Neratinib and Capecitabine for the Treatment of Leptomeningeal Metastases from HER2-Positive Breast Cancer: A Series in the Setting of a Compassionate Program

Simple Summary

Leptomeningeal metastases represent an unmet need due to the lack of effective therapy and poor survival. The tyrosine kinase inhibitor, neratinib, has demonstrated promising activity against brain metastases from HER2-positive breast cancer, as reported by the TBCRC and NALA trials, thus suggesting a potential activity also in leptomeningeal metastases when associated with capecitabine. The aim of the study was to investigate the efficacy and tolerability of neratinib in association with capecitabine in leptomeningeal metastases from heavily-pretreated breast cancer patients who failed multiple lines of treatment. Primary endpoints were 6-month overall survival and intracranial progression-free survival. Secondary endpoints were the responses assessed by whole CNS MRI performed every 8 weeks, neurological improvement, and safety. We obtained a median overall survival of 10 months, an intracranial progression-free survival of 4 months, neurological improvement and stable disease on an MRI lasting 6.5 months in six patients (60%). These preliminary findings suggest a potential activity of this treatment in LM from HER2-positive breast cancer that needs to be further investigated in larger datasets.

Abstract

Background: Leptomeningeal metastasis is a neurological complication from HER2-positive breast cancer with a poor prognosis and limited treatment options. This study has evaluated the activity of neratinib in association with capecitabine in 10 patients with LM from HER2-positive BC after the failure of multiple lines of treatment, including trastuzumab-based therapy, within a compassionate program, and a comparison was made with a historical control group of 10 patients. Methods: Patients aged ≥ 18 years with histological diagnosis of primary HER2-positive BC, either amplified or mutated, and newly-diagnosed LM were enrolled. Coexistence of BM that has or has not received radiotherapy, as well as prior chemotherapy, hormone therapy, or monoclonal HER2-targeting antibodies or antibody–drug conjugates, were allowed, with the exclusion of lapatinib. Results: Six-months OS was 60% with a median OS of 10 months (95% CI: 2.00–17.0). Three-month intracranial PFS was 60% with a median intracranial PFS of 4.0 months (95% CI: 2.00–6.0). The neurological benefit was observed in 70% of patients with a median duration of neurological response of 6.5 months. The best radiological response was stable disease in 60% of patients. Conclusions: This small series shows that the combination of neratinib and capecitabine is a safe treatment in LM from heavily pretreated HER2-positive BC with clinical efficacy in some patients and is worth investigating in a larger study.

Leptomeningeal Metastases from Solid Tumors: Recent Advances in Diagnosis and Molecular Approaches

Leptomeningeal metastases (LM) from solid tumors represent an unmet need of increasing importance due to an early use of MRI for diagnosis and improvement of outcome of some molecular subgroups following targeted agents and immunotherapy. In this review, we first discussed factors limiting the efficacy of targeted agents in LM, such as the molecular divergence between primary tumors and CNS lesions and CNS barriers at the level of the normal brain, brain tumors and CSF. Further, we reviewed pathogenesis and experimental models and modalities, such as MRI (with RANO and ESO/ESMO criteria), CSF cytology and liquid biopsy, to improve diagnosis and monitoring following therapy. Efficacy and limitations of targeted therapies for LM from EGFR-mutant and ALK-rearranged NSCLC, HER2-positive breast cancer and BRAF-mutated melanomas are reported, including the use of intrathecal administration or modification of traditional cytotoxic compounds. The efficacy of checkpoint inhibitors in LM from non-druggable tumors, in particular triple-negative breast cancer, is discussed. Last, we focused on some recent techniques to improve drug delivery.

Management of Brain and Leptomeningeal Metastases from Breast Cancer

The management of breast cancer (BC) has rapidly evolved in the last 20 years. The improvement of systemic therapy allows a remarkable control of extracranial disease. However, brain (BM) and leptomeningeal metastases (LM) are frequent complications of advanced BC and represent a challenging issue for clinicians. Some prognostic scales designed for metastatic BC have been employed to select fit patients for adequate therapy and enrollment in clinical trials. Different systemic drugs, such as targeted therapies with either monoclonal antibodies or small tyrosine kinase molecules, or modified chemotherapeutic agents are under investigation. Major aims are to improve the penetration of active drugs through the blood-brain barrier (BBB) or brain-tumor barrier (BTB), and establish the best sequence and timing of radiotherapy and systemic therapy to avoid neurocognitive impairment. Moreover, pharmacologic prevention is a new concept driven by the efficacy of targeted agents on macrometastases from specific molecular subgroups. This review aims to provide an overview of the clinical and molecular factors involved in the selection of patients for local and/or systemic therapy, as well as the results of clinical trials on advanced BC. Moreover, insight on promising therapeutic options and potential directions of future therapeutic targets against BBB and microenvironment are discussed.

How we treat patients with leptomeningeal metastases

The goal of treatment of leptomeningeal metastasis is to improve survival and to maintain quality of life by delaying neurological deterioration. Tumour-specific therapeutic options include intrathecal pharmacotherapy, systemic pharmacotherapy and focal radiotherapy. Recently, improvement of leptomeningeal disease-related progression-free survival by adding intrathecal liposomal cytarabine to systemic treatment versus systemic treatment alone has been observed in a randomised phase III trial for patients with breast cancer with newly diagnosed leptomeningeal metastasis. Safety and efficacy of intrathecal administration of new agents such as trastuzumab are under evaluation. Systemic therapy using targeted agents and immunotherapy has also improved outcome in patients with brain metastasis, and its emerging role in the management of leptomeningeal metastasis needs to better studied in prospective series. Focal radiotherapy is commonly indicated for the treatment of macroscopic disease such as meningeal nodules or clinically symptomatic central nervous system structures, for example, base of skull with cranial nerve involvement or cauda equine syndrome. The role of whole brain radiotherapy is decreasing. An individualised combination of different therapeutic options should be used considering the presentation of leptomeningeal metastasis, as well as the histological and molecular tumour characteristics, the presence of concomitant brain and systemic metastases, and prior cancer-directed treatments.