Tucatinib vs Placebo, Both in Combination With Trastuzumab and Capecitabine, for Previously Treated ERBB2 (HER2)-Positive Metastatic Breast Cancer in Patients With Brain Metastases: Updated Exploratory Analysis of the HER2CLIMB Randomized Clinical Trial

Clinical characteristics and prognostic factors in patients with breast cancer and leptomeningeal metastases from a large registry of BMBC

BACKGROUND

Leptomeningeal metastases (LM) in patients with breast cancer (BC) are associated with a dismal prognosis. We explored clinical characteristics and prognostic factors in patients with BC and LM in the German Brain Metastases in Breast Cancer Registry.

METHODS

All patients with histologically confirmed BC and diagnosis of LM (defined as the presence of tumor cells in the cerebrospinal fluid, or presence of typical clinical symptoms in combination with typical magnetic resonance imaging findings) were included.

RESULTS

A total of 3857 patients were included in the analysis (n = 859 (22.3 %) with LM). Among patients with LM a median progression-free survival was 4.2 months (95 % CI 3.6-4.8), and median overall survival was 5.7 months (95 % CI 4.9-6.7). In the multivariate analysis older age ( ≥ 60 vs. <60 years, Hazard ratio (HR): 1.65, 95 %CI: 1.25-2.18), worse performance status (ECOG 2-4 vs. 0-1 HR: 2.15, 95 %CI: 1.63-2.82), hormone receptor positive/HER2-negative (HR+/HER2-) or triple-negative subtype (HR: 1.54 95CI%: 1.07-2.23 and HR: 1.87, 95 %CI: 1.25-2.81), and higher number of BM (2-3 vs. 1, HR: 1.49, 95 %CI: 1.05-2.11 4) were significantly associated with a higher risk of death. Stereotactic radiotherapy (HR 0.49 95 %CI 0.30-0.79) and whole brain irradiation (HR: 0.58, 95 %CI: 0.42-0.80), endocrine therapy in patients with HR + BC (HR: 0.31, 95 %CI: 0.21-0.45) as well as HER2-targeted therapy for patients with HER2+ BC (HR 0.41, 95 %CI: 0.25-0.68) were associated with a significantly longer survival.

CONCLUSIONS

Clinicopathological factors associated with survival can help clinicians identify patients who are candidates for treatment (de)escalation in clinical trials.

Efficacy and safety of trastuzumab deruxtecan in HER2-positive breast cancer patients with brain metastases after failure of pyrotinib-based therapy

Tyrosine kinase inhibitors (TKIs) and trastuzumab deruxtecan (T-DXd) have shown efficacy in HER2-positive patients with brain metastases (BMs). This paper analyzed the efficacy and safety of T-DXd in HER2-positive breast cancer patients with BMs who progressed after pyrotinib treatment. We conducted a single-center, retrospective cohort study. HER2-positive patients with BMs who received T-DXd treatment after disease progression following pyrotinib therapy were identified from electronic medical records. The primary endpoint of this study was central nervous system progression-free survival (CNS-PFS). From April 2021 to July 2023, 15 patients were included in the study. The median CNS-PFS was 7.4 months [95% confidence interval (CI) 6.1-8.8 months], the median PFS for patients with extracranial/total lesions was 6.4 months (95% CI 4.4-8.3 months), and the median OS was 9.8 months (95% CI 5.9-13.8 months). The ORRs for intracranial, extracranial, and overall lesions were 33.3%, 71.4%, and 73.3%, respectively. Adverse events of grade 3 or higher with an incidence rate ≥ 5% included leukopenia (20.0%), neutropenia (13.3%), thrombocytopenia (6.7%), and nausea (6.7%). Adverse events of specific interest, interstitial lung disease or pneumonitis, occurred in 2 patents (13.3%), and both were grade 1. The preliminary data in this study suggest that in clinical practice in China, T-DXd is an optional treatment for patients with active/stable BMs who have progressed on pyrotinib. However, further studies are needed to determine its efficacy and the best treatment sequence for these patients.

Real-World Experience of HER2-Positive Advanced Breast Cancer (ABC) Treatment and Evaluation of Blood Biomarkers in a Public Institution in Latin America (LATAM)

Background

Advanced breast cancer (ABC) is an incurable disease, with a median overall survival (OS) of 3 years, even in high-income countries. Oncological treatment has improved survival rates, particularly for hormone receptor-positive and HER2-positive subtypes; however, access to new therapies in Latin American (LATAM) countries is limited.

Objectives

The impact of sequencing 2 lines of therapy in Peruvian patients with HER2-positive ABC in a single public institution was evaluated. First-line (1L) treatment consisted of trastuzumab and chemotherapy (CT, with taxanes), followed by second-line (2L) treatment with lapatinib plus capecitabine.

Design

In this retrospective study, we analyze clínico-pathological features (including blood biomarkers) collected from medical records of patients with HER2-positive ABC treated in a public Peruvian oncologic institution and its association with survival between 2020 and 2022.

Methods

Efficacy was measured using OS and progression-free survival (PFS). A discussion was added on the impact of OS based on clinicopathological characteristics, including outcomes in 2L "long-term responder" patients (who achieved response to 2L therapy ⩾6 months) and the evaluation of blood biomarkers.

Results

Treatment sequencing has been demonstrated to enhance OS in patients with HER2-positive ABC, with a median OS of 34 months. This effect is more pronounced among long-term responders (37 months), particularly those without central nervous system (CNS) involvement, as compared with those with CNS metastases (51 vs 34 months). Blood biomarkers were not found to be prognostic indicators for either PFS or OS.

Conclusions

Treatment sequencing has been demonstrated to enhance OS in LATAM patients with HER2-positive ABC. This study did not identify any prognostic blood biomarkers. These outcomes could influence the selection criteria for patients to receive treatment sequencing in countries without full access to innovative oncological therapies.

Advances in Targeted Therapy for Brain Metastases in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Breast Cancer: A Focus on ADCs and TKIs

Aim

Brain metastasis remains a significant therapeutic challenge in HER2-positive breast cancer, contributing to poor prognosis and limited treatment options. This review aims to summarize recent advancements in targeted therapies for brain metastasis in HER2-positive breast cancer, with a focus on the efficacy, mechanisms, and clinical implications of antibody-drug conjugates (ADCs) and tyrosine kinase inhibitors (TKIs).

Methods

We conducted a comprehensive review of clinical trials, real-world studies, and preclinical research.

Main Content

This review summarizes the latest clinical and preclinical evidence on targeted therapies for brain metastasis in HER2-positive breast cancer. Key therapies, including trastuzumab deruxtecan (T-DXd) and tucatinib, are discussed, with a focus on their mechanisms, efficacy, and ability to overcome the blood-brain barrier (BBB). Clinical trials such as HER2CLIMB and DESTINY-Breast03, as well as real-world studies, are highlighted to demonstrate the superior intracranial response rates and survival benefits of these therapies.

Conclusion

ADCs and TKIs represent a paradigm shift in the management of brain metastases, offering new hope for patients with HER2-positive breast cancer. Future research should focus on optimizing combination therapies, exploring novel biomarkers, and addressing resistance mechanisms to further improve outcomes. This review underscores the importance of continued innovation in targeted therapies for brain metastasis.

HER2-Positive Breast Cancer-Current Treatment Management and New Therapeutic Methods for Brain Metastasis

Background: Breast cancer can be classified based on the immunohistochemistry (IHC) phenotypes, defined by the presence or absence of the main IHC markers. IHC phenotyping is important as it determines the prognosis and guides treatment. For example, human epidermal growth factor receptor 2 (HER2) overexpression, which triggers cell growth and division, is observed in HER2-positive breast cancer. Methods: The standard treatment is based on trastuzumab plus pertuzumab in combination with taxane chemotherapy. The possibility of developing metastases depends on those phenotypes. Approximately 25-50% of patients with HER2-positive breast cancer experience brain metastases. This aspect is especially important, as 20% of those patients die as a result. Results: Through the years, many advanced therapies have been introduced to treat brain metastases, including whole brain radiotherapy, stereotactic radiosurgery, and a tyrosine kinase inhibitor (TKI), neratinib. Nonetheless, this still remains a therapeutic challenge. Conclusions: In this review, we focus on the treatment and efficiency of therapies targeting HER2-positive breast cancer, mainly concentrating on the current and newly developed treatment options for brain metastases, such as trastuzumab deruxtecan and tucatinib.

The curse of blood-brain barrier and blood-tumor barrier in malignant brain tumor treatment

The blood-brain barrier (BBB) is crucial for brain homeostasis but is a major obstacle in delivering anticancer drugs to brain tumors. However, this perspective requires re-evaluation, particularly for malignant brain tumors, such as gliomas and brain metastases. In these aggressive tumors, the BBB undergoes significant alterations, leading to the formation of a more permeable blood-tumor barrier. While this increased permeability allows better drug penetration, heterogeneity in blood-tumor barrier (BTB) integrity across different tumor regions remains a challenge. Additionally, the main challenge in treating brain tumors lies not in BBB penetration but in the lack of effective drugs. Conventional chemotherapies, including temozolomide and nitrosourea agents, have shown limited efficacy, and resistance mechanisms often reduce their long-term benefits. The "BBB curse" has often been blamed for the slow progress in drug development. However, emerging evidence suggests that even larger-molecule therapies, such as antibody-drug conjugates, can successfully target brain tumors. This review aims to critically reassess the roles of the BBB and BTB in brain tumor therapy, highlighting their impact on drug delivery and evaluating the current landscape of chemotherapeutic strategies. Furthermore, it explores new approaches to overcome treatment limitations, emphasizing the need for personalized and targeted therapeutic strategies.

Exploring the Role of ADCs in Brain Metastases and Primary Brain Tumors: Insight and Future Directions

Primary and secondary brain tumors have always been a challenge due to their high morbidity and poor prognosis. The incidence of brain metastasis is also increasing with the advent of effective new treatments. Traditional systemic treatments have historically had limited success, partly due to poor central nervous system (CNS) penetration. However, the advent in recent decades of new therapies that have shown high encephalic response rates are challenging this paradigm. ADCs represent a new class of compounds revolutionizing cancer treatment with high systemic response rates and lower toxicities. The continuing evolution of ADCs has shown that certain structural features such as payload, linker, and drug-to-antibody ratio (DAR) are essential in determining their efficacy at the encephalic level, and some ADCs have started to exhibit promising efficacy in treating primary and secondary brain tumors. Unfortunately, most patients with untreated encephalic metastases are excluded from clinical trials, with data primarily from retrospective studies or post hoc analyses. This review describes the early signs of ADC efficacy in brain tumors, the role of complementary treatments like radiation therapy, and critical points to improve ADC efficacy in brain malignancies.

Anti‑HER2‑targeted therapies for the treatment of advanced HER2‑positive breast cancer with brain metastases (Review)

Compared with other metastatic sites, breast cancer brain metastases (BCBMs) are associated with the shortest survival time. In addition, human epidermal growth factor receptor 2 (HER2) is observed to be amplified in 20-25% of breast cancer cases where it is a poor prognostic factor for brain metastases. Various anti-HER2 targeted therapies have brought both new opportunities and challenges to patients with HER2-positive BCBM over the past decade. However, prolonging survival time and improving quality of life of patients have become controversial issues in the field of clinical research on BCBMs. On the basis of the latest literature, the present review documents the anti-HER2 targeted drugs applied in patients with HER2-positive BCBM. Further studies on the efficacy and safety of novel HER2-targeted drugs and combined or sequential therapy in clinical treatment are expected to provide more effective strategies for the treatment of patients with HER2-positive BCBM.

Stereotactic radiosurgery for patients with brain metastases: current principles, expanding indications and opportunities for multidisciplinary care

The management of brain metastases is challenging and should ideally be coordinated through a multidisciplinary approach. Stereotactic radiosurgery (SRS) has been the cornerstone of management for most patients with oligometastatic central nervous system involvement (one to four brain metastases), and several technological and therapeutic advances over the past decade have broadened the indications for SRS to include polymetastatic central nervous system involvement (>4 brain metastases), preoperative application and fractionated SRS, as well as combinatorial approaches with targeted therapy and immune-checkpoint inhibitors. For example, improved imaging and frameless head-immobilization technologies have facilitated fractionated SRS for large brain metastases or postsurgical cavities, or lesions in proximity to organs at risk. However, these opportunities come with new challenges and questions, including the implications of tumour histology as well as the role and sequencing of concurrent systemic treatments. In this Review, we discuss these advances and associated challenges in the context of ongoing clinical trials, with insights from a global group of experts, including recommendations for current clinical practice and future investigations. The updates provided herein are meaningful for all practitioners in clinical oncology.

Impact of brain metastasis size at the time of radiotherapy on local control and radiation necrosis

PURPOSE

No consensus has been reached regarding whether upfront versus deferred radiation to small, asymptomatic brain metastases is most optimal. We sought to assess the relationship between tumor size at radiation and subsequent development of local recurrence and radiation necrosis to make data-driven recommendations regarding timing of radiation utilization.

METHODS

We identified 2268 patients with 6308 newly diagnosed brain metastases between 2010 and 2022 managed with brain-directed radiotherapy at Brigham and Women's Hospital/Dana-Farber Cancer Institute (Boston, MA). Tumors were grouped by maximal unidimensional size: <0.5 cm, 0.5 to < 1 cm, 1 cm to < 2 cm, and ≥ 2 cm; local recurrence and radiation necrosis by tumor size were assessed using competing risks regression.

RESULTS

Among metastases initially treated with stereotactic radiation or whole brain radiotherapy, lesions 1 to < 2 cm (HR 2.30 [95% CI, 1.38-3.81], p = 0.001 and HR 2.61 [95% CI 1.76-3.89], p < 0.001, respectively) and ≥ 2 cm (HR 3.10 [95% CI, 1.62-5.94], p < 0.001 and HR 3.03 [95% CI 1.92-4.79], p < 0.001, respectively) displayed greater local recurrence compared to tumors < 0.5 cm. In addition, among patients treated with stereotactic radiation, significantly higher risk of radiographic and symptomatic necrosis was observed in tumors ≥ 0.5 cm versus < 0.5 cm at radiotherapy, with hazard ratios ranging from 3.27 to 18.90.

CONCLUSION

Larger metastasis size is associated with markedly poorer local control and increased necrosis following brain-directed radiation, suggesting a role for earlier utilization of radiation therapy in patients with small, asymptomatic metastases and a favorable prognosis.

Repeat stereotactic radiosurgery for recurrent brain metastases: a retrospective comparison of local progression and distant brain metastases after prior radiosurgery

AIM

This study evaluated the efficacy and safety of repeat stereotactic radiosurgery (SRS) for recurrent brain metastases (BMs), focusing on failure patterns of local progression (LP) and distant brain metastases (DBM).

METHODS

Patients who underwent first-time SRS for newly diagnosed BMs (2011-2022) and repeat SRS (until June 2024) were included. Treatment courses were first-time or repeat SRS, with repeat SRS classified as LP and DBM. The primary endpoint was the 1-year local control rate (LCR). Secondary endpoints included survival and radiation necrosis (RN) incidence.

RESULTS

Among 723 courses (427 patients, 4,524 BMs), 404 (141 patients, 2,924 BMs) met criteria. First-time SRS was performed in 141 courses (775 BMs), and repeat SRS in 263 (2,149 BMs), including 45 LP (38 patients, 224 BMs) and 218 DBM (126 patients, 1,925 BMs). The median age was 65 years, and 75.9% had lung cancer. LP had a longer interval from prior SRS (12.6 vs. 6.3 months, P < 0.001) but similar follow-up (12.4 vs. 13.7 months). The 1-year LCR was lower in LP (72.4% vs. 88.3%, P = 0.0022), though survival was similar (17.9 vs. 16.3 months). LP had higher RN incidence (20.6% vs. 5.7%, P < 0.001) and symptomatic RN (13.3% vs. 2.8%, P < 0.001). Multivariate analysis identified LP failure as a significant factor for increased local failure (subdistribution hazard ratio [SHR] 2.35, P = 0.039) and RN (SHR 3.41, P < 0.001).

CONCLUSIONS

Despite similar survival, LP failure was associated with lower LCR and higher RN incidence, highlighting the need for optimized repeat SRS strategies.

Expert Perspectives on Controversies and Critical Knowledge Gaps in Breast Cancer Management: Proceedings of the First Bridging the Gaps in Breast Cancer Symposium

PURPOSE

Breast cancer is the most common type of cancer for women in the United States and accounts for nearly 25% of all cancers and 16% of cancer deaths worldwide. New treatment options continue to emerge offering improved management options for patients with breast cancer. However, as these new treatments become available, clinicians are left with many questions regarding how to best utilize these treatments and improve outcomes for patients with breast cancer.

MATERIALS AND METHOD

The Bridging the Gaps in Breast Cancer panel was assembled to address challenges in the management of breast cancer. Bridging the Gaps in Breast Cancer co-chairs and session moderators identified areas of controversy and uncertainty in breast cancer management and were responsible for organizing the presentations and discussion with the expert panel of faculty throughout the meeting.

RESULTS

The Bridging the Gaps in Breast Cancer panel discussions are presented. Key critical knowledge gaps surrounding the evolving breast cancer treatment landscape identified include how to identify which patients will benefit the most from therapeutic intervention, the mechanism of resistance to newly approved therapies, which therapies may be safely omitted from a treatment regimen without harm to the patient, and the most important metric(s) in defining successful treatment in various stages and subtypes of breast cancer.

CONCLUSIONS

The treatment armamentarium for the management of breast cancer continues to grow and evolve. With those new treatment options, new questions continue to arise for clinicians. Future studies are needed to address these critical gaps in knowledge about how to best utilize treatments for improved patient outcomes.

Diagnostic and therapeutic advances for HER2-expressing or amplified gynecologic cancers

HER2-targeting therapies are well-described in breast, gastric, and lung cancers, however accumulating data supports a role for HER2-targeted therapies in gynecologic cancers. Despite varied methodologies for HER2 testing, evidence supports that a substantial proportion of endometrial, ovarian, cervical, and vulvar cancers overexpress HER2. This underscores the rationale for HER2-targeted therapies in these malignancies, including the use of HER2-directed tyrosine kinase inhibitors, antibody-drug conjugates, and immune-stimulating antibody conjugates. Understanding mechanisms of resistance to HER2-targeted therapies will inform possible combinatorial strategies.

TUXEDO-4: phase II study of trastuzumab-deruxtecan in HER2-low breast cancer with new or progressing brain metastases

CLINICAL TRIAL REGISTRATION

NCT06048718 (clinicaltrials.gov); 2023 -506,702-39-00 (EudraCT number).

Molecular evolution of central nervous system metastasis and therapeutic implications

The increasing prevalence and poor prognosis of central nervous system (CNS) metastases pose a significant challenge in oncology, necessitating improved therapeutic strategies. Recent research has shed light on the complex genomic landscape of brain metastases, identifying unique and potentially actionable genetic alterations. These insights offer new avenues for targeted therapy, highlighting the potential of precision medicine approaches in treating CNS metastases. However, translating these discoveries into clinical practice requires overcoming challenges such as availability of tissue for characterization, access to molecular testing, drug delivery across the blood-brain barrier (BBB) and addressing intra- and intertumoral genetic heterogeneity. This review explores novel insights into the evolution of CNS metastases, the molecular mechanisms underlying their development, and implications for therapeutic interventions.

Tucatinib and trastuzumab in HER2-mutated metastatic breast cancer: a phase 2 basket trial

Human epidermal growth factor receptor 2 (HER2, also known as ERBB2) signaling promotes cell growth and differentiation, and is overexpressed in several tumor types, including breast, gastric and colorectal cancer. HER2-targeted therapies have shown clinical activity against these tumor types, resulting in regulatory approvals. However, the efficacy of HER2 therapies in tumors with HER2 mutations has not been widely investigated. SGNTUC-019 is an open-label, phase 2 basket study evaluating tucatinib, a HER2-targeted tyrosine kinase inhibitor, in combination with trastuzumab in patients with HER2-altered solid tumors. The study included a cohort of 31 heavily pretreated female patients with HER2-mutated metastatic breast cancer who were also HER2 negative per local testing. Hormone receptor (HR)-positive patients also received fulvestrant. The overall response rate (primary endpoint) was 41.9% (90% confidence interval (CI): 26.9-58.2). Secondary endpoints of duration of response and progression-free survival were 12.6 months (90% CI: 4.7 to not estimable) and 9.5 months (90% CI: 5.4-13.8), respectively. No new safety signals were detected. Responses were observed across various HER2 mutations, including mutations in the tyrosine kinase and extracellular domains. The chemotherapy-free regimen of tucatinib and trastuzumab showed clinically meaningful antitumor activity with durable responses and favorable tolerability in heavily pretreated patients with HER2 mutations. These data support further investigation of HER2-targeted therapies in this patient population. ClinicalTrials.gov registration: NCT04579380 .

Precision radiotherapy with molecular-profiling of CNS tumours

Diagnoses of CNS malignancies in the primary and metastatic setting have significantly advanced in the last decade with the advent of molecular pathology. Using a combination of immunohistochemistry, next-generation sequencing, and methylation profiling integrated with traditional histopathology, patient prognosis and disease characteristics can be understood to a much greater extent. This has recently manifested in predicting response to targeted drug therapies that are redefining management practices of CNS tumours. Radiotherapy, along with surgery, still remains an integral part of treating the majority of CNS tumours. However, the rapid advances in CNS molecular diagnostics have not yet been effectively translated into improving CNS radiotherapy. We explore several promising strategies under development to integrate molecular oncology into radiotherapy, and explore future directions that can serve to use molecular diagnostics to personalize radiotherapy. Evolving the management of CNS tumours with molecular profiling will be integral to supporting the future of precision radiotherapy.

Impact of HER2-targeting antibody drug conjugates in treatment strategies for patients with breast cancer

Antibody drug conjugates (ADCs) are novel drugs that exert specific cytotoxicity against breast cancer. Although ADCs such as trastuzumab emtansine and trastuzumab deruxtecan have significantly improved survival for patients with breast cancer expressing HER2, there is still controversy over options after ADCs. The radiotherapy and ablation should also be used as an effective strategy for oligoprogressions. Herein, we conducted a review of ADCs, and then discussed several strategies to maximize the potential benefit to patients with HER2 expression breast cancer.

Neurological symptom management in breast cancer meningeal carcinomatosis

No treatment has been established for meningeal carcinomatosis (MC) in advanced metastatic breast cancer, and its prognosis is poor. In recent years, systemic therapies such as trastuzumab deruxtecan and tucatinib have been reported effective for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, however, these cannot be used for all MC. The difficulty in diagnosing and treating MC is attributed to its diverse pathology. As a result, in clinical practice, diagnosis is often delayed, and symptoms persist. This review focuses on whether neurological symptoms can be effectively alleviated even with unestablished treatments by classifying the pathology of MC into meningitis, hydrocephalus-related intracranial hypertension symptoms, focal brain damage such as epilepsy, cranial nerve disorders, and spinal cord symptoms and evaluating the diagnosis and condition. Hydrocephalus can be managed with drainage and ventriculoperitoneal shunt surgery, and meningitis symptoms and cranial nerve disorders can be managed with whole brain radiotherapy. Antiepileptic drugs are essential for epilepsy, and supportive care is necessary, as are steroids for cranial nerve disorders. However, MC is not caused by a single condition but can occur in combination thus the therapeutic effectiveness of palliative therapy for neurological symptoms is currently unknown, and research is limited. In the future, if a lineup of highly effective systemic therapies such as tyrosine kinase inhibitors for ALK gene-positive lung cancer is established, treatment strategies for MC may change. However at present, rapid diagnosis and prompt neurological palliative treatment play an important role in the neurological symptoms management of MC.

Prognostic Factors in Therapy Regimes of Breast Cancer Patients with Brain Metastases: A Retrospective Monocentric Analysis

Background: Breast cancer patients who develop brain metastases have a high mortality rate and a massive decrease in quality of life. Approximately 10-15% of all patients with breast cancer (BC) and 5-40% of all patients with metastatic BC develop brain metastasis (BM) during the course of the disease. However, there is only limited knowledge about prognostic factors in the treatment of patients with brain metastases in breast cancer (BMBC). Therefore, we retrospectively analyzed data of BMBC patients from the University Hospital of Würzburg for treatment patterns to find characteristics associated with a better or worse prognosis. These findings should help to treat the ever-increasing collective of patients with BMBC better in the future. Methods: The clinical data of 337 patients with cerebral metastatic breast cancer (date of death between 2004 and 2021) treated at the Department of Gynecology and Obstetrics of the University Hospital Würzburg were retrospectively analyzed, with a focus on patients' survival. Results: The involvement of regional lymph nodes at initial diagnosis, the immunohistochemical subtype of TNBC at the onset of BMBC, and extracranial metastases at the time of BM diagnosis (bone, liver, lung metastases) were associated with a worse prognosis. In contrast, the immunohistochemical subtype of HER2/neu, the sole occurrence of a singular BM, the local surgical removal of BMs, and radiotherapy (especially stereotactic radiotherapy) were associated with prolonged survival. The number of therapies before the diagnosis of BMs also had a prognostic influence. Conclusions: Looking back at data is crucial for pinpointing risk elements affecting survival after a BM diagnosis. In our investigation, along with established factors like immunohistologic subtype, BM count, surgical excision, stereotactic irradiation, and type of extracranial metastasis, we also found that the number of therapies before BM diagnosis and the initial lymph node status were associated with patients' survival. Potentially, these factors could be included in prospective prognostic scores for evaluating brain metastasis survival rates, thereby aiding in making appropriate treatment suggestions for impacted patients.

Analysis of HER2 expression changes from breast primary to brain metastases and the impact of HER2-low expression on overall survival

BACKGROUND

There are limited data regarding HER2-low expression dynamics between matched primary tumors and brain metastases (BrMs) in breast cancer. HER2-low expression has emerged as a new therapeutic biomarker for highly active antibody-drug conjugates with emerging intracranial activity.

METHODS

Patients with metastatic breast cancer and BrMs seen at an NCI-designated center between 2003 and 2023 were identified. HER2 expression was defined as HER2-positive (3+, 2+/ISH amplified), HER2-low (1+, 2+/ISH negative), or HER2-0 by ASCO-CAP guidelines. Estrogen receptor (ER) status was defined as ER ≥1%. Multivariate survival analyses by Cox proportional hazard models were determined from the time of BrM resection to death or last follow-up between the 3 subtypes, controlling for ER and age.

RESULTS

Among 197 matched primary and resected BrMs, 81% exhibited HER2 expression in the brain: 61% HER2-positive, 20% HER2-low, and 19% HER2-0. Concordance was high in HER2-positive primary tumors with 100% retaining HER2 expression (97% retained HER2-positive expression and 2.7% switched to HER2-low). HER2-0 primaries frequently showed HER2 gain in BrMs to HER2-low (35%) or HER2-positive (5.4%) status. Among 48 HER2-low primary tumors, 52% were discordant for HER2 status in the brain with 21% testing HER2-positive and 31% testing HER2-0. In adjusted analyses, patients with HER2-positive BrMs had significantly lower death risk than patients with HER2-low BrMs (HR = 0.41, P = .0006); no difference was observed between HER2-0 and HER2-low.

CONCLUSIONS

In this retrospective analysis, HER2 expression is common in breast cancer BrMs, emphasizing the need for improved, noninvasive diagnostics. Patients with HER2-low and HER2-0 BrMs face inferior survival, presenting an unmet clinical need.

Strategies to enhance management of HER2-positive breast cancer in the elderly: an expert consensus perspective

Therapeutic decision-making for older patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer highlights the importance of a comprehensive geriatric assessment (CGA). This assessment considers the functional status, comorbidities, and relevant conditions of the patient, and allows for an estimation of life expectancy, but it does not facilitate individualized treatment plans. There are also other challenges to consider related to the cardiac toxicity of the treatments and the under-representation of older patients in clinical trials. The Oncogeriatrics Section of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica, SEOM), the Spanish Group for Breast Cancer Research (Grupo Español de Investigación en Cáncer de Mama, GEICAM) and the Spanish Group of Study, Treatment and other Experimental Strategies in Solid Tumours (Grupo Español de Estudio, Tratamiento y otras Estrategias Experimentales en Tumores Sólidos, SOLTI) have gathered an expert committee to evaluate the scientific evidence on the management of older patients with HER2-positive breast cancer and to establish recommendations based on a comprehensive review of the existing literature. These recommendations underscore the importance of individualizing treatment plans based on the patient's physical status and tolerability to maximize efficacy while minimizing toxicity. Emphasis is placed on adapting neoadjuvant and adjuvant therapies according to geriatric assessment and specific patient needs. A careful selection of treatment schedules for advanced stages is needed to improve survival and quality of life, assuming that scientific evidence in this age group is limited.

Central Nervous System Metastases in Breast Cancer

OPINION STATEMENT

Breast cancer metastasizing to the central nervous system (CNS) encompasses two distinct entities: brain metastases involving the cerebral parenchyma and infiltration of the leptomeningeal space, i.e., leptomeningeal disease. CNS metastases affect 10-15% of patients with hormone receptor-positive-status and nearly one-half of those with HER2-positive and triple-negative breast cancer with distant metastatic disease. Significant clinical morbidity and heterogeneous penetration of the blood-brain barrier by systemic therapies contribute to the poor prognosis associated with brain metastases. Recent advances in radiotherapy, including stereotactic approaches and morbidity-reducing strategies such as the use of memantine and hippocampal avoidance in whole brain radiation, coupled with the development of more effective CNS-penetrant systemic therapies, including small molecules and antibody-drug conjugates, have significantly improved patient outcomes. Consequently, patients with breast cancer CNS metastases have improved survival compared to prior decades, and longitudinal care has become increasingly complex, necessitating a multidisciplinary approach to achieve optimal outcomes for patients.

Return to work in younger patients with brain metastases who survived for 2 years or more

PURPOSE

The study's purpose was to analyze return to work and other long-term outcomes in younger patients with newly diagnosed brain metastases, treated before they reached legal retirement age, i.e. younger than 65 years.

METHODS

We included patients who survived greater than 2 years after their first treatment, regardless of approach (systemic therapy, neurosurgical resection, whole-brain or stereotactic radiotherapy). The primary endpoint was the proportion of patients who worked 2 years after their initial treatment for brain metastases. Outcomes beyond the 2-year cut-off were also abstracted from comprehensive electronic health records, throughout the follow-up period.

RESULTS

Of 455 patients who received active therapy for brain metastases, 62 (14%) survived for > 2 years. Twenty-eight were younger than 65 years. The actuarial median survival was 81 months and the 5-year survival rate 53%. For patients alive after 5 years, the 10-year survival rate was 54%. At diagnosis, 25% of patients (7 of 28) were permanently incapacitated for work/retired. Of the remaining 21 patients, 33% did work 2 years later. However, several of these patients went on to receive disability pension afterwards. Eventually, 19% continued working in the longer run. Younger age, absence of extracranial metastases, presence of a single brain metastasis, and Karnofsky performance status 90-100 were common features of patients who worked after 2 years.

CONCLUSION

Long-term survival was achieved after vastly different therapeutic approaches, regarding both upfront and sequential management. Many patients required three or more lines of brain-directed treatment. Few patients continued working in the longer run.

Expert consensus on the prevention of brain metastases in patients with HER2-positive breast cancer

BACKGROUND

Patients with HER2-positive breast cancer have a significant risk of developing brain metastases (BrM), which have detrimental effects on survival outcomes and quality of life. Although there are several systemic treatment options available that may delay the appearance of BrM and secondary progression of previously treated BrM, there are still substantial unmet needs for this patient population and primary prevention remains elusive.

METHODS

A group of experts created consensus statements, through a modified Delphi process, to bridge the gap between current unmet needs, available evidence, and international guidelines.

RESULTS

The steering committee reviewed all relevant literature and formed research questions to be answered by the subsequent consensus statements. In total, 61 contributors provided feedback on the consensus statements, with 34 statements reaching agreement out of the 55 statements that were voted on altogether. Statements with consensus aimed to define BrM primary and secondary prevention, screening procedures, assessment of symptoms, treatment efficacy, and preventing the occurrence and progression of BrM, while acknowledging the possibilities and limitations in daily clinical practice. Some statements did not reach agreement for a variety of reasons, mostly due to lack of evidence.

CONCLUSIONS

The consensus statements outlined in this publication provide a point of reference for daily clinical practice and can act as recommendations for clinical trial procedures and future guidelines.

Metastatic brain tumors: from development to cutting-edge treatment

Metastatic brain tumors, also called brain metastasis (BM), represent a challenging complication of advanced tumors. Tumors that commonly metastasize to the brain include lung cancer and breast cancer. In recent years, the prognosis for BM patients has improved, and significant advancements have been made in both clinical and preclinical research. This review focuses on BM originating from lung cancer and breast cancer. We briefly overview the history and epidemiology of BM, as well as the current diagnostic and treatment paradigms. Additionally, we summarize multiomics evidence on the mechanisms of tumor occurrence and development in the era of artificial intelligence and discuss the role of the tumor microenvironment. Preclinically, we introduce the establishment of BM models, detailed molecular mechanisms, and cutting-edge treatment methods. BM is primarily treated with a comprehensive approach, including local treatments such as surgery and radiotherapy. For lung cancer, targeted therapy and immunotherapy have shown efficacy, while in breast cancer, monoclonal antibodies, tyrosine kinase inhibitors, and antibody-drug conjugates are effective in BM. Multiomics approaches assist in clinical diagnosis and treatment, revealing the complex mechanisms of BM. Moreover, preclinical agents often need to cross the blood-brain barrier to achieve high intracranial concentrations, including small-molecule inhibitors, nanoparticles, and peptide drugs. Addressing BM is imperative.

Expert recommendations on treatment sequencing and challenging clinical scenarios in human epidermal growth factor receptor 2-positive (HER2-positive) metastatic breast cancer

Human epidermal growth factor receptor 2 (HER2) overexpression and/or ERBB2 gene amplification occurs in approximately 15-20% of breast cancers and is associated with poor prognosis. While the introduction of HER2-targeted therapies has significantly improved survival in patients with HER2-positive metastatic breast cancer, the incidence of brain metastases has increased due to patients living longer. Current recommendations sequence treatments by line of therapy, as well as by the status of brain metastases in patients with HER2-positive breast cancer. However, in the third-line treatment setting and beyond, there is a lack of clarity of the preferred choice of therapy. In clinical practice, clinicians may also encounter challenging scenarios where the optimal therapeutic approach has not been defined by clinical studies, so there is a need for clarity in such situations. Two consensus meetings of expert oncologists (12 from Europe and one from Canada) were convened to discuss these scenarios. We subsequently developed this article to present an overview of current treatment recommendations for HER2-positive metastatic breast cancer and give practical guidance on addressing challenging scenarios in a real-world setting. Based on our clinical experience, we provide a unanimous consensus concerning the treatment of elderly patients as well as those with brain-only metastases, leptomeningeal disease, oligometastatic disease, central nervous system oligo-progressive disease or ERBB2-mutant disease. We also discuss how to combine HER2-targeted therapy with endocrine therapy in patients with HER2-positive/hormone-receptor-positive disease, considerations for potential discontinuation of HER2-targeted therapy in patients with long-term remission and how to treat patients whose metastatic biopsy no longer confirms their HER2-positive status.

HER2-Positive Breast Cancer Treatment and Resistance

HER2-positive (+) breast cancer is an aggressive disease with poor prognosis, a narrative that changed drastically with the advent and approval of trastuzumab, the first humanized monoclonal antibody targeting HER2. In addition to another monoclonal antibody, more classes of HER2-targeted agents, including tyrosine kinase inhibitors, and antibody-drug conjugates were developed in the years that followed. While these potent therapies have substantially improved the outcome of patients with HER2+ breast cancer, resistance has prevailed as a clinical challenge ever since the arrival of targeted agents. Efforts to develop new treatment regimens to treat/overcome resistance is futile without a primary understanding of the mechanistic underpinnings of resistance. Resistance could be attributed to mechanisms that are either specific to the tumor epithelial cells or those that emerge through changes in the tumor microenvironment. Reactivation of the HER receptor layer due to incomplete blockade of the HER receptor layer or due to alterations in the HER receptors is one of the major mechanisms. In other instances, resistance may occur due to deregulations in key downstream signaling such as the PI3K/AKT or RAS/MEK/ERK pathways or due to the emergence of compensatory pathways such as ER, other RTKs, or metabolic pathways. Potent new targeted agents and approaches to target key actionable drivers of resistance have already been identified, many of which are in early clinical development or under preclinical evaluation. Ongoing and future translational research will continue to uncover additional therapeutic vulnerabilities, as well as new targeted agents and approaches to treat and/or overcome anti-HER2 treatment resistance.

Clinical Implications of Breast Cancer Intrinsic Subtypes

Estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) breast cancers have different genomic architecture and show large-scale gene expression differences consistent with different cellular origins, which is reflected in the luminal (i.e., ER+) versus basal-like (i.e., ER-) molecular class nomenclature. These two major molecular subtypes have distinct epidemiological risk factors and different clinical behaviors. Luminal cancers can be subdivided further based on proliferative activity and ER signaling. Those with a high expression of proliferation-related genes and a low expression of ER-associated genes, called luminal B, have a high risk of early recurrence (i.e., within 5 years), derive significant benefit from adjuvant chemotherapy, and may benefit from adding immunotherapy to chemotherapy. This subset of luminal cancers is identified as the genomic high-risk ER+ cancers by the MammaPrint, Oncotype DX Recurrence Score, EndoPredict, Prosigna, and several other molecular prognostic assays. Luminal A cancers are characterized by low proliferation and high ER-related gene expression. They tend to have excellent prognosis with adjuvant endocrine therapy. Adjuvant chemotherapy may not improve their outcome further. These cancers correspond to the genomic low-risk categories. However, these cancers remain at risk for distant recurrence for extended periods of time, and over 50% of distant recurrences occur after 5 years. Basal-like cancers are uniformly highly proliferative and tend to recur within 3-5 years of diagnosis. In the absence of therapy, basal-like breast cancers have the worst survival, but these also include many highly chemotherapy-sensitive cancers. Basal-like cancers are often treated with preoperative chemotherapy combined with an immune checkpoint inhibitor which results in 60-65% pathologic complete response rates that herald excellent long-term survival. Patients with residual cancer after neoadjuvant therapy can receive additional postoperative chemotherapy that improves their survival. Currently, there is no clinically actionable molecular subclassification for basal-like cancers, although cancers with high androgen receptor (AR)-related gene expression and those with high levels of immune infiltration have better prognosis, but currently their treatment is not different from basal-like cancers in general. A clinically important, minor subset of breast cancers are characterized by frequent HER2 gene amplification and high expression of a few dozen genes, many residing on the HER2 amplicon. This is an important subset because of the highly effective HER2 targeted therapies which are synergistic with endocrine therapy and chemotherapy. The clinical behavior of HER2-enriched cancers is dominated by the underlying ER subtype. ER+/HER2-enriched cancers tend to have more indolent course and lesser chemotherapy sensitivity than their ER counterparts.

Neratinib enhances the efficacy of CDK4/6 inhibitor plus endocrine therapy in HR+/HER2-low breast cancer cell line ZR-75-1 via hsa-miR-23a-5p

HR+/HER2-low breast cancer is a significant subgroup of conventional HR+/HER2-negative breast cancer, and combination of CDK4/6 inhibitor and endocrine therapy is the standard first-line and second-line treatments for advanced HR+/HER2-low breast cancer. Nevertheless, it remains uncertain whether HER2 signaling affects the effectiveness of CDK4/6 inhibitor administered in combination with endocrine therapy for HR+/HER2-low breast cancer and suitable intervention measures. This study revealed poor efficacy for CDK4/6 inhibitor combined with endocrine therapy for HR+/HER2-low breast cancer in vitro and in vivo models. Secondly, suppression of HER2 gene expression in HR+/HER2-low breast cancer cells resulted in significantly improved efficacy for CDK4/6 inhibitor combined with endocrine therapy. Furthermore, the anti-HER inhibitor neratinib was administered to enhance the effectiveness of CDK4/6 inhibitor combined with endocrine therapy in HR+/HER2-low breast cancer by inhibiting the HER2 pathway and lowering HER2 mRNA expression. Strikingly, neratinib reversed the efficacy of CDK4/6 inhibitor and endocrine therapy by reducing HER2 mRNA stability in HR+/HER2-low breast cancer through the interaction of HER2 3'-UTR region with hsa-miR-23a-5p. Even after reducing neratinib dosage to the standard 1/2 dose (20 mg/kg), it remained highly effective and well-tolerated. This study provides a viable and well-tolerated triple combination therapy for clinical HR+/HER2-low breast cancer.

BMScope: A scoping review to chart the evolving clinical study landscape in brain and leptomeningeal metastasis

BACKGROUND

Recent studies have challenged the notion that patients with brain metastasis (BM) or leptomeningeal metastasis (LM) should be excluded from systemic therapy clinical trials. This scoping study summarizes the BM/LM clinical studies published between 2010 and 2023.

METHODS

MEDLINE, CINAHL, CAB Abstracts, PsycINFO, Cochrane Library, HINARI, International Pharmaceutical Abstracts, PubMed, Scopus, Web of Science, and EMBASE electronic databases were searched on June 21, 2021. An updated search was performed on February 21, 2023. Eligible studies investigated a therapeutic intervention in solid tumor patients with BM and/or LM and reported a patient outcome. Extracted study-level data, including study type, publication date, geographical location, number of BM/LM patients in the study, primary tumor type, and type of therapeutic intervention, were collected.

RESULTS

4921 unique studies were eligible for analysis. The key finding is that BM/LM clinical research is expanding globally, both in observational studies and clinical trials. Despite the shift over time toward a higher proportion of systemic therapy trials, the majority still do not include patients with symptomatic disease and lack reporting of BM/LM-specific endpoints. Globally, there has been a trend to more international collaboration in BM/LM clinical studies.

CONCLUSIONS

Our analysis of the BM/LM literature charts the evolving landscape of studies involving this previously excluded population. Given the increasing clinical research activity, particularly involving late-stage systemic therapy trials, it is imperative that due consideration is given to the intracranial activity of new investigational agents. Wider adoption of standardized reporting of intracranial-specific endpoints will facilitate the evaluation of relative intracranial efficacy.

Emerging Therapies for Brain Metastases in NSCLC, Breast Cancer, and Melanoma: A Critical Review

PURPOSE OF REVIEW

Advancements in precision medicine have shifted the treatment paradigm of brain metastases (BM) from non-small cell lung cancer (NSCLC), breast cancer, and melanoma, especially through targeted therapies focused on specific molecular drivers. These novel agents have improved outcomes by overcoming challenges posed by the blood-brain barrier (BBB) and resistance mechanisms, enabling more effective treatment of BM.

RECENT FINDINGS

In NSCLC, therapies such as osimertinib have improved efficacy in treating EGFR-mutant BM, with emerging combinations such as amivantamab and lazertinib offering promising alternatives for patients resistant to frontline therapies. In HER2-positive breast cancer, significant advancements with tucatinib and trastuzumab deruxtecan (T-DXd) have transformed the treatment landscape, achieving improved survival and intracranial control in patients with BM. Similarly, in triple-negative breast cancer (TNBC), novel therapies such as sacituzumab govitecan (SG) and datopotamab deruxtecan (Dato-DXd) offer new hope for managing BM. For melanoma, the combination of immune checkpoint inhibitors such as nivolumab and ipilimumab has proven effective in enhancing survival for patients with BM, both in BRAF-mutant and wild-type cases. Developing targeted therapies penetrating the BBB has revolutionized BM treatment by targeting key drivers like EGFR, ALK, HER2, and BRAF. Despite improved survival, challenges persist, particularly for patients with resistant genetic alterations. Future research should optimise combination therapies, overcome resistance, and refine treatment sequencing. Continued emphasis on personalized, biomarker-driven approaches offers the potential to further improve outcomes, even for complex cases.

Unveiling the future of breast cancer therapy: Cutting-edge antibody-drug conjugate strategies and clinical outcomes

Breast cancer has become the most prevalent malignant tumor worldwide and remains one of the leading causes of cancer-related mortality among women globally. The prognosis for patients with metastatic breast cancer remains poor, necessitating the exploration of novel therapeutic strategies to improve survival rates. In the era of precision medicine, antibody-drug conjugates (ADCs) have gained significant attention as a targeted therapeutic strategy in breast cancer treatment. ADCs, a relatively new treatment for breast cancer, deliver cytotoxic drugs (payloads), directly into the tumor space, turning chemotherapy into a targeted agent, which enables patients to experience significant improvements with manageable drug toxicity. For the treatment of breast cancer, there are three ADCs approved for breast cancer treatment: Trastuzumab emtansine (T-DM1), Trastuzumab Deruxtecan (T-Dxd) targeting HER-2, and Sacituzumab Govitecan (SG) targeting Trop-2. Recent clinical studies have demonstrated that the benefits of ADC therapies extend beyond HER2-positive breast cancer toinclude hormone receptor (HR)-positive breast cancer, triple-negative breast cancer (TNBC), and HER2-low expressing breast cancer. Notably, the DESTINY-Breast series of studies, particularly focusing on T-Dxd, encompass neoadjuvant, adjuvant, and multiple lines of therapy for advanced breast cancer. This marks the advent of a comprehensive ADC era in breast cancer treatment. This review summarizes the efficacy and adverse effects of ADC therapies that have completed or are currently undergoing phase I-III clinical trials. Additionally, it analyzes potential combination strategies to overcome ADC resistance, aiming to provide clinicians with a comprehensive clinical guide to the use of ADCs in breast cancer treatment.

Trastuzumab deruxtecan in HER2-positive advanced breast cancer with or without brain metastases: a phase 3b/4 trial

Trastuzumab deruxtecan (T-DXd) intracranial activity has been observed in small or retrospective patient cohorts with human epidermal growth factor receptor 2-positive (HER2+) advanced/metastatic breast cancer (mBC) and stable or active (untreated/previously treated and progressing) brain metastases (BMs). The phase 3b/4 DESTINY-Breast12 study investigated T-DXd in patients with HER2+ mBC and is, to our knowledge, the largest prospective study of T-DXd in patients with BMs in this setting. Patients (stable/active BMs (n = 263) and no BMs (n = 241)) treated with one or more prior anti-HER2-based regimens received T-DXd (5.4 mg per kg). Primary endpoints were progression-free survival (PFS; BMs cohort) and objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 (non-BMs cohort). Additional endpoints included central nervous system (CNS) PFS, ORR, time to second progression, CNS ORR (BMs cohort), incidence of new symptomatic CNS metastases (non-BMs cohort), time to progression, duration of response, overall survival and safety (both cohorts). No formal hypothesis testing was conducted for this single-arm, open-label study. In the BMs cohort, 12-month PFS was 61.6% (95% confidence interval (CI): 54.9-67.6), and 12-month CNS PFS was 58.9% (95% CI: 51.9-65.3). In the non-BMs cohort, ORR was 62.7% (95% CI: 56.5-68.8). Grade 3 or higher adverse events occurred in 51% (BMs cohort) and 49% (non-BMs cohort) of patients. Investigator-reported interstitial lung disease/pneumonitis occurred in 16% (grade ≥3: 3%) of patients with BMs and 13% (grade ≥3: 1%) of patients without BMs. These data show substantial and durable overall and intracranial activity for T-DXd, supporting its use in previously treated patients with HER2+ mBC irrespective of stable/active baseline BMs. ClinicalTrials.gov identifier: NCT04739761 .

Immunotherapeutic and Targeted Strategies for Managing Brain Metastases from Common Cancer Origins: A State-of-the-Art Review

PURPOSE OF REVIEW

This review examines contemporary strategies for managing brain metastases (BM) from common cancers such as lung, breast, and melanoma. We evaluate the efficacy and applicability of targeted therapies and immunotherapies, exploring their potential to cross the blood-brain barrier and improve patient outcomes.

RECENT FINDINGS

Recent studies have shown that tyrosine kinase inhibitors, immune checkpoint inhibitors, and ADCs effectively treat BM. These treatments can overcome the challenges posed by the blood-brain barrier and improve therapeutic outcomes. ADCs are promising because they can deliver cytotoxic agents directly to tumor cells, which reduces systemic toxicity and increases drug delivery efficiency to the brain. Personalized medicine is becoming increasingly significant in treatment decisions, with biomarkers playing an essential role. Advances in molecular genetics and drug development have led to more refined treatments, emphasizing the precision medicine framework. The management of BM is evolving, driven by drug efficacy, resistance mechanisms, and the need for personalized medicine. Integrating ADCs into treatment regimens represents a significant advancement in targeting metastatic brain tumors. Despite these advances, BM management still presents considerable challenges, requiring ongoing research and multi-institutional trials to optimize therapeutic strategies. This review outlines the current state and future directions in treating BM, highlighting the critical need for continued innovation and comprehensive clinical evaluations to improve survival rates and quality of life for affected patients.

Updates in Treatment of HER2-positive Metastatic Breast Cancer

OPINION STATEMENT

The therapeutic landscape for HER2-positive metastatic breast cancer has exploded in the last two decades following the initial advent of trastuzumab, a monoclonal antibody. While the first line treatment has remained a combination of dual HER2 blockade with taxane chemotherapy, we now have several exciting options in the second line and beyond. The introduction of antibody-drug conjugates, in specific trastuzumab deruxtecan, has resulted in the best progression-free survival among patients with this subtype of breast cancer. Given the excellent outcomes of these drugs, clinical trials are now evaluating the role of ADCs in the front-line setting in previously untreated patients. In addition, there are also clinical trials evaluating the role of other targets in patients with HER2-positive cancers, including PI3KCA mutations, PD-L1 and CDK4/6. Given the predilection for brain metastases in this population, there is enthusiasm to identify the optimal combination of effective treatments. Tucatinib, capecitabine, and trastuzumab combination represent one such promising strategy. With the increasing longevity of these patients, important clinical questions include optimal treatment sequencing, the role of de-escalation of treatment in excellent responders, and the associated financial toxicity. Despite the aggressive nature of this subtype of breast cancer, the outcomes continue to improve for these patients with the evolving treatments.

Role of antibody drug conjugates in the treatment of patients with breast cancer brain metastases

Breast cancer remains a leading cause of brain metastases (BM), which carry a poor prognosis. The current approach to managing BMs in breast cancer patients involves a combination of local therapies (surgery, radiotherapy) and systemic treatments. Developing newer antibody-drug conjugates (ADCs) has sparked a revolution in metastatic breast cancer (MBC) care. ADCs such as ado-trastuzumab emtansine, trastuzumab deruxtecan, and sacituzumab govitecan have demonstrated significant improvement in patient outcomes and are standard of care in the treatment of MBC. Most of the ADC registration studies included patients with stable BMs but excluded individuals with active BM, making intracranial (IC) response assessment a challenge. Promising data has recently emerged, suggesting relevant IC activity for certain ADCs and ongoing studies in patients with active BM that will expand our knowledge. This review aims to summarize the effectiveness of approved ADCs as well as promising new ADCs in development for breast cancer with BM.

Neratinib and ado-trastuzumab emtansine for pretreated and untreated human epidermal growth factor receptor 2 (HER2)-positive breast cancer brain metastases: Translational Breast Cancer Research Consortium trial 022

BACKGROUND

Treatment options for human epidermal growth factor receptor 2 (HER2)-positive breast cancer brain metastases (BCBMs) remain limited. We previously reported central nervous system (CNS) activity for neratinib and neratinib-capecitabine. Preclinical data suggest that neratinib may overcome resistance to ado-trastuzumab emtansine (T-DM1) when given in combination. In Translational Breast Cancer Research Consortium (TBCRC) 022's cohort 4, we examined the efficacy of neratinib plus T-DM1 in patients with HER2-positive BCBM.

PATIENTS AND METHODS

In this multicenter, phase II study, patients with measurable HER2-positive BCBM received neratinib 160 mg daily plus T-DM1 3.6 mg/kg intravenously every 21 days in three parallel-enrolling cohorts [cohort 4A-previously untreated BCBM, cohorts 4B and 4C-BCBM progressing after local CNS-directed therapy without (4B) and with (4C) prior exposure to T-DM1]. Cycle 1 diarrheal prophylaxis was required. The primary endpoint was the Response Assessment in Neuro-Oncology-Brain Metastases (RANO-BM) by cohort. The overall survival (OS) and toxicity were also assessed.

RESULTS

Between 2018 and 2021, 6, 17, and 21 patients enrolled in cohorts 4A, 4B, and 4C. Enrollment was stopped prematurely for slow accrual. The CNS objective response rate in cohorts 4A, 4B, and 4C was 33.3% [95% confidence interval (CI) 4.3% to 77.7%], 35.3% (95% CI 14.2% to 61.7%), and 28.6% (95% CI 11.3% to 52.2%), respectively; 38.1%-50% experienced stable disease for ≥6 months or response. Diarrhea was the most common grade 3 toxicity (22.7%). The median OS was 30.2 [cohort 4A; 95% CI 21.9-not reached (NR)], 23.3 (cohort 4B; 95% CI 17.6-NR), and 20.9 (cohort 4C; 95% CI 14.9-NR) months.

CONCLUSIONS

We observed intracranial activity for neratinib plus T-DM1, including those with prior T-DM1 exposure, suggesting synergistic effects with neratinib. Our data provide additional evidence for neratinib-based combinations in patients with HER2-positive BCBM, even those who are heavily pretreated.

Modeling the management of patients with human epidermal growth factor receptor 2-positive breast cancer with liquid biopsy: the future of precision medicine

PURPOSE OF REVIEW

In the evolving landscape of human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) management, liquid biopsy offers unprecedented opportunities for guiding clinical decisions. Here, we review the most recent findings on liquid biopsy applications in HER2-positive BC and its potential role in addressing challenges specific to this BC subtype.

RECENT FINDINGS

Recent studies have highlighted the significance of liquid biopsy analytes, primarily circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), in stratifying patients' prognosis, predicting treatment response, and monitoring tumor evolution in both early and advanced stages of BC. Liquid biopsy holds promise in studying minimal residual disease to detect and potentially treat disease recurrence before it manifests clinically. Additionally, liquid biopsy may have significant implication in the management of brain metastasis, a major challenge in HER2-positive BC, and could redefine parameters for determining HER2 positivity. Combining ctDNA and CTCs is crucial for a comprehensive understanding of HER2-positive tumors, as they provide complementary insights.

SUMMARY

Research efforts are needed to address analytical challenges, validate, and broaden the application of liquid biopsy in HER2-positive BC. This effort will ultimately facilitate its integration into clinical practice, optimizing the care of patients with HER2-positive tumors.

Dual HER2 inhibition: mechanisms of synergy, patient selection, and resistance

HER2-targeted therapies for patients with HER2+ breast cancer are rapidly evolving, offering a range of more complex and personalized treatment options. Currently, an array of anti-HER2 monoclonal antibodies, tyrosine kinase inhibitors and antibody-drug conjugates are administered, sometimes alongside chemotherapy or endocrine therapy, both in curative and palliative contexts. However, the heterogeneous nature of HER2+ breast cancer demands a deeper understanding of disease biology and its role in responsiveness to novel HER2-targeted agents, as well as non-HER2-targeted therapies, in order to optimize patient outcomes. In this Review, we revisit the mechanisms of action of HER2-targeted agents, examine the evidence supporting the use of dual HER2 blockade in patients with HER2-amplified tumours, and explore the role of biomarkers in guiding future treatment strategies. We also discuss potential implications for the future treatment of patients with HER2+ breast cancer.

Unraveling the future: Innovative design strategies and emerging challenges in HER2-targeted tyrosine kinase inhibitors for cancer therapy

Human epidermal growth factor receptor 2 (HER2) is a transmembrane receptor-like protein with tyrosine kinase activity that plays a vital role in processes such as cell proliferation, differentiation, and angiogenesis. The degree of malignancy of different cancers, notably breast cancer, is strongly associated with HER2 amplification, overexpression, and mutation. Currently, widely used clinical HER2 tyrosine kinase inhibitors (TKIs), such as lapatinib and neratinib, have several drawbacks, including susceptibility to drug resistance caused by HER2 mutations and adverse effects from insufficient HER2 selectivity. To address these issues, it is essential to create innovative HER2 TKIs with enhanced safety, effectiveness against mutations, and high selectivity. Typically, SPH5030 has advanced to phase I clinical trials for its strong suppression of four HER2 mutations. This review discusses the latest research progress in HER2 TKIs, with a focus on the structural optimization process and structure-activity relationship analysis. In particular, this study highlights promising design strategies to address these challenges, providing insightful information and inspiration for future development in this field.

Pyrotinib plus capecitabine for patients with HER2-positive metastatic breast cancer and brain metastases (PERMEATE trial): overall survival results from a multicenter, single-arm, two-cohort, phase 2 trial

Background

The phase 2 PERMEATE study has shown the antitumor activity and safety of pyrotinib plus capecitabine in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer and brain metastases. In this report, survival results were updated with extended follow-up.

Methods

Between January 29, 2019 and July 10, 2020, adult patients with HER2-positive metastatic breast cancer who had radiotherapy-naïve brain metastases (cohort A, n = 59) or progressive disease after radiotherapy (cohort B, n = 19) were enrolled and received pyrotinib (400 mg once daily) and capecitabine (1000 mg/m2 twice daily on days 1-14 of each 21-day cycle) until disease progression or unacceptable toxicity. Secondary endpoints progression-free survival (PFS) and overall survival (OS) were updated, and post-hoc central nervous system (CNS)-PFS was analyzed. This study is registered with ClinicalTrials.gov (NCT03691051).

Findings

As of February 2, 2023, the median follow-up duration was 30.9 months (interquartile range, 16.1-39.8). Median PFS was 10.9 months (95% confidence interval [CI], 7.6-14.6) in cohort A and 5.7 months (95% CI, 3.4-11.5) in cohort B. Median OS was 35.9 months (95% CI, 24.4-not reached) in cohort A and 30.6 months (95% CI, 12.6-33.3) in cohort B. Median CNS-PFS was 13.6 months (95% CI, 9.0-15.8) in cohort A and 5.7 months (95% CI, 3.4-11.5) in cohort B. Median OS was 34.1 months (95% CI, 21.7-not reached) for 14 patients with intracranial progression only in cohort A who restarted pyrotinib plus capecitabine after local radiotherapy.

Interpretation

These data support further validation in a randomized controlled trial for the assessment of pyrotinib in combination with capecitabine as systemic therapy for patients with HER2-positive breast cancer and brain metastases.

Funding

National Cancer Center Climbing Foundation Key Project of China, Jiangsu Hengrui Pharmaceuticals.

Population Pharmacokinetic Analysis of Tucatinib in Healthy Participants and Patients with Breast Cancer or Colorectal Cancer

BACKGROUND AND OBJECTIVE

Tucatinib is a highly selective, oral, reversible, human epidermal growth factor receptor 2 (HER2)-specific tyrosine kinase inhibitor. Tucatinib is approved at a 300-mg twice-daily dose in adults in combination with trastuzumab and capecitabine for advanced HER2-postitive (HER2+) unresectable or metastatic breast cancer and in combination with trastuzumab for RAS wild-type HER2+ unresectable or metastatic colorectal cancer. This study sought to characterize the pharmacokinetics (PK) and assess sources of PK variability of tucatinib in healthy volunteers and in patients with HER2+ metastatic breast or colorectal cancers.

METHODS

A population pharmacokinetic model was developed based on data from four healthy participant studies and three studies in patients with either HER2+ metastatic breast cancer or metastatic colorectal cancer using a nonlinear mixed-effects modeling approach. Clinically relevant covariates were evaluated to assess their impact on exposure, and overall model performance was evaluated by prediction-corrected visual predictive checks.

RESULTS

A two-compartment pharmacokinetic model with linear elimination and first-order absorption preceded by a lag time adequately described tucatinib pharmacokinetic profiles in 151 healthy participants and 132 patients. Tumor type was identified as a significant covariate affecting tucatinib bioavailability and clearance, resulting in a 1.2-fold and 2.1-fold increase in tucatinib steady-state exposure (area under the concentration-time curve) in HER2+ metastatic colorectal cancer and HER2+ metastatic breast cancer, respectively, compared with healthy participants. No other covariates, including mild renal or hepatic impairment, had an impact on tucatinib pharmacokinetics.

CONCLUSIONS

The impact of statistically significant covariates identified was not considered clinically meaningful. No tucatinib dose adjustments are required based on the covariates tested in the final population pharmacokinetic model.

CLINICAL TRIAL REGISTRATION

NCT03723395, NCT03914755, NCT03826602, NCT03043313, NCT01983501, NCT02025192.

Stereotactic radiosurgery for brain metastases from human epidermal receptor 2 positive breast Cancer: an international, multi-center study

PURPOSE

To report patient outcomes and local tumor control rates in a cohort of patients with biopsy-proven HER-2 positive breast cancer treated with stereotactic radiosurgery (SRS) for brain metastases (BM).

METHODS

This international, retrospective, multicenter study, included 195 female patients with 1706 SRS-treated BM. Radiologic and clinical outcomes after SRS were determined and prognostic factors identified.

RESULTS

At SRS, median patient age was 55 years [interquartile range (IQR) 47.6-62.0], and 156 (80%) patients had KPS ≥ 80. The median tumor volume was 0.1 cm3 (IQR 0.1-0.5) and the median prescription dose was 16 Gy (IQR 16-18). Local tumor control (LTC) rate was 98%, 94%, 93%, 90%, and 88% at six-, 12-, 24-, 36- and 60-months post-SRS, respectively. On multivariate analysis, tumor volume (p = < 0.001) and concurrent pertuzumab (p = 0.02) improved LTC. Overall survival (OS) rates at six-, 12-, 24-, 36-, 48-, and 60-months were 90%, 69%, 46%, 27%, 22%, and 18%, respectively. Concurrent pertuzumab improved OS (p = 0.032). In this patient subgroup, GPA scores ≥ 2.5 (p = 0.038 and p = 0.003) and rare primary tumor histologies (p = 0.01) were associated with increased and decreased OS, respectively. Asymptomatic adverse radiation events (ARE) occurred in 27 (14.0%) and symptomatic ARE in five (2.6%) patients. Invasive lobular carcinoma primary (p = 0.042) and concurrent pertuzumab (p < 0.001) conferred an increased risk for overall but not for symptomatic ARE.

CONCLUSION

SRS affords effective LTC for selected patients with BM from HER-2 positive breast cancer. Concurrent pertuzumab improved LTC and OS but at the same time increased the risk for overall, but not symptomatic, ARE.

Emerging Therapies for the Management of Human Epidermal Growth Factor Receptor 2-/ERBB2-Altered Advanced Biliary Tract Cancers

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

Defining the role of surgery for patients with multiple brain metastases

PURPOSE

To better define the role of surgery, we investigated survival and functional outcomes in patients with multiple brain metastases.

METHODS

Pertinent clinical and radiological data of 131 consecutive patients (156 surgeries) were analyzed retrospectively.

RESULTS

Surgical indications included mass effect (84.6%) and need for tissue acquisition (44.9%, for molecularly informed treatment: 10 patients). Major (i.e. CTCAE grade 3-5) neurological, surgical and medical complication were observed in 6 (3.8%), 12 (7.7%), and 12 (7.7%) surgical cases. Median preoperative and discharge KPS were 80% (IQF: 60-90%). Median overall survival (mOS) was 7.4 months. However, estimated 1 and 2 year overall survival rates were 35.6% and 25.1%, respectively. Survival was dismal (i.e. mOS ≤ 2.5 months) in patients who had no postoperative radio- and systemic therapy, or who incurred major complications. Multivariate analysis with all parameters significantly correlated with survival as univariate parameters revealed female sex, oligometastases, no major new/worsened neurological deficits, and postoperative radio- and systemic therapy as independent positive prognostic parameters. Univariate positive prognostic parameters also included histology (best survival in breast cancer patients) and less than median (0.28 cm3) residual tumor load.

CONCLUSIONS

Surgery is a reasonable therapeutic option in many patients with multiple brain metastases. Operations should primarily aim at reducing mass effect thereby preserving the patients' functional health status which will allow for further local (radiation) and systemic therapy. Surgery for the acquisition of metastatic tissue (more recently for molecularly informed treatment) is another important surgical indication. Cytoreductive surgery may also carry a survival benefit by itself.

Enhanced anti-tumor effects by combination of tucatinib and radiation in HER2-overexpressing human cancer cell lines

BACKGROUND

Tucatinib (TUC), a HER2-directed tyrosine kinase inhibitor, is the first targeted drug demonstrating intracranial efficacy and significantly prolonged survival in metastatic HER2-positive breast cancer (BC) patients with brain metastases. Current treatments for brain metastases often include radiotherapy, but little is known about the effects of combination treatment with TUC. Therefore, we examined the combined effects of irradiation and TUC in human HER2-overexpressing BC, non-small cell lung cancer (NSCLC), and colorectal cancer (CRC) cell lines. For the latter two, a standard therapy successfully targeting HER2 is yet to be established.

METHODS

Nine HER2-overexpressing (BC: BT474, ZR7530, HCC1954; CRC: LS411N, DLD1, COLO201; NSCLC: DV90, NCI-H1781) and three control cell lines (BC: MCF7, HCC38; NSCLC: NCI-H2030) were examined. WST-1 assay (metabolic activity), BrdU ELISA (proliferation), γH2AX assay (DNA double-strand breaks (DSB), Annexin V assay (apoptosis), and clonogenic assay (clonogenicity) were performed after treatment with TUC and/or irradiation (IR). The relevance of the treatment sequence was analyzed exemplarily.

RESULTS

In BC, combinatorial treatment with TUC and IR significantly decreased metabolic activity, cell proliferation, clonogenicity and enhanced apoptotis compared to IR alone, whereby cell line-specific differences occurred. In the PI3KCA-mutated HCC1954 cell line, addition of alpelisib (ALP) further decreased clonogenicity. TUC delayed the repair of IR-induced DNA damage but did not induce DSB itself. Investigation of treatment sequence indicated a benefit of IR before TUC versus IR after TUC. Also in CRC and NSCLC, the combination led to a stronger inhibition of metabolic activity, proliferation, and clonogenic survival (only in NSCLC) than IR alone, whereby about 10-fold higher concentrations of TUC had to be applied than in BC to induce significant changes.

CONCLUSION

Our data indicate that combination of TUC and IR could be more effective than single treatment strategies for BC. Thereby, treatment sequence seems to be an important factor. The lower sensitivity to TUC in NSCLC and particularly in CRC (compared to BC) implicates, that tumor promotion there might be less HER2-related. Combination with inhibitors of other driver mutations may aid in overcoming partial TUC resistance. These findings are of high relevance to improve long-time prognosis especially in brain-metastasized situations given the intracranial activity of TUC.

6th and 7th International consensus guidelines for the management of advanced breast cancer (ABC guidelines 6 and 7)

This manuscript describes the Advanced Breast Cancer (ABC) international consensus guidelines updated at the last two ABC international consensus conferences (ABC 6 in 2021, virtual, and ABC 7 in 2023, in Lisbon, Portugal), organized by the ABC Global Alliance. It provides the main recommendations on how to best manage patients with advanced breast cancer (inoperable locally advanced or metastatic), of all breast cancer subtypes, as well as palliative and supportive care. These guidelines are based on available evidence or on expert opinion when a higher level of evidence is lacking. Each guideline is accompanied by the level of evidence (LoE), grade of recommendation (GoR) and percentage of consensus reached at the consensus conferences. Updated diagnostic and treatment algorithms are also provided. The guidelines represent the best management options for patients living with ABC globally, assuming accessibility to all available therapies. Their adaptation (i.e. resource-stratified guidelines) is often needed in settings where access to care is limited.

"Positioning of tucatinib in the new clinical scenario of HER2-positive metastatic breast cancer: An Italian and Spanish consensus paper"

INTRODUCTION

Advancements in monoclonal antibodies, tyrosine kinase inhibitors, and antibody drug conjugates (ADCs) have notably enhanced outcomes for metastatic HER2-positive breast cancer patients. Despite the expanding treatment options and clinical complexities, determining the optimal sequence of HER2-targeted therapies remains partly uncertain, influenced by various factors.

METHODS

To refine HER2-positive metastatic breast cancer management, particularly regarding tucatinib's position, a Steering Committee of leading oncologists in breast cancer care devised a panel of statements via a Delphi approach, focusing on five key topics: general clinical management, therapeutic approaches for patients with HER2-positive breast cancer and brain metastases, treatment sequence, and tucatinib's safety and efficacy.

RESULTS

A total of 29 statements were deliberated, with strong consensus achieved for most. However, no consensus emerged regarding the management of brain progression alongside stable extracranial disease: 48 % advocated for switching to tucatinib, while 53 % favored a stereotactic brain radiotherapy (SBRT) approach if feasible.

CONCLUSION

The unanimous consensus attained in this Delphi panel, particularly regarding tucatinib's efficacy and safety, underscores oncologists' recognition of its clinical significance based on existing trial data. These findings align closely with current literature, shedding light on areas necessitating further investigation, not thoroughly explored in prior studies. Moreover, the results underscore the scarcity of data on managing brain progression alongside stable extracranial disease, emphasizing the imperative for dedicated research to address these gaps and yield definitive insights.