Abstract P2-16-08: LORHA: Efficacy and safety of 1st-line trastuzumab based treatment, administered for at least 3 years, in patients with HER2-positive metastatic or locally advanced breast cancer - Final results

Background: A subset of patients with HER2-positive metastatic (mBC) or locally advanced breast cancer (aBC) respond to 1st line trastuzumab-based regimen and have no disease progression for several years. These long-term responders were evaluated in daily practice in the LORHA study. Patients and disease characteristics were presented earlier (ESMO 2012). Material and Methods: Lorha is an ambispective, multicenter, non-interventional study conducted in 57 centers in France. Eligible patients were women aged more than 18 years with HER2-positive mBC or aBC treated with 1st line trastuzumab and progression-free for at least 3 years after starting trastuzumab. The primary objective was to describe clinical and tumor characteristics. Secondary objectives included Progression Free Survival (PFS), Overall Survival (OS), treatment administration and safety. Patients were followed-up for 12 months. Final results are presented here. Results: Overall 160 patients were enrolled; 128 were eligible for efficacy analysis and 154 for safety analysis. Median age was 61 years [34-95]. Tumor characteristics were: invasive ductal carcinoma for 112 patients (88%), positive hormonal receptors in 72 patients (58%). At initial diagnosis, 91 patients (71%) had stage I - II tumors and 37 patients (29%) had de novo mBC or aBC. The main metastatic localizations were bone, liver, lymph nodes and lung in 54 (43%), 44 (35%), 25 (20%) and 24 (19%) patients, respectively. Median 1st line trastuzumab treatment duration was 4.5 years [0.8 - 12.1]. Trastuzumab 1st line was associated with a taxane-based chemotherapy in 104/128 patients (81%). Median PFS was 6.4 years [5.7; - Not reached] and median overall survival was not reached. At 1-year follow-up, 23 deaths (15% of patients) were reported, mainly due to disease progression (21 patients - 91%). No toxic death related to trastuzumab was observed. Grade 3-4 adverse events reported prospectively occurred in 14 patients (10%) and included two patients (1.2%) with grade 3-4 cardiac events related to trastuzumab (congestive cardiac failure and left ventricular dysfunction), both events resolved, one with sequelae. Conclusions: Final results of the LORHA study show that long responding patients receiving first-line trastuzumab-based treatment for aBC or mBC in daily practice, can reach a median PFS of more than 6 years, combined with an acceptable safety profile. Median overall survival is still not reached. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-08.