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).

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 erythrodysesthesia (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.