Cardiac safety of adjuvant pegylated liposomal doxorubicin with concurrent trastuzumab: a randomized phase II trial

Background The cardiac safety of trastuzumab concurrent with pegylated liposomal doxorubicin (PLD) in an adjuvant breast cancer treatment regimen is unknown. Patients and methods Women with resected node-positive or intermediate-risk node-negative HER2 overexpressing breast cancer and baseline left ventricular ejection fraction (LVEF) ≥55% were randomized (1 : 2) to doxorubicin 60 mg/m2 (A) + cyclophosphamide 600 mg/m2 (C) every 21 days (q21d) for four cycles or PLD 35 mg/m2 + C q21d + trastuzumab 2 mg/kg weekly (H) for 12 weeks. Both groups then received paclitaxel (Taxol, T) 80 mg/m2 with H for 12 weeks followed by H to complete 1 year. The primary end point was cardiac event rate or inability to administer 1 year of trastuzumab. Results Of 181 randomized patients, 179 underwent cardiac analysis. The incidence of cardiac toxicity or inability to administer trastuzumab due to cardiotoxicity was 18.6% [n = 11; 95% confidence interval (CI) 9.7% to 30.9%] with A + C → T + H and 4.2% (n = 5; 95% CI 1.4% to 9.5%) with PLD + C + H → T + H (P = 0.0036). All events, except one, were asymptomatic systolic dysfunction or mildly symptomatic heart failure. Mean absolute LVEF reduction at cycle 8 was greater with doxorubicin (5.6% versus 2.1%; P = 0.0014). Conclusion PLD + C + H → T + H is feasible and results in lower early cardiotoxicity rates compared with A + C → T + H.