Phase II trial of pegylated liposomal doxorubicin-cyclophosphamide combination as first-line chemotherapy in older metastatic breast cancer patients

Anticancer and cardio-protective effects of liposomal doxorubicin in the treatment of breast cancer

Breast cancer (BC) is a highly prevalent disease, accounting for the second highest number of cancer-related mortalities worldwide. The anthracycline doxorubicin (DOX), isolated from Streptomyces peucetius var. caesius, is a potent chemotherapeutic drug that is successfully used to treat various forms of liquid and solid tumors and is currently approved to treat BC. DOX exerts its effects by intercalation into DNA and inhibition of topoisomerases I and II, causing damage to DNA and the formation of reactive oxygen species (ROS), resulting in the activation of caspases, which ultimately leads to apoptosis. Unfortunately, DOX also can cause cardiotoxicity, with patients only allowed a cumulative lifetime dose of 550 mg/m². Efforts to decrease cardiotoxicity and to increase the blood circulation time of DOX led to the US Food and Drug Administration (FDA) approval of a PEGylated liposomal formulation (L-DOX), Doxil^® (known internationally as Caelyx^®). Both exhibit better cardiovascular safety profiles; however, they are not currently FDA approved for the treatment of metastatic BC. Here, we provide detailed insights into the mechanism of action of L-DOX and its most common side effects and highlight results of its use in clinical trials for the treatment of BC as single agent and in combination with other commonly used chemotherapeutics.

Efficacy and toxicity of pegylated liposomal doxorubicin-based chemotherapy in early-stage breast cancer: a multicenter retrospective case-control study

AIM

PEGylated liposomal doxorubicin (PLD) has comparable efficacy and differing toxicity from conventional anthracyclines used to treat advanced breast cancer. This study compared disease-free survival and toxicity between PLD-based and conventional anthracycline-based regimens as adjuvant treatments for early-stage breast cancer.

METHODS

We analyzed disease-free survival (DFS) rates, and adverse events in 102 women with early-stage (I-IIIa) breast cancer who received adjuvant PLD-based chemotherapy from 2002 to 2008. Each patient was matched for age, stage at diagnosis, HER-2 expression and hormone therapy use to a patient treated with an epirubicin-based regimen. Fisher's exact and Pearson's chi-square tests were used for categorical data analysis. Kaplan-Meier analysis and Cox regression models were used to analyze DFS.

RESULTS

DFS at 5 years was 81.3% for PLD-based regimen and 82.3% for epirubicin-based regimen. This difference was not significant (p = 0.939). Stage IIIa disease was associated with a shorter DFS in univariate analysis (p = 0.048). In multivariate analysis that controlled for adjuvant treatment, age at diagnosis, stage, HER-2 expression, type of surgery and hormone and radiation therapy, stage IIIa disease (P = 0.023) and lack of hormone therapy (P = 0.024) were each independently associated with shorter DFS. Adverse events were evaluated, and with the exception of hand-foot syndrome, more grade 3 and 4 toxicities occurred in patients who received epirubicin-based regimens than in those given PLD-based regimens.

CONCLUSION

For patients with early-stage breast cancer who received PLD-based adjuvant chemotherapy, 5-year DFS was comparable and toxicity was acceptable, yet different from those of patients who received epirubicin-based regimens.

Chemotherapy treatment for older women with metastatic breast cancer: what is the evidence?

While the over-representation of the elderly in the breast cancer population is projected to dramatically increase within the next two decades, data on chemotherapy for elderly patients with metastatic breast carcinoma (MBC) remain very limited. The aim of the present study is to investigate whether elderly patients included in clinical studies for MBC are representative of the population seen during usual clinical practice. Firstly, a review of the literature was performed identifying 39 publications about chemotherapy for MBC focusing on elderly patients and we examined patient characteristics in each of these publications. Comparison of the age distribution of patients included in these studies with that of a large cohort of consecutive MBC patients aged 65years who received chemotherapy in our institution over the last ten years (n=573) indicated that trials tend to include relatively younger patients. Furthermore, criteria to assess external validity of the results are seldom reported. Possible ways to improve the applicability of results such as increasing the minimum age for inclusion and the use of CGA are proposed.

First-line chemotherapy for metastatic breast cancer in patients ≥75 years: a retrospective single-centre analysis

Data on chemotherapy for elderly patients with metastatic breast carcinoma (MBC) are limited. We performed a 7-year retrospective analysis of MBC patients at our institution receiving first-line chemotherapy aged ≥75 years. Of 117 patients, 103 received monotherapy (67 capecitabine, 29 vinorelbine, 5 docetaxel, 2 liposomal doxorubicin) and 14 received polychemotherapy (12 anthracycline-based, 2 vinorelbine-gemcitabine). Chemotherapy demonstrated acceptable tolerability. Median progression-free survival (PFS) and overall survival (OS) from initiation of chemotherapy were 6.2 months and 13.8 months, respectively. At 2 years, 25% of patients were alive; however, 25% died within 3 months of beginning chemotherapy. Independent prognostic factors for longer PFS were good performance status, absence of visceral disease and capecitabine treatment. Good performance status and lack of visceral disease were also significant for OS. These results suggest that palliative chemotherapy should not be systematically excluded in this setting, but should be carefully discussed as it appears to be feasible with apparent benefit in selected patients.

A multicentric observational trial of pegylated liposomal doxorubicin for metastatic breast cancer

BACKGROUND

Pegylated liposomal doxorubicin (PLD) is active in metastatic breast cancer. This observational study evaluated the efficacy and safety of PLD in patients treated during routine clinical practice.

METHODS

Eligible patients had metastatic breast cancer and were treated with PLD according to the dose and schedule determined by their physician as part of routine practice. The primary objectives were to analyze the efficacy and toxicity of PLD therapy.

RESULTS

125 patients were assessable. Median age was 62 years, 78% had performance status 0-1, and 60% had estrogen-receptor-positive disease. PLD treatment was second- or third-line in 69% of patients. Prior anthracyclines (adjuvant or metastatic) had been used in 56% of patients. The majority of patients (79%) received PLD every 4 weeks at a median dose of 40 mg/m2. Overall response rate was 43% in all patients and 34% in those previously treated with anthracyclines. The most common grade 3/4 adverse events were skin toxicity/hand-foot syndrome (6%), and leukopenia (3%).

CONCLUSIONS

This observational study supports the activity and tolerability of PLD in metastatic breast cancer as demonstrated in PLD clinical trials.