Abstract
Introduction: Human epidermal growth factor receptor 2 (HER-2) targeted therapy regimens can improve tumor response in HER-2-positive metastatic breast cancer (MBC), with overall survival benefits. Objective: We evaluated the efficacy of dual HER-2 blockade combined with chemotherapy for HER-2-positive MBC patients as a first-line therapy in our patient population. Patients and Methods: We identified 75 patients at King Faisal Specialist Hospital and Research Center that received trastuzumab, pertuzumab, and docetaxel as a first-line therapy in HER-2 positive MBC in 2013-2016. Results: Median age at diagnosis was 45 years; 54.7% were estrogen receptor (ER)-positive. 10% of patients presented with only bone metastasis. The median follow-up time was 36 months with an objective response rate of 74.7% (complete response [CR] 18.7%; partial response [PR] 56%). The 5-year progression-free survival (PFS) and overall survival (OS) were 21% and 71.9% respectively, with a median PFS of 36 months (95% confidence interval [CI] 23.6-48.4). The 5-year OS for ER-negative and ER-positive patients was 93.9% and 59.4% respectively (p = 0.189); 23 patients experienced grade 1/2 toxicity and 2 patients had grade 3/4 toxicity. In terms of OS and PFS, the site of metastasis did not make any significant difference. Conclusions: First line pertuzumab, trastuzumab, and docetaxel for HER-2-positive MBC patients was found to be an effective and safe therapy in the Saudi population. This finding was consistent with the results seen in the CLEOPATRA trials.