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

Abstract

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 yrs). T group mets included bone (n=553, 48%), liver (n=336, 29%) and brain (n=283, 24%) mets; TL group had bone mets (n=225, 79%), brain mets (n=167, 59%) and liver mets (n=153, 54%). Mean no. of chemotherapy agents received was lower in T group 3.3 (SD 1.7) compared to TL group 5.8 (SD 2.1) (p=0.0002). The time from 1st mBC diagnosis to treatment with T or L was 117 (SD 217) days in T group and 107 (SD 208) days in TL group. For TL group, time between index date and treatment was 114 (SD 214) days for T and 690 (SD 400) days for L. The mean treatment duration was shorter in T group 417 (SD 366) days compared to TL group 724 (SD 433) days (p<0.0001). TL patients received 579 (SD 402) days of T and 205 (SD 234) days with L. Number of hospitalizations and total cost of care (mean monthly) were 0.1 (SD 0.2) and $12561 (SD $10,975), respectively for T group and 0.1 (SD 0.1) and $13,532 (SD $7,220), respectively for TL group. Conclusions: Mean treatment duration and mean number of chemotherapy agents suggest that the TL group may have received more lines of treatment than the T group. There was no difference in mean monthly costs between the two groups. Medical chart data will be used to confirm treatment patterns and evaluate treatment outcomes in both groups.