first metastatic relapse, or differences in TTP on treatment as compared with a series of matched controls. Although not significant, differences in coexisting mutations (CDH1, ESR1, and KRAS) were noted between the ERBB2-mutated and the control group.

INHBA is a mediator of aggressive tumor behavior in HER2+ basal breast cancer

Background

Resistance to HER2-targeted therapeutics remains a significant clinical problem in HER2+ breast cancer patients with advanced disease. This may be particularly true for HER2+ patients with basal subtype disease, as recent evidence suggests they receive limited benefit from standard of care HER2-targeted therapies. Identification of drivers of resistance and aggressive disease that can be targeted clinically has the potential to impact patient outcomes.

Methods

We performed siRNA knockdown screens of genes differentially expressed between lapatinib-responsive and -resistant HER2+ breast cancer cells, which corresponded largely to luminal versus basal subtypes. We then validated hits in 2-d and 3-d cell culture systems.

Results

Knockdown of one of the genes, INHBA, significantly slowed growth and increased sensitivity to lapatinib in multiple basal HER2+ cell lines in both 2-d and 3-d cultures, but had no effect in luminal HER2+ cells. Loss of INHBA altered metabolism, eliciting a shift from glycolytic to oxidative phosphorylative metabolism, which was also associated with a decrease in tumor invasiveness. Analysis of breast cancer datasets showed that patients with HER2+ breast cancer and high levels of INHBA expression had worse outcomes than patients with low levels of INHBA expression.

Conclusions

Our data suggest that INHBA is associated with aggressiveness of the basal subtype of HER2+ tumors, resulting in poor response to HER2-targeted therapy and an invasive phenotype. We hypothesize that targeting this pathway could be an effective therapeutic strategy to reduce invasiveness of tumor cells and to improve therapeutic response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01512-4.

Disease characterization in liquid biopsy from HER2-mutated, non-amplified metastatic breast cancer patients treated with neratinib

Metastatic breast cancer (mBC) patients have a high risk of progression and face poor prognosis overall, with about one third (34%) surviving five years or more. In rare instances (2-4% of cases) patients with mBC have ERBB2 (HER2) activating mutations but are ERBB2 non-amplified. Neratinib is a potent, irreversible inhibitor that binds HER2 and inhibits downstream signaling. We used the previously validated high-definition single cell assay (HDSCA) workflow to investigate the clinical significance of the liquid biopsy in ERBB2 mutant, non-amplified, post-menopausal mBC patients starting neratinib and fulvestrant combination therapy. Characterization with a comprehensive liquid biopsy methodology (HDSCA) included genomic analysis of both the cell-free DNA (cfDNA) and single circulating tumor cells (CTCs) to monitor tumor evolution and identify potential mutational variants unique to the patient's clinical response. A limited series of five sequentially enrolled patients presented here were from the MutHER ( https://www.clinicaltrials.gov , NCT01670877) or SUMMIT ( https://www.clinicaltrials.gov , NCT01953926) trials. Patients had an average of 5.4 lines of therapy before enrollment, variable hormone receptor status, and ERBB2 mutations at diagnosis and during treatment. CTC enumeration alone was not sufficient to predict clinical response. Treatment pressure was shown to lead to an observable change in CTC morphology and genomic instability (GI), suggesting these parameters may inform prognosis. Single cell copy number alteration (CNA) analysis indicated that the persistence or development of a clonal population of CTCs during treatment was associated with a worse response. Hierarchical clustering analysis of the single cells across all patients and timepoints identified distinct aberrant regions shared among patients, comprised of 26 genes that are similarly affected and may be related to drug resistance. Additionally, the genomic analysis of the cfDNA, identified new mutations in ERBB2, PIK3CA, and TP53 that arose likely due to treatment pressure in a patient with poor response, further providing insights on the dynamics of the cancer genome over the course of therapy. The data presented in this small cohort study demonstrates the feasibility of real-time molecular profiling of the cellular and acellular fractions of the liquid biopsy using the HDSCA methodology. Additional studies are necessary to determine the potential use of morphometric and genomic analysis as a prognostic tool to advance personalized oncology.

Targetable HER3 functions driving tumorigenic signaling in HER2-amplified cancers

Effective inactivation of the HER2-HER3 tumor driver has remained elusive because of the challenging attributes of the pseudokinase HER3. We report a structure-function study of constitutive HER2-HER3 signaling to identify opportunities for targeting. The allosteric activation of the HER2 kinase domain (KD) by the HER3 KD is required for tumorigenic signaling and can potentially be targeted by allosteric inhibitors. ATP binding within the catalytically inactive HER3 KD provides structural rigidity that is important for signaling, but this is mimicked, not opposed, by small molecule ATP analogs, reported here in a bosutinib-bound crystal structure. Mutational disruption of ATP binding and molecular dynamics simulation of the apo KD of HER3 identify a conformational coupling of the ATP pocket with a hydrophobic AP-2 pocket, analogous to EGFR, that is critical for tumorigenic signaling and feasible for targeting. The value of these potential target sites is confirmed in tumor growth assays using gene replacement techniques.

Neratinib causes non-recoverable gut injury and reduces intestinal cytochrome P450 3A enzyme in mice

Neratinib is a pan-HER tyrosine kinase inhibitor newly approved by FDA in 2017 to treat HER2-positive breast cancer, but the phase III trial of neratinib showed that 96% of the patients taking neratinib experienced diarrhea. So far very few mechanistic studies explore neratinib-induced gastrointestinal (GI) toxicity. Hereby, we performed toxicity studies in mice to characterize the potential mechanism underlying this adverse effect. C57BL/6 J mice were separated into three groups A, B, C. Group A received vehicle; group B was orally dosed with 100 mg/kg neratinib once daily for 18 days. Group C was dosed with 100 mg/kg neratinib for 12 days and switched to vehicle for 6 days. Intestine and liver were collected for further analysis. Human intestine-derived cells were treated with neratinib in vitro. Our results showed that 12 days treatment of neratinib caused persistent histological damage in mouse GI tract. Both gene expression and activity of Cyp3a11, the major enzyme metabolizing neratinib in mice was reduced in small intestine. The gene expression of proinflammatory cytokines increased throughout the GI tract. Such damages were not recovered after 6 days without neratinib treatment. In addition, in vitro data showed that neratinib was potent in killing human intestine-derived cell lines. Based on such findings, we hypothesized that neratinib downregulates intestinal CYP3A enzyme to cause excessive drug disposition, eventually leading to gut injury.

Therapeutic Landscape of Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

Human epidermal growth factor receptor 2-positive breast cancer (HER2+BC) is a common malignancy that is prone to recurrence and metastasis in the early stages, resulting in a poor prognosis for patients. Many studies have suggested that targeted therapy promotes clinical outcomes in HER2+BC. With the introduction of trastuzumab in 1998, the prognosis of patients with early HER2+BC has improved significantly. However, owing to obstinate drug resistance and adverse events, the addition of new agents in standardized treatment has become a research hotspot. These promising agents include antibodies, antibody-drug conjugates, tyrosine kinase inhibitors, and anti-HER2 combined therapies. This article provides a brief description of the biology of BC and the expression of HER2, with the aim to provide an overview of the therapeutic landscape of HER2+BC by reviewing research results and introducing the latest evidence to provide a reference for clinical treatment.

Therapeutic Drug Monitoring of Protein Kinase Inhibitors in Breast Cancer Patients

Protein kinase inhibitors (PKIs) represent up-to-date therapeutic approach in breast cancer treatment. Although cancer is a rapidly progressive disease, many substances, including PKIs, are usually used at fixed doses without regard to each patient's individuality. Therapeutic drug monitoring (TDM) is a tool that allows individualization of therapy based on drug plasma levels. For TDM conduct, exposure-response relationships of drug substances are required. The pharmacokinetic data and exposure-response evidence supporting the use of TDM for 6 PKIs used in breast cancer treatment, one of the most common female tumour diseases, are discussed in this review.

Quantification of EGFR-HER2 Heterodimers in HER2-Overexpressing Breast Cancer Cells Using Liquid-Phase Electron Microscopy

Currently, breast cancer patients are classified uniquely according to the expression level of hormone receptors, and human epidermal growth factor receptor 2 (HER2). This coarse classification is insufficient to capture the phenotypic complexity and heterogeneity of the disease. A methodology was developed for absolute quantification of receptor surface density ρ_R, and molecular interaction (dimerization), as well as the associated heterogeneities, of HER2 and its family member, the epidermal growth factor receptor (EGFR) in the plasma membrane of HER2 overexpressing breast cancer cells. Quantitative, correlative light microscopy (LM) and liquid-phase electron microscopy (LPEM) were combined with quantum dot (QD) labeling. Single-molecule position data of receptors were obtained from scanning transmission electron microscopy (STEM) images of intact cancer cells. Over 280,000 receptor positions were detected and statistically analyzed. An important finding was the subcellular heterogeneity in heterodimer shares with respect to plasma membrane regions with different dynamic properties. Deriving quantitative information about EGFR and HER2 ρ_R, as well as their dimer percentages, and the heterogeneities thereof, in single cancer cells, is potentially relevant for early identification of patients with HER2 overexpressing tumors comprising an enhanced share of EGFR dimers, likely increasing the risk for drug resistance, and thus requiring additional targeted therapeutic strategies.

Heart Failure in Breast Cancer Survivors: Focus on Early Detection and Novel Biomarkers

PURPOSE OF REVIEW

Breast cancer survival rate has greatly improved in the last two decades due to the emergence of next-generation anti-cancer agents. However, cardiotoxicity remains a significant adverse effect arising from traditional and emerging chemotherapies as well as targeted therapies for breast cancer patients. In this review, we will discuss cardiotoxicities of both traditional and emerging therapies for breast cancer. We will discuss current practices to detect cardiotoxicity of these therapies with the focus on new and emerging biomarkers. We will then focus on 'omics approaches, especially the use of epigenetics to discover novel biomarkers and therapeutics to mitigate cardiotoxicity.

RECENT FINDINGS

Significant cardiotoxicities of conventional chemotherapies remain and new and unpredictable new forms of cardiac and/or vascular toxicity emerge with the surge in novel and targeted therapies. Yet, there is no clear guidance on detection of cardiotoxicity, except for significant left ventricular systolic dysfunction, and even then, there is no uniform definition of what constitutes cardiotoxicity. The gold standard for detection of cardiotoxicity involves a serial echocardiography in conjunction with blood-based biomarkers to detect early subclinical cardiac dysfunction. However, the ability of these tests to detect early disease remains limited and not all forms of toxicity are detectable with these modalities. There is an unprecedented need to discover novel biomarkers that are sensitive and specific for early detection of subclinical cardiotoxicity. In that space, novel echocardiographic techniques, such as strain, are becoming more common-place and new biomarkers, discovered by epigenetic approaches, seem to become promising alternatives or adjuncts to conventional non-specific cardiac biomarkers.

Multiple strategies for the treatment of invasive breast carcinoma: A comprehensive prospective

In this review, we emphasize on evolving therapeutic strategies and advances in the treatment of breast cancer (BC). This includes small-molecule inhibitors under preclinical and clinical investigation, phytoconstituents with antiproliferative potential, targeted therapies as antibodies and antibody-drug conjugates (ADCs), vaccines as immunotherapeutic agents and peptides as a novel approach inhibiting the interaction of oncogenic proteins. We provide an update of molecules under different phases of clinical investigation which aid in the identification of loopholes or shortcomings that can be overcomed with future breast cancer research.

The Expanding Role of Pyridine and Dihydropyridine Scaffolds in Drug Design

Pyridine-based ring systems are one of the most extensively used heterocycles in the field of drug design, primarily due to their profound effect on pharmacological activity, which has led to the discovery of numerous broad-spectrum therapeutic agents. In the US FDA database, there are 95 approved pharmaceuticals that stem from pyridine or dihydropyridine, including isoniazid and ethionamide (tuberculosis), delavirdine (HIV/AIDS), abiraterone acetate (prostate cancer), tacrine (Alzheimer's), ciclopirox (ringworm and athlete's foot), crizotinib (cancer), nifedipine (Raynaud's syndrome and premature birth), piroxicam (NSAID for arthritis), nilvadipine (hypertension), roflumilast (COPD), pyridostigmine (myasthenia gravis), and many more. Their remarkable therapeutic applications have encouraged researchers to prepare a larger number of biologically active compounds decorated with pyridine or dihydropyridine, expandeing the scope of finding a cure for other ailments. It is thus anticipated that myriad new pharmaceuticals containing the two heterocycles will be available in the forthcoming decade. This review examines the prospects of highly potent bioactive molecules to emphasize the advantages of using pyridine and dihydropyridine in drug design. We cover the most recent developments from 2010 to date, highlighting the ever-expanding role of both scaffolds in the field of medicinal chemistry and drug development.

Development and Validation of Targeted Gene Sequencing Panel Based Companion Diagnostic for Korean Patients with Solid Tumors

Simple Summary

We have developed and analytically validated the Korean Pan-cancer Companion Diagnostic (CDX) Panel to apply targeted anticancer drugs to Korean patients based on the molecular characteristics of tumors using tumor samples without matched patient normal samples. The panel included 31 genes with reported single nucleotide variants, 9 genes with reported copy number variations, and 15 genes with predictive responses to targeted drugs under clinical testing, enabling the panel to be analyzed for the targets of 30 targeted anticancer drugs. It is cost-effective and optimized for cancer type-specific therapy in Korean cancer patients across solid cancer types while minimizing the limitations of existing approaches. This gene screening method is expected to reduce test turnaround time and cost, making it a balanced approach to investigate solid cancer-related gene regions.

Abstract

Recently, several panels using two representative targeting methods have been developed but they do not reflect racial specificity, especially for Asians. We have developed and analytically validated the Korean Pan-cancer Companion Diagnostic (CDX) Panel to apply targeted anticancer drugs to Korean patients based on the molecular characteristics of tumors using tumor samples without matched patient normal samples. The panel included 31 genes with reported single nucleotide variants, 9 genes with reported copy number variations, and 15 genes with predictive responses to targeted drugs under clinical testing, enabling the panel to be analyzed for the targets of 30 targeted anticancer drugs. It is cost-effective and optimized for cancer type-specific therapy in Korean cancer patients across solid cancer types while minimizing the limitations of existing approaches. In addition, the optimized filtering protocol for somatic variants from tumor-only samples enables researchers to use this panel without matched normal samples. To verify the panel, 241 frozen tumor tissues and 71 formalin-fixed paraffin-embedded (FFPE) samples from several institutes were registered. This gene screening method is expected to reduce test turnaround time and cost, making it a balanced approach to investigate solid cancer-related gene regions.