Central nervous system disease in phase III studies for advanced HER2 positive breast cancer: A review

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Breast cancer brain metastases genomic profiling identifies alterations targetable by immune-checkpoint and PARP inhibitors

Understanding the genomic landscape of breast cancer brain metastases (BCBMs) is key to developing targeted treatments. In this study, targetable genomic profiling was performed on 822 BCBMs, 11,988 local breast cancer (BC) biopsies and 15,516 non-central nervous system (N-CNS) metastases (all unpaired samples) collected during the course of routine clinical care by Foundation Medicine Inc (Boston, MA). Clinically relevant genomic alterations were significantly enriched in BCBMs compared to local BCs and N-CNS metastases. Homologous recombination deficiency as measured by BRCA1/2 alteration prevalence and loss-of-heterozygosity and immune checkpoint inhibitor (ICI) biomarkers [Tumor mutation burden (TMB)-High, Microsatellite instability (MSI)-High, PD-L1/L2)] were significantly more prevalent in BCBM than local BC and N-CNS. High PD-L1 protein expression was observed in ER-negative/HER2-negative BCBMs (48.3% vs 50.0% in local BCs, 21.4% in N-CNS). Our data highlights that a high proportion of BCBMs are potentially amenable to treatment with targeted therapeutic agents including PARP inhibitors and ICIs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Assessment of Phase 3 Randomized Clinical Trials Including Patients With Leptomeningeal Disease: A Systematic Review

This systematic review examines the proportion of patients with leptomeningeal disease included in phase 3 randomized clinical trials for patients with metastatic breast cancer, lung cancer, and melanoma.

Epidemiology, clinical outcomes, and unmet needs of patients with human epidermal growth factor receptor 2-positive breast cancer and brain metastases: A systematic literature review

BACKGROUND

There is an increasing need for developing effective therapies for managing intracranial disease in patients with human epidermal growth factor receptor 2-positive (HER2 +) metastatic breast cancer and brain metastases (BM), as this population is growing and has historically been excluded from large clinical trials. In this systematic literature review, we aimed to provide a comprehensive overview of the epidemiology, unmet needs, and global treatment landscape for patients with HER2 + metastatic breast cancer and BM, with a particular focus on heterogeneity across clinical trial designs in this setting.

METHODS

We conducted literature searches of PubMed and select congress websites up to March 2022 and filtered for publications with a significant focus on epidemiology, unmet needs, or treatment outcomes in patients with HER2 + metastatic breast cancer and BM.

RESULTS

Key clinical trials of HER2-targeting treatments for HER2 + metastatic breast cancer had varying eligibility criteria relating to BM, with only two trials-HER2CLIMB and DEBBRAH-including patients with both active and stable BM. We also observed variance across assessed central nervous system (CNS)-focused endpoints (CNS objective response rate vs CNS progression-free survival vs time to CNS progression) and robustness of statistical analysis (prespecified vs exploratory).

CONCLUSIONS

There is an unmet need for standardization of clinical trial design for patients with HER2 + metastatic breast cancer and BM, to aid the interpretation of the global treatment landscape and ensure patients with all types of BM can access effective treatments.

Comparative Efficacy of Tyrosine Kinase Inhibitors and Antibody–Drug Conjugates in HER2-Positive Metastatic Breast Cancer Patients with Brain Metastases: A Systematic Review and Network Meta-Analysis

Simple Summary

Comparisons between the efficacy of tyrosine kinase inhibitors (TKIs) and antibody–drug conjugates (ADCs) in treating HER2-positive breast cancer brain metastasis (BCBM) patients have not previously been conducted. We performed a systematic review and Bayesian-based network meta-analysis to pool the estimates of progression-free survival, overall survival, and incidence of central nervous system (CNS) disease progression. The current study indicated that both T-DXd and T-DM1 presented better efficacy than TKIs regarding survival outcomes. Treatments containing neratinib or T-DM1 tended to rank the best in reducing the recurrent rate of CNS. Our study provides more evidence for the clinical decision making for patients with HER2-positive BCBM. More high-quality studies with standardized entry criteria and comparable CNS-related endpoints are warranted in the future.

Abstract

HER2-positive breast cancer brain metastasis (BCBM) is an important clinical problem. A systematic review and network meta-analysis were conducted to compare the efficacy of tyrosine kinase inhibitors (TKIs) and antibody–drug conjugates (ADCs), two categories of emerging agents in this field. We implemented a comprehensive literature search of PubMed, Embase, the Cochrane Library, ClinicalTrials.gov, and abstracts of oncology conferences. A network meta-analysis following Bayesian approaches was performed. Pooled hazard ratios (HRs) and odds ratios (ORs) with credible intervals (CrIs) were calculated to estimate progression-free survival (PFS), overall survival (OS), and the incidence of central nervous system (CNS) disease progression. Sixteen studies were included. Pairwise comparisons of PFS showed salient divergency between T-DXd and the physician’s choice of treatment (HR 0.17; 95% CrI 0.03–0.82) or afatinib (HR 0.14; 95% CrI 0.02–1.00). T-DXd and T-DM1 ranked first regarding PFS and OS, respectively, followed by TKI-containing regimens. The incidence of CNS disease progression was analyzed separately according to baseline BCBM status, among which neratinib-containing regimens were most likely to rank the best. In conclusion, ADCs including T-DXd and T-DM1 showed better efficacy than TKIs in the survival outcomes for HER2-positive BCBM patients. Treatments based on neratinib or T-DM1 revealed favorable results in reducing the recurrent rate of CNS.