Treatment patterns and outcomes with HER2-directed therapy for the treatment of HER2-positive metastatic breast cancer.

e11063 Background: The goal of this study was to compare treatment patterns and outcomes in patients receiving a HER2 directed therapy for the treatment of HER2+ metastatic breast cancer (mBC). Methods: Female mBC patients (with ≥2 claims with ICD9 diagnosis codes for mBC), age ≥18 years receiving treatment with trastuzumab (T) or lapatinib (L) between 1/1/06 and 8/31/11 were identified in the HealthCore Integrated Research Database (HIRDSM). The earliest mBC claim was defined as index date. Patients with <12 months preindex and ≥6 months postindex continuous eligibility were excluded. Two cohorts were identified: T group received T only; TL group received both L and T (sequentially or together). Treatment duration, metastasis site (mets) at mBC diagnosis, no. of chemotherapy agents, no. of hospitalizations, and total cost of care were assessed in the two groups. Results: Of 1449 patients who received a HER2 directed agent, 1165 were in the T group (mean age 56 yrs) and 284 in the TL group (mean age 54 yr...