Reduced cardiotoxicity and comparable efficacy in a phase III trial of pegylated liposomal doxorubicin HCl (CAELYX™/Doxil®) versus conventional doxorubicin for first-line treatment of metastatic breast cancer

Background: This study was designed to demonstrate that efficacy [progression-free survival (PFS)] of CAELYX™ [pegylated liposomal doxorubicin HCl (PLD)] is non-inferior to doxorubicin with significantly less cardiotoxicity in first-line treatment of women with metastatic breast cancer (MBC). Patients and methods: Women (n = 509) with MBC and normal cardiac function were randomized to receive either PLD 50 mg/m² (every 4 weeks) or doxorubicin 60 mg/m² (every 3 weeks). Cardiac event rates were based on reductions in left ventricular ejection fraction as a function of cumulative anthracycline dose. Results: PLD and doxorubicin were comparable with respect to PFS [6.9 versus 7.8 months, respectively; hazard ratio (HR) = 1.00; 95% confidence interval (CI) 0.82-1.22]. Subgroup results were consistent. Overall risk of cardiotoxicity was significantly higher with doxorubicin than PLD (HR = 3.16; 95%CI 1.58-6.31; P <0.001). Overall survival was similar (21 and 22 months for PLD and doxorubicin, respectively; HR = 0.94; 95%CI 0.74-1.19). Alopecia. (overall, 66% versus 20%; pronounced, 54% versus 7%), nausea (53% versus 37%), vomiting (31% versus 19%) and neutropenia (10% versus 4%) were more often associated with doxorubicin than PLD. Palmar-plantar erythrodysesthiesia (48% versus 2%), stomatitis (22% versus 15%) and mucositis (23% versus 13%) were more often associated with PLD than doxorubicin. Conclusions: In first-line therapy for MBC, PLD provides comparable efficacy to doxorubicin, with significantly reduced cardiotoxicity, myelosuppression, vomiting and alopecia.