Long term continuous Trastuzumab use for HER2-positive advanced breast cancer

Abstract

Objectives: Trastuzumab is the standard of care for locally advanced / metastatic her2-positive breast cancer. However, most of these patients will progress within 12 months of trastuzumab therapy. In contrast, there is a paucity of data available on the long-term treatment of patients with Trastuzumab. Our study was conducted to report efficacy and safety data for patients with locally recurrent / metastatic her2-positive breast cancer who received long-term therapy with Trastuzumab (≥5 years). Methods: This study was a prospective single-arm study of continuous Trastuzumab in patients who were histologically her2-positive and radiologically confirmed inoperable locally recurrent or metastatic breast cancer after complete one year of Trastuzumab plus chemotherapy (in hormone negative/hormone resistance) treatment then continuous Trastuzumab alone , or with hormone therapy (in sensitive hormone positive) without progression [complete or partial response or stable disease].  A total of 50 inoperable local recurrent and metastatic breast cancer  patients were treated with continuous intravenous Trastuzumab therapy administered according to the standard Trastuzumab every 3-weeks (8 mg/kg loading dose followed by 3-weekly 6  mg/kg maintenance doses starting 3 weeks after the loading dose) schedule, from January 2014 to January 2019 at the Najaf Cancer Clinic (NCC). Results: All 50 patients were evaluated with CR occur only in 20% (10/50) with an OAR of 50% (25/50). The cardiac status of these patients remained stable over time for the majority of patients with no marked changes in LVEF%. No treatment-related death was observed. The median OS and median PFS is 61 months and 20 months, respectively. Conclusion: In her2-positive recurrent and metastatic breast cancer patients, who initially respond to palliative treatment with trastuzumab, continuous trastuzumab can achieve a long-term tumor remission of several years and had significantly improved survival with tolerated and acceptable adverse events.