Efficacy and safety of oral lapatinib in HER2 positive metastatic breast cancer / 肿瘤

ABSTRACT

Objective: To determine the effectiveness and safety of lapatinib for patients with human epidermal growth factor receptor-2 (HER2) positive metastatic breast cancer. Methods: In this retrospective study, 40 patients with HER2 positive metastatic breast cancer (MBC) received lapatinib-based regimen. The clinical records and follow-up information were collected and analyzed. Results: Forty patients with HER2 positive MBC were enrolled in this study, and 90.0% (36/40) of the patients had received trastuzumab-based regimen during the recurrent/metastatic period, the median interval of trastuzumab treatment was 12.0 months (95% confidence interval 10.5-13.5 months) (range 2.0-54.0 months); 5.0% (2/40) of the patients had received adjuvant trastuzumab, but the disease-free survival (DFS) was two years or less; 5.0% (2/40) of the patients had never received trastuzumab, but the brain was the first metastatic organ. Of 40 patients, 31 (77.5%) received lapatinib combined with chemotherapy, 6 (15.0%) combined with endocrine therapy, and 3 (7.5%) combined with trastuzumab. The objective response to lapatinib-based therapy was evaluable in all patients. Ten (25.0%) patients achieved partial response (PR), 21 (52.5%) patients had stable disease (SD), 9 (22.5%) had progressive disease (PR), and no one achieved complete response (CR). The objective response rate (ORR) (CR+PR) was 25.0%, and the clinical benefit rate (CBR) (CR+PR+SD≥ 6 months) was 50.0%. The median progression-free survival (PFS) was 6.0 months (95% confidence interval 4.6-7.5 months) (range 1.0-20.0 months). The main toxicities related to lapatinib were grade 1-2 diarrhea in 8 patients (20.0%), and grade 1-2 rash in 6 patients (15.0%). Conclusion: Lapatinib-based therapy is an effective treatment for patients with HER2 positive metastatic breast cancer after prior exposure to trastuzumab.