Pharmacoeconomics of liposomal anthracycline therapy

Beyond Formulation: Contributions of Nanotechnology for Translation of Anticancer Natural Products into New Drugs

Nature is the largest pharmacy in the world. Doxorubicin (DOX) and paclitaxel (PTX) are two examples of natural-product-derived drugs employed as first-line treatment of various cancer types due to their broad mechanisms of action. These drugs are marketed as conventional and nanotechnology-based formulations, which is quite curious since the research and development (R&D) course of nanoformulations are even more expensive and prone to failure than the conventional ones. Nonetheless, nanosystems are cost-effective and represent both novel and safer dosage forms with fewer side effects due to modification of pharmacokinetic properties and tissue targeting. In addition, nanotechnology-based drugs can contribute to dose modulation, reversion of multidrug resistance, and protection from degradation and early clearance; can influence the mechanism of action; and can enable drug administration by alternative routes and co-encapsulation of multiple active agents for combined chemotherapy. In this review, we discuss the contribution of nanotechnology as an enabling technology taking the clinical use of DOX and PTX as examples. We also present other nanoformulations approved for clinical practice containing different anticancer natural-product-derived drugs.

[A phase Ⅰ dose-escalating trial of pegylated liposomal doxorubicin in combination with cyclophosphamide, vincristine and prednisone for aggressive non-Hodgkin lymphoma]

Objective: To explore the maximum tolerated dose of pegylated liposomal doxorubicin (PLD) in combination with cyclophosphamide, vincristine and prednisone as a modified CHOP regimen for aggressive non-Hodgkin lymphoma. Methods: Patients with newly diagnosed aggressive non-Hodgkin lymphoma were eligible for this trial. PLD was administered in cycle 1 and categorized into 4 dose level (30 mg/m², 35 mg/m², 40 mg/m², 45 mg/m² D1) according to a 3 + 3 approach for dose-escalation. Doxorubin was used in cycles 2-6. In this combination regimen, the doses of cyclophosphamide (750 mg/m² D1), vincristine (1.4 mg/m² D1, maximum dose of 2 mg) and prednisone (100 mg D1-5) were fixed. Toxicities of cycle 1 were documented. Results: Totally, 21 patients were enrolled in this trial. Among them, 15 patients had T-cell lymphoma and 6 had B-cell lymphoma. When the dose of PLD was escalated to the level of 45 mg/m², 2 of 3 patients developed grade 3 mucositis, which met the criteria of dose-limiting toxicity. Therefore, the dose was de-escalated for one level. At the level of 40 mg/m², only one among 12 patients had pneumonia and grade 4 neutropenia. In all dose levels, the grade 3/4 toxicities observed were neutropenia (13 cases, 61.9% ), mucositis (2 cases, 9.5% ), thrombocytopenia (1 case, 4.8%) and pneumonia (1 case, 4.8%). Conclusion: When combined with cyclophosphamide, vincristine and prednisone as a combination regimen, the maximum tolerated dose of PLD was 40 mg/m².

Doxorubicin liposome-loaded microbubbles for contrast imaging and ultrasound-triggered drug delivery

Targeted drug delivery under image guidance is gaining more interest in the drug-delivery field. The use of microbubbles as contrast agents in diagnostic ultrasound provides new opportunities in noninvasive image-guided drug delivery. In the present study, the imaging and therapeutic properties of novel doxorubicin liposome-loaded microbubbles are evaluated. The results showed that at scanning settings (1.7 MHz and mechanical index 0.2), these microbubbles scatter sufficient signal for nonlinear ultrasound imaging and can thus be imaged in real time and be tracked in vivo. In vitro therapeutic evaluation showed that ultrasound at 1 MHz and pressures up to 600 kPa in combination with the doxorubicin liposomeloaded microbubbles induced 4-fold decrease of cell viability compared with treatment with free doxorubicin or doxorubicin liposome-loaded microbubbles alone. The therapeutic effectiveness is correlated to an ultrasound-triggered release of doxorubicin from the liposomes and an enhanced uptake of the free doxorubicin by glioblastoma cells. The results obtained demonstrate that the combination of ultrasound and the doxorubicin liposome-loaded microbubbles can provide a new method of noninvasive image-guided drug delivery.

Improving the therapeutic index of anthracycline chemotherapy: focus on liposomal doxorubicin (Myocet)

Anthracyclines are valuable cytotoxic agents in cancer treatment. However, their usefulness is limited by cumulative dose-dependent cardiotoxicity that may manifest as life-threatening congestive heart failure. To avoid cardiotoxicity, the use of doxorubicin is typically capped at a safe cumulative dose. Liposomal formulations may reduce cardiac risks whilst maintaining anti-cancer efficacy. Efficacy and safety studies of non-pegylated liposomal doxorubicin (NPLD) in metastatic breast cancer (MBC) are reviewed, along with studies that examine efficacy and cardiac tolerability in combination with newer agents such as paclitaxel and trastuzumab. These show that cardiac safety of liposomal doxorubicin is similar to that of epirubicin in cumulative dose, but that the formulation, unlike epirubicin, has similar anti-cancer efficacy to doxorubicin at equimolar doses. Liposomal doxorubicin may have a better therapeutic index than non-liposomal anthracyclines. This justifies further studies in patients where cumulative cardiotoxicity is a concern, as does study of its use with other potentially cardiotoxic agents.

Treatment of recurrent ovarian cancer relapsing 6-12 months post platinum-based chemotherapy

Platinum-containing regimens are the mainstay of initial treatment for ovarian cancer and for platinum-sensitive recurrent disease. In recurrent ovarian cancer, the effectiveness of platinum retreatment is dependent on the relapse-free and treatment-free intervals. Platinum agents can be effectively re-administered to patients with disease that relapses >12 months after completion of a platinum regimen. Ovarian cancer that relapses 6-12 months after treatment with a platinum regimen is considered partially platinum sensitive. Phase III studies of combination regimens versus platinum monotherapy and comparing various non-platinum agents administered as monotherapy generally do not report separate data for partially platinum-sensitive patients. Studies reporting data in patients with a platinum-free interval > or =6 months demonstrate advantages for pegylated liposomal doxorubicin (PLD) versus paclitaxel and PLD versus topotecan. A platinum-taxane combination or single-agent PLD is recommended for the treatment of partially platinum-sensitive disease by the UK National Institute for Health and Clinical Excellence.

Nanotechnology: intelligent design to treat complex disease

The purpose of this expert review is to discuss the impact of nanotechnology in the treatment of the major health threats including cancer, infections, metabolic diseases, autoimmune diseases, and inflammations. Indeed, during the past 30 years, the explosive growth of nanotechnology has burst into challenging innovations in pharmacology, the main input being the ability to perform temporal and spatial site-specific delivery. This has led to some marketed compounds through the last decade. Although the introduction of nanotechnology obviously permitted to step over numerous milestones toward the development of the "magic bullet" proposed a century ago by the immunologist Paul Ehrlich, there are, however, unresolved delivery problems to be still addressed. These scientific and technological locks are discussed along this review together with an analysis of the current situation concerning the industrial development.

Liposomal encapsulated anti-cancer drugs

Among several drug delivery systems, liposomal encapsulated anti-cancer agents represent an advanced and versatile technology. Several formulations of liposomal anthracyclines are approved, e.g. for the treatment of metastatic breast cancer (pegylated and non-pegylated liposomal doxorubicin) or AIDS-related Kaposi's sarcoma (pegylated liposomal doxorubicin and liposomal daunorubicin). Meanwhile, virtually all anti-cancer drugs have been encapsulated in liposomes using different technologies. This review will summarize preclinical and clinical data of approved and exemplary emerging liposomal anti-cancer agents.