Abstract P6-13-02: Efficacy of first-line bevacizumab (BEV)-containing therapy for poor-prognosis advanced breast cancer (aBC): Subgroup analyses of the German AVANTI observational study
Authors: Mueller V , Jakob A , Aktas B , Pott D , Grafe A , Jungberg P , Maerz W , Fett W , Bruch H-R , Klare P , Boller E , Hoefflin S , Schneeweiss A 
Published: May 2019

Background: The multicenter AVANTI observational study is evaluating the safety and effectiveness of EU-approved BEV-containing regimens (BEV + paclitaxel [PAC] or BEV + capecitabine [CAP]) as first-line therapy for HER2-negative aBC in German routine oncology practice.

Methods: Eligible patients (pts) had received no prior chemotherapy (CT) for aBC and had no BEV contraindications. CT schedule, diagnostics, and frequency of follow-up visits are at the physician's discretion. Data are collected for 1 year after starting BEV, with 6-monthly follow-up for 1.5 years thereafter. We explored treatment outcomes in pts with triple-negative aBC (TNBC), pts considered at high risk according to a simple prognostic index for OS in BEV-treated pts [Llombart, 2014], and subgroups defined by timing of BEV+CT initiation.

Results: Between Oct 2009 and Feb 2015, 2168 pts treated at 331 centers received BEV+PAC (n=1774) or BEV+CAP (n=394). Of these, 445 (21%) had TNBC and 306 (14%) met the high-risk criteria. Within the hormone receptor-positive (HR+) subgroup, pts receiving endocrine therapy (ET) before BEV+CT were older than pts starting BEV+CT immediately (median age 65 vs 60 years, respectively) and included a smaller proportion with ECOG performance status 0 (39% vs 47%), visceral metastases (70% vs 77%), or prior (neo)adjuvant CT exposure (46% vs 57%). In all subgroups, median BEV treatment duration was longer than median CT duration. At the data cutoff for this interim analysis (Mar 1, 2015), median duration of observation was 10.8 (range &lt;0.1–47.5) months. The table shows treatment exposure and efficacy overall and in selected subgroups.

table 1 All pts (n=2168)TNBC (n=445)aHR+ with immediate BEV+CT (n=1260)a,bHR+ with ET before BEV+CT (n=309)a,bHigh riskc (n=306)bBEV+PAC, n (%)1774 (82)352 (79)b1062 (84)238 (77)229 (75)Treated until PD, n (%)b,d640 (30)180 (40)314 (25)104 (34)125 (41)BEV+CT until PD449 (21)143 (32)210 (17)61 (20)99 (32)Single-agent BEV until PD191 (9)37 (8)104 (8)43 (14)26 (8)Median BEV duration, months (95% CI)5.9 (5.6–6.3)5.1 (4.9–5.6)6.4 (5.9–7.0)5.6 (5.1–6.5)5.1 (4.6–5.6)Median CT duration, months4.6 (4.4–4.9)3.9 (3.5–4.2)4.9 (4.6–5.1)4.6 (4.2–5.1)3.9 (3.3–4.4)No. of PFS events/pts (%)e1238/2154 (57)302/441 (68)667/1255 (53)187/307 (61)210/306 (69)Median PFS, months (95% CI)10.1 (9.7–10.7)7.2 (6.2–8.0)11.5 (10.8–12.3)9.0 (8.3–10.0)6.4 (5.9–7.4)a154 pts could not be classified as TNBC or HR+ because of missing HR status information. bPost hoc analysis. c≥3 of the 5 risk factors (disease-free interval ≤24 months; ECOG performance status ≥2; liver metastases and/or ≥3 metastatic organ sites; TNBC; prior (neo)adjuvant anthracycline and/or taxane). dData available only in pts with documented end of treatment. ePFS data missing in 14 pts.

Conclusions: Interim results from this large observational study indicate that first-line BEV+CT is an effective therapy in all risk subgroups of a general population of pts with HER2-negative aBC treated in routine oncology practice, including pts with a particularly poor prognosis. Results of these exploratory subgroup analyses suggest that BEV+CT could be considered irrespective of HR status.

Citation Format: Mueller V, Jakob A, Aktas B, Pott D, Grafe A, Jungberg P, Maerz W, Fett W, Bruch H-R, Klare P, Boller E, Hoefflin S, Schneeweiss A. Efficacy of first-line bevacizumab (BEV)-containing therapy for poor-prognosis advanced breast cancer (aBC): Subgroup analyses of the German AVANTI observational study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-13-02.