Baseline Characteristics, Treatment Patterns, and Outcomes in Patients with HER2-Positive Metastatic Breast Cancer by Hormone Receptor Status from SystHERs

Abstract

Purpose: We report treatments and outcomes in a contemporary patient population with HER2-positive metastatic breast cancer (MBC) by hormone receptor (HR) status from the Systemic Therapies for HER2-positive Metastatic Breast Cancer Study (SystHERs). Experimental Design: SystHERs (NCT01615068) was an observational, prospective registry study of U.S.-based patients with newly diagnosed HER2-positive MBC. Endpoints included treatment patterns and clinical outcomes. Results: Of 977 eligible patients (enrolled from 2012 to 2016), 70.1% (n ¼ 685) had HR-positive and 29.9% (n ¼ 292) had HR-negative disease. Overall, 59.1% (405/685) of patients with HR-positive disease received any first-line endocrine therapy (with or without HER2-targeted therapy or chemotherapy); 34.9% (239/ 685) received HER2-targeted therapy þ chemotherapy þ sequential endocrine therapy. Patients with HR-positive versus HR-negative disease had longer median overall survival (OS; 53.0 vs 43.4 months; hazard ratio, 0.70; 95% confidence interval, 0.56-0.87). Compared with patients with high HR-positive staining (10%-100%, n ¼ 550), those with low HR-positive staining (1%-9%, n ¼ 60) received endocrine therapy less commonly (64.2% vs 33.3%) and had shorter median OS (53.8 vs 40.1 months). Similar median OS (43.4 vs 40.1 months) was observed in patients with HR-negative versus low HR-positive tumors (1%-9%). Conclusions: Despite evidence that first-line HER2-targeted therapy, chemotherapy, and sequential endocrine therapy improves survival in patients with HR-positive, HER2-positive disease, only 34.9% of patients in this real-world setting received such treatment. Patients with low tumor HR positivity (1%-9%) had lower endocrine therapy use and worse survival than those with high tumor HR positivity (10%-100%).

Therapeutic Strategies for the Management of Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Positive (HR+/HER2+) Breast Cancer: A Review of the Current Literature

“…The end-of-study results of this trial revealed that patients treated with the pertuzumab-containing regimen had an OS of 57.1 months (95% confidence interval (CI) 50-72), compared with 40.8 months (95% CI 36-48) for those treated with the placebo-containing regimen, and that the eight-year OS rates were 37% (95% CI 31-42) and 23% (19)(20)(21)(22)(23)(24)(25)(26)(27)(28), respectively [41]. Endocrine therapy was excluded in this trial, yet is frequently added after the completion of taxane therapy in routine practice, as endorsed in the guidelines [7] and supported by the registHER and SystHER observational studies, which showed clinically meaningful improvements in outcomes of patients with HR+/HER2+ BC treated with maintenance endocrine therapy [75,76].…”

Prognostic role of distant disease-free interval from completion of adjuvant trastuzumab in HER2-positive early breast cancer: analysis from the ALTTO (BIG 2-06) trial

“…12 With a larger sample size, our analysis shows the important prognostic role In addition, our results provide further evidence on the different behaviour of HER2-positive tumours according to hormone receptor status. [13][14][15][16][17][18] As compared to patients with hormone receptor-positive disease, those with hormone receptor-negative tumours had higher likelihood to relapse within 12 months following completion of adjuvant trastuzumab and had poorer OS irrespective of TFI. These data further highlight the need to pursue in research efforts aiming to improve the outcomes of patients with metastatic HER2-positive disease with different approaches according to hormone receptor status.…”

Survival before and after the introduction of pertuzumab and T-DM1 in HER2-positive advanced breast cancer, a study of the SONABRE Registry

“…The number at risk consisted of patients still alive who did not (yet) receive the HER2-targeted therapy of interest. As we expected that HR status might influence the implementation of pertuzumab and T-DM1 in the real world, we additionally looked at the implementation rate, treatment pattern for the first three lines of systemic therapy, and outcome per HR subtype [ 8 , 21 , 22 ].…”