Abstract P4-13-26: Efficacy, safety, and treatment decision-making in the AVANTI German observational study of first-line bevacizumab (BEV)-containing therapy for locally advanced, recurrent, or metastatic breast cancer (aBC)

Abstract

Abstract Background: In Europe, BEV is approved as first-line therapy for metastatic breast cancer in combination with either paclitaxel (PAC) or capecitabine (CAP). Methods: The ongoing multicenter non-interventional AVANTI study aims to determine the safety and efficacy of first-line BEV–PAC or BEV–CAP in the context of routine oncology practice in Germany and to assess selection criteria that influence therapy choice. Eligible patients (pts) have previously untreated aBC and no contraindications for BEV. Chemotherapy schedule, diagnostics, and frequency of follow-up visits are at the physician's discretion. Data are collected for 1 year after the start of BEV, with 6-monthly follow-up for 1.5 years after the end of documented observation or BEV discontinuation, whichever occurs first. Results: Between Oct 2009 and Feb 2015, 2168 pts treated at 331 German centers received BEV–PAC (N=1774) or BEV–CAP (N=394). The most common reasons driving treatment choice were efficacy (66% BEV–PAC, 60% BEV–CAP), guidelines (55% BEV–PAC, 50% BEV–CAP), and tolerability (40% BEV–PAC, 45% BEV–CAP). Compared with pts receiving BEV–PAC, the BEV–CAP subgroup included relatively fewer pts with ≥3 metastatic sites, visceral metastases, and stage IV disease at diagnosis, and relatively more pts with triple-negative aBC (TNBC) and prior (neo)adjuvant chemotherapy. At the time of data cut-off for this interim analysis (Mar 1, 2015), median duration of observation was 10.8 months (range <0.1–47.5). BEV was typically continued for longer than chemotherapy (median 5.9 months [95% CI 5.6–6.3] vs 4.6 months [95% CI 4.4–4.9], respectively). Among pts with hormone receptor-positive disease, only 9% received concurrent endocrine therapy with BEV. The most common reason for stopping treatment was disease progression (483 of 1529 [32%] who had stopped BEV–PAC; 157/345 [46%] who had stopped BEV–CAP). At data cut-off, 1245 pts (57%) had experienced a PFS event. Median PFS was 10.1 months (95% CI 9.6–10.7) overall, 10.7 months (95% CI 10.1–11.3) for BEV–PAC, and 8.1 months (95% CI 6.6–9.0) for BEV–CAP. Median PFS in clinically important subgroups was: TNBC 7.1 months (95% CI 6.2–8.0); ≥3 metastatic sites 9.7 months (8.7–11.2); anthracycline- and/or taxane-pretreated 9.2 months (8.5–9.9); ≥65 years old 9.9 months (9.1–10.7). Safety was consistent with the well-established safety profiles of the two regimens. Grade ≥3 adverse events occurred in 17% of pts (16% BEV–PAC, 18% BEV–CAP). There were no new safety signals. Conclusions: Interim results of this large non-interventional study indicate that first-line BEV-containing regimens represent an active and well-tolerated therapy option for aBC. Data collection in non-inferiority studies based on routine clinical practice typically differs from that in prospective clinical trials. Nevertheless, these results from AVANTI suggest that the efficacy and tolerability of BEV–PAC and BEV–CAP seen in the E2100, RIBBON-1, and TURANDOT trials can be replicated in routine oncology practice. Further analyses focusing on the incidence, management, and potential risk factors for elevation of blood pressure are ongoing. Citation Format: Müller V, Jakob A, Aktas B, Grafe A, Fett W, März W, Bruch H, Pott D, Klare P, Boller E, Kiewitz C, Schneeweiss A. Efficacy, safety, and treatment decision-making in the AVANTI German observational study of first-line bevacizumab (BEV)-containing therapy for locally advanced, recurrent, or metastatic breast cancer (aBC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-13-26.