Non-pegylated liposomal doxorubicin combined with gemcitabine as first-line treatment for metastatic or locally advanced breast cancer. Final results of a phase I/II trial

Non-Pegylated Liposomal Doxorubicin in Combination with Cyclophosphamide or Docetaxel as First-Line Therapy in Metastatic Breast Cancer: A Retrospective Analysis

Aims and background

Anthracyclines such as doxorubicin play a central role in the management of advanced breast cancer. Unfortunately, the clinical benefits of anthracyclines are limited by cardiotoxicity that can lead to the development of potentially fatal congestive heart failure. In order to limit anthracycline-related cardiotoxicity, liposomal formulations of doxorubicin have been developed. This retrospective analysis evaluated the experience obtained with non-pegylated liposomal doxorubicin as first-line therapy in 34 patients with metastatic breast cancer.

Methods

Patients received non-pegylated liposomal doxorubicin in combination with either cyclophosphamide (n = 14) or docetaxel (n = 20) for up to eight cycles, and efficacy and safety were assessed according to standard criteria.

Results

The overall response rate was 71%. The median progression-free survival was 8 months in patients receiving non-pegylated liposomal doxorubicin plus cyclophosphamide and 13.8 months in those receiving non-pegylated liposomal doxorubicin plus docetaxel (P = 0.2). The most commonly observed toxicities were grade 1–2 leucopenia, alopecia, nausea and vomiting; no grade 3–4 toxicities were observed. Overall, three patients (9%) experienced grade 1 cardiac toxicity.

Conclusions

Our results support the use of non-pegylated liposomal doxorubicin as an alternative to conventional doxorubicin formulations in combination regimens for the first-line therapy of metastatic breast cancer.

Development of nanotheranostics against metastatic breast cancer--A focus on the biology & mechanistic approaches

Treatment for metastatic breast cancer still remains to be a challenge since the currently available diagnostic and treatment strategies fail to detect the micro-metastasis resulting in higher mortality rate. Moreover, the lack of specificity to target circulating tumor cells is also a factor. In addition, currently available imaging modalities to identify the secondaries vary with respect to various metastatic anatomic areas and size of the tumor. The drawbacks associated with the existing clinical management of the metastatic breast cancer demands the requirement of multifunctional nanotheranostics, which could diagnose at macro- and microscopic level, target the solid as well as circulating tumor cells and control further progression with the simultaneous evaluation of treatment response in a single platform. However, without the understanding of the biology as well as preferential homing ability of circulating tumor cells at distant organs, it is quite impossible to address the existing challenges in the present diagnostics and therapeutics against the breast cancer metastasis. Hence this review outlines the severity of the problem, basic biology and organ specificity with the sequential steps for the secondary progression of disease followed by the various mechanistic approaches in diagnosis and therapy at different stages.

Multifunctional polymersomes for cytosolic delivery of gemcitabine and doxorubicin to cancer cells

Although liposomes are widely used as carriers of drugs and imaging agents, they suffer from a lack of stability and the slow release of the encapsulated contents at the targeted site. Polymersomes (vesicles of amphiphilic polymers) are considerably more stable compared to liposomes; however, they also demonstrate a slow release for the encapsulated contents, limiting their efficacy as a drug-delivery tool. As a solution, we prepared and characterized echogenic polymersomes, which are programmed to release the encapsulated drugs rapidly when incubated with cytosolic concentrations of glutathione. These vesicles encapsulated air bubbles inside and efficiently reflected diagnostic-frequency ultrasound. Folate-targeted polymersomes showed an enhanced uptake by breast and pancreatic-cancer cells in a monolayer as well as in three-dimensional spheroid cultures. Polymersomes encapsulated with the anticancer drugs gemcitabine and doxorubicin showed significant cytotoxicity to these cells. With further improvements, these vesicles hold the promise to serve as multifunctional nanocarriers, offering a triggered release as well as diagnostic ultrasound imaging.

[Non-pegylated doxorubicin (Myocet®) as the less cardiotoxic alternative of free doxorubicin]

Anthracyclines have probably been considered to be the most active agents for the treatment of breast cancer and some other solid tumors and hematological malignancies. However, they are associated with dose-related cardiotoxicity, which can lead to progressive myocardial damage and limits the maximal cumulative dose that can be given. This review focuses on the non-pegylated liposome-encapsulated doxorubicin (Myocet®), which has been developed to increase the therapeutic index of free doxorubicin. The encapsulation of doxorubicin within a macromolecular vector, such as a liposome ("nanoparticle based drug delivery system") reduces its distribution volume, diminishing its toxicity for healthy tissues while increasing the concentration within the neoplastic tissue. The most common adverse event is neutropenia, which is consistent with previous experience with free doxorubicin. Available evidence suggests that the incidence of hematological toxicity is lower than with conventional doxorubicin. Myocet® both as a single agent and in combination is effective and safe with an associated reduction in incidence and severity of cardiac events. Nagykálnai T. Non-pegylated doxorubicin (Myocet®) as the less cardiotoxic alternative of free doxorubicin.

Update on non-viral delivery methods for cancer therapy: possibilities of a drug delivery system with anticancer activities beyond delivery as a new therapeutic tool

IMPORTANCE OF THE FIELD

Cancer is the most formidable human disease. Owing to the heterogeneity of cancer, a single-treatment modality is insufficient for the complete elimination of cancer cells. Therapeutic strategies from various aspects are needed for cancer therapy. These therapeutic agents should be carefully selected to enhance multiple therapeutic pathways. Non-viral delivery methods have been utilized to enhance the tumor-selective delivery of therapeutic molecules, including proteins, synthetic oligonucleotides, small compounds and genes.

AREAS COVERED IN THIS REVIEW

As non-viral delivery methods, liposomes and polymer-based delivery materials to target tumors mainly by systemic delivery, physical methods including electroporation, sonoporation, and so on, to locally inject therapeutic molecules, and virosomes to use the viral infectious machinery for the delivery of therapeutic molecules are summarized.

WHAT THE READER WILL GAIN

This article aims to provide an overview of the characteristic properties of each non-viral vector. It will be beneficial to utilize appropriately the vector for cancer treatment.

TAKE HOME MESSAGE

Efficient and minimally invasive vectors are generally considered to be the ideal drug delivery system (DDS). However, against cancer, DDS equipped with antitumor activities may be a therapeutic choice. By combining therapeutic molecules with DDS having antitumor activities, enhancement of the multiple therapeutic pathways may be achieved.