Safety and efficacy of non-pegylated liposomal doxorubicin (NPLD) in HER2 negative metastatic breast cancer (mBC) patients (PTS) as second-line (2L) and beyond: a restrospective single institution analysis

Background: NPLD has shown comparable efficacy but lower risk of cardiotoxicity, compared to conventional anthracyclines, in mBC pts. Up today, its label indication is limited to the first-line treatment, however, in daily clinical practice, it is widely used in pretreated pts, where limited data exist. Materials and methods: we retrospectively collected all consecutive, HER2 negative, mBC pts treated at our institution with NPLD 60 mg/mq iv every 21 days in 2L or beyond. We reported cpts characteristics, outcomes and adverse events (AEs). Results: Between Nov 2010 to date, we identified 42 pts. Median age: 52 years (range 34 - 73). Molecular subtypes: luminal A 17 (40%); luminalB 20 (48%); triple negative 5 (12%). 18 pts (43%) were previous exposed to anthracyclines (anthra): 16 (38%) pts in neo/adjuvant and 2 pts (5%) in metastatic setting. 10 pts (24%) received adjuvant radiotherapy on the left breast and among them 6 pts (14%) were treated with anthra. NPLD was administered as: 2L in 14 pts (33%); third-line (3L) in 12 pts (29%) while 16 pts (38%) received it after three or more lines. 36 pts (86%) had visceral disease. Median number of cycles was 5 (range 1 - 11). Overall 40 pts were evaluable. Partial response was reported in 7 pts (17,5%) and 13 pts (32,5%) had stable disease with a clinical benefit of 50%. 20 pts (50%) showed a progressive disease (PD) as best response. Median PFS was: 5,3 months (mos) (range 0,7-18,3) in 2L, 3,9 mos (range 0,7-11,36) in 3L and 4,4 mos (range 0,7-18,7) in fourth-line and beyond. There was no difference in mPFS between patients previously exposed or not to anthra: 5,1 mos (range 0,7-18,7) vs 5,6 mos (range 0,69-12,93) respectively (p > 0.05). AEs were mild: nausea G1-2 in 19 pts (45%), fatigue G1-2 in 18 pts (43%), vomiting G1-2 in 7 pts (20%), skin toxicity G1-2 in 7 pts (20%), mucositis G1 in 12 pts (29%) and anemia G1 in 11 pts (26%). The most common G3-4 AEs was neutropenia observed in 12 pts (28%). An asymptomatic reduction in the left ventricular ejection fraction (LVEF) of G1 was shown only in 2 pts (5%). One of them received previous anthra. Conclusions: with the limitation of the retrospective nature of the analysis, our single institution, real life experience demonstrate that NPLD is effective and safe in mBC pts, also as 2L or beyond, irrespective of previous exposure to anthracyclines.