A real-world study on implementation of new therapeutic options, especially bevacizumab, in a cohort of HER2-negative metastatic breast cancer patients treated with first-line chemotherapy.

Abstract

e17549 Background: Treatment of patients with metastatic breast cancer is changing rapidly and real-world data are scarce. Effective implementation of new drugs becomes increasingly important, also from a societal perspective. We questioned how and to whom bevacizumab (BEV) was given in the past few years, also in comparison to the EMA registration trial (NEJM 2007;357:2666-76). Methods: A cohort study was performed, including 480 consecutive breast cancer patients diagnosed with distant metastases in eight Dutch hospitals in the years 2008/2009. We analyzed the real world uptake of first-line chemotherapy with or without BEV in patients with a HER2 negative tumor. Results: Of the 193 HER2 negative patients, 33 received taxane (TAX)-BEV, 29 TAX monotherapy, 63 anthracyclines and 41 capecitabine as first-line chemotherapy after diagnosis of distant metastases. Median follow-up was 2.1 (0.08-3.3) yrs. Median progression-free survival was 7.3 (range 4.3-13.0), 2.7 (1.0-6.2), 5.0 (4.2-5.9) and 4.0 (1.1–4.6) months, respectively (p-value 0.02). Overall survival was 28.4 (14.0-nr), 30.9 (18.2-nr), 17.7 (13.7-22.1), and 24.7 (13.7-28.2) months, respectively (p=0.11). Patients treated with TAX-BEV were younger than those with TAX monotherapy (15% > 65 yrs vs. 27% > 65 yrs; p=0.05), had less co-morbidity and more often received adjuvant chemotherapy (81% vs. 57%; p= <0.0001), also as compared to the EMA registration trial (39%). Patients treated with non-TAX (non-BEV) chemotherapy were older (33% > 65 yrs) and were less likely to have received prior adjuvant chemotherapy (38%). Conclusions: We conclude that real world uptake of BEV was lower than expected and was offered to a selected population. Patient selection differed from the EMA registration trial, which may explain the lower progression-free survival. We recommend the use of broader inclusion criteria in future clinical studies and/or more strict adherence to these criteria in daily practice to guarantee effective implementation of new drugs. Funding: Netherlands Organization for Health Research and Development (ZonMw: 80-82500-98-8003) and Roche Netherlands.