Abstract P3-06-09: Plasma biomarker analysis in patients with HER2-negative locally recurrent or metastatic breast cancer (LR/MBC) treated with first-line bevacizumab (A) and paclitaxel (T) without or with capecitabine (X)
Authors: Lam Siu W , Nota Nienke M , de Groot Steffen M , Jager Agnes , Bos Monique MEM , Linn Sabine C , van den Bosch Joan , Braun Hans J , van der Velden Ankie MT , Los Maartje , Portielje Johanneke EA , Kroep Judith R , Honkoop Aafke H , Smorenburg Carolien H , Tanis Bea , van Riel Johanna MGH , Meerum Terwogt Jetske M , den Boer Marien O , Douma Joep , Jeurissen Frank , Berends Johan , van Tinteren Harm , Boven Epie 
Published: May 2015

Abstract
Background
The phase II ATX trial aimed at evaluating safety and efficacy of first-line AT or ATX for HER2-negative LR/MBC (NTR1348; BOOG 2006-06). Plasma samples were collected for investigation of circulating proteins involved in angiogenesis and their possible association with therapy outcome. We here report the prognostic value of plasma VEGF-A, soluble (s)VEGFR-2, ANG2, sTIE2, IL6, IL8 and CA9 at baseline (C1D1) and their changes after cycle 1 (C2D1).
Methods
312 patients were randomized 1:1 to AT (T 90 mg/m2 d1, 8, 15 & A 10 mg/kg d1, 15 q4w x 6 cycles → A 15 mg/kg d1 q3w for next cycles) or ATX (T 90 mg/m2 d1, 8, A 15 mg/kg d1 & X 825 mg/m2 bid d1–14 q3w x 8 cycles → A & X at same dose q3w for next cycles). Plasma proteins were measured by immunoassays (R&D Systems and MSD). The association of (continuous) protein levels on C1D1 and their changes on C2D1 with response, PFS and OS were evaluated by Mann-Whitney U test and univariate Cox regression analysis.
Results
The biomarker cohort (n=181) and trial cohort had similar baseline characteristics and clinical outcome. After a median follow-up of 46 months, there were 178 (98%) PFS events and 152 (84%) deaths.
On C1D1, levels of ANG2 and sTIE2 were significantly higher in patients with hormone-receptor positive disease compared to those with triple-negative disease (p=.025 and p=.001, respectively). A high level of VEGF-A was noted in patients with visceral metastases (p=.028) and those with an increasing number of metastatic sites (p=.017). High levels of ANG2, IL6, IL8 and CA9 were significantly associated with poor PFS and OS (Table 1). Protein levels were not associated with response.
Table 1. Association of circulating proteins at baseline with PFS and OSPFS HR (95%CI)PFS p-valueOS HR (95%CI)OS p-valueANG22.3 (1.0-4.9).043.1 (1.4-7.0).007IL61.6 (1.1-2.3).021.9 (1.3-2.8).001IL81.9 (1.3-2.8).0012.8 (1.8-4.3)&lt;.001CA91.8 (1.2-2.7).0061.9 (1.3-2.9).002
On C2D1, levels of all proteins, except for IL6, had significantly changed. Whereas VEGF-A, ANG2, sTIE2 and IL8 decreased significantly, sVEGFR2 and CA9 showed a significant increase. The median relative change of both IL8 and sVEGFR2 was significantly different between patients having CR/PR vs. SD/PD (for IL8: -19.4% vs. 22.3%, p=.001 and for sVEGFR2: 6.5 vs. 2.1%, p=.01). A large relative increase in CA9 level was associated with better PFS (HR = 0.36, 95% CI, 0.19 – 0.68, p=.002) and OS (HR = 0.50, 95% CI, 0.27 – 0.94, p=.03). All patients had very low levels of free VEGF-A on C2D1 (median 8 pg/ml).
Conclusions
In patients with HER2-negative LR/MBC receiving first-line bevacizumab-containing chemotherapy, high baseline plasma levels of ANG2, IL6, IL8 and CA9 indicate a high risk for poor PFS and OS. These proteins might be useful for stratification according to prognosis. Moreover, relative decrease in IL8 and increase in sVEGFR2 on C2D1 are associated with response, whereas a large relative increase in CA9 is associated with better PFS and OS. Changes in these proteins after one cycle might be early indicators of efficacy of bevacizumab combined with chemotherapy.
Financial support from Roche Netherlands.
Citation Format: Siu W Lam, Nienke M Nota, Steffen M de Groot, Agnes Jager, Monique MEM Bos, Sabine C Linn, Joan van den Bosch, Hans J Braun, Ankie MT van der Velden, Maartje Los, Johanneke EA Portielje, Judith R Kroep, Aafke H Honkoop, Carolien H Smorenburg, Bea Tanis, Johanna MGH van Riel, Jetske M Meerum Terwogt, Marien O den Boer, Joep Douma, Frank Jeurissen, Johan Berends, Harm van Tinteren, Epie Boven. Plasma biomarker analysis in patients with HER2-negative locally recurrent or metastatic breast cancer (LR/MBC) treated with first-line bevacizumab (A) and paclitaxel (T) without or with capecitabine (X) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-09.