352P - Clinical profile and outcome of HER2 positive breast cancer patients with brain metastases treated with HER2 targeted therapy: Real-world experience

Abstract

BackgroundBrain metastases (BM) is a commonly encountered clinical scenario in patients with HER2 positive breast cancer (BC). We report here the clinical profile and outcome of patients with HER2 positive breast cancer with brain metastasis (BCBM) who were treated with HER2 targeted therapy at a single institution. MethodsClinical and outcome data of patients with HER2 positive BCBM treated with HER2 targeted agents were retrospectively collected. Efficacy variables were progression-free survival (PFS, time from diagnosis of BM to first progression or death due to any cause, whichever was earlier) and overall survival (OS). ResultsBetween 2013 and 2017, 102 HER2 positive BCBM patients with median age 52 (IQR 45-57) years were treated with HER2 targeted therapy. Of these, 40 (39.2%) had ER positive disease, 98 (96.1%) were symptomatic at diagnosis of BM, 69 (67.6%) had received ≥2 lines of chemotherapy before BM, 22 (25.3%) had solitary brain lesion, 22 (25.3%) had 2-5 lesions and 43 (49.4%) had > 5 lesions. After BM diagnosis, whole brain radiotherapy (WBRT) was administered in 93 (91.2%) patients, stereotactic radiosurgery (SRS) in 4 (4.0%), WBRT and SRS in 4 (4%), and 9 (8.9%) patients underwent surgical resection of BM. The first HER2 targeted therapy after BM diagnosis was lapatinib in 70 (68.6%), trastuzumab in 19 (18.6%), lapatinib and trastuzumab in 3 (2.9%), trastuzumab emtansine in 4 (3.9%) and intrathecal trastuzumab in 5 (4.9%), patients. After diagnosis of BM, 17 (16.7%) patients received ≥3 lines of therapy. At a median follow-up of 13.5 months, there were 91 PFS events and 80 deaths. The median PFS after BM was 8 [95% confidence interval (CI), 6.2-9.8] months and median OS was 14 (95%CI, 10.8-17.2) months with a 2-year OS of 25% (95% CI, 16.7-34.4%). Median PFS in patients who received lapatinib-capecitabine regimen (n=62) was 9.0 (95%CI, 7.3-10.7) months. ConclusionsThe median OS in patients with HER2 positive BCBM, treated with HER2 targeted therapy, is good and exceeds that reported in metastatic triple negative breast cancer. The difference between median PFS and OS suggests that continued treatment after first or subsequent progression may be therapeutically beneficial in some patients. Legal entity responsible for the studySudeep Gupta. FundingHas not received any funding. DisclosureJ. Bajpai: Research grant / Funding (institution): Eli Lilly; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Roche; Research grant / Funding (institution): Samsung Bioepis; Research grant / Funding (institution): Sun Pharma. S. Gupta: Advisory / Consultancy, Research grant / Funding (institution): Roche; Advisory / Consultancy, Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): Johnson & Johnson; Research grant / Funding (institution): Amgen; Research grant / Funding (institution): Celltrion; Advisory / Consultancy, Research grant / Funding (institution): Oncosten; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Intas; Research grant / Funding (institution): Eisai; Advisory / Consultancy, Research grant / Funding (institution): Biocon; Advisory / Consultancy: Dr. Reddy’s Laboratories; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Core Diagnostics. All other authors have declared no conflicts of interest.