Trastuzumab deruxtecan in HER2-positive breast cancer with brain metastases: a single-arm, phase 2 trial

Antibody-drug conjugates in metastatic breast cancer: sequencing, combinations and resistances

PURPOSE OF REVIEW

Significant advancements have been made in treating metastatic breast cancer (MBC) with antibody drug conjugates (ADCs). However, due to the development of resistance, patients experience disease progression. The aim of this review is to summarize current evidence on ADCs sequencing strategies and combination approaches in the treatment of MBC.

RECENT FINDINGS

Concerning HER2 positive MBC, current evidence on the optimal ADC-sequencing is primarily about T-DXd, which demonstrated therapeutic value when used post-T-DM1. Conversely, data are limited about the reverse sequence. Similarly, in HER2-negative MBC, recent studies evaluated the sequential use of Sacituzumab Govitecan and T-DXd, which was associated with poor responses. Retrospective analyses have not demonstrated an optimal sequencing strategy for ADCs, and it is still very unclear whether switching the payload or targeting a different antigen may represent the best approach. Combinations may better overcome ADC resistance: interesting data associating immunotherapy or tyrosine kinase inhibitors to ADCs appear promising, albeit data are still immature.

SUMMARY

In MBC, ADCs have expanded treatment options but their sequential use requires further study. Evidence suggests that sequencing ADCs with similar payloads is ineffective, though current data are inconclusive. More research is needed to optimize treatment strategies, including potential combination therapies.

Safety and Efficacy of Trastuzumab Deruxtecan for Metastatic HER2+ and HER2-low Breast Cancer: An Updated Systematic Review and Meta-Analysis of Clinical Trials

OBJECTIVES

Trastuzumab deruxtecan (T-DXd) is a novel antibody-drug conjugate (ADC) promising in treating metastatic HER2+ and HER2-low breast cancer. This updated systematic review and meta-analysis, integrating data from the latest clinical trials, aimed to evaluate the safety and efficacy of T-DXd in this patient population.

METHODS

We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A comprehensive search was conducted across PubMed, Scopus, and Web of Science up to January 2024, focusing on clinical trials that assessed T-DXd's efficacy and safety. Eligibility criteria were based on the PICOS framework, and selected studies underwent rigorous quality assessment and data extraction. The primary outcomes were progression-free survival (PFS), overall survival (OS), and the incidence of adverse events. A random-effects meta-analysis was performed to synthesize the data.

RESULTS

Seven studies involving 2,201 patients met the inclusion criteria. The pooled analysis revealed that T-DXd significantly improved PFS (OR=0.37, 95% CI: 0.27-0.52), indicating a robust efficacy in slowing disease progression. However, treatment was associated with an increased risk of anemia (OR=2.10, 95% CI: 1.36-3.25), fatigue (OR=1.56, 95% CI: 1.21-2.02), nausea (OR=6.42, 95% CI: 4.37-9.42), vomiting (OR=6.21, 95% CI: 3.14-12.25), constipation (OR=2.26, 95% CI: 1.53-3.34), and notably, drug-related interstitial lung disease (OR=10.89, 95% CI: 3.81-31.12). The efficacy outcomes demonstrated significant heterogeneity, which was addressed through sensitivity analysis.

CONCLUSIONS

T-DXd shows significant efficacy in treating metastatic HER2+ and HER2-low breast cancer, offering a valuable therapeutic option for patients with advanced disease. However, the treatment is associated with notable adverse events, including a heightened risk of ILD. These findings underscore the need for careful patient selection, monitoring, and management strategies to mitigate risks. Future research should focus on optimizing treatment protocols and exploring methods to enhance safety profiles.

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.

The efficacy of trastuzumab-deruxtecan for the treatment of patients with advanced HER2-low breast cancer

INTRODUCTION

Until recently, the available human receptor epidermal growth factor 2 (HER2) targeted agents were ineffective for treating patients with HER2-low expressing breast cancer (defined as immunohistochemical expression of 1+ or 2+ without amplification). The development of novel and potent HER2-directed antibody-drug conjugates, affective at treating HER2-low expressing breast cancers, have changed the way we think about HER2-low expression and expanded the treatment options for many patients with advanced disease.

AREAS COVERED

In this review, we summarize the current management of HER2-low breast cancer and commonly encountered challenges such as treatment sequencing and toxicity management.

EXPERT OPINION

trastuzumab deruxtecan (T-DXd) is a treatment option for patients with advanced, HER2-low breast cancer, irrespective of the hormone receptor status. The current optimal place in treatment algorithms is after the first line of chemotherapy, both in HR-positive and triple-negative breast cancer; however, other agents are available in this setting and risks and benefits for each should be considered in shared decision making. Up to 10-15% of patients receiving T-DXd develop interstitial lung disease. Patient and clinician education are key to safely implement T-DXd in clinical practice.

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.

A Phase II Study of Atezolizumab, Pertuzumab, and High-Dose Trastuzumab for Central Nervous System Metastases in Patients with HER2-Positive Breast Cancer

PURPOSE

Patients with HER2-positive breast cancer brain metastases have few effective systemic therapy options. In a prior study, pertuzumab with high-dose trastuzumab demonstrated a high clinical benefit rate (CBR) in the central nervous system (CNS) in patients with brain metastases. The current trial evaluated whether the addition of atezolizumab to this regimen would produce further improvements in CNS response.

PATIENTS AND METHODS

This was a single-arm, multicenter, phase II trial of atezolizumab, pertuzumab, and high-dose trastuzumab for patients with HER2-positive breast cancer brain metastases. Participants received atezolizumab 1,200 mg i.v. every 3 weeks, pertuzumab (loading dosage 840 mg i.v., then 420 mg i.v. every 3 weeks), and high-dose trastuzumab (6 mg/kg i.v. weekly for 24 weeks, then 6 mg/kg i.v. every 3 weeks). The primary endpoint was CNS overall response rate per Response Assessment in Neuro-Oncology Brain Metastases criteria. Key secondary endpoints included CBR, overall survival, and safety and tolerability of the combination.

RESULTS

Among 19 enrolled participants, two had a confirmed intracranial partial response for a CNS overall response rate of 10.5% (90% confidence interval, 1.9%-29.6%). The study did not meet the prespecified efficacy threshold and was terminated early. The CBR was 42.1% at 18 weeks and 31.6% at 24 weeks. Seven patients (36.8%) required a dose delay or hold, and the most frequent any-grade adverse events were diarrhea (26.3%) and fatigue (26.3%).

CONCLUSIONS

The addition of atezolizumab to pertuzumab plus high-dose trastuzumab does not result in improved CNS responses in patients with HER2-positive breast cancer brain metastases.

Targeting HER2 in breast cancer with brain metastases: a pharmacological point of view with special focus on the permeability of blood-brain barrier to targeted treatments

Understanding the capability of a drug to penetrate the blood-brain barrier (BBB) is an unmet medical need in patients with positive human epidermal growth factor receptor 2 (HER2 positive) and brain metastases. The National Comprehensive Cancer Network (NCCN) guidelines recommend the use of tyrosine kinase inhibitors (TKIs) lapatinib, neratinib, and tucatinib in co-administration with monoclonal antibodies or chemotherapy drugs and the antibody-drug conjugates (ADCs) trastuzumab-deruxtecan and trastuzumab-emtansine. Predicting the BBB permeability of these therapeutic agents is a pharmacological challenge due to the various factors involved in the barrier functions. In this review article, we discuss about the molecular and cellular features of the barriers located in the central nervous system and the pharmacological parameters found to be important in predicting BBB permeability in human normal brain and in the presence of brain metastases. Finally, we reported the clinical outcomes and intracranial response of patients with HER2-positive breast cancer with brain metastases treated with targeted TKIs and ADCs.

Invasive disease-free survival and brain metastasis rates in patients treated with neoadjuvant chemotherapy with trastuzumab and pertuzumab

Patients with HER2(+) early breast cancer (EBC) receiving neoadjuvant systemic therapy (NAST) have poorer outcomes if they have residual disease (RD). We analyzed IDFS and brain metastasis (BM) rates in patients with HER2(+) EBC treated with NAST and report the outcomes of patients with HER2(-) RD. Patients with HER2(+) EBC who received NAST between 1 Jan 2019 and 31 Jan 2022 were reviewed. IDFS was defined as the time from surgery until first occurrence of invasive breast cancer recurrence, distant recurrence, or death from any cause. The total cohort was 594 patients. pCR (ypT0/isN0) was achieved in 325(55%) and RD was seen in 269(45%) patients. In 269 patients with RD, 45(17%) did not have HER2 retesting and were excluded. In the remaining 224 patients, 143(64%) were HER2(+) and 81(36%) were HER2(-). With a median follow up of 24 months, 8 patients developed BM at initial recurrence, 4/325(1.2%) with pCR and 4/143(2.8%) with HER2(+) RD. IDFS events occurred in 22/594(3%) patients; 14/269(5%) in RD and 8/325(2%) in pCR (p = 0.04). There was no difference in IDFS between 9/143(6%) patients with HER2(+) RD or 5/81(6%) with HER2(-) RD (p = 0.10). Patients with RD had higher IDFS events than those with pCR. In those with RD, 36% lost HER2(+) status; IDFS events appeared similar in those with HER2(+) RD versus those with HER2(-) RD. The BM events seen in those with RD and pCR highlights the need for more effective therapy in NAST and adjuvant setting to minimize BM risk.

Antibody-Drug Conjugates for the Treatment of Non-Small Cell Lung Cancer with Central Nervous System Metastases

Antibody-drug conjugates (ADCs) represent an emerging class of targeted anticancer agents that have demonstrated impressive efficacy in numerous cancer types. In non-small cell lung cancer (NSCLC), ADCs have become a component of the treatment armamentarium for a subset of patients with metastatic disease. Emerging data suggest that some ADCs exhibit impressive activity even in central nervous system (CNS) metastases, a disease site that is difficult to treat and associated with poor prognosis. Herein, we describe and summarize the existing evidence surrounding ADCs in NSCLC with a focus on CNS activity.

Safety and efficacy of antibody-drug conjugates plus immunotherapy in solid tumours: A systematic review and meta-analysis

BACKGROUND

Combining antibody-drug conjugate (ADCs) with immune checkpoint inhibitors (ICIs) is emerging as a promising treatment option to increase efficacy outcomes. However, concerns arise regarding the safety of these combinations, as some toxicities may overlap. Currently, there is still limited information about the safety profiles of this strategy.

METHODS

A systematic review and meta-analysis was conducted to identify clinical trials investigating FDA-approved ADCs in combination with ICI drugs in the metastatic setting across all solid tumors. The primary endpoint of this study was the percentage of adverse events (AEs) of any grade and grade ≥ 3. Secondary endpoints include the percentage of patients with AEs leading to death, treatment discontinuation, proportion of complete responses (CR) and overall response rate (ORR). A parallel search was conducted to quantify the safety profile of ADCs and ICIs in monotherapy. Random effects models were used to estimate pooled outcomes.

RESULTS

Sixteen trials involving 1,133 patients treated with ADC plus ICI met the inclusion criteria with six different ADCs evaluated. Overall, 55.3 % of patients developed grade ≥ 3 AEs, 30.0 % of patients had treatment discontinuation, and 3.0 % experienced AEs leading to death. When compared to trials evaluating ADC or ICI as monotherapy, the combination results in similar rates of the most common AEs. However, it increases the risk of specific toxicities, such as ILD/pneumonitis (15.0 % with T-DXd plus ICI vs. 11.5 % with T-DXd alone). The pooled ORR was 48.8 % (95 %CI 39.4 % - 58.4 %) and the CR rate was 9.0 % (95 %CI 5.5 - 14.5). PD-L1-positive tumors showed numerically better efficacy outcomes.

CONCLUSIONS

This meta-analysis shows that the safety profile of the ADC plus ICI is comparable to that of ADC monotherapy. However, it increases the risk of certain toxicities of special interest, such as ILD/pneumonitis, highlighting the need for careful monitoring.

Targeted Therapy in Breast Cancer: Advantages and Advancements of Antibody-Drug Conjugates, a Type of Chemo-Biologic Hybrid Drugs

Cancer is a significant health challenge globally, with millions of people affected every year, resulting in high morbidity and mortality. Although other treatment options are available with limitations, chemotherapy, either standalone or combined with other therapeutic procedures, is the most commonly used practice of treating cancer. In chemotherapy, cancer cells/malignant tumors are targeted; however, due to less target specificity, along with malignant cells, normal cells are also affected, which leads to various off-target effects (side effects) that impact the patient quality of life. Out of all the different types of cancers, breast cancer is the most common type of cancer in humans worldwide. Current anticancer drug discovery research aims to develop therapeutics with higher potency and lower toxicity, which is only possible through target-specific therapy. Antibody-drug conjugates (ADCs) are explicitly designed to target malignant tumors and minimize off-target effects by reducing systemic cytotoxicity. Several ADCs have been approved for clinical use and have shown moderate to good efficacy so far. Considering various aspects, chemotherapy and ADCs are useful in treating cancer. However, ADCs provide a more focused and less toxic approach, which is especially helpful in cases where resistance to chemotherapy (drug resistance) occurs and in the type of malignancies in which specific antigens are overexpressed. Ongoing ADC research aims to develop more target-specific cancer treatments. In short, this study presents a concise overview of ADCs specific to breast cancer treatment. This study provides insight into the classifications, mechanisms of action, structural aspects, and clinical trial phases (current status) of these chemo-biologic drugs (ADCs).

Cardiac toxicity of HER-2 targeting antibody-drug conjugates: overview and clinical implications

Antibody-drug conjugates (ADCs) have recently emerged as a promising therapeutic option that combine the specificity of monoclonal antibodies and the cytotoxic effect of chemotherapy. With numerous ADCs approved and on the market, a particular concern of ADCs that target HER-2 has been their cardiac side effects, in view of the crucial role of HER-2 in cardiac development and physiology. While rarely toxic and generally safe, numerous publications have outlined the consistent association of trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) with the development of cardiac toxicity. Despite not being clinically relevant in most cases, cardiac baseline evaluation, monitoring and early detection of cardiac adverse events remain pivotal with HER-2 targeting ADCs. This review aims to summarize and better characterize the complete cardiac toxicity profile of HER-2 ADCs, with the goal of improving clinical understanding of this adverse event, leading to better recognition, monitoring and management.

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.

Durable responses to trastuzumab deruxtecan in patients with leptomeningeal metastases from breast cancer with variable HER2 expression

PURPOSE

Emerging data suggest that trastuzumab deruxtecan (T-DXd) is an active treatment for brain metastases from HER2 + breast cancer. We aimed to characterize the activity of T-DXd in the treatment of leptomeningeal metastases (LM) from a range of HER2-altered cancers.

METHODS

We reviewed neuro-oncology clinic records between July 2020 and December 2023 to identify patients who received T-DXd to treat LM.

RESULTS

Of 18 patients identified, 6 had HER2 + breast cancer, 8 had HER2-low/negative breast cancer, 2 had HER2 + gastroesophageal cancer, and 2 had HER2-mutant non-small cell lung cancer (NSCLC). 10/18 (56%) patients had cytologically confirmed LM by CSF cytology or circulating tumor cell (CTC) capture. A partial response (PR) on MRI using the EORTC/RANO-LM Revised-Scorecard occurred in 4/6 (67%) patients with HER2 + breast LM, 2/8 (25%) patients with HER2-low/negative breast cancer, and 0/4 (0%) patients with HER2 + gastroesophageal cancer or HER2-mutant NSCLC. Median overall survival after initiating T-DXd was 5.8 months. Survival after initiating T-DXd was numerically longer for HER2 + breast cancer patients compared with HER2-low/negative breast and HER2-altered non-breast cancer patients (13.9 months vs. 5.2 months and 4.6 months, respectively). Landmark analysis showed that patients with radiologic LM response to T-DXd by 2.5 months had longer survival than non-responders (14.2 months vs. 2.6 months, HR 0.18, 95% CI 0.05-0.63, p < 0.05), and landmark analyses at 3.5 and 4.5 months after starting T-DXd showed a similar but nonsignificant trend.

CONCLUSION

T-DXd induces LM responses in a subset of patients, and such responses may be associated with prolongation of survival. Prospective trials are needed to clarify the role of T-DXd in treating LM and which patients are most likely to benefit.

Present and Future of Immunotherapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) lacks the expression of estrogen receptors (ERs), human epidermal growth factor receptor 2 (HER2), and progesterone receptors (PRs). TNBC has the poorest prognosis among breast cancer subtypes and is more likely to respond to immunotherapy due to its higher expression of PD-L1 and a greater percentage of tumor-infiltrating lymphocytes. Immunotherapy has revolutionized TNBC treatment, especially with the FDA's approval of pembrolizumab (Keytruda) combined with chemotherapy for advanced cases, opening new avenues for treating this deadly disease. Although immunotherapy can significantly improve patient outcomes in a subset of patients, achieving the desired response rate for all remains an unmet clinical goal. Strategies that enhance responses to immune checkpoint blockade, including combining immunotherapy with chemotherapy, molecularly targeted therapy, or radiotherapy, may improve response rates and clinical outcomes. In this review, we provide a short background on TNBC and immunotherapy and explore the different types of immunotherapy strategies that are currently being evaluated in TNBC. Additionally, we review why combination strategies may be beneficial, provide an overview of the combination strategies, and discuss the novel immunotherapeutic opportunities that may be approved in the near future for TNBC.

A comprehensive review of current treatment modalities for leptomeningeal carcinomatosis in breast cancer

Leptomeningeal carcinomatosis (LC) is a metastatic complication of breast cancer that imparts a very poor prognosis and distressing neurologic symptoms in affected patients. While the incidence of LC has risen with improving survival rates for cancer patients, there remains no established treatment protocol for LC and clinical trial data comparing available therapies is limited. Here, a comprehensive literature search of the pubmed and Cochrane databases was performed. Current treatment modalities and their safety/ efficacy profiles are summarized for LC in breast cancer. Roles for emerging therapies in LC are discussed, including targeted agents, CAR-T, immune checkpoint inhibitors, CDK inhibitors and novel antibody conjugates. A treatment pathway for LC is also proposed to guide clinicians through management of this severe metastatic complication of breast cancer.

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 .

A pooled analysis of trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer with brain metastases

BACKGROUND

This exploratory pooled analysis investigated the efficacy and safety of trastuzumab deruxtecan (T-DXd) versus comparator treatment in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) with brain metastases (BMs) at baseline, categorized according to previous local treatment.

PATIENTS AND METHODS

T-DXd data were pooled from DESTINY-Breast01/-02/-03. Comparator data, from patients receiving physician's choice therapy and trastuzumab emtansine, were pooled from DESTINY-Breast02 and -03, respectively. Baseline BM status was assessed according to US Food and Drug Administration criteria. The endpoints included intracranial objective response rate (ORR; complete or partial response in the brain) per blinded independent central review (BICR) by RECIST version 1.1, time to intracranial response, intracranial duration of response (DoR), central nervous system progression-free survival (CNS-PFS) by BICR, overall survival (OS), and safety.

RESULTS

A total of 148 patients who received T-DXd and 83 patients who received comparator treatment had BMs at baseline. In those treated with T-DXd, the intracranial ORR of patients with treated/stable and untreated/active BMs was 45.2% and 45.5%, respectively. The median (range) time to intracranial response was 2.8 months (1.1-13.9 months) and 1.5 months (1.2-13.7 months) in patients with treated/stable and untreated/active BMs, respectively. For those with treated/stable BMs, the median intracranial DoR was 12.3 [95% confidence interval (CI) 9.1-17.9] months, and for those with untreated/active BMs, it was 17.5 months (95% CI 13.6-31.6 months). The median CNS-PFS and OS were 12.3 months (95% CI 11.1-13.8 months) and not reached (95% CI 22.1 months-not estimable) in those with treated/stable BMs, and 18.5 months (95% CI 13.6-23.3 months) and 30.2 months (95% CI 21.3 months-not estimable) in those with untreated/active BMs, respectively. Drug-related treatment-emergent adverse events grade ≥3 were experienced by 43.2% of patients with BMs and 46.4% without BMs with T-DXd.

CONCLUSIONS

T-DXd demonstrated meaningful intracranial efficacy and clinical benefit in OS, with an acceptable and manageable safety profile in patients with HER2-positive mBC with treated/stable and untreated/active BMs.

Trastuzumab deruxtecan in patients with previously treated HER2-low advanced breast cancer and active brain metastases: the DEBBRAH trial

BACKGROUND

Trastuzumab deruxtecan (T-DXd) is approved for human epidermal growth factor receptor 2 (HER2)-positive and HER2-low advanced breast cancer (ABC). T-DXd has shown encouraging intracranial activity in HER2-positive ABC patients with stable or active brain metastases (BMs); however, its efficacy in patients with HER2-low ABC with BMs is not well established yet.

METHODS

DEBBRAH is a single-arm, five-cohort, phase II study evaluating T-DXd in patients with central nervous system involvement from HER2-positive and HER2-low ABC. Here, we report results from patients with heavily pretreated HER2-low ABC and active BMs, enrolled in cohorts 2 (n = 6, asymptomatic untreated BMs) and 4 (n = 6, progressing BMs after local therapy). Patients received 5.4 mg/kg T-DXd intravenously once every 21 days. The primary endpoint was intracranial objective response rate per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) for both cohorts.

RESULTS

Intracranial objective response rate per RANO-BM was 50.0% [3/6 patients; 95% confidence interval (CI) 11.8% to 88.2%] and 33.3% [2/6 patients; 95% CI 4.3% to 77.7%; P = 0.033 (one-sided)] in cohorts 2 and 4, respectively. All responders had partial responses. Median time to intracranial response was 2.3 months (range, 1.5-4.0 months) and median duration of intracranial response was 7.2 months (range, 2.8-16.8 months). Median progression-free survival per RECIST v.1.1. was 5.4 months (95% CI 4.1-10.0 months). Treatment-emergent adverse events occurred in all patients included (16.7% grade 3). Three patients (25.0%) had grade 1 interstitial lung disease/pneumonitis.

CONCLUSIONS

T-DXd demonstrated promising intracranial activity in pretreated HER2-low ABC patients with active BMs. Further studies are needed to validate these results in larger cohorts. This trial is registered with ClinicalTrials.gov, NCT04420598.

Trastuzumab-Deruxtecan: Redefining HER2 as a Tumor Agnostic Biomarker

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) targeting HER2-positive malignancies across various tumor types. Through its unique composition, T-DXd achieves selective payload delivery, inducing cell death and halting tumor progression. Clinical trials initially investigated T-DXd's efficacy in HER2-positive advanced or metastatic breast, gastric, lung, and colorectal cancers; however, recent results from the DESTINY-PanTumor02 trial further underscore T-DXd's versatility, prompting T-DXd's US FDA approval for HER2-positive (immunohistochemistry [IHC] 3+) solid tumors. Moreover, in addition to T-DXd's efficacy against brain metastasis, T-DXd is showing promising results in HER2-low and HER2-ultra-low metastatic breast cancer, indicating a broader population of patients who may benefit.

Effect of HER2-low status on brain metastasis-free survival and survival after brain metastasis in patients with breast cancer

AIMS AND OBJECTIVES

The discovery of novel human epidermal growth factor receptor 2 (HER2)-directed antibody‒drug conjugates has accelerated the identification of the HER2-low subtype. However, the biological significance of low HER2 expression in breast cancer brain metastasis (BCBM) is unclear.

METHODS

Patients with HER2-negative BC and brain metastasis were retrospectively screened between February 2012 and November 2023. Brain metastasis-free survival (BMFS) and survival after brain metastasis (SABM) were analyzed according to HER2 expression.

RESULTS

A total of 201 female patients, 84 of whom were HER2-low and 117 of whom were HER2-zero, were evaluated. The median BMFS in the entire cohort was 35.6 months (95% CI 29.8-41.4). Although HER2-low patients had numerically longer median BMFS than HER2-zero patients (43.7 m vs. 30.1 m, p = 0.025), multivariate analysis revealed that the difference was not significant (p = 0.167). BMFS between the HER2-low and HER2-zero groups was similar in the hormone receptor (HR)-positive (52.8 m vs. 47.6 m, p = 0.276) and HR-negative (15.3 m vs. 19.7 m, p = 0.930) cohorts. The median SABM in the entire cohort was 6.0 months (95% CI 3.8-8.1). HER2-low and HER2-zero patients had similar median SAMB (5.4 m vs. 6.1 m, p = 0.816). The SABM between the HER2-low and HER2-zero groups was similar in the HR-positive (6.3 m vs. 8.7 m, p = 0.375) and HR-negative (3.3 m vs. 4.2 m, p = 0.783) cohorts.

CONCLUSIONS

Low HER2 expression does not affect BMFS or SAMB in brain metastatic breast cancer patients in this real-world population.

Sacituzumab Govitecan in patients with breast cancer brain metastases and recurrent glioblastoma: a phase 0 window-of-opportunity trial

Sacituzumab Govitecan (SG) is an antibody-drug conjugate that has demonstrated efficacy in patients with TROP-2 expressing epithelial cancers. In a xenograft model of intracranial breast cancer, SG inhibited tumor growth and increased mouse survival. We conducted a prospective window-of-opportunity trial (NCT03995706) at the University of Texas Health Science Center at San Antonio to examine the intra-tumoral concentrations and intracranial activity of SG in patients undergoing craniotomy for breast cancer with brain metastases (BCBM) or recurrent glioblastoma (rGBM). We enrolled 25 patients aged ≥18 years diagnosed with BCBM and rGBM to receive a single intravenous dose of SG at 10 mg/kg given one day before resection and continued on days 1 and 8 of 21-day cycles following recovery. The PFS was 8 months and 2 months for BCBM and rGBM cohorts, respectively. The OS was 35.2 months and 9.5 months, respectively. Grade≥3 AE included neutropenia (28%), hypokalemia (8%), seizure (8%), thromboembolic event (8%), urinary tract infection (8%) and muscle weakness of the lower limb (8%). In post-surgical tissue, the median total SN-38 was 249.8 ng/g for BCBM and 104.5 ng/g for rGBM, thus fulfilling the primary endpoint. Biomarker analysis suggests delivery of payload by direct release at target site and that hypoxic changes do not drive indirect release. Secondary endpoint of OS was 35.2 months for the BCBM cohort and 9.5 months for rGBM. Non-planned exploratory endpoint of ORR was 38% for BCBM and 29%, respectively. Exploratory endpoint of Trop-2 expression was observed in 100% of BCBM and 78% of rGBM tumors. In conclusion, SG was found to be well tolerated with adequate penetration into intracranial tumors and promising preliminary activity within the CNS. Trial Registration: Trial (NCT03995706) enrolled at Clinical Trials.gov as Neuro/Sacituzumab Govitecan/Breast Brain Metastasis/Glioblastoma/Ph 0: https://clinicaltrials.gov/study/NCT03995706?cond=NCT03995706 .

Has the blood-brain barrier finally been busted?

Faith in the blood-brain barrier has been remarkably resilient. This commentary questions its importance in the treatment of brain metastases.

Mechanism insights and therapeutic intervention of tumor metastasis: latest developments and perspectives

Metastasis remains a pivotal characteristic of cancer and is the primary contributor to cancer-associated mortality. Despite its significance, the mechanisms governing metastasis are not fully elucidated. Contemporary findings in the domain of cancer biology have shed light on the molecular aspects of this intricate process. Tumor cells undergoing invasion engage with other cellular entities and proteins en route to their destination. Insights into these engagements have enhanced our comprehension of the principles directing the movement and adaptability of metastatic cells. The tumor microenvironment plays a pivotal role in facilitating the invasion and proliferation of cancer cells by enabling tumor cells to navigate through stromal barriers. Such attributes are influenced by genetic and epigenetic changes occurring in the tumor cells and their surrounding milieu. A profound understanding of the metastatic process's biological mechanisms is indispensable for devising efficacious therapeutic strategies. This review delves into recent developments concerning metastasis-associated genes, important signaling pathways, tumor microenvironment, metabolic processes, peripheral immunity, and mechanical forces and cancer metastasis. In addition, we combine recent advances with a particular emphasis on the prospect of developing effective interventions including the most popular cancer immunotherapies and nanotechnology to combat metastasis. We have also identified the limitations of current research on tumor metastasis, encompassing drug resistance, restricted animal models, inadequate biomarkers and early detection methods, as well as heterogeneity among others. It is anticipated that this comprehensive review will significantly contribute to the advancement of cancer metastasis research.

Trastuzumab-deruxtecan in solid tumors with HER2 alterations: from early phase development to the first agnostic approval of an antibody-drug conjugate

INTRODUCTION

Antibody-drug conjugates (ADCs) represent a revolutionary approach in the systemic treatment for both solid and hematologic tumors. Constituted by an antibody, a cytotoxic payload, and a linker, ADCs aim to selectively deliver cytotoxic agents to tumors while sparing normal tissues. Various ADCs have been tested and approved for multiple solid tumors so far, but if there is one that had a major impact on clinical practice, this is Trastuzumab-deruxtecan (T-DXd). Notably, T-DXd was approved for HER2-positive and HER2-low metastatic breast cancer (MBC), HER2-positive gastric cancer (GC), HER2-mutant non-small cell lung cancer (NSCLC) and HER2 3+ solid tumors. Moreover, it received Breakthrough Therapy Designation for HER2-positive colorectal cancer (CRC).

AREAS COVERED

We review preclinical and clinical data of T-DXd, focusing on early-phase ongoing trials exploring combination therapies to enhance the activity of T-DXd in HER2-expressing solid tumors.

EXPERT OPINION

The clinical use of T-DXd still raises questions about selection of patients, treatment duration, prioritization over other approved ADCs, and management of resistance. Concerns regarding the toxicity of T-DXd remain, particularly with combinations involving potentially toxic drugs. Advancements in biomarker identification and combination therapies offer promising avenues to enhance efficacy and overcome resistance to T-DXd, ultimately improving outcomes for patients with cancer.

The incidence of brain metastases in breast cancer according to molecular subtype and stage: a 10-year single institution analysis

BACKGROUND

Breast cancer (BC) is the second most common etiology of brain metastases (BrM). We aimed to examine the incidence of BrM among all BC patients presenting to a large tertiary cancer centre over one decade.

METHODS

We included all BC patients presenting consecutively between 2009 and 2019 and cross referenced that cohort to a radiotherapy database, identifying patients treated for BrM at any time following their initial presentation. Cumulative incidences (CI) of BrM diagnoses were calculated using death as a competing risk and compared using the Fine-Gray method. Overall survival was estimated using the Kaplan Meier method.

RESULTS

We identified 12,995 unique patients. The CI of BrM in patients who initially presented with Stage 0-4 disease was 2.1%, 3.7%, 9.4%, 10.6%, and 28.7%, respectively at 10 years. For 8,951 patients with available molecular subtype data, 6,470 (72%), 961 (11%), 1,023 (11%), and 497 (6%) had hormone-receptor (HR)-positive/ERBB2-, HR-negative/ERBB2-, HR-positive/ERBB2 + , and HR-negative/ERBB2 + disease, respectively; the CI of BrM in each was 7.6%, 25.3%, 24.1%, and 26.6%, at 10 years following BC diagnosis, respectively. Median overall survival (OS) following BC diagnosis and BrM diagnosis was 28 years 95% CI [25, 32] and 10 months 95% CI [9, 12], respectively.

CONCLUSIONS

From a large, registry-based study, we observed that patients with ERBB2 + and triple negative BC have the highest incidence of BrM. Our data supports prospective surveillance brain MRI studies. Given advancements in BrM treatment, clinicians should have a low threshold for brain imaging in BC patients with high risk subtypes.

Effectiveness and Safety of Pyrotinib-Based Therapy in the Treatment of HER2-Positive Breast Cancer Patients with Brain Metastases: A Multicenter Real-World Study

BACKGROUND

Approximately 30% to 50% of patients with human epidermal growth factor receptor 2-positive metastatic breast cancer develop brain metastasis (BMs). Pyrotinib has shown promising efficacy in these patients. However, real-world evidence supporting its use is scarce. Therefore, we evaluate the efficacy and safety of pyrotinib-based regimens in the real world.

MATERIALS AND METHODS

We enrolled patients with BMs from various healthcare facilities in China's Shandong region and used an updated breast-graded prognostic assessment (breast-GPA) to predict survival outcomes.

RESULTS

Efficacy and toxicity were assessed in 101 patients. Overall, the median progression-free survival (PFS) was 11.0 months (95% CI, 7.6-14.4 months). PFS was shorter in patients with a breast-GPA of 0 to 2.0 (P< .001). Previous treatment with pertuzumab plus trastuzumab (P = .039) and varying numbers of BMs (P = .028) had a significant positive correlation with PFS. Additionally, radiotherapy (P = .033) for BMs, especially pyrotinib concurrent with radiotherapy (P = .013), significantly prolonged the PFS. In patients with a breast-GPA of 0 to 2.0, a significant difference in PFS was observed depending on whether the brain was the first metastatic site (P< .001). Furthermore, a breast-GPA (0-2.0 vs. 2.5-4.0), and radiotherapy for BMs were found to be independent predictors of PFS. Overall, the objective response rate was 42.6%, while the disease control rate was 88.1%. Diarrhea emerged as the most common adverse event.

CONCLUSION

Pyrotinib-based therapy is effective and tolerable in human epidermal growth factor receptor 2-positive metastatic breast cancer with BMs. Patients who underwent radiotherapy for BMs, particularly those who received pyrotinib concurrently with radiotherapy, exhibited a more favorable prognosis.

[Brain metastases]

Cerebral metastases in patients with metastatic lung cancer are found in more than 30% of patients at baseline and manifest themselves in two out of three patients during disease evolution. For a long time, the cerebral manifestation of the disease was classified as prognostically unfavorable and hence such patients were regularly excluded from therapy studies. In the context of targeted molecular therapy strategies and established immuno-oncological systemic therapies, the blood-brain barrier no longer represents an insurmountable barrier. However, the treatment of brain metastases requires decision making in a multidisciplinary team within dedicated lung cancer and/or oncology centers. The differentiated treatment decision is based on the number, size and location of the brain metastases, neurology and general condition, comorbidities, potential life expectancy and the patient's wishes, but also tumor biology including molecular targets, extra-cranial tumor burden and availability of a CNS-effective therapy. Systemic therapies as well as neurosurgical and radiotherapeutic concepts are now often combined for optimized and prognosis-improving therapeutic strategies.

Treatment of HER2-Positive Breast Cancer with Brain Metastases Using Anlotinib and Trastuzumab Deruxtecan: A Case Report

Breast cancer with brain metastasis accounts for the second largest number of brain metastases among solid malignancies. Despite advances in HER2-targeted therapy, 50% of patients with human epidermal growth factor receptor 2-positive (HER2+) breast cancer develop brain metastases and are associated with poor outcomes. In this article, we report the case of a patient with HER2+ metastatic breast cancer who developed brain metastases, despite experiencing a durable effect on extracranial metastases after treatment with trastuzumab and pertuzumab. The patient exhibited intracranial progression while receiving treatment with trastuzumab deruxtecan monotherapy after secondary brain radiotherapy and multiple lines of therapy with anti-HER2 agents, such as pyrotinib, lapatinib, tucatinib, and ado-trastuzumab emtansine. However, the administration of anlotinib (an antiangiogenesis medication) and trastuzumab deruxtecan resulted in intracranial and extracranial partial response and was linked to manageable side effects. The present case indicates that the combination of anlotinib and trastuzumab deruxtecan may be a promising treatment option for patients with HER2+ breast cancer with brain metastasis. Nevertheless, further studies are warranted to verify the present findings.

Exploring the feasibility and implications of cranioencephalic computed tomography in HER2-positive breast cancer: A pilot study

Background

Breast cancer has several subtypes, including HER2-positive breast cancer, which is characterized by overexpression of human epidermal growth factor receptor 2 (HER2), aggressiveness, poor prognosis, and high risk of recurrence and metastasis. Brain metastases are a common complication of HER2-positive breast cancer, but brain imaging is not included in the initial staging of this disease. This prospective pilot study aimed to evaluate the usefulness of brain computed tomography (CT) in the initial staging of HER2-positive breast cancer.

Patients and methods

Fifty-eight patients were enrolled and demographic, clinical, and breast cancer-specific data were collected after the informed consent and ethical approval were obtained.

Results

A descriptive analysis was performed. The median age of the patients was 55 years, and the majority had good performance status. Brain CT scans were performed at diagnosis, and no brain metastases were detected in early-stage patients. However, brain CT identified brain metastases in one advanced-stage patient with clinical suspicion.

Conclusions

This study suggests that brain CT may have limited utility in the initial staging of early HER2-positive breast cancer, while it could be a valuable tool in advanced cases. Further research is needed, including a higher number of patients to identify those with high risk, which may benefit from brain imaging.

Using Trastuzumab Deruxtecan to treat advanced metastatic breast cancer in patients with varying HER2 expression levels: A single-center experience in Taiwan

To observe the clinical outcomes of patients diagnosed with metastatic breast cancer undergoing Trastuzumab Deruxtecan (T-DXd) therapy in a real-world setting. The study retrospectively reviewed and collected medical data from 13 patients at Shin Kong Wu Ho-Su Memorial Hospital who underwent T-DXd treatment over a period from April 2022 to June 2023. Demographics, pathological characteristics, treatment patterns, and outcomes were descriptively analyzed. Thirteen patients diagnosed with metastatic breast cancer underwent T-DXd treatment between April 2022 and June 2023. This study observed that T-DXd was effective in patients with high human epidermal growth factor receptor 2 (HER2) levels. In patients with low HER2, the majority also experienced favorable responses. Only 2 patients exhibited poor or no response: one was a BRCA2 carrier with unmanageable disease progression, and the other had a HER2 1 + status with multiorgan metastases whose cancer was not controlled by T-DXd. Additionally, 2 patients with no HER2 expression responded well to T-DXd treatment. T-DXd is a valuable treatment alternative for patients with breast cancer, including those with HER2-high, HER2-low, and HER2-negative statuses. In this study, the majority of patients experienced positive therapeutic effects. However, this evaluation relied on a limited sample size and short-term observations. Additional studies involving larger and more diverse patient groups and long follow-up durations are required.

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.

Final outcome analysis from the phase II TUXEDO-1 trial of trastuzumab-deruxtecan in HER2-positive breast cancer patients with active brain metastases

BACKGROUND

Brain metastases (BM) are a devastating complication of HER2-positive metastatic breast cancer (BC) and treatment strategies providing optimized local and systemic disease control are urgently required. The antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) improved progression-free survival (PFS) and overall survival (OS) over trastuzumab emtansine but data regarding intracranial activity is limited. In the primary outcome analysis of TUXEDO-1, a high intracranial response rate (RR) was reported with T-DXd. Here, we report final PFS and OS results.

PATIENTS AND METHODS

TUXEDO-1 accrued adult patients with HER2-positive BC and active BM (newly diagnosed or progressing) without indication for immediate local therapy. The primary endpoint was intracranial RR; secondary endpoints included PFS, OS, safety, quality-of-life (QoL), and neurocognitive function. PFS and OS were estimated with the Kaplan-Meier method and analysed in the per-protocol population.

RESULTS

At 26.5 months median follow-up, median PFS was 21 months (95% CI 13.3-n.r.) and median OS was not reached (95% CI 22.2-n.r.). With longer follow-up, no new safety signals were observed. The most common grade 3 adverse event was fatigue (20%). Grade 2 interstitial lung disease and a grade 3 symptomatic drop of left-ventricular ejection fraction were observed in one patient each. QoL was maintained over the treatment period.

DISCUSSION

T-DXd yielded prolonged intra- and extracranial disease control in patients with active HER2-positive BC BM in line with results from the pivotal trials. These results support the concept of ADCs as systemic therapy for active BM.

Recent Update on Nanocarrier(s) as the Targeted Therapy for Breast Cancer

Despite ongoing advances in cancer therapy, the results for the treatment of breast cancer are not satisfactory. The advent of nanotechnology promises to be an essential tool to improve drug delivery effectiveness in cancer therapy. Nanotechnology provides an opportunity to enhance the treatment modality by preventing degradation, improving tumour targeting, and controlling drug release. Recent advances have revealed several strategies to prevent cancer metastasis using nano-drug delivery systems (NDDS). These strategies include the design of appropriate nanocarriers loaded with anti-cancer drugs that target the optimization of physicochemical properties, modulate the tumour microenvironment, and target biomimetic techniques. Nanocarriers have emerged as a preferential approach in the chemotropic treatment for breast cancer due to their pivotal role in safeguarding the therapeutic agents against degradation. They facilitate efficient drug concentration in targeted cells, surmount the resistance of drugs, and possess a small size. Nevertheless, these nanocarrier(s) have some limitations, such as less permeability across the barrier and low bioavailability of loaded drugs. To overcome these challenges, integrating external stimuli has been employed, encompassing infrared light, thermal stimulation, microwaves, and X-rays. Among these stimuli, ultrasound-triggered nanocarriers have gained significant attention due to their cost-effectiveness, non-invasive nature, specificity, ability to penetrate tissues, and capacity to deliver elevated drug concentrations to intended targets. This article comprehensively reviews recent advancements in different nanocarriers for breast cancer chemotherapy. It also delves into the associated hurdles and offers valuable insights into the prospective directions for this innovative field.

HER2-Low Breast Cancer: Now and in the Future

Breast cancer is a heterogeneous disease, and its subtypes are characterized by hormone receptor and human epidermal growth factor receptor 2 (HER2) expression status. "HER2-low" tumors, which exhibit a low level of HER2 expression (immunohistochemistry 1+ or 2+ without gene amplification), were conventionally considered not amenable to anti-HER2 targeting agents based on the results of a phase III trial of trastuzumab. However, this perspective is being challenged by the emergence of novel anti-HER2 antibody-drug conjugates, such as trastuzumab-deruxtecan. These innovative therapies have demonstrated remarkable efficacy against HER2-low breast cancer, shedding new light on a previously overlooked category of breast cancer. Such promising results highlight the need for in-depth investigations of the biology and prognostic implications of HER2-low tumors. In this review, we comprehensively summarize the current evidence surrounding this topic and highlight areas that warrant further exploration and research in the future.

[Treatment-related adverse events associated with antibody drug conjugate in breast cancer]

Therapeutic options for breast cancer have recently been enriched by new antibody-drug conjugates (ADC), which are now being utilized across all known molecular subtypes. ADCs represent a groundbreaking class of therapies that combine a cytotoxic agent with a monoclonal antibody via a combination molecule (linker). The primary objective is to selectively deliver chemotherapy to cells expressing the target antigen, thereby enhancing the therapeutic index. Trastuzumab-emtansine marked the pioneering use of this approach for HER2-overexpressed breast cancer. More recently, trastuzumab-deruxtecan and sacituzumab-govitecan have demonstrated efficacy in progression-free survival and overall survival in HER2-overexpressed and HER2-low breast cancer for the former, and HER2-non-overexpressed (including HER-low) for the latter. Numerous other ADCs are currently under development in breast cancer. While ADCs were initially designed to widen the therapeutic index and mitigate toxicities, managing ADC-related adverse events in the clinical setting remains a challenge. This review article aims to provide an overview of the toxicity profiles of these drugs already in current clinical practice or under development, drawing from results observed in various studies.

Sacituzumab govitecan in metastatic triple-negative breast cancer patients treated at Institut Curie Hospitals: efficacy, safety, and impact of brain metastases

BACKGROUND

Sacituzumab govitecan (SG) has been approved by FDA in April 2021 for pre-treated metastatic triple-negative breast cancer (mTNBC), following the ASCENT trial results.

METHODS

We set up an ambispective bicentric cohort study to assess the real-world effectiveness and safety of SG in patients with mTNBC treated at Institut Curie Hospitals, with a focus on patients with brain metastases.

RESULTS

This study included 99 patients treated through the French Early Access Program to SG from May 2021 to January 2023. Median age was 55 years [26-89], N = 8 patients (8%) had BRCA1/2 mutation, N = 12 (12%) de novo stage IV disease and N = 31 (31%) brain metastases. Patients had previously received a median of two [1-10] lines of treatment in advanced setting. After a median follow-up of 9.7 months, the median progression-free survival (PFS) and overall survival (OS) were 3.9 months (95%CI[3.4-5.0]) and 8.6 months (95%CI[7.1-11.9]), respectively, while objective response rate was 29% (95%CI[21-39]). Among patients with brain metastases, median PFS and OS were 3.7 months (95%CI[2.6-6.2]) and 6.7 months (95%CI[6.3-NR]), respectively, with intracranial tumor responses. Dose reductions were required in N = 17 patients (17%) within a median of three [2-11] cycles, due to gastrointestinal toxicity (N = 6; 6%), hematological toxicity (N = 9; 9%) including febrile neutropenia (N = 2; 2%), liver enzyme elevation (N = 1; 1%), and physical deterioration (N = 1; 1%). There was no related death to SG.

CONCLUSIONS

The observed response rate and safety of SG are consistent with the results of the ASCENT trial, with efficacy observed in patients with brain metastases, but observed PFS and OS are numerically shorter.

What Is Ailing Oncology Clinical Trials? Can We Fix Them?

Evidence from phase three clinical trials helps shape clinical practice. However, a very small minority of patients with cancer participate in clinical trials and many trials are not completed on time due to slow accrual. Issues with restrictive eligibility criteria can severely limit the patients who can access trials, without any convincing evidence that these restrictions impact patient safety. Similarly, regulatory, organizational, and institutional hurdles can delay trial activation, ultimately making some studies irrelevant. Additional issues during trial conduct (e.g., mandatory in-person visits, central confirmation of standard biomarkers, and inflexible drug dosage modification) contribute to making trials non-patient-centric. These real-life observations from experienced clinical trialists can seem nonsensical to investigators and patients alike, who are trying to bring effective drugs to patients with cancer. In this review, we delve into these issues in detail, and discuss potential solutions to make clinical trials more accessible to patients.

Subcutaneous Trastuzumab: An Observational Study of Safety and Tolerability in Patients With Early HER2-Positive Breast Cancer

Purpose: In Peru, breast cancer (BC) stands as the most predominant malignancy neoplasm among women. Trastuzumab has marked a significant milestone in the management of this disease. It has been shown to improve prognosis in human epidermal growth factor receptor 2 (HER2)-expressing female patients, but its repercussions and efficacy are yet to be analyzed in a context with limited resources. Methods: The study population is made of woman patients aged 18 years and older diagnosed with HER2-positive BC at Instituto Nacional de Enfermedades Neoplásicas (INEN, Lima, Peru) during 2019-2021 and treated with at least one dose of subcutaneous trastuzumab. We reviewed medical records to register treatment characteristics, adverse events (AEs), disease progression, and survival status. We considered a median follow-up time of 36 and 45 months for progression and survival status. Results: The majority of patients were over 50 years old (54.29%). Tumor size averaged 19.7 ± 16.1 mm. Lymph nodes were present in 44.78% of patients. Most patients received adjuvant chemotherapy (63.8%) as first-line treatment. Descriptive analyses of treatment outcomes revealed a 30% toxicity rate, primarily attributed to arthralgia (47.62%), followed by diarrhea, fatigue, and injection site reactions, with relatively lower discontinuation rates compared to larger scale studies. Differences in demographic, clinical, and treatment characteristics were not statistically significant concerning the emergence of AEs (p > 0.05). Progression appeared in nine patients, and the overall survival (OS) rate stood at 98.6% and 92.8%, respectively, during a median follow-up of 36 and 45 months. Conclusion: The research suggests that subcutaneous trastuzumab is comparable in effectiveness and safety to the intravenous administration. Regional-specific studies may provide valuable insights into demographic factors influencing treatment outcomes in Peru or other countries. Furthermore, it could represent a more accessible alternative, potentially enhancing patient adherence and optimizing healthcare resource logistics.

Distinct uptake and elimination profiles for trastuzumab, human IgG, and biocytin-TMR in experimental HER2+ brain metastases of breast cancer

BACKGROUND

The aim of this study is an improved understanding of drug distribution in brain metastases. Rather than single point snapshots, we analyzed the time course and route of drug/probe elimination (clearance), focusing on the intramural periarterial drainage (IPAD) pathway.

METHODS

Mice with JIMT1-BR HER2+ experimental brain metastases were injected with biocytin-TMR and either trastuzumab or human IgG. Drugs/probes circulated for 5 min to 48 h, followed by perfusion. Brain sections were stained for human IgG, vascular basement membrane proteins laminin or collagen IV, and periarterial α-SMA. A machine learning algorithm was developed to identify metastases, metastatic microenvironment, and uninvolved brain in confocally scanned brain sections. Drug/probe intensity over time and total imaged drug exposure (iAUC) were calculated for 27,249 lesions and co-immunofluorescence with IPAD-vascular matrix analyzed in 11,668 metastases.

RESULTS

In metastases, peak trastuzumab levels were 5-fold higher than human IgG but 4-fold less than biocytin-TMR. The elimination phase constituted 85-93% of total iAUC for all drugs/probes tested. For trastuzumab, total iAUC during uptake was similar to the small molecule drug probe biocytin-TMR, but slower trastuzumab elimination resulted in a 1.7-fold higher total iAUC. During elimination trastuzumab and IgG were preferentially enriched in the α-SMA+ periarterial vascular matrix, consistent with the IPAD clearance route; biocytin-TMR showed heterogeneous elimination pathways.

CONCLUSIONS

Drug/probe elimination is an important component of drug development for brain metastases. We identified a prolonged elimination pathway for systemically administered antibodies through the periarterial vascular matrix that may contribute to the sustained presence and efficacy of large antibody therapeutics.

Mechanisms of action and resistance to anti-HER2 antibody-drug conjugates in breast cancer

Human epidermal growth factor 2 (HER2)-positive breast cancer (BC) represents nearly 20% of all breast tumors. Historically, these patients had a high rate of relapse and dismal prognosis. The advent of HER2-targeting monoclonal antibodies such as trastuzumab followed by pertuzumab had improved the prognosis of HER2-positive metastatic BC. More recently, antibody-drug conjugates (ADCs) are now reshaping the treatment paradigm of solid tumors, especially breast cancer. Tratsuzumab emtansine (T-DM1) was one of the first ADC developed in oncology and was approved for the management of HER2-positive metastatic BC. In a head-to-head comparison, trastuzumab deruxtecan (T-DXd) defeated T-DM1 as a second-line treatment. The efficacy of ADCs is counterbalanced by the appearance of acquired resistance to these agents. In this paper, we summarize the mechanisms of action and resistance of T-DM1 and T-DXd, as well as their clinical efficacy. Additionally, we also discuss potential strategies for addressing resistance to ADC.

Preclinical evidence for the use of anti-Trop-2 antibody-drug conjugate Sacituzumab govitecan in cerebral metastasized castration-resistant prostate cancer

PURPOSE

Improved survival rates have been observed in castration-resistant prostate cancer (CRPC) due to advancements in treatment options. However, individuals with brain metastases still have limited therapeutic options and an unfavorable prognosis. Therefore, there is an urgent need to explore new therapeutic avenues, such as antibody-drug conjugates (ADCs), which have demonstrated significant clinical activity against active brain metastases in solid tumors. Our objective was to determine the expression levels of the ADC targets Trop-2 and NECTIN-4 in cerebral metastasized CRPC (mCRPC).

METHODS

Immunohistochemical staining of Trop-2 and NECTIN-4 with evaluation of H-score was performed in CRPC brain metastases (n = 31). Additionally, we examined Trop-2 protein expression in prostate cancer cell lines and studied their responsiveness to the anti-Trop-2 ADC Sacituzumab govitecan (SG) in vitro.

RESULTS

Our analysis revealed that most patients exhibited moderate to strong Trop-2 expression [n = 27/31 with H-score ≥100, median H-score 220 (IQR 180-280)], while NECTIN-4 was absent in all cerebral metastases. Mechanistically, we demonstrated that the efficacy of SG depends on Trop-2 expression levels in vitro. Overexpression of Trop-2 in Trop-2-negative PC-3 cells led to sensitization to SG, whereas CRISPR-Cas9-mediated knockdown of Trop-2 in Trop-2-expressing DU-145 cells conferred resistance to SG.

CONCLUSION

The substantial expression of Trop-2 in cerebral metastases, along with our preclinical in vitro results, supports the efficacy of SG in treating cerebral mCRPC. Thus, our results extend the understanding of the potential of ADCs in prostate cancer treatment and provide an additional treatment strategy for the challenging subset of patients with cerebral metastases.

Trastuzumab deruxtecan in breast cancer

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate (ADC) consisting of a humanised, anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibody covalently linked to a topoisomerase I inhibitor cytotoxic payload (DXd). The high drug-to-antibody ratio (8:1) ensures a high DXd concentration is delivered to target tumour cells, following internalisation of T-DXd and subsequent cleavage of its tetrapeptide-based linker. DXd's membrane-permeable nature enables it to cross cell membranes and potentially exert antitumour activity on surrounding tumour cells regardless of HER2 expression. T-DXd's unique mechanism of action is reflected in its efficacy in clinical trials in patients with HER2-positive advanced breast cancer (in heavily pretreated populations and in those previously treated with a taxane and trastuzumab), as well as HER2-low metastatic breast cancer. Thus, ADCs such as T-DXd have the potential to change the treatment paradigm of targeting HER2 in metastatic breast cancer, including eventually within the adjuvant/neoadjuvant setting.

Systemic Therapy in Breast Cancer

Therapeutic advances in breast cancer have significantly improved outcomes in recent decades. In the early setting, there has been a gradual shift from adjuvant-only to neoadjuvant strategies, with a growing focus on customizing post-neoadjuvant treatments through escalation and de-escalation based on pathologic response. At the same time, the transition from a pre-genomic to a post-genomic era, utilizing specific assays in the adjuvant setting and targeted sequencing in the advanced stage, has deepened our understanding of disease biology and aided in identifying molecular markers associated with treatment benefit. Finally, the introduction of new drug classes such as antibody-drug conjugates, and the incorporation in the (neo)adjuvant setting of therapies previously investigated in the advanced stage, like immunotherapy and CDK4-6 inhibitors, poses new challenges in treatment sequencing.

Navigating Breast Cancer Oligometastasis and Oligoprogression: Current Landscape and Future Directions

PURPOSE

We examine the potential for curative approaches among metastatic breast cancer (MBC) patients by exploring the recent literature on local ablative therapies like surgery and stereotactic body radiation therapy (SBRT) in patients with oligometastatic (OM) breast cancer. We also cover therapies for MBC patients with oligoprogressive (OP) disease.

KEY FINDINGS

Surgery and SBRT have been studied for OM and OP breast cancer, mainly in retrospective or non-randomized trials. While many studies demonstrated favorable results, a cooperative study and single-institution trial found no support for surgery/SBRT in OM and OP cases, respectively.

CONCLUSION

While there is interest in applying local therapies to OM and OP breast cancer, the current randomized data does not back the routine use of surgery or SBRT, particularly when considering the potential for treatment-related toxicities. Future research should refine patient selection through advanced imaging and possibly explore these therapies specifically in patients with hormone receptor-positive or HER2-positive disease.

HER2-Altered Non-Small Cell Lung Cancer: A Journey from Current Approaches to Emerging Strategies

For patients diagnosed with advanced HER2-altered non-small cell lung cancer (NSCLC), the current standard of care is represented by a platinum-pemetrexed-based chemotherapy, eventually in combination with immunotherapy. Different pan-HER tyrosine kinase inhibitors have been evaluated in limited phase II trials, yielding generally unsatisfactory outcomes, although certain genotypes demonstrated some clinical benefit. Conversely, antibody-drug conjugates (ADCs) targeting HER2, particularly trastuzumab-deruxtecan, have shown promising results against HER2-mutant disease, including a great intracranial activity in patients with brain metastasis. Based on the results obtained from DESTINY-Lung01 and DESTINY-Lung02 trials, trastuzumab deruxtecan received regulatory approval as the first targeted therapy for pre-treated, HER2-mutant, advanced NSCLC patients. More recently, the Food and Drug Administration (FDA) granted the accelerated approval of trastuzumab deruxtecan for advanced, pre-treated HER2-positive solid tumours with no other treatment options. In this scenario, emerging evidence is increasingly pointing towards the exploration of combination regimens with synergistic effects in the advanced disease. In this review, we provide a detailed summary of current approaches and emerging strategies in the management of HER2-altered NSCLC, also focusing on unmet needs, including the treatment of patients with brain metastases.

[Staging and systemic treatment of ocular and periocular metastases]

Metastases of malignant diseases are the most frequent tumors diagnosed in the human eye. They occur in approximately 5-10% of patients with solid tumors during the course of the disease. Their frequency is particularly high in patients with breast and lung cancer. Many highly sensitive periorbital tissues can be affected by the localization of the metastatic lesions and pose a number of clinical challenges. The main goal of the therapy of ocular metastases consists of the control of tumor growth (including the control of other possible manifestations throughout the body), the preservation of the affected eye and the minimization of potential iatrogenic damage to adjacent tissues. Overall, the purpose of this strategy is also to maintain the quality of life and especially the eyes and vision of the patient. Furthermore, pain should be avoided or at least alleviated. Of special importance is the differentiation between a curative or palliative situation. Patients with ocular metastases usually undergo systemic treatment appropriate for the underlying tumor entity, which is often accompanied by concomitant or sequential radiotherapy. In addition to classical chemotherapy, targeted treatment, treatment with monoclonal antibodies and antibody-drug conjugates as well as immunotherapy with checkpoint antibodies are currently available for many cancer types. This review article gives an overview of the currently available treatment options for patients with ocular metastases of solid tumors.

The efficacy of sacituzumab govitecan and trastuzumab deruxtecan on stable and active brain metastases in metastatic breast cancer patients-a multicenter real-world analysis

BACKGROUND

Fifteen to thirty percent of all patients with metastatic breast cancer (MBC) develop brain metastases (BCBMs). Recently, the antibody-drug conjugates (ADCs) sacituzumab govitecan (SG) and trastuzumab deruxtecan (T-DXd) have shown to be highly effective in the treatment of MBC. However, there are only limited data whether these macromolecules are also effective in patients with BCBMs. We therefore aimed to examine the efficacy of SG and T-DXd in patients with stable and active BCBMs in a multicenter real-world analysis.

PATIENTS AND METHODS

Female patients with stable or active BCBMs who were treated with either SG or T-DXd at three breast centers in Germany before 30 June 2023 were included. As per local clinical praxis, chemotherapy efficacy was evaluated by whole-body computed tomography and cranial magnetic resonance imaging at baseline and at least every 3 months according to local standards. Growth dynamics of BCBMs were assessed by board-certified neuroradiologists.

RESULTS

Of 26 patients, with a median of 2.5 prior therapy lines in the metastatic setting (range 2-15), 12 (43%) and 16 (57%) patients received SG and T-DXd, respectively. Out of the 12 patients who received SG, 2 (17%) were subsequently treated with T-DXd. Five out of 12 (42%) and 5 out of 16 (31%) patients treated with SG and T-DXd, respectively, had active BCBMs at treatment initiation. The intracranial disease control rate was 42% [95% confidence interval (CI) 13% to 71%] for patients treated with SG and 88% (95% CI 72% to 100%) for patients treated with T-DXd. After a median follow-up of 12.7 months, median intracranial progression-free survival was 2.7 months (95% CI 1.6-10.5 months) for SG and 11.2 months (95% CI 7.5-23.7 months) for T-DXd.

CONCLUSIONS

SG and T-DXd showed promising clinical activity in both stable and active BCBMs. Further prospective clinical studies designed to investigate the efficacy of modern ADCs on active and stable BCBMs are urgently needed.