Systemic Therapy of Central Nervous System Metastases of Breast Cancer

New Frontiers in the Treatment of Patients with HER2+ Cancer and Brain Metastases: Is Radiotherapy Always Useful?

Brain metastases (BM) pose a significant challenge in the management of HER2+ breast cancer since almost 50% of patients with HER2+ breast cancer develop brain tumors. The complex process of brain metastases involves genetic mutations, adaptations and mechanisms to overcome the blood-brain barrier. While radiotherapy is still fundamental in local therapy, its use is associated with cognitive adverse effects and limited long-term control, necessitating the exploration of alternative treatments. Targeted therapies, including tyrosine kinase inhibitors, monoclonal antibodies, and antibody-drug conjugates, offer promising options for HER2+ breast cancer patients with BM. Clinical trials have demonstrated the efficacy of these agents in controlling tumor growth and improving patient outcomes, posing the question of whether radiotherapy is always the unique choice in treating this cancer. Ongoing research into novel anti-HER2 antibodies and innovative combination therapies holds promise for advancing treatment outcomes and enhancing patient care in this clinical scenario. This narrative review provides a comprehensive overview of traditional medical treatments, molecularly targeted therapy and investigational agents in the management of HER2+ breast cancer with BM, highlighting the evolving landscape and potential future directions in treatment strategies to improve patient survival and quality of life.

Overcoming brain-derived therapeutic resistance in HER2+ breast cancer brain metastasis

Brain metastasis of HER2+ breast cancer occurs in about 50% of all women with metastatic HER2+ breast cancer and confers poor prognosis for patients. Despite effective HER2-targeted treatments of peripheral HER2+ breast cancer with Trastuzumab +/-HER2 inhibitors, limited brain permeability renders these treatments inefficient for HER2+ breast cancer brain metastasis (BCBM). The scarcity of suitable patient-derived in-vivo models for HER2+ BCBM has compromised the study of molecular mechanisms that promote growth and therapeutic resistance in brain metastasis. We have generated and characterized new HER2+ BCBM cells (BCBM94) isolated from a patient HER2+ brain metastasis. Repeated hematogenic xenografting of BCBM94 consistently generated BCBM in mice. The clinically used receptor tyrosine kinase inhibitor (RTKi) Lapatinib blocked phosphorylation of all ErbB1-4 receptors and induced the intrinsic apoptosis pathway in BCBM94. Neuregulin-1 (NRG1), a ligand for ErbB3 and ErbB4 that is abundantly expressed in the brain, was able to rescue Lapatinib-induced apoptosis and clonogenic ability in BCBM94 and in HER2+ BT474. ErbB3 was essential to mediate the NRG1-induced survival pathway that involved PI3K-AKT signalling and the phosphorylation of BAD at serine 136 to prevent apoptosis. High throughput RTKi screening identified the brain penetrable Poziotinib as highly potent compound to reduce cell viability in HER2+ BCBM in the presence of NRG1. Successful in-vivo ablation of BCBM94- and BT474-derived HER2+ brain tumors was achieved upon two weeks of treatment with Poziotinib. MRI revealed BCBM remission upon poziotinib, but not with Lapatinib treatment. In conclusion, we have established a new patient-derived HER2+ BCBM in-vivo model and identified Poziotinib as highly efficacious RTKi with excellent brain penetrability that abrogated HER2+ BCBM brain tumors in our mouse models.

Genomic profiling and pre-clinical modelling of breast cancer leptomeningeal metastasis reveals acquisition of a lobular-like phenotype

Breast cancer leptomeningeal metastasis (BCLM), where tumour cells grow along the lining of the brain and spinal cord, is a devastating development for patients. Investigating this metastatic site is hampered by difficulty in accessing tumour material. Here, we utilise cerebrospinal fluid (CSF) cell-free DNA (cfDNA) and CSF disseminated tumour cells (DTCs) to explore the clonal evolution of BCLM and heterogeneity between leptomeningeal and extracranial metastatic sites. Somatic alterations with potential therapeutic actionability were detected in 81% (17/21) of BCLM cases, with 19% detectable in CSF cfDNA only. BCLM was enriched in genomic aberrations in adherens junction and cytoskeletal genes, revealing a lobular-like breast cancer phenotype. CSF DTCs were cultured in 3D to establish BCLM patient-derived organoids, and used for the successful generation of BCLM in vivo models. These data reveal that BCLM possess a unique genomic aberration profile and highlight potential cellular dependencies in this hard-to-treat form of metastatic disease.

Neratinib for HER2-positive breast cancer with an overlooked option

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

CAR T-cells to treat brain tumors

Tremendous success using CAR T therapy in hematological malignancies has garnered significant interest in developing such treatments for solid tumors, including brain tumors. This success, however, has yet to be mirrored in solid organ neoplasms. CAR T function has shown limited efficacy against brain tumors due to several factors including the immunosuppressive tumor microenvironment, blood-brain barrier, and tumor-antigen heterogeneity. Despite these considerations, CAR T-cell therapy has the potential to be implemented as a treatment modality for brain tumors. Here, we review adult and pediatric brain tumors, including glioblastoma, diffuse midline gliomas, and medulloblastomas that continue to portend a grim prognosis. We describe insights gained from different preclinical models using CAR T therapy against various brain tumors and results gathered from ongoing clinical trials. Furthermore, we outline the challenges limiting CAR T therapy success against brain tumors and summarize advancements made to overcome these obstacles.

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

Importance

It is estimated that up to 50% of patients with ERBB2 (HER2)-positive metastatic breast cancer (MBC) will develop brain metastases (BMs), which is associated with poor prognosis. Previous reports of the HER2CLIMB trial have demonstrated that tucatinib in combination with trastuzumab and capecitabine provides survival and intracranial benefits for patients with ERBB2-positive MBC and BMs.

Objective

To describe overall survival (OS) and intracranial outcomes from tucatinib in combination with trastuzumab and capecitabine in patients with ERBB2-positive MBC and BMs with an additional 15.6 months of follow-up.

Design, Setting, and Participants

HER2CLIMB is an international, multicenter, randomized, double-blind, placebo-controlled clinical trial evaluating tucatinib in combination with trastuzumab and capecitabine. The 612 patients, including those with active or stable BMs, had ERBB2-positive MBC previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine. The study was conducted from February 23, 2016, to May 3, 2019. Data from February 23, 2016, to February 8, 2021, were analyzed.

Interventions

Patients were randomized 2:1 to receive tucatinib (300 mg orally twice daily) or placebo (orally twice daily), both in combination with trastuzumab (6 mg/kg intravenously or subcutaneously every 3 weeks with an initial loading dose of 8 mg/kg) and capecitabine (1000 mg/m2 orally twice daily on days 1-14 of each 3-week cycle).

Main Outcomes and Measures

Evaluations in this exploratory subgroup analysis included OS and intracranial progression-free survival (CNS-PFS) in patients with BMs, confirmed intracranial objective response rate (ORR-IC) and duration of intracranial response (DOR-IC) in patients with measurable intracranial disease at baseline, and new brain lesion-free survival in all patients. Only OS was prespecified before the primary database lock.

Results

At baseline, 291 of 612 patients (47.5%) had BMs. Median age was 52 years (range, 22-75 years), and 289 (99.3%) were women. At median follow-up of 29.6 months (range, 0.1-52.9 months), median OS was 9.1 months longer in the tucatinib-combination group (21.6 months; 95% CI, 18.1-28.5) vs the placebo-combination group (12.5 months; 95% CI, 11.2-16.9). The tucatinib-combination group showed greater clinical benefit in CNS-PFS and ORR-IC compared with the placebo-combination group. The DOR-IC was 8.6 months (95% CI, 5.5-10.3 months) in the tucatinib-combination group and 3.0 months (95% CI, 3.0-10.3 months) in the placebo-combination group. Risk of developing new brain lesions as the site of first progression or death was reduced by 45.1% in the tucatinib-combination group vs the placebo-combination group (hazard ratio, 0.55 [95% CI, 0.36-0.85]).

Conclusions and Relevance

This subgroup analysis found that tucatinib in combination with trastuzumab and capecitabine improved OS while reducing the risk of developing new brain lesions, further supporting the importance of this treatment option for patients with ERBB2-positive MBC, including those with BMs.

Trial Registration

ClinicalTrials.gov Identifier: NCT02614794.

Brain metastasis as the first and only metastatic relapse site portends worse survival in patients with advanced HER2 + breast cancer

PURPOSE

Current systemic therapy guidelines for patients with HER2 + breast cancer brain metastases (BCBrM) diverge based on the status of extracranial disease (ECD). An in-depth understanding of the impact of ECD on outcomes in HER2 + BCBrM has never been performed. Our study explores the implications of ECD status on intracranial progression-free survival (iPFS) and overall survival (OS) after first incidence of HER2 + BCBrM and radiation.

METHODS

A retrospective analysis was performed of 151 patients diagnosed with initial HER2 + BCBrM who received radiation therapy to the central nervous system (CNS) at Duke between 2008 and 2021. The primary endpoint was iPFS defined as the time from first CNS radiation treatment to intracranial progression or death. OS was defined as the time from first CNS radiation or first metastatic disease to death. Systemic staging scans within 30 days of initial BCBrM defined ECD status as progressive, stable/responding or none (isolated brain relapse).

RESULTS

In this cohort, > 70% of patients had controlled ECD with either isolated brain relapse (27%) or stable/responding ECD (44%). OS from initial metastatic disease to death was markedly worse for patients with isolated intracranial relapse (median = 28.4 m) compared to those with progressive or stable/responding ECD (48.8 m and 71.5 m, respectively, p = 0.0028). OS from first CNS radiation to death was significantly worse for patients with progressive ECD (16.9 m) versus stable/responding (36.6 m) or isolated intracranial relapse (28.4 m, p = 0.007). iPFS did not differ statistically based on ECD status. Receipt of systemic therapy after first BCBrM significantly improved iPFS (HR 0.45, 95% CI: 0.25-0.81, p = 0.008) and OS (HR: 0.43 (95% CI: 0.23-0.81); p = 0.001).

CONCLUSION

OS in patients with HER2 + isolated BCBrM was inferior to those with concurrent progressive or stable/responding ECD. Studies investigating initiation of brain-penetrable HER2-targeted therapies earlier in the disease course of isolated HER2 + intracranial relapse patients are warranted.

Fatty acid synthase: A druggable driver of breast cancer brain metastasis

INTRODUCTION

Brain metastasis (BrM) is a key contributor to morbidity and mortality in breast cancer patients, especially among high-risk epidermal growth factor receptor 2-positive (HER2+) and triple-negative/basal-like molecular subtypes. Optimal management of BrM is focused on characterizing a "BrM dependency map" to prioritize targetable therapeutic vulnerabilities.

AREAS COVERED

We review recent studies addressing the targeting of BrM in the lipid-deprived brain environment, which selects for brain-tropic breast cancer cells capable of cell-autonomously generating fatty acids by upregulating de novo lipogenesis via fatty acid synthase (FASN). Disruption of FASN activity impairs breast cancer growth in the brain, but not extracranially, and mapping of the molecular causes of organ-specific patterns of metastasis has uncovered an enrichment of lipid metabolism signatures in brain metastasizing cells. Targeting SREBP1-the master regulator of lipogenic gene transcription-curtails the ability of breast cancer cells to survive in the brain microenvironment.

EXPERT OPINION

Targeting FASN represents a new therapeutic opportunity for patients with breast cancer and BrM. Delivery of brain-permeable FASN inhibitors and identifying strategies to target metabolic plasticity that might compensate for impaired brain FASN activity are two potential roadblocks that may hinder FASN-centered strategies against BrM.

Management of HER2-Positive Breast Cancer for a Young Patient with Visceral Crisis—The Adjuvant Role of Lifestyle Changes

The safety profile and effectiveness of existing anti-HER2-targeted therapies have not been evaluated in patients with breast cancer and visceral crisis. We report the case of a 26-year-old woman who was diagnosed with advanced HER2-positive breast cancer and initially treated with curative intent therapy in a neoadjuvant setting, using Trastuzumab and Pertuzumab in combination with Docetaxel; her cancer recurred two years later, with liver metastases and pulmonary lymphangitic carcinomatosis, causing visceral crisis. Furthermore, the patient’s clinical status worsened when she developed respiratory failure, hepatomegaly and a severe hepatocytolysis. Since the patient was free of disease more than six months, we started with Paclitaxel half dose because of the hepatic dysfunction, and we gradually reintroduced Trastuzumab and then Pertuzumab. In the meantime, the patient changed her lifestyle by increasing her consumption of fresh fruits and vegetables and fiber and reducing her intake of processed meat, dairy and sugar. As a result, the patient showed a significant improvement in her respiratory symptoms and liver tests in less than two months. Imaging reevaluation showed partial remission of liver metastases and pulmonary lymphangitic carcinomatosis. She underwent seven months of dual anti-HER2 blockade before relapsing cerebrally. Our results suggest that the sequential combination therapy with Trastuzumab, Pertuzumab and Paclitaxel presented in this study, associated with a healthy lifestyle, may be a good management for recurrent HER2-positive breast cancer with pulmonary visceral crisis and severe liver dysfunction.

Intracranial Response Rate in Patients with Breast Cancer Brain Metastases after Systemic Therapy

Simple Summary

For many years, patients with breast cancer and brain metastases were excluded from participation in clinical trials. It was believed that anticancer drugs could not cross the blood–brain barrier. However, recent evidence strongly suggests that some drugs can act against brain metastases, with the greatest intracranial response rate reported in the case of capecitabine, neratinib plus capecitabine, trastuzumab deruxtecan and tucatinib plus trastuzumab and capecitabine. In this article, we discuss the achievements in systemic therapy of breast cancer patients with brain metastases. We stress on the newest clinical trial results which indicate tremendous progress in HER2-positive breast cancer. On the other hand, in patients with triple-negative breast cancer or hormone-receptor-positive brain metastases, much fewer compounds were discovered. Based on the presented results, patients with active brain metastases should be routinely included in clinical trials with novel agents.

Abstract

Brain metastases are detected in 5% of patients with breast cancer at diagnosis. The rate of brain metastases is higher in HER2-positive and triple-negative breast cancer patients (TNBC). In patients with metastatic breast cancer, the risk of brain metastases is much higher, with up to 50% of the patients having two aggressive biological breast cancer subtypes. The prognosis for such patients is poor. Until recently, little was known about the response to systemic therapy in brain metastases. The number of trials dedicated to breast cancer with brain metastases was scarce. Our review summarizes the current knowledge on this topic including very significant results of clinical trials which have been presented very recently. We focus on the intracranial response rate of modern drugs, including new antibody–drug conjugates, HER2- targeted tyrosine kinase inhibitors and other targeted therapies. We highlight the most effective and promising drugs. On the other hand, we also suggest that further efforts are needed to improve the prognosis, especially patients with TNBC and brain metastases. The information contained in this article can help oncologists make treatment-related decisions.

Mapping molecular subtype specific alterations in breast cancer brain metastases identifies clinically relevant vulnerabilities

The molecular events and transcriptional plasticity driving brain metastasis in clinically relevant breast tumor subtypes has not been determined. Here we comprehensively dissect genomic, transcriptomic and clinical data in patient-matched longitudinal tumor samples, and unravel distinct transcriptional programs enriched in brain metastasis. We report on subtype specific hub genes and functional processes, central to disease-affected networks in brain metastasis. Importantly, in luminal brain metastases we identify homologous recombination deficiency operative in transcriptomic and genomic data with recurrent breast mutational signatures A, F and K, associated with mismatch repair defects, TP53 mutations and homologous recombination deficiency (HRD) respectively. Utilizing PARP inhibition in patient-derived brain metastatic tumor explants we functionally validate HRD as a key vulnerability. Here, we demonstrate a functionally relevant HRD evident at genomic and transcriptomic levels pointing to genomic instability in breast cancer brain metastasis which is of potential translational significance.

Prognostic factors of brain metastasis and survival among HER2-positive metastatic breast cancer patients: a systematic literature review

BACKGROUND

Patients with breast cancer who overexpress the human epidermal growth factor receptor 2 (HER2) and subsequently develop brain metastasis (BM) typically experience poor quality of life and low survival. We conducted a comprehensive literature review to identify prognostic factors for BM and predictors of survival after developing BM, and the effects of therapies with different mechanisms of action among patients with HER2+ breast cancer (BC).

METHODS

A prespecified search strategy was used to identify research studies investigating BM in patients with HER2+ BC published in English during January 1, 2009-to June 25, 2021. Articles were screened using a two-phase process, and data from selected articles were extracted.

RESULTS

We identified 25 published articles including 4097 patients with HER2+ BC and BM. Prognostic factors associated with shorter time to BM diagnosis after initial BC diagnosis included younger age, hormone receptor negative status, larger tumor size or higher tumor grade, and lack of treatment with anti-HER2 therapy. Factors predictive of longer survival after BM included having fewer brain lesions (< 3 or a single lesion) and receipt of any treatment after BM, including radiosurgery, neurosurgery and/or systemic therapy. Patients receiving combination trastuzumab and lapatinib therapy or trastuzumab and pertuzumab therapy had the longest median survival compared with other therapies assessed in this review.

CONCLUSIONS

More research is needed to better understand risk factors for BM and survival after BM in the context of HER2+ BC, as well as the assessment of new anti-HER2 therapy regimens that may provide additional therapeutic options for BM in these patients.

Neurosurgical resection for locally recurrent brain metastasis

BACKGROUND

In patients with locally recurrent brain metastases (LRBMs), the role of (repeat) craniotomy is controversial. This study aimed to analyze long-term oncological outcomes in this heterogeneous population.

METHODS

Craniotomies for LRBM were identified from a tertiary neuro-oncological institution. First, we assessed overall survival (OS) and intracranial control (ICC) stratified by molecular profile, prognostic indices, and multimodality treatment. Second, we compared LRBMs to propensity score-matched patients who underwent craniotomy for newly diagnosed brain metastases (NDBM).

RESULTS

Across 180 patients, median survival after LRBM resection was 13.8 months and varied by molecular profile, with >24 months survival in ALK/EGFR+ lung adenocarcinoma and HER2+ breast cancer. Furthermore, 102 patients (56.7%) experienced intracranial recurrence; median time to recurrence was 5.6 months. Compared to NDBMs (n = 898), LRBM patients were younger, more likely to harbor a targetable mutation and less likely to receive adjuvant radiation (p < 0.05). After 1:3 propensity matching stratified by molecular profile, LRBM patients generally experienced shorter OS (hazard ratio 1.67 and 1.36 for patients with or without a mutation, p < 0.05) but similar ICC (hazard ratio 1.11 in both groups, p > 0.20) compared to NDBM patients with similar baseline. Results across specific molecular subgroups suggested comparable effect directions of varying sizes.

CONCLUSIONS

In our data, patients with LRBMs undergoing craniotomy comprised a subgroup of brain metastasis patients with relatively favorable clinical characteristics and good survival outcomes. Recurrent status predicted shorter OS but did not impact ICC. Craniotomy could be considered in selected, prognostically favorable patients.

Treating Advanced Unresectable or Metastatic HER2-Positive Breast Cancer: A Spotlight on Tucatinib

The management of HER2 positive breast cancer has been transformed by the development of targeted therapies. Dual blockade with the monoclonal antibodies, trastuzumab and pertuzumab, added to first-line taxane chemotherapy and second-line therapy with the antibody-drug conjugate, T-DM1, are internationally agreed standards of care for advanced HER2 positive breast cancer, where available. However, until recently, options for patients for third-line therapy and beyond were of modest efficacy or limited by toxicity. In 2019, the results of trials of two exciting new agents for this space were presented. A third-generation HER2 tyrosine kinase inhibitor, tucatinib, combines the efficacy of the second-generation drug, neratinib, with a more manageable toxicity profile and has become a new standard of care after T-DM1, in combination with capecitabine and trastuzumab. The antibody-drug conjugate, trastuzumab deruxtecan, demonstrated remarkable efficacy in heavily pre-treated patients and received accelerated approval in the United States, whilst confirmatory Phase 3 trials are completed. This review will discuss the available data for the post-T-DM1 setting, focusing on tyrosine kinase inhibitors including tucatinib.

Favourable outcome of patients with breast cancer brain metastases treated with dual HER2 blockade of trastuzumab and pertuzumab

Background:

Dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab (TP) is a standard therapy of metastatic and localized HER2-positive breast cancer (BC), but its activity in breast cancer brain metastases (BCBM) is unknown.

Methods:

Patients with HER2-positive BCBM were identified from the Vienna Brain Metastasis Registry and clinical data including patient characteristics, therapies and overall survival (OS) were obtained. Patients were grouped into ‘TP’, ‘other-HER2-targeted therapy’ and ‘no-HER2-targeted therapy’ according to received first-line systemic therapy after diagnosis of BCBM. Radiological re-assessment of intracranial lesions was performed in patients treated with TP as systemic first-line therapy according to RANO response criteria for brain metastases (BM).

Results:

A total of 252 HER2-positive BC patients with BM were available for this analysis. Patients treated with TP as systemic first-line therapy after diagnosis of BM had a significantly longer OS compared with treatment with other-HER2-targeted therapy and no-HER2-targeted therapy (44 versus 17 versus 3 months, p < 0.001; log-rank test). Among radiologically re-assessed patients treated with TP as systemic first-line therapy after diagnosis of BM, 5/14 patients (35.7%) had complete intracranial remission (CR), 8/14 patients (57.1%) partial intracranial remission (PR), 1/14 patients (7.1%) stable intracranial disease (SD) and 0/14 patients (0.0%) progressive intracranial disease (PD) as best response resulting in an intracranial objective response rate (iORR) of 92.9% and an intracranial clinical benefit rate (iCBR) of 100.0%.

Conclusion:

First-line therapy with dual HER2-inhibition of TP after BM diagnosis was associated with the longest median OS times in patients with BCBM.

Tyrosine Kinase Inhibitors in the Combination Therapy of HER2 Positive Breast Cancer

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) accounts for about 20% to 30% of all BC subtypes and is characterized by invasive disease and poor prognosis. With the emergence of anti-HER2 target drugs, HER2-positive BC patient outcomes have changed dramatically. However, treatment failure is mostly due to drug resistance and the special treatment needs of different subgroups. Small molecule tyrosine kinase inhibitors can inhibit multiple targets of the human epidermal growth factor receptor family and activate PI3K/AKT, MAPK, PLC γ, ERK1/2, JAK/STAT, and other pathways affecting the expression of MDM2, mTOR, p27, and other transcription factors. This can help regulate the differentiation, apoptosis, migration, growth, and adhesion of normal cells and reverse drug resistance to a certain extent. These inhibitors can cross the blood-brain barrier and be administered orally. They have a good synergistic effect with effective drugs such as trastuzumab, pertuzumab, t-dm1, and cyclin-dependent kinase 4 and 6 inhibitors. These advantages have resulted in small-molecule tyrosine kinase inhibitors attracting attention. The new small-molecule tyrosine kinase inhibitor was investigated in multi-target anti-HER2 therapy, showed a good effect in preclinical and clinical trials, and to some extent, improved the prognosis of HER2-positive BC patients. Its use could lead to a de-escalation of treatment in some patients, possibly preventing unnecessary procedures along with the associated side effects and costs.

Medical management of brain metastases

The development of brain metastases occurs in 10–20% of all patients with cancer. Brain metastases portend poor survival and contribute to increased cancer mortality and morbidity. Despite multimodal treatment options, which include surgery, radiotherapy, and chemotherapy, 5-year survival remains low. Besides, our current treatment modalities can have significant neurological comorbidities, which result in neurocognitive decline and a decrease in a patient’s quality of life. However, innovations in technology, improved understanding of tumor biology, and new therapeutic options have led to improved patient care. Novel approaches in radiotherapy are minimizing the neurocognitive decline while providing the same therapeutic benefit. In addition, advances in targeted therapies and immune checkpoint inhibitors are redefining the management of lung and melanoma brain metastases. Similar approaches to brain metastases from other primary tumors promise to lead to new and effective therapies. We are beginning to understand the appropriate combination of these novel approaches with our traditional treatment options. As advances in basic and translational science and innovative technologies enter clinical practice, the prognosis of patients with brain metastases will continue to improve.

Blood-Brain Barrier- and Blood-Brain Tumor Barrier-Penetrating Peptide-Derived Targeted Therapeutics for Glioma and Malignant Tumor Brain Metastases

Glioma is the most common malignant tumor of the central nervous system (CNS). Therapeutic efficacy of glioma treatment is greatly limited by the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB), which restrict the passage of most drugs into the brain and tumors. Developing drug delivery systems that cross the BBB and BBTB will aid in the treatment of glioma and malignant brain metastases. One emerging solution is to identify peptide vectors that penetrate the BBB/BBTB. Herein, a novel BBB/BBTB-penetrating peptide was identified from the phage-displayed peptide library. Peptide-drug conjugates (PDCs) were derived and applied to treat glioma and breast cancer brain metastases. Antitumor activity was achieved in both tumor models with synergistic effects when combined with the currently used chemotherapy drug temozolomide. The peptide reported herein can serve as a universal vector for shuttling compounds across the BBB; therefore, it may have wide applications for treating brain tumors and other CNS diseases.

Real-world data on T-DM1 efficacy - results of a single-center retrospective study of HER2-positive breast cancer patients

T-DM1 is an antibody drug conjugate that combines trastuzumab with emtansine via a stable thioether linker. In two phase III clinical trials, EMILIA and TH3RESA, T-DM1 was shown to be effective in HER2-positive metastatic breast cancer patients who had progressed to taxanes and trastuzumab. We have performed a real-world study to complement the findings of the clinical trials. From 2012 to 2016, 15 patients with HER2-positive breast cancer who had progressed to prior treatment received T-DM1 at our center. We have retrospectively analyzed outcomes in these patients and compared our findings with those of the two clinical trials. Progression-free survival (PFS) was 10 months compared with the 9.6 months of the EMILIA trial and the 6.2 months of the TH3RESA trial, overall survival was 34 months compared with the 29.9 months of the EMILIA trial and the 22.7 months of the TH3RESA trial. PFS was ≥12 months in five patients, three of whom attained a PFS of ≥23 months. Among five patients with metastases of the central nervous system, PFS was six months, OS was not reached, and the objective response rate was 80%. Our findings are in line with those of the EMILIA study and slightly superior to those of the TH3RESA study. In our series of patients, T-DM1 has demonstrated efficacy in the treatment of HER2-positive metastatic breast cancer. Our real-world data thus confirm and support the findings of the two major phase III trials and indicate the usefulness of T-DM1 in routine clinical practice.