Pegylated Liposomal Doxorubicin (Doxil®) for Metastatic Breast Cancer: The Cancer Research Network, Inc., Experience

Pegylated liposomal doxorubicin (Doxil) was formulated to improve the safety profile of doxorubicin. The major toxicities, mucositis and palmar-plantar erythrodysesthesia, are dose and schedule dependent, respectively. Anecdotal experience suggests that a dosage of 40 mg/m2 every 4 weeks is well tolerated. To evaluate the safety and efficacy of this regimen in women with metastatic breast cancer, we performed a retrospective chart review at a private practice. Forty women received a median initial dose of 42.5 mg/m2 usually every 4 weeks and a median cumulative dose of 135 mg/m2 (range: 40-595 mg/m2). There were 10 partial responses and seven patients with stable disease for more than 6 months resulting in a clinical benefit rate of 43% in the intent-to-treat analysis. The median time to progression was 4 months in all patients, 6.5 months in patients who had partial responses, and 10 months in patients who had stable disease for more than 6 months. There was no grade 4 toxicity. The only grade 3 toxicities were leukopenia in seven (18%) patients, mucositis in one (3%), and palmar-plantar erythrodysesthesia in one (3%). More studies are warranted to confirm our findings, which suggest that pegylated liposomal doxorubicin at a dosage of 40-45 mg/m2 every 4 weeks is clinically active in, and well tolerated by, women with metastatic breast cancer.