Abstract P2-15-07: Real-world multicenter, prospective study of the effects ofnab-paclitaxel on clinical outcomes and quality of life of patients with metastatic breast cancer in Greece. The ‘ABReast’ study

Introduction: Nanoparticle albumin-bound (nab)-paclitaxel (nab-P) is approved for the treatment of patients with metastatic breast cancer (MBC) who have failed first-line treatment for metastatic disease and for whom standard, anthracycline containing therapy is not indicated. Real-world evidence on the effectiveness of nab-P is sparse. From this perspective, this non-interventional study was designed to assess the impact of nab-P on the clinical outcomes and the quality of life of patients with MBC in the routine care of Greece. Materials and methods: This multicenter prospective study enrolled consented females with MBC initiated (≤7 days prior to enrollment) on nab-P according to physicians decision. Clinicopathologic parameters and patient-reported outcomes [Functional Assessment of Cancer Therapy-Breast (FACT-B)] were collected at approximately 9-week intervals during the first 12 months of study participation and approximately every 18 weeks thereafter, until the end of the study observation period (maximum 30 months). Results: Between April 2016 and October 2017, 150 eligible patients (99.3% Caucasian) were enrolled in the study in 16 oncology centers. The patients’ median age was 64.5 years (range: 30.7-84.0) and ECOG performance status was 0 in 66.4% and 1 in 26.2%. 45.3% of patients had ≥1 comorbidity (21.3% cardiovascular diseases). The median time elapsed since MBC diagnosis was 22.4 months, while 36.0% of patients were de novo metastatic. The distribution of hormone receptor (HR)/human epidermal growth factor receptor 2 (HER2) status was 74.6% HR+/HER2-, 11.9% HR-/HER2-, 11.2% HR+/HER2+, and 2.2% HR-/HER2+. Most commonly occurring metastatic sites were the bones (55.3%), lung (50.0%), and liver (40.0%). Prior taxane-based therapy was annotated in 40.0% of patients. Of the patients, 11.3% received nab-P as first, 36.0% as second, 23.3% as third, and 29.3% as fourth or further treatment line. A median of 6 cycles (range: 1-33) was administered; 42.7% of the patients completed >6 and 22.0% >8 cycles. Dose reductions were required for 26.0% of the patients, mainly due to toxicity. The objective response rate was 26.7% and the clinical benefit rate was 44.0%. After a median follow-up of 19.3 months, 92 patients had progressed and 57 had died (14 without progression). The median progression-free survival (PFS) was 6.2 months [95% confidence interval (CI): 5.2-7.3]. The 6- and 12-month PFS rates were 50.6% and 30.5%, respectively. The median overall survival was 21.1 months (95% CI: 17.2-not estimable). Liver [hazard ratio (HR): 1.81; 95% CI: 1.24-2.66] and lung (HR: 1.53; 95% CI: 1.04-2.25) metastases were associated with a higher risk of progression or death. No statistically significant change in the patients’ baseline FACT-B total score (median: 93.0) was observed. The serious and non-serious adverse event (AE) incidence rates were 12.7% and 48.0%, respectively with a total of 37 grade ≥3 AEs (not including disease progression) reported. Conclusion: This study generated real-world evidence on the effectiveness of nab-paclitaxel; no new safety signals emerged. Citation Format: Anna Koumarianou, Paris Makrantonakis, Flora Zagouri, Christos Papadimitriou, Athina Christopoulou, Epaminontas Samantas, Christos Christodoulou, Amanda Psyrri, Dimitris Bafaloukos, Gerasimos Aravantinos, Pavlos Papakotoulas, Sofia Baka, Charalampos Andreadis, Athanasios Alexopoulos, Iliada Bombolaki, Katerina Kampoli, Sofia Liori, Kiki Karvounis, Alexandros Ardavanis. Real-world multicenter, prospective study of the effects of nab-paclitaxel on clinical outcomes and quality of life of patients with metastatic breast cancer in Greece. The ‘ABReast’ study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-15-07.