Early use of lapatinib and trastuzumab is active in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer, a new study published online in the Journal of Clinical Oncology has shown.
For the phase 2 study, researchers enrolled 87 patients with metastatic breast cancer. Patients were divided into two cohorts: (1) those with no prior trastuzumab for metastatic breast cancer and at least 1 year from adjuvant trastuzumab, if given, and (2) those who received one to two lines of chemotherapy including trastuzumab for metastatic breast cancer and/or recurrence less than 1 year from adjuvant trastuzumab.
Results showed that among 85 evaluable patients, the confirmed objective response rate was 50.0% (95% CI: 33.8, 66.2) and 22.2% (95% CI: 11.3, 37.3) in cohorts 1 and 2, respectively. Moreover, researchers found that the clinical benefit rate was 57.5% (95% CI: 40.9, 73.0) and 40.0% (95% CI: 25.7, 55.7), respectively.
The study also demonstrated a median progression-free survival of 7.4 months in cohort 1 and 5.3 months in cohort 2.
In addition, patients who did not achieve a week-1 [18F]fluorodeoxyglucose positron emission tomography imaging ([18F]FDG-PET/CT) response were associated with failure to achieve an objective response, suggesting that [18F]FDG-PET/CT may help to identify patients who can be treated with targeted regimens such as this one and avoid toxicities caused by chemotherapy.
Lin NU, Guo H, Yap JT, et al. Phase II study of lapatinib in combination with trastuzumab in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer: clinical outcomes and predictive value of early [18F]fluorodeoxyglucose positron emission tomography imaging (TBCRC 003). J Clin Oncol. 2015. [epub ahead of print]. doi: 10.1200/JCO.2014.60.0353.