A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

Efficacy and safety of trastuzumab deruxtecan in Chinese patients with HER2-positive and HER2-low advanced breast cancer: a multicenter, observational, real-world study

Objective

Limited real-world efficacy and safety data exist regarding the use of trastuzumab deruxtecan (T-DXd) in the Chinese population with human epidermal growth factor receptor (HER2)-positive and HER2-low advanced breast cancer (BC). This multicenter, observational, real-world study aimed to evaluate the efficacy and safety of T-DXd for the treatment of Chinese patients with HER2-positive and HER2-low advanced BC.

Methods

The medical records of 61 patients were collected from The Second Hospital of Dalian Medical University, Beijing Chaoyang District Sanhuan Cancer Hospital, Beijing Jingxin Hospital, and Cancer Hospital of the Chinese Academy of Medical Sciences. The primary endpoint of the study was progression-free survival (PFS), and the secondary endpoints were overall survival (OS), objective response rate (ORR), disease control rate (DCR), time to response (TTR), and safety. PFS and OS were analyzed using the Kaplan-Meier method and log-rank test.

Results

The primary endpoint, PFS was 10.51 months (95% confidence interval (CI), 3.02-NE) in the HER2-low group and 10.18 months (95% CI, 3.88-NE) in the HER2-positive group. Regarding the secondary endpoints in the HER2-low and HER2-positive groups, OS data were immature, ORR rates were 37.93% and 62.50%, DCR rates were 79.31% and 87.50%, and the median TTR rates were 1.28 and 1.31 months, respectively. In the subgroup analysis, front-line treatment with T-DXd was associated with increased beneficial effects. The primary adverse events (AEs) related to T-DXd treatment were gastrointestinal reactions and bone marrow suppression, which were predominantly grades 1-2, with no severe grade 4/5 AEs reported, only one patient developed infectious pneumonia.

Conclusion

This study was the first multicenter, real-world study of T-DXd for advanced BC in China. The findings demonstrated that T-DXd may be an effective antitumor treatment with controllable adverse reactions in patients with advanced BC irrespective of HER2 expression levels.

Trastuzumab deruxtecan in human epidermal growth factor receptor 2-positive breast cancer brain metastases: A systematic review and updated meta-analysis

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has shown promising activity in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) and central nervous system (CNS) involvement. In this updated meta-analysis, we explore the effectiveness of T-DXd in a large subset of patients with HER2-positive BC and CNS disease.

METHODS

A systematic search was made on September 16th, 2024, for studies investigating T-DXd in the scenario of HER2-positive BC and brain metastases (BMs) and/or leptomeningeal disease (LMD). We used random effects models for all statistical analyses.

RESULTS

We included 18 studies with 786 HER2-positive BC patients with CNS involvement (16 studies with 750 BMs patients and three studies with 36 LMD patients). We observed high overall antitumor responses (objective response rate [ORR], 60.4 %; disease control rate [DCR], 94.4 %; and clinical benefit rate [CBR], 79.3 %) and a 12-month PFS of 64.7 % and OS of 82.7 %. Intracranial ORR, DCR, and CBR were seen in 62.2 %, 88.6 %, and 68.6 % of patients, respectively, and 67.4 % achieved intracranial PFS at 12 months. Both stable and active BMs subgroups derived similar benefit from T-DXd. Better intracranial responses were seen for 33 patients with untreated BMs compared to 56 patients with previously treated or progressing lesions (odds ratio 3.82, 95 % confidence interval 1.3-10.8, p = 0.01). For the LMD group, T-DXd elicited intracranial ORR and CBR in 59.4 % and 94.1 % of patients, respectively.

CONCLUSIONS

This updated meta-analysis continues to support the overall and intracranial activity of T-DXd in patients with HER2-positive BC and CNS involvement, including those with LMD.

Trastuzumab Deruxtecan for HER2-Positive Breast Cancer with Central Nervous System Metastasis

Introduction

Metastasis to the central nervous system (CNS) is frequently observed in human epidermal growth factor receptor (HER2)-positive breast cancer, leading to reduced quality of life and poor prognosis. Brain metastases (BMs) are common, whereas spinal cord metastases are rare and no standardized treatment approach has been reported for their management. Herein, we report the outcomes of treatment with trastuzumab deruxtecan (T-DXd) in a patient with BMs and intramedullary spinal cord metastasis (ISCM) and another patient with BMs.

Case Presentation

The first patient was a woman in her 30s. After the surgery for HER2-positive right breast cancer, T-DXd was used as fourth-line treatment for multiple BMs and ISCM. Both the BMs and ISCM reduced, and partial response was maintained for 12 months. Grade 1 fatigue was the only adverse event observed in this patient. The second patient was a woman in her 40 s with multiple BMs after primary treatment for HER2-positive right breast cancer, as well as multiple bone and lymphoid node metastases. T-DXd was administered as second-line treatment. The multiple BMs have now shrunk, and the primary tumor and bone/lymph node metastases have not shown significant changes; the patient has maintained partial response for 6 months.

Conclusion

Metastasis to the CNS has a very poor prognosis and limited therapeutic response because it is difficult for drugs to cross the blood-brain barrier. However, T-DXd has yielded positive results for BMs in clinical trials. Additionally, a therapeutic effect of T-DXd on ISCM and BMs was observed in the reported cases.

Recent advances in breast cancer metastasis with special emphasis on metastasis to the brain

Understanding the underlying mechanisms of breast cancer metastasis is of vital importance for developing treatment approaches. This review emphasizes contemporary breakthrough studies with special focus on breast cancer brain metastasis. Acquired mutational changes in metastatic lesions are often distinct from the primary tumor, suggesting altered mutagenesis pathways. The concept of micrometastases and heterogeneity within the tumors unravels novel therapeutic targets at genomic and molecular levels through epigenetic and proteomic profiling. Several pre-clinical studies have identified mechanisms involving the immune system, where tumor associated macrophages are key players. Expression of cell proteins like Syndecan1, fatty acid-binding protein 7 and tropomyosin kinase receptor B have been implicated in aiding the transmigration of breast cancer cells to the brain. Changes in the proteomic landscape of the blood-brain-barrier show altered permeability characteristics, supporting entry of cancer cells. Findings from laboratory studies pave the path for the emergence of new biomarkers, especially blood-based miRNA and circulating tumor cell markers for prognostic staging. The constantly evolving therapeutics call for clinical trials backing supportive evidence of efficacies of both novel and existing approaches. The challenge lying ahead is discovering innovative techniques to replace use of human samples and optimize small-scale patient recruitment in trials.

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.