Multidisciplinary management of HER2-positive breast cancer with brain metastases: An evidence-based pragmatic approach moving from pathophysiology to clinical data

Inetetamab-based therapy in real-world treatment patterns with HER2-positive advanced breast cancer patients: a retrospective single-center study

Background

Inetetamab is a novel antibody targeting human epidermal growth factor receptor 2 (HER2) developed in China. Due to its optimized antibody-dependent cell-mediated cytotoxicity effect compared with trastuzumab, it has shown good efficacy and safety in the treatment of HER2-positive advanced breast cancer (ABC).

Objectives

This study aimed to investigate the efficacy and safety of inetetamab combination therapy in the treatment of HER2-positive ABC in real-world clinical practice.

Design

Retrospective study.

Methods

A total of 133 patients with HER2-positive ABC who were treated with inetetamab-based regimens between March 2020 and January 2024 were retrospectively included in this study. The main endpoint was median progression-free survival (mPFS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), and safety.

Results

The study included 133 HER2-positive ABC patients, and the median age was 55 years. The mPFS was 8.0 (6.7-9.3) months. The ORR was 50.4%, while the DCR was 88.7%. The mPFS for patients receiving inetetamab-based therapy as first to second, third to fourth, and later lines of metastatic treatment were 14.0, 7.0, and 6.0 months, respectively. Patients treated with inetetamab plus pyrotinib plus chemotherapy, especially with capecitabine, had the best outcomes (mPFS = 14.0 months). Multivariate analysis revealed that prior HER2-TKI treatment was significantly associated with worse PFS (hazard ratios 2.829, 95% confidence interval 1.265-6.328, p = 0.011). Subgroup analysis indicated that patients without visceral metastases had significantly better PFS (14.0 months vs 8.0 months, p = 0.003). The overall incidence of any grade adverse events (AEs) was 100%, with most being grades 1-2. Severe complications included neutropenia (37.6%) and leukopenia (33.1%).

Conclusions

Inetetamab-based combination therapy shows promising efficacy and good safety in patients with HER2-positive ABC. It is one of the late-line treatment options for Chinese patients with HER2-positive ABC.

Comparing the difference of adverse events with HER2 inhibitors: a study of the FDA adverse event reporting system (FAERS)

Aim and background: This study attempted to identify similarities and differences in adverse events (AEs) between human epidermal growth factor receptor 2 (HER2) inhibitors, especially those related to hemorrhagic events and nervous system disorders. Methods: This study summarized the types, frequencies, and system organ classes (SOCs) of AEs of HER2 inhibitors. The US Food and Drug Administration Adverse Event Reporting System (FAERS) data from January 2004 through March 2022 was collected and analyzed. Disproportionality analyses were conducted to detect AEs signals for every HER2 inhibitor. The chi-square test, Wilcoxon test, and descriptive analysis were used to compare the differences of AEs for specific SOCs or drugs. Results: A total of 47,899 AE reports were obtained for eight HER2 inhibitors. Trastuzumab-related AEs were reported in the highest number and combination of regimens. In monotherapy, trastuzumab had the highest reported rate of cardiac disorders-related AEs (24.0%). However, small-molecule drugs exceeded other drugs in the reported rates of AEs related to gastrointestinal disorders, metabolism and nutrition disorders. The highest reported rates of respiratory disorders (47.3%) and hematologic disorders (22.4%) were associated with treatment with trastuzumab deruxtecan (T-DXd). Patients treated with trastuzumab emtansine (TDM-1) had the highest reported rate (7.28%) of hemorrhagic events, especially intracranial haemorrhage events. In addition, patients treated with TDM-1 with concomitant thrombocytopenia were likely to experience hemorrhagic events compared to other HER2 inhibitors (p < 0.001). The median time to onset of intracranial haemorrhage associated with trastuzumab (0.5 months) and TDM-1 (0.75 months) was short. However, there was no significant difference in median time to onset intracranial haemorrhage between patients in different age groups or with different outcomes. Disproportionality analysis results reveal that cerebral haemorrhage is a positive signal associated with T-DXd and TDM-1. In addition, tucatinib was the drug with the highest rate of reported nervous system disorders (31.38%). Memory impairment (83 cases) is a positive signal for tucatinib. Conclusion: The types and reporting rates of AEs associated with different HER2 inhibitors vary across multiple systems. In addition, hemorrhagic events concomitant with TDM-1 treatment and nervous system disorders concomitant with tucatinib treatment may be worthy of attention.