HR+/HER2- Advanced Breast Cancer Treatment in the First-Line Setting: Expert Review

Vepdegestrant for the treatment of HR+/HER2- breast cancer

INTRODUCTION

The treatment of advanced hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer has been improved through the development of endocrine therapy (ET) and targeted agents. However, resistance to ET, particularly caused by ESR1 mutations, has not been fully addressed.

AREAS COVERED

Vepdegestrant is a first-in-class, selective, and orally bioavailable PROteolysis TArgeting Chimera (PROTAC) estrogen receptor (ER) degrader. Preclinical studies have suggested promising activity of vepdegestrant irrespective of ESR1 genotypes. Phase I and II clinical studies have revealed a favorable safety profile and encouraging efficacy of vepdegestrant as a single agent and in combination with other targeted agents.

EXPERT OPINION

The results of the phase III VERITAC-2 study, comparing vepdegestrant with fulvestrant, are expected to be available in 2025, and will provide the first data on the true clinical significance of vepdegestrant. Several phase III studies of combinations with vepdegestrant including + atirimociclib (a cyclin-dependent kinase 4 inhibitor) have been or are planned to be conducted. The results of these may not only transform the treatment landscape for advanced HR+/HER2- breast cancer but may pave the way for PROTAC as a new class of anti-cancer drugs that may make previously undruggable targets druggable.

Clinician's guide: expert insights on the use of CDK4/6 inhibitors in patients with early breast cancer

The introduction of the cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors abemaciclib and ribociclib to the adjuvant setting marks a significant advancement in the treatment of hormone-receptor-positive, human epidermal growth factor receptor 2-negative early breast cancer (HR+, HER2- EBC). Despite significant strides in early detection and treatment, many patients continue to face the risk of disease recurrence, highlighting the need for more effective adjuvant therapies. These CDK4/6 inhibitors, combined with adjuvant endocrine therapy, have shown promising efficacy in reducing recurrence rates while maintaining a manageable safety profile, as evidenced by the monarchE and NATALEE trials. This paper explores the integration of adjuvant CDK4/6 inhibitors into clinical practice, focusing on disease-free survival and safety outcomes. Key considerations in selecting between abemaciclib and ribociclib are discussed, including patient risk profiles, efficacy and safety profiles, treatment duration, and individual patient preferences. In addition, we discuss managing adverse events to prevent premature discontinuation, with strategies that include dose holds, dose reductions, proactive symptom management, and patient education. The paper also highlights strategies to enhance patient medication adherence and the involvement of multidisciplinary care teams to support treatment delivery. As research continues to evolve, additional follow-ups of the monarchE and NATALEE trials and future trials will further refine patient selection and treatment sequencing, ultimately improving outcomes and enhancing the quality of life for patients with HR+, HER2- EBC.

CDK4/6 as a Therapeutic Target in HR+/HER2- Breast Cancer Cells-Current Treatment Status

Breast cancer is the most frequently diagnosed neoplasm in the world. It can be classified into four main subtypes, each of them showing differences in the expression of hormone receptor (HR), human epidermal growth factor receptor 2 (HER2), and in cell metabolism. Since 2015, when The U.S. Food and Drug Administration (FDA) approved the first cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor that regulates the cell cycle, treatment of HR+/HER2- BC has become much more effective. Currently, palbociclib, ribociclib, and abemaciclib are more often used both in combination with endocrine therapy as well as in monotherapy. Their application has been extensively verified in many clinical trials such as PALOMA-1,2,3, MONALEESA-1,2,3,7, and MONARCH-1,2,3, which allowed the verification of differences in their effectiveness, dosage, and adverse effects. Subsequent studies, MonarchE and NATALEE, examined the role of these inhibitors as adjuvant therapy, as well as at verifying their safety. Moreover, dalpiciclib is being investigated in HR+/HER2- BC treatment. This article will summarize clinical efficacy, recommendations, and differences in toxicity profile between palbociclib, ribociclib, and abemaciclib and will also discuss the possibility of using dalpiciclib in the treatment of breast cancer.

Application status and research progress of targeted therapy drugs for hormone receptor-positive breast cancer

Breast cancer (BC) is the most common malignant tumor in women and the leading cause of cancer-related deaths in women. As one of the most common subtypes of breast cancer, patients with hormone receptor-positive (HR+) breast cancer usually experience disease progression over an extended period of time, triggering the search for therapeutic strategies other than endocrine therapy. In recent years, continuous research on various targets has led to dramatic changes in the treatment of hormone receptor-positive breast cancer patients, resulting in prolonged clinical survival. With the redefinition of human epidermal growth factor-2 (HER2) expression, more precise and individualized treatment is possible. This review comprehensively reviews targeted therapies and critical clinical trials for HR+ breast cancer and tracks the latest advances. It also provides valuable insights into the future direction of targeted therapies.

Evaluating the simultaneous electrochemical determination of antineoplastic drugs using LaNiO3/g-C3N4@RGH nanocomposite material

A novel electrochemical sensor based on LaNiO3/g-C3N4@RGH nanocomposite material was developed to simultaneously determine Ribociclib (RIBO) and Alpelisib (ALPE). Ribociclib and Alpelisib are vital anticancer medications used in the treatment of advanced breast cancer. The sensor exhibited excellent electrocatalytic activity towards the oxidation of RIBO and ALPE, enabling their simultaneous detection. The fabricated sensor was characterized using various techniques, including energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), which confirmed the successful synthesis of the LaNiO3/g-C3N4@RGH composite material. Electrochemical characterization revealed enhanced conductivity and lower resistance of the modified electrode compared to the bare electrode. The developed sensor exhibited high repeatability, reproducibility, stability, and selectivity toward RIBO detection. Furthermore, the sensor displayed high sensitivity with low detection limits of 0.88 nM for RIBO and 6.1 nM for ALPE, and linear ranges of 0.05-6.2 μM and 0.5-6.5 μM, respectively. The proposed electrochemical sensor offers a promising approach for simultaneously determining RIBO and ALPE in pharmaceutical formulations and biological samples with recovery data of 98.7-102.0 %, providing a valuable tool for anticancer drug analysis and clinical research.

Advances in the mechanism of CDK4/6 inhibitor resistance in HR+/HER2- breast cancer

Among women, breast cancer is the most prevalent form of a malignant tumour. Among the subtypes of breast cancer, hormone receptor (HR) positive and human epidermal growth factor receptor (HER2) negative kinds make up the biggest proportion. The advent of cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors, which are dependent on cell cycle proteins, has greatly enhanced the prognosis of patients with advanced HR+/HER2- breast cancer. This is a specific treatment that stops the growth of cancer cells by preventing them from dividing. Nevertheless, the drug resistance of the disease unavoidably impacts the effectiveness of treatment and the prognosis of patients. This report provides a thorough analysis of the current research advancements about the resistance mechanism of CDK4/6 inhibitors in HR+/HER2- breast cancer. It presents an in-depth discussion from numerous viewpoints, such as aberrant cell cycle regulation and changes in signalling pathways. In response to the drug resistance problem, subsequent treatment strategies are also being explored, including switching to other CDK4/6 inhibitor drugs, a combination of novel endocrine therapeutic agents, an optimal combination of targeted therapies and switching to chemotherapy. An in-depth study of the resistance mechanism can assist in identifying creative tactics that can overcome or postpone drug resistance, alleviate the problem of restricted treatment strategies following drug resistance and enhance the prognosis of patients.

Analysis of PIK3CA mutations in the primary and recurrent tumors of hormone receptor positive/human epidermal growth factor receptor 2 negative breast cancer

OBJECTIVE

Our aim was to compare the PIK3CA mutation status in matched primary and recurrent tumors of hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer (BC) to gain insight into the optimization of patient selection and detection time for PIK3CA-targeted therapy.

METHODS

The data were from 3035 patients with BC diagnosed at the Breast Disease Center, Peking University First Hospital, between January 2008 and December 2017. Matched primary and recurrent samples were profiled using amplification-refractory mutation system-polymerase chain reaction covering 11 mutational hotspots in PIK3CA.

RESULTS

PIK3CA mutations were detected in 54.3% primary tumors and 48.6% corresponding recurrences. PIK3CA mutation was detected in 37.5% cases in the locoregional recurrent group and 40.0% of distant metastasis, without a statistical difference. Besides, PIK3CA mutations were concordant in 88.6% of the matched pairs. For patients treated with neoadjuvant chemotherapy, 100% concordance was observed. However, PIK3CA mutation was neither correlated with clinicopathological features nor associated with clinical outcomes.

CONCLUSIONS

Mutations in PIK3CA in HR+/HER2- BC generally progressed to recurrent tumors. The high concordance rate of PIK3CA mutation status between primary tumors and corresponding recurrences suggests that the detection of primary tumors could be a substitute approach when recurrent samples are not easily obtainable.

Confirming the efficacy and safety of CDK4/6 inhibitors in the first-line treatment of HR+ advanced breast cancer: a systematic review and meta-analysis

Objective: Cyclin-dependent kinase (CDK) 4 and 6 inhibitors (abemaciclib, palbociclib and ribociclib) have been recommended in the first-line treatment of hormone receptor-positive (HR+) breast cancer in China. Our study aims to evaluate the efficacy and safety of CDK4/6 inhibitors by processing survival data using fractional polynomial modeling methods. Methods: Phase II or III randomized controlled trials in treatment-naive HR + patients with advanced breast cancer were systematically searched through the preset search strategy. The fractional polynomial (FP) model was used to relax the proportional hazard assumption and obtain time-varying hazard ratio (HR). Progression-free life years (PFLYs) and life years (LYs) were calculated from the area under curve (AUC) of the predicted progression-free survival (PFS) and overall survival (OS) curves to evaluate the long-term efficacy benefit. Odds ratio (OR) of grade≥3 adverse events were analyzed for safety outcomes. Results: 6 randomized controlled trials with 2,638 patients were included. The first-order FP model (p = -1) and the first-order FP model (p = 1) were used to calculate the time-varying HR of PFS and OS, respectively. Extrapolating to 240 months, abemaciclib obtained a PFS benefit of 3.059 PFLYs and 6.275 LYs by calculating the AUC of the PFS and OS curves. Palbociclib obtained 2.302 PFLYs and 6.351 LYs. Ribociclib obtained 2.636 PFLYs and 6.543 LYs. In terms of safety, the use of CDK4/6 inhibitors resulted in a higher risk of adverse events (OR = 9.84, 95% CI: 8.13-11.95), especially for palbociclib (OR = 14.04, 95% CI: 10.52-18.90). Conclusion: The use of CDK4/6 inhibitors in treatment-naive patients with HR + advanced breast cancer significantly improves survival, but also increases the risk of adverse events. Abemaciclib and ribociclib may be the best options for prolonging PFS and OS in treatment-naïve patients, respectively.

Cardiac safety of ribociclib evaluated with 24-hour rhythm Holter electrocardiogram

OBJECTIVE

We aimed to evaluate cardiac safety profile of ribociclib with 24-h rhythm Holter ECG.

MATERIAL AND METHOD

Forty-two female metastatic breast cancer patients were included in the study. Rhythm Holter ECG was performed before starting treatment with ribociclib and after 3 months of the treatment initiation.

RESULTS

The mean age of the patients was 56.36 ± 12.73. 52.4% (n = 22) of the patients were using ribociclib in combination with fulvestrant and 47.6% (n = 20) with aromatase inhibitors. None of the patients developed cardiotoxicity. When the rhythm Holter results before and in third month of the treatment were compared, there was no statistically significant difference.

CONCLUSION

This is the first study evaluating effects of ribociclib treatment on cardiac rhythm with Holter ECG. The findings suggested ribociclib has a low risk of causing early cardiotoxicity.

Do proton pump inhibitors affect the effectiveness of cyclin-dependent kinase 4/6 inhibitors in advanced HR positive, HER2 negative breast cancer? A meta-analysis

Background

The CDK 4/6 inhibitors, including palbociclib and ribociclib, are the standard first-line treatment for hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer. Proton pump inhibitors are one of the most globally prescribed types of medications as part of the treatment for gastroesophageal reflux and heartburn complaints. Medication interactions have been demonstrated, leading to a decrease in the effectiveness of chemotherapy drugs such as capecitabine and pazopanib. However, their role and interaction with targeted therapies such as CDK inhibitors are still poorly understood.

Methods

We searched PubMed, Embase and Web of Science databases for studies that investigated the use of PPI with CDK 4/6 inhibitors versus CDK4/6 alone for advanced or metastatic breast cancer. We systematically searched for the currently available CDK inhibitors: palbociclib, ribociclib and abemaciclib. We computed hazard ratios (HRs), with 95% confidence intervals (CIs). We used DerSimonian and Laird random-effect models for all endpoints. Heterogeneity was assessed using I2 statistics. R, version 4.2.3, was used for statistical analyses.

Results

A total of 2,737 patients with advanced breast cancer in 9 studies were included, with six studies described the status menopausal as 217 (7.9%) pre-menopause and 1851 (67.6%) post-menopause, for endocrine sensitivity only five studies described1489 (54.4%) patients were endocrine-sensitive and 498 (182%) endocrine-resistent, 910 (33.2%) patients used PPIs. The overall Progression-Free Survival was in favor of the PPI non-users (HR 2.0901; 95% CI 1.410-2.9498; p < 0.001). As well as the subgroup taking palbociclib, revealing statistical relevance for the PPI non-users (HR 2.2539; 95% CI 1.3213-3.8446; p = 0.003) and ribociclib subgroup with a slight decrease in hazard ratio (HR 1.74 95% CI 1.02-2.97; p = 0.04; I2 = 40%). In the multivariate analysis, there was no statistical signifance with ECOG (HR 0.9081; 95% CI 0.4978-16566; p 0.753) and Age (HR 1.2772; 95% CI 0.8790-1.8559; p = 0.199). Either, the univariate analysis did not show statistical significance.

Conclusion

Women with HR+ and HER2-advanced metastatic breast undergoing treatment with targeted therapies, specifically CDK 4/6 inhibitors, should be monitored for the use of proton pump inhibitors. Therefore, the use of PPIs should be discussed, weighing the advantages and disadvantages for specific cases. It should be individualized based on the necessity in clinical practice for these cases.

Systematic Review Registration

identifier CRD42023484755.

Real-World Treatment Patterns and Clinical Outcomes among Patients Receiving CDK4/6 Inhibitors for Metastatic Breast Cancer in a Canadian Setting Using AI-Extracted Data

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) are widely used in patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) advanced/metastatic breast cancer (ABC/MBC) in first line (1L), but little is known about their real-world use and clinical outcomes long-term, in Canada. This study used Pentavere's previously validated artificial intelligence (AI) to extract real-world data on the treatment patterns and outcomes of patients receiving CDK4/6i+endocrine therapy (ET) for HR+/HER2- ABC/MBC at Sinai Health in Toronto, Canada. Between 1 January 2016 and 1 July 2021, 48 patients were diagnosed with HR+/HER2- ABC/MBC and received CDK4/6i + ET. A total of 38 out of 48 patients received CDK4/6i + ET in 1L, of which 34 of the 38 (89.5%) received palbociclib + ET. In 2L, 12 of the 21 (57.1%) patients received CDK4/6i + ET, of which 58.3% received abemaciclib. In 3L, most patients received chemotherapy (10/12, 83.3%). For the patients receiving CDK4/6i in 1L, the median (95% CI) time to the next treatment was 42.3 (41.2, NA) months. The median (95% CI) time to chemotherapy was 46.5 (41.4, NA) months. The two-year overall survival (95% CI) was 97.4% (92.4, 100.0), and the median (range) follow-up was 28.7 (3.4-67.6) months. Despite the limitations inherent in real-world studies and a limited number of patients, these AI-extracted data complement previous studies, demonstrating the effectiveness of CDK4/6i + ET in the Canadian real-world 1L, with most patients receiving palbociclib as CDK4/6i in 1L.

Therapeutic evolution in HR+/HER2- breast cancer: from targeted therapy to endocrine therapy

Breast cancer, a complex and varied disease, has four distinct subtypes based on estrogen receptor and human epidermal growth factor receptor 2 (HER2) levels, among which a significant subtype known as HR+/HER2-breast cancer that has spurred numerous research. The prevalence of breast cancer and breast cancer-related death are the most serious threats to women's health worldwide. Current progress in treatment strategies for HR+/HER2-breast cancer encompasses targeted therapy, endocrine therapy, genomic immunotherapy, and supplementing traditional methods like surgical resection and radiotherapy. This review article summarizes the current epidemiology of HR+/HER2-breast cancer, introduces the classification of HR+/HER2-breast cancer and the commonly used treatment methods. The mechanisms of action of various drugs, including targeted therapy drugs and endocrine hormone therapy drugs, and their potential synergistic effects are deeply discussed. In addition, clinical trials of these drugs that have been completed or are still in progress are included.

Brain FADE syndrome: the final common pathway of chronic inflammation in neurological disease

Importance

While the understanding of inflammation in the pathogenesis of many neurological diseases is now accepted, this special commentary addresses the need to study chronic inflammation in the propagation of cognitive Fog, Asthenia, and Depression Related to Inflammation which we name Brain FADE syndrome. Patients with Brain FADE syndrome fall in the void between neurology and psychiatry because the depression, fatigue, and fog seen in these patients are not idiopathic, but instead due to organic, inflammation involved in neurological disease initiation.

Observations

A review of randomized clinical trials in stroke, multiple sclerosis, Parkinson's disease, COVID, traumatic brain injury, and Alzheimer's disease reveal a paucity of studies with any component of Brain FADE syndrome as a primary endpoint. Furthermore, despite the relatively well-accepted notion that inflammation is a critical driving factor in these disease pathologies, none have connected chronic inflammation to depression, fatigue, or fog despite over half of the patients suffering from them.

Conclusions and relevance

Brain FADE Syndrome is important and prevalent in the neurological diseases we examined. Classical "psychiatric medications" are insufficient to address Brain FADE Syndrome and a novel approach that utilizes sequential targeting of innate and adaptive immune responses should be studied.

The Effectiveness and Safety of Stereotactic Body Radiation Therapy (SBRT) in the Treatment of Oligoprogressive Breast Cancer: A Systematic Review

Stereotactic body radiotherapy (SBRT) has emerged as a technique to treat oligoprogressive sites among patients with breast cancer who are otherwise doing well on systemic therapy. This study systematically reviewed the efficacy and safety of SBRT in the setting of oligoprogressive breast cancer. A literature search was conducted in the MEDLINE database. Studies regarding SBRT and oligoprogressive breast cancer were included. Key outcomes of interest were toxicity, local control, progression, and overall survival. From 863 references, five retrospective single-center cohort studies were identified. All studies included patients with both oligometastatic and oligoprogressive disease; 112 patients with oligoprogressive breast cancer were identified across these studies. Patient age ranged from 22 to 84, with a median of 55 years of age. Most patients had hormone-receptor-positive and HER2-negative disease. SBRT doses varied from 24 to 60 Gy in 1-10 fractions based on the location/size of the lesion. Forty toxicity events were reported, of which the majority (n = 25, 62.5%) were grade 1-2 events. Among 15 patients who received SBRT concurrently with a CDK4/6 inhibitor, 37.5% of patients experienced grade 3-5 toxicities. Progression-free and overall survival ranged from 17 to 57% and 62 to 91%, respectively. There are limited data on the role of SBRT in oligoprogressive breast cancer, and prospective evaluation of this strategy is awaited to inform its safety and efficacy.