Favourable outcome of patients with breast cancer brain metastases treated with dual HER2 blockade of trastuzumab and pertuzumab
Elisabeth Bergen, Amelie Binter, Angelika M. Starzer, Gerwin Heller, Barbara Kiesel, Kristina Tendl-Schulz, Zsuzsanna Bagó-Horváth, Julia Furtner, J. Leitner, Ruth Exner, Florian Fitzal, Karin Dieckmann, Georg Widhalm, Matthias Preusser, Anna S. Berghoff, Rupert Bartsch
Abstract
Background: Dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab (TP) is a standard therapy of metastatic and localized HER2-positive breast cancer (BC), but its activity in breast cancer brain metastases (BCBM) is unknown. Methods: Patients with HER2-positive BCBM were identified from the Vienna Brain Metastasis Registry and clinical data including patient characteristics, therapies and overall survival (OS) were obtained. Patients were grouped into ‘TP’, ‘other-HER2-targeted therapy’ and ‘no-HER2-targeted therapy’ according to received first-line systemic therapy after diagnosis of BCBM. Radiological re-assessment of intracranial lesions was performed in patients treated with TP as systemic first-line therapy according to RANO response criteria for brain metastases (BM). Results: A total of 252 HER2-positive BC patients with BM were available for this analysis. Patients treated with TP as systemic first-line therapy after diagnosis of BM had a significantly longer OS compared with treatment with other-HER2-targeted therapy and no-HER2-targeted therapy (44 versus 17 versus 3 months, p < 0.001; log-rank test). Among radiologically re-assessed patients treated with TP as systemic first-line therapy after diagnosis of BM, 5/14 patients (35.7%) had complete intracranial remission (CR), 8/14 patients (57.1%) partial intracranial remission (PR), 1/14 patients (7.1%) stable intracranial disease (SD) and 0/14 patients (0.0%) progressive intracranial disease (PD) as best response resulting in an intracranial objective response rate (iORR) of 92.9% and an intracranial clinical benefit rate (iCBR) of 100.0%. Conclusion: First-line therapy with dual HER2-inhibition of TP after BM diagnosis was associated with the longest median OS times in patients with BCBM.