Efficacy of pegylated-liposomal doxorubicin in the treatment of AIDS-related Kaposi's sarcoma after failure of standard chemotherapy

Systemic Treatment Initiation in Classical and Endemic Kaposi's Sarcoma: Risk Factors and Global Multi-State Modelling in a Monocentric Cohort Study

Simple Summary

Over the past decades, clinical features and patients’ outcome of iatrogenic and HIV-related KS epidemiological subtypes have been widely described in large cohort series. Due to their lower incidence and the limited resources available in endemic KS countries, classical and endemic KS epidemiological studies remain scarce, thus increasing the challenge of such clinically heterogeneous chronic diseases’ management. In this large retrospective cohort study, six risk factors for treatment initiation were identified: time between first symptoms and diagnosis ≥1 year, endemic KS, total number of lesions ≥10, visceral or head/neck localization and edema. No response or treatment-free time difference was observed between the most frequently used therapeutic options: chemotherapy and interferon-alpha. Assessment for systemic treatment risk factors provides guidance for adequate follow-up and patients’ information on disease outcome. Absence of efficacy difference between systemic regimens allows treatment choice based on fitness.

Abstract

Background: Although several studies described the clinical course of epidemic and post-transplant Kaposi’s Sarcoma (KS), the lack of large cohorts of classic/endemic KS, precluded such characterization. Methods: We used multi-state modelling in a retrospective monocentric study to evaluate global disease evolution and identify risk factors for systemic treatment (ST) initiation. 160 classic/endemic KS patients consecutively diagnosed between 1990 and 2013 were included. Results: 41.2% of classic/endemic KS patients required ST. Cumulative incidence of ST after 2 years of follow-up was 28.4% [95% CI: 20.5; 35.5]. Multivariate analysis identified six risk factors for ST initiation: time between first symptoms and diagnosis ≥1 year, endemic KS, total number of lesions ≥10, visceral, head or neck localization and presence of edema. Type of ST, type of KS, age and time between diagnosis and ST were not associated with response. Mean treatment-free time during the first 5 years following ST was 44 months for interferon and 44.6 months for chemotherapy treated patients (Mean difference: −0.5 months [95% CI: −9.5; 4.9]). Conclusions: Our study reveals ST risk factors in classic/endemic KS and highlights the clinical aggressiveness of the endemic KS subtype. No efficacy difference was observed between standard of care treatments, enabling treatment choice based on patient’s fitness.

Specific Targeting of PEGylated Liposomal Doxorubicin (Doxil®) to Tumour Cells Using a Novel TIMP3 Peptide

Doxorubicin is a cytotoxic anthracycline derivative that has been used as a chemotherapeutic in many different forms of human cancer with some success. However, doxorubicin treatment has several side-effects, the most serious of which is cardiomyopathy, that can be fatal. Doxorubicin encapsulation in PEGylated liposomes (Doxil^®) has been shown to increase tumour localisation and decrease cardiotoxicity. Conversely, the stability of such liposomes also leads to increased circulation times and accumulation in the skin, resulting in palmar planter erythrodysesthesia, while also limiting release of the drug at the tumour site. Specific targeting of such liposomes to tumour cells has been attempted using various receptor-specific peptides and antibodies. However, targeting a single epitope limits the likely number of tumour targets and increases the risk of tumour resistance through mutation. In this report, Doxil^® was coupled to peptide sequence p700 derived from tissue inhibitor of metalloproteinase 3. This Doxil^® -P700 complex results in an approximately 100-fold increase in drug uptake, relative to Doxil^® alone, by both mouse and human breast cancer cells and immortalised vascular cells resulting in an increase in cytotoxicity. Using p700 to target liposomes in this way may enable specific delivery of doxorubicin or other drugs to a broad range of cancers.

The Confluence of Innovation in Therapeutics and Regulation: Recent CMC Considerations

The field of human therapeutics has expanded tremendously from small molecules to complex biological modalities, and this trend has accelerated in the last two decades with a greater diversity in the types and applications of novel modalities, accompanied by increasing sophistication in drug delivery technology. These innovations have led to a corresponding increase in the number of therapies seeking regulatory approval, and as the industry continues to evolve regulations will need to adapt to the ever-changing landscape. The growth in this field thus represents a challenge for regulatory authorities as well as for sponsors. This review provides a brief description of novel biologics, including innovative antibody therapeutics, genetic modification technologies, new developments in vaccines, and multifunctional modalities. It also describes a few pertinent drug delivery mechanisms such as nanoparticles, liposomes, coformulation, recombinant human hyaluronidase for subcutaneous delivery, pulmonary delivery, and 3D printing. In addition, it provides an overview of the current CMC regulatory challenges and discusses potential methods of accelerating regulatory mechanisms for more efficient approvals. Finally, we look at the future of biotherapeutics and emphasize the need to bring these modalities to the forefront of patient care from a global perspective as effectively as possible.

An Elucidative Review to Analytically Sieve the Viability of Nanomedicine Market

The advent of the twenty-first century marked a paradigm shift in the healthcare sector with coming of automated, sensitive, targeted medicines and technologies having diagnostic, prophylactic and therapeutic effects. Nanomedicines also attained wide acclamation in their initial years, but the transformation from being the proof of concept to successfully marketed products seems very daunting. Although the reason for this may be attributed to slow but incremental character of many present-day technologies, the review asserts that there are other significant facets that may purvey a thorough explanation of this scenario. The article elaborately discusses the hurdles hindering clinical translation of nanomedicines including scale-up challenges, in vitro in vivo cascade of toxicology assays, along with unrefined manufacturing guidelines, inadequate regulatory approvals, competitive conventional market, etc., leading to hesitant investments by pharmaceutical giants. The paper also explores the economic viability of nanobiotechnology sector through an empirical investigation of the revenue data of various pharmaceutical industries manufacturing nano-based drugs, which indicates minor commercial importance of these medicines. We also laid down a comprehensive set of recommendations to smoothen the translational pathway of nanomedicines from an idea to reality, efface the consumer distrust and push boundaries for development and launching of safe, efficient and commercially successful products. Graphical abstract.

AIDS-Related Kaposi Sarcoma, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology

As treatment of HIV has improved, people living with HIV (PLWH) have experienced a decreased risk of AIDS and AIDS-defining cancers (non-Hodgkin's lymphoma, Kaposi sarcoma, and cervical cancer), but the risk of Kaposi sarcoma in PLWH is still elevated about 500-fold compared with the general population in the United States. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for AIDS-Related Kaposi Sarcoma provide diagnosis, treatment, and surveillance recommendations for PLWH who develop limited cutaneous Kaposi sarcoma and for those with advanced cutaneous, oral, visceral, or nodal disease.

Endothelial capture using antibodies and nanoparticles in human tissues: Antigen identification and liver segment imaging

BACKGROUND

The unique phenomenon of endothelial antibody capture (endocapt) leads to site-specific accumulation of antibodies on the endothelium after its locoregional injection. The potential of this phenomenon has already been demonstrated in animal models. In the present study, the translational potential of several human endothelium-specific antibodies for their use in the endocapt-based approach was analysed.

METHODS

The binding of different endothelium-surface specific monoclonal antibody clones was analysed in human tissue and in endothelial cells using image-based immunofluorescence and the determination of half-maximal effective concentration (EC₅₀). The potential of endocapt-based locoregional application of antibodies or antibody-coated liposomes was analysed ex vivo using isolated mouse liver perfusion and in vivo using superselective injection in tumour models.

RESULTS

Eight out of ten antibody clones were assigned to the group of "fast binding antibodies". Different antibody clones showed various binding kinetics to the same endothelial marker whereas the binding kinetics of single antibody clones was independent from the tissue type. Anti-CD49e, anti-CD31, anti-CD34 and anti-CD102 antibodies showed the lowest EC₅₀ of antibody binding concentration and constant results in EC₅₀ determination of antibody binding to cells and human tissue. Experimental studies using anti-mouse CD49e antibody and coated immunoliposomes confirmed their effective capture by endothelial cells in vitro and in vivo by which fluorescent liver segment labelling was achieved.

CONCLUSIONS

Our findings identify the high potential of several human antibody clones, especially anti-CD49e, -CD31, -CD34 and -CD102, for endocapt technology. We also propose important translational implications of these antibodies for image-guided liver surgery and for use of nanoparticles/immunoliposomes. Toxicological studies are indispensable for further translational development of new antibodies for endocapt.

STATEMENT OF SIGNIFICANCE

The phenomenon of endothelial antibody capture (endocapt) leads to site-specific accumulation of antibodies on the endothelium after its locoregional injection. This phenomenon broadly prevents systemic circulation of the antibody or antibody-drug conjugates. In the present study, our findings identify several human antibody clones promising for endothelial capture technology. This study provided the experimental demonstration of liver segment labelling ex vivo using isolated mouse liver perfusion and in vivo using superselective injection in tumor models. In addition, this study proposed the important translational implications of selected antibodies for image-guided liver surgery and for use of nanoparticles/immunoliposomes.

Survey of Clinical Translation of Cancer Nanomedicines-Lessons Learned from Successes and Failures

In 1995, the year the first cancer nanomedicine, Doxil, was approved by the Food and Drug Administration (FDA), only 23 manuscripts appeared in a PubMed search for "nanoparticles for cancer" keywords. Now, over 25 000 manuscripts can be found using those same keywords, yet only 15 nanoparticle-based cancer nanomedicines are approved globally. Based on the clinicaltrials.gov database, a total of 75 cancer nanomedicines are under clinical investigation involving 190 clinical trials summarized here. In this Account, we focus on cancer nanomedicines that have been approved or reached clinical trials to understand this high attrition rate. We classify the various nanomedicines, summarize their clinical outcomes, and discuss possible reasons for product failures and discontinuation of product development efforts. Among ongoing and completed clinical trials, 91 (48 completed) are phase 1, 78 (59 completed) phase 2, and 21 (11 completed) phase 3. The success rate of phase 1 trials has been high-roughly 94%. Of those phase 1 trials with identified outcomes, 45 showed positive safety and efficacy results, with only one negative result (low efficacy) and two terminated due to adverse reactions. In some cases, findings from these trials have not only shown improved pharmacokinetics, but also avid drug accumulation within tumor tissues among active-targeting nanoparticles, including BIND-014, CALAA-01, and SGT-94. However, the success rate drops to ∼48% among completed phase 2 trials with identified outcomes (31 positive, 15 negative, and 4 terminated for toxicity or poor efficacy). A majority of failures in phase 2 trials were due to poor efficacy (15 of 19), rather than toxicity (4 of 19). Unfortunately, the success rate for phase 3 trials slumps to a mere ∼14%, with failures stemming from lack of efficacy. Although the chance of success for cancer nanomedicines starting from the proof-of-concept idea in the laboratory to valuable marketed product may seem daunting, we should not be discouraged. Despite low success rates, funding from the government, foundations, and research organizations are still strong-an estimated > $130 M spent by the National Institutes of Health (NIH) on R01s focused on nanomedicine in 2018 alone. In addition, the NIH created several special initiatives/programs, such as the National Cancer Institute (NCI) Alliance, to facilitate clinical translation of nanomedicines. Companies developing cancer nanomedicines raised diverse ranges of funds from venture capital, capital markets, and industry partnerships. In some cases, the development efforts resulted in regulatory approvals of cancer nanomedicines. In other cases, clinical failures and market pressure from improving standard of care products resulted in product terminations and business liquidation. Yet, recent approvals of nanomedicine products for orphan cancers and continuing development of nanoparticle based drugs for immune-oncology applications fuel continuing industrial and academic interest in cancer nanomedicines.

Liposomal Nanostructures for Drug Delivery in Gastrointestinal Cancers

Gastrointestinal (GI) cancers like liver, pancreatic, colorectal, and gastric cancer remain some of the most difficult and aggressive cancers. Nanoparticles like liposomes had been approved in the clinic for cancer therapy dating as far back as 1995. Over the years, liposomal formulations have come a long way, facing several roadblocks and failures, and advancing by optimizing formulations and incorporating novel design approaches to navigate therapeutic delivery challenges. The first liposomal formulation for a GI cancer drug was approved recently in 2015, setting the stage for further clinical developments of liposome-based delivery systems for therapies against GI malignancies. This article reviews the design considerations and strategies that can be used to deliver drugs to GI tumors, the wide range of therapeutic agents that have been explored in preclinical as well as clinical studies, and the current therapies that are being investigated in the clinic against GI malignancies.

Primary Cardiac Epithelioid Angiosarcoma in a Latin American Patient: Case Report and Literature Review

Cardiac angiosarcoma is a rare and clinically challenging pathology. It is a high-grade primary malignant tumor of the heart tissue that has many variants, of which the epithelioid variant is rarely present in the heart or the great vessels. As with many other cardiac tumors, it is mainly a diagnosis of exclusion and the initial diagnostic test is an echocardiogram followed by a biopsy with immunohistochemistry analysis to ascertain the type of tumor. The differential diagnosis of cardiac tumors is challenging due to the overlapping clinical manifestations with different cardiac tumors and systemic diseases. Cardiac angiosarcomas are often aggressive with a poor prognosis even with treatment. Herein, we present a case of the epithelioid variant of a cardiac angiosarcoma in addition to a thorough review of the recent literature on the clinical manifestation, diagnosis, and treatment of this type of tumors.

Liposome-ligand conjugates: a review on the current state of art

Early researchers focussed on developing stimuli-responsive liposomes in order to manipulate drug release at the site of action or under certain conditions. In recent times, a great deal of efforts has been made to modify the surface of liposomes with ligands for the purpose of achieving targeted drug delivery. Due to the morphology of liposomes, their surfaces can be engineered by attaching molecules such as oligosaccharides, peptides, antibodies, antigens and oligonucleotides to the bilayer structure. Over the years, a number of techniques including the use of covalent and non-covalent linkages have been utilised in designing ligand-liposome conjugates. In this review, various strategies for the functionalisation of liposomes as well as the different types of ligand-liposome conjugates have been discussed. Finally, the pros and cons of conjugation in liposomes are concisely summarised.

Overcoming Biological Barriers in Neuroblastoma Therapy: The Vascular Targeting Approach with Liposomal Drug Nanocarriers

Neuroblastoma is a rare pediatric cancer characterized by a wide clinical behavior and adverse outcome despite aggressive therapies. New approaches based on targeted drug delivery may improve efficacy and decrease toxicity of cancer therapy. Furthermore, nanotechnology offers additional potential developments for cancer imaging, diagnosis, and treatment. Following these lines, in the past years, innovative therapies based on the use of liposomes loaded with anticancer agents and functionalized with peptides capable of recognizing neuroblastoma cells and/or tumor-associated endothelial cells have been developed. Studies performed in experimental orthotopic models of human neuroblastoma have shown that targeted nanocarriers can be exploited for not only decreasing the systemic toxicity of the encapsulated anticancer drugs, but also increasing their tumor homing properties, enhancing tumor vascular permeability and perfusion (and, consequently, drug penetration), inducing tumor apoptosis, inhibiting angiogenesis, and reducing tumor glucose consumption. Furthermore, peptide-tagged liposomal formulations are proved to be more efficacious in inhibiting tumor growth and metastatic spreading of neuroblastoma than nontargeted liposomes. These findings, herein reviewed, pave the way for the design of novel targeted liposomal nanocarriers useful for multitargeting treatment of neuroblastoma.

Kaposi sarcoma

Kaposi sarcoma (KS) gained public attention as an AIDS-defining malignancy; its appearance on the skin was a highly stigmatizing sign of HIV infection during the height of the AIDS epidemic. The widespread introduction of effective antiretrovirals to control HIV by restoring immunocompetence reduced the prevalence of AIDS-related KS, although KS does occur in individuals with well-controlled HIV infection. KS also presents in individuals without HIV infection in older men (classic KS), in sub-Saharan Africa (endemic KS) and in transplant recipients (iatrogenic KS). The aetiologic agent of KS is KS herpesvirus (KSHV; also known as human herpesvirus-8), and viral proteins can induce KS-associated cellular changes that enable the virus to evade the host immune system and allow the infected cell to survive and proliferate despite viral infection. Currently, most cases of KS occur in sub-Saharan Africa, where KSHV infection is prevalent owing to transmission by saliva in childhood compounded by the ongoing AIDS epidemic. Treatment for early AIDS-related KS in previously untreated patients should start with the control of HIV with antiretrovirals, which frequently results in KS regression. In advanced-stage KS, chemotherapy with pegylated liposomal doxorubicin or paclitaxel is the most common treatment, although it is seldom curative. In sub-Saharan Africa, KS continues to have a poor prognosis. Newer treatments for KS based on the mechanisms of its pathogenesis are being explored.

Long-term cure of soft tissue sarcoma with pegylated-liposomal doxorubicin after doxorubicin and ifosfamide failure

Background

Doxorubicin is one of the most active drugs available for the treatment of sarcoma. Pegylated-liposomal doxorubicin (PLD) is a formulation of doxorubicin in which the doxorubicin is encapsulated in liposomes coated with methoxypoly (ethylene glycol); this formulation results in decreased uptake by the reticuloendothelial system, higher concentrations of drug in tumor, and less toxicity, including reduced cardiotoxicity, nausea, alopecia, and myelosuppression. No premedication is necessary. While PLD has a better toxicity profile than free doxorubicin, there is no consensus on the relative efficacy of PLD and free doxorubicin in sarcoma.

Case presentation

In this report, we describe a patient with high-grade metastatic soft tissue sarcoma with rapid recurrence after adjuvant treatment with free doxorubicin, cisplatin, ifosfamide, and dacarbazine. Second-line treatment with PLD resulted in long-term disease remission during a 20-year follow-up period. Mucositis and hand-foot syndrome were controlled by adjustment of dose and treatment interval.

Conclusions

This case illustrates the curative potential of PLD after failure of free doxorubicin and the absence of long term cardiotoxicity with PLD. As with all drugs, individual adjustment of dose and treatment interval is important.

Recent advances in "smart" delivery systems for extended drug release in cancer therapy

Advances in nanomedicine have become indispensable for targeted drug delivery, early detection, and increasingly personalized approaches to cancer treatment. Nanoparticle-based drug-delivery systems have overcome some of the limitations associated with traditional cancer-therapy administration, such as reduced drug solubility, chemoresistance, systemic toxicity, narrow therapeutic indices, and poor oral bioavailability. Advances in the field of nanomedicine include “smart” drug delivery, or multiple levels of targeting, and extended-release drug-delivery systems that provide additional methods of overcoming these limitations. More recently, the idea of combining smart drug delivery with extended-release has emerged in hopes of developing highly efficient nanoparticles with improved delivery, bioavailability, and safety profiles. Although functionalized and extended-release drug-delivery systems have been studied extensively, there remain gaps in the literature concerning their application in cancer treatment. We aim to provide an overview of smart and extended-release drug-delivery systems for the delivery of cancer therapies, as well as to introduce innovative advancements in nanoparticle design incorporating these principles. With the growing need for increasingly personalized medicine in cancer treatment, smart extended-release nanoparticles have the potential to enhance chemotherapy delivery, patient adherence, and treatment outcomes in cancer patients.

Diagnosis and Treatment of Kaposi Sarcoma

Kaposi sarcoma (KS) is the most common neoplasm of people living with HIV today. In Sub-Saharan Africa, KS is among the most common cancers in men, overall. Not only HIV-positive individuals present with KS; any immune compromised person infected with KS-associated herpesvirus (KSHV) or human herpesvirus 8 is at risk: the elderly, children in KSHV-endemic areas, and transplant recipients. KS diagnosis is based on detection of the viral protein latency-associated nuclear antigen (LANA) in the biopsy, but not all cases of KS are the same or will respond to the same therapy. Standard KS therapy has not changed in 20 years, but newer modalities are on the horizon and will be discussed.

Role of Pegylated Lyposomal Doxorubicin (PLD) in Systemic Kaposi's Sarcoma: A Systematic Review

Kaposi's sarcoma (KS) is a form of skin cancer that can involve internal organs. It is often found in patients with acquired immunodeficiency syndrome (AIDS) and can be fatal. Kaposi's sarcoma produces pink, purple or brown tumors on the skin, mucous membranes or internal organs. Treatment goals for KS are simple: to reduce the severity of the symptoms, shrink tumors and prevent disease progression. Unfortunately, there is no single best treatment-plan that can achieve all these goals. With widespread KS lesions over the body surface or evidence of spreading to other parts of the body, the physicians need to treat the patients with systemic chemotherapy. A new class of drugs, called liposomal anthracyclines, appears to produce good results with fewer toxic side effects than more conventional cytotoxic drugs. One of these drugs, pegylated liposomal doxorubicin (PLD) has become the treatment of choice. This article summarizes all the studies with PLD in systemic Kaposi's sarcoma.

A liposomal drug platform overrides peptide ligand targeting to a cancer biomarker, irrespective of ligand affinity or density

One method for improving cancer treatment is the use of nanoparticle drugs functionalized with targeting ligands that recognize receptors expressed selectively by tumor cells. In theory such targeting ligands should specifically deliver the nanoparticle drug to the tumor, increasing drug concentration in the tumor and delivering the drug to its site of action within the tumor tissue. However, the leaky vasculature of tumors combined with a poor lymphatic system allows the passive accumulation, and subsequent retention, of nanosized materials in tumors. Furthermore, a large nanoparticle size may impede tumor penetration. As such, the role of active targeting in nanoparticle delivery is controversial, and it is difficult to predict how a targeted nanoparticle drug will behave in vivo. Here we report in vivo studies for α_vβ₆-specific H2009.1 peptide targeted liposomal doxorubicin, which increased liposomal delivery and toxicity to lung cancer cells in vitro. We systematically varied ligand affinity, ligand density, ligand stability, liposome dosage, and tumor models to assess the role of active targeting of liposomes to α_vβ₆. In direct contrast to the in vitro results, we demonstrate no difference in in vivo targeting or efficacy for H2009.1 tetrameric peptide liposomal doxorubicin, compared to control peptide and no peptide liposomes. Examining liposome accumulation and distribution within the tumor demonstrates that the liposome, and not the H2009.1 peptide, drives tumor accumulation, and that both targeted H2009.1 and untargeted liposomes remain in perivascular regions, with little tumor penetration. Thus H2009.1 targeted liposomes fail to improve drug efficacy because the liposome drug platform prevents the H2009.1 peptide from both actively targeting the tumor and binding to tumor cells throughout the tumor tissue. Therefore, using a high affinity and high specificity ligand targeting an over-expressed tumor biomarker does not guarantee enhanced efficacy of a liposomal drug. These results highlight the complexity of in vivo targeting.

Efficient electroporation of liposomes doped with pore stabilizing nisin

CONTEXT

Liposomes have a long history as passive and active drug carriers. Recently, a few methods have been realized to control the release from liposomes, including heating, ultrasound and laser.

OBJECTIVE

We report on a new approach to drive release from liposomes using electric fields.

MATERIALS AND METHODS

Liposomes were manufactured containing a high concentration of (quenched) 5-6 carboxyfluorescein dye. Nisin, a well-known amphiphilic peptide lantibiotic that works by stabilizing pores formed in cell membranes, was mixed in solution inside or outside the liposomes. The liposomes were then electroporated using a range of voltages, and assayed for increases in fluorescence due to release of dye. Release was measured against positive and negative controls, with positive control release driven by a strong detergent.

RESULTS

Our results demonstrate that the addition of nisin significantly reduces the electric field required to release the contents of liposomes, from 2000 V/m to approximately 200 V/m. This result proves that, in principle, electroporation (EP) of liposomes doped with small amounts of amphiphilic pore stabilizing peptides may be a practical means to drive release of liposomal contents in vivo.

CONCLUSION

Drug delivery from liposomes doped with amphiphilic peptides using EP is feasible. This technique could be developed into a potent adjuvant to tumor ablation using irreversible EP.

A porcine model of complement-mediated infusion reactions to drug carrier nanosystems and other medicines

Intravenous administration of low (milligram) doses of nanoparticulate materials in pigs can lead to acute cardiopulmonary, hemodynamic, hematological, biochemical and dermatological changes within minutes, mimicking the human infusion (or anaphylactoid) reactions to many state-of-the-art (nano)medicines and biologicals. Because of the causal role of complement (C) activation, the phenomenon was called C activation-related pseudoallergy (CARPA). This review summarizes the available information on porcine CARPA caused by different liposomes and polymers. It provides methodical details of the model and addresses the quantitation, sensitivity, specificity, reproducibility and variability of symptoms caused by different reactogenic drugs. We describe a unique feature of the model: the rise of tachyphylaxis (self-induced tolerance) as a function of structural properties of reactogenic agents. For drugs that cause tachyphylactic CARPA, such as liposomal doxorubicin (Doxil), the review recapitulates a recently reported method of desensitization, which may prevent this, as well as many similar hypersensitivity reactions. In explaining the underlying mechanism of tachyphylactic CARPA, a new theory on "double hit" is outlined, wherein the pulmonary intravascular macrophages (PIM cells) of pigs give aggravated response to simultaneous stimulation of their anaphylatoxin and other surface receptors (e.g., toll-like, PAMP, DAMP or mannose) that recognize vesicle surface molecular patterns. The porcine CARPA model might provide unique advantages in studying the mechanism of severe hypersensitivity reactions in man to i.v. drugs, as well as in identifying drugs and drug carriers that may cause such reactions.

Drug conjugates such as Antibody Drug Conjugates (ADCs), immunotoxins and immunoliposomes challenge daily clinical practice

Drug conjugates have been studied extensively in preclinical in vitro and in vivo models but to date only a few compounds have progressed to the clinical setting. This situation is now changing with the publication of studies demonstrating a significant impact on clinical practice and highlighting the potential of this new class of targeted therapies. This review summarizes the pharmacological and molecular background of the main drug conjugation systems, namely antibody drug conjugates (ADCs), immunotoxins and immunoliposomes. All these compounds combine the specific targeting moiety of an antibody or similar construct with the efficacy of a toxic drug. The aim of this strategy is to target tumor cells specifically while sparing normal tissue, thus resulting in high efficacy and low toxicity. Recently, several strategies have been investigated in phase I clinical trials and some have entered phase III clinical development. This review provides a detailed overview of various strategies and critically discusses the most relevant achievements. Examples of the most advanced compounds include T-DM1 and brentuximab vedotin. However, additional promising strategies such as immunotoxins and immunoliposmes are already in clinical development. In summary, targeted drug delivery by drug conjugates is a new emerging class of anti-cancer therapy that may play a major role in the future.

Pegylated liposomal doxorubicin in malignant pleural mesothelioma: a possible guardian for long-term survival

Malignant pleural mesothelioma is a rare and aggressive malignancy of the pleura correlated with exposure to asbestos, with a medium survival of 11–12 months after diagnosis. A case of a 67-year-old male who had previously worked in the asbestos industry and is a current smoker is reported. The computed tomography evaluation revealed a right pleural mass with pleural thickening, and the pleural biopsy confirmed a diagnosis of malignant pleural mesothelioma. He was treated with chemotherapy consisting of etoposide, paclitaxel, and pegylated liposomal doxorubicin hydrochloride. After completion of chemotherapy, radiologic evaluation confirmed a reduction of pleural thickening and improvement in his symptoms. A complete presentation of each drug formulation and characteristics are also included in this paper. The patient’s follow-up is continuing, and computed tomography reveals stable disease 9 years after initial examination.

Molecular-targeted nanotherapies in cancer: enabling treatment specificity

Chemotherapy represents a mainstay and powerful adjuvant therapy in the treatment of cancer. The field has evolved from drugs possessing all-encompassing cell-killing effects to those with highly targeted, specific mechanisms of action; a direct byproduct of enhanced understanding of tumorigenic processes. However, advances regarding development of agents that target key molecules and dysregulated pathways have had only modest impacts on patient survival. Several biological barriers preclude adequate delivery of drugs to tumors, and remain a formidable challenge to overcome in chemotherapy. Currently, the field of nanomedicine is enabling the delivery of chemotherapeutics, including repositioned drugs and siRNAs, by giving rise to carriers that provide for protection from degradation, prolonged circulation times, and increased tumor accumulation, all the while resulting in reduced patient morbidity. This review aims to highlight several innovative, nanoparticle-based platforms with the potential of providing clinical translation of several novel chemotherapeutic agents. We will also summarize work regarding the development of a multistage drug delivery strategy, a robust carrier platform designed to overcome several biological barriers while en route to tumors.

Engineered nanostructural materials for application in cancer biology and medicine

Nanotechnology covers a wide variety of fields of research, including chemistry, physics, biology and medicine, with extensive applications in cancer, ranging from accurate, early detection of malignant lesions to minimizing metastasis. Continued development of cancer-targeted therapy has promising advantages: maximizing the effectiveness of anticancer drugs while decreasing the harmful systemic effects; tumor destruction via heating that takes advantage of magnetic nanoparticles' size, magnetization and biocompatibility; novel drug-delivery systems; and gene therapy functions to facilitate controlled drug loading and release inside the cytoplasm. These and other nanotechnology applications can contribute essential new knowledge in the fight against cancer.

Nanomedicine in cancer therapy: innovative trends and prospects

Cancer is a leading cause of morbidity and mortality worldwide, with recent advancements resulting in modest impacts on patient survival. Nanomedicine represents an innovative field with immense potential for improving cancer treatment, having ushered in several established drug delivery platforms. Nanoconstructs such as liposomes are widely used in clinics, while polymer micelles are in advanced phases of clinical trials in several countries. Currently, the field of nanomedicine is generating a new wave of nanoscale drug delivery strategies, embracing trends that involve the functionalization of these constructs with moieties that enhance site-specific delivery and tailored release. Herein, we discuss several advancements in established nanoparticle technologies such as liposomes, polymer micelles, and dendrimers regarding tumor targeting and controlled release strategies, which are being incorporated into their design with the hope of generating a more robust and efficacious nanotherapeutic modality. We also highlight a novel strategy known as multistage drug delivery; a rationally designed nanocarrier aimed at overcoming numerous biological barriers involved in drug delivery through the decoupling of various tasks that comprise the journey from the moment of systemic administration to arrival at the tumor site.

The use of single chain Fv as targeting agents for immunoliposomes: an update on immunoliposomal drugs for cancer treatment

IMPORTANCE OF THE FIELD

Targeted liposomal drugs represent the next evolution of liposomal drug delivery in cancer treatment. In various preclinical cancer models, antibody-targeted PEGylated liposomal drugs have demonstrated superior therapeutic effects over their non-targeted counterparts. Single chain Fv (scFv) has gained popularity in recent years as the targeting agent of choice over traditional targeting agents such as monoclonal antibodies (mAb) and antibody fragments (e.g., Fab').

AREAS COVERED IN THIS REVIEW

This review is focused mainly on advances in scFv-targeted liposomal drug delivery for the treatment of cancers, based on a survey of the recent literature, and on experiments done in a murine model of human B-lymphoma, using anti-CD19 targeted liposomes targeted with whole mAb, Fab' fragments and scFv fragments.

WHAT THE READER WILL GAIN

This review examines the recent advances in PEGylated immunoliposomal drug delivery, focusing on scFv fragments as targeting agents, in comparison with Fab' and mAb.

TAKE HOME MESSAGE

For clinical development, scFv are potentially preferred targeting agents for PEGylated liposomes over mAb and Fab', owing to factors such as decreased immunogenicity, and pharmacokinetics/biodistribution profiles that are similar to non-targeted PEGylated (Stealth) liposomes.

Extended remission of metastatic epithelioid angiosarcoma of the heart with liposomal doxorubicin

Angiosarcoma is the most common primary malignant tumour of the heart. It is a rare and aggressive neoplasm that almost always has a short and fatal evolution. By the time it produces symptoms it has usually progressed to a mass causing haemodynamic compromise. Initial presentation with metastatic disease is unusual. We report the case of a 72-year-old man who presented with painful skin lesions on both hands. The skin biopsy was diagnosed as intravascular metastasis of epithelioid angiosarcoma. Body computed tomography scan disclosed a solid mass in the left atrium. The tumour was judged unresectable and the patient was treated with systemic chemotherapy, consisting of liposomal doxorubicin, which resulted in a complete clinical response. The patient remains free of disease after 48 months of follow-up. The excellent clinical evolution of our patient verifies that liposomal doxorubicin may be effective in the treatment of these tumours and significantly prolong patients' lifespan.

Safety and efficacy of pegylated liposomal doxorubicin in HIV-associated Kaposi's sarcoma

Kaposi’s sarcoma is a vascular tumor linked to the presence of Kaposi’s sarcoma-associated herpesvirus (human herpesvirus-8) and the incidence of which has increased considerably the world over after the onset of the human immunodeficiency virus (HIV) pandemic. Antiretroviral therapy combined with cytotoxic agents has been established as the treatment of choice in the past 10 years. Among chemotherapeutic agents, pegylated liposomal doxorubicin has become the preferred one for patients with HIV-associated Kaposi’s sarcoma in Western countries. The drug in this formulation localizes better to the tumor and has higher efficacy. Skin toxicity, mucositis, and leukopenia/neutropenia are the main side effects. Hepatotoxicity and mild cardiotoxicity are observed less frequently. Pegylated liposomal doxorubicin impacts favorably on quality of life. Although cost effective in Western countries, the drug is less so in developing countries.

Advances of cancer therapy by nanotechnology

Recent developments in nanotechnology offer researchers opportunities to significantly transform cancer therapeutics. This technology has enabled the manipulation of the biological and physicochemical properties of nanomaterials to facilitate more efficient drug targeting and delivery. Clinical investigations suggest that therapeutic nanoparticles can enhance efficacy and reduced side effects compared with conventional cancer therapeutic drugs. Encouraged by rapid and promising progress in cancer nanotechnology, researchers continue to develop novel and efficacious nanoparticles for drug delivery. The use of therapeutic nanoparticles as unique drug delivery systems will be a significant addition to current cancer therapeutics.

Successful treatment with liposomal doxorubicin for widespread Kaposi's sarcoma and human herpesvirus-8 related severe hemophagocytic syndrome in a patient with acquired immunodeficiency syndrome

Hemophagocytic syndrome (HPS) sometimes occurres in patients with acquired immunodeficiency syndrome (AIDS). Human herpesvirus-8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus has so far been recognized as a trigger of HPS in immunosuppressed subject. We describe a 39-year-old man with AIDS who had widespread mucocutaneous and pulmonary KS and severe HPS. No opportunistic infections or neoplasias were detected except for KS. HHV-8-DNA could be detected in this patient by polymerase chain reaction (PCR) in the serum. Clinical symptoms and cytopenia originating from HPS were reduced by pulse therapy of corticosteroid, antibiotics, and virucides, but recurred with dose reduction of the steroid. Mucocutaneous tumors, edema, and dyspnea had progressed rapidly at this time. Liposomal doxorubicin was given and showed marked effects on both mucocutaneous and plural tumors. HPS also subsided and the serum HHV-8 DNA level markedly decreased after initial treatment with liposomal doxorubicin. HHV-8 clearance with liposomal doxorubicin has recently been reported. Liposomal doxorubicin suppressed not only the widespread KS tumors, but also HHV-8 viremia resulting in decreased HPS in this patient.

Enhanced Antitumor Efficacy of Clinical-Grade Vasculature-Targeted Liposomal Doxorubicin

Purpose: In vivo evaluation of good manufacturing practice-grade targeted liposomal doxorubicin (TVT-DOX), bound to a CD13 isoform expressed on the vasculature of solid tumors, in human tumor xenografts of neuroblastoma, ovarian cancer, and lung cancer.

Experimental Design: Mice were implanted with lung, ovarian, or neuroblastoma tumor cells via the pulmonary, peritoneal, or orthotopic (adrenal gland) routes, respectively, and treated, at different days post inoculation, with multiple doses of doxorubicin, administered either free or encapsulated in untargeted liposomes (Caelyx) or in TVT-DOX. The effect of TVT-DOX treatment on tumor cell proliferation, viability, apoptosis, and angiogenesis was studied by immunohistochemical analyses of neoplastic tissues and using the chick embryo chorioallantoic membrane assay.

Results: Compared with the three control groups (no doxorubicin, free doxorubicin, or Caelyx), statistically significant improvements in survival was seen in all three animal models following treatment with 5 mg/kg (maximum tolerated dose) of TVT-DOX, with long-term survivors occurring in the neuroblastoma group; increased survival was also seen at a dose of 1.7 mg/kg in mice bearing neuroblastoma or ovarian cancer. Minimal residual disease after surgical removal of neuroblastoma primary mass, and the enhanced response to TVT-DOX, was visualized and quantified by bioluminescence imaging and with magnetic resonance imaging. When treated with TVT-DOX, compared with Caelyx, all three tumor models, as assayed by immunohistochemistry and chorioallantoic membrane, showed statistically significant reductions in cell proliferation, blood vessel density, and microvessel area, showing increased cell apoptosis.

Conclusion: TVT-DOX should be evaluated as a novel angiostatic strategy for adjuvant therapy of solid tumors.

Sarcoma

Sarcomas comprise a heterogeneous group of mesenchymal neoplasms. They can be grouped into 2 general categories, soft tissue sarcoma and primary bone sarcoma, which have different staging and treatment approaches. This review includes a discussion of both soft tissue sarcomas (malignant fibrous histiocytoma, liposarcoma, leiomyosarcoma, synovial sarcoma, dermatofibrosarcoma protuberans, angiosarcoma, Kaposi sarcoma, gastrointestinal stromal tumor, aggressive fibromatosis or desmoid tumor, rhabdomyosarcoma, and primary alveolar soft-part sarcoma) and primary bone sarcomas (osteosarcoma, Ewing sarcoma, giant cell tumor, and chondrosarcoma). The 3 most important prognostic variables are grade, size, and location of the primary tumor. The approach to a patient with a sarcoma begins with a biopsy that obtains adequate tissue for diagnosis without interfering with subsequent optimal definitive surgery. Subsequent treatment depends on the specific type of sarcoma. Because sarcomas are relatively uncommon yet comprise a wide variety of different entities, evaluation by oncology teams who have expertise in the field is recommended. Treatment and follow-up guidelines have been published by the National Comprehensive Cancer Network (www.nccn.org).

Binding and internalization of NGR-peptide-targeted liposomal doxorubicin (TVT-DOX) in CD13-expressing cells and its antitumor effects

In an effort to develop new agents and molecular targets for the treatment of cancer, aspargine-glycine-arginine (NGR)-targeted liposomal doxorubicin (TVT-DOX) is being studied. The NGR peptide on the surface of liposomal doxorubicin (DOX) targets an aminopeptidase N (CD13) isoform, specific to the tumor neovasculature, making it a promising strategy. To further understand the molecular mechanisms of action, we investigated cell binding, kinetics of internalization as well as cytotoxicity of TVT-DOX in vitro. We demonstrate the specific binding of TVT-DOX to CD13-expressing endothelial [human umbilical vein endothelial cells (HUVEC) and Kaposi sarcoma-derived endothelial cells (SLK)] and tumor (fibrosarcoma, HT-1080) cells in vitro. Following binding, the drug was shown to internalize through the endosomal pathway, eventually leading to the localization of doxorubicin in cell nuclei. TVT-DOX showed selective toxicity toward CD13-expressing HUVEC, sparing the CD13-negative colon-cancer cells, HT-29. Additionally, the nontargeted counterpart of TVT-DOX, Caelyx, was less cytotoxic to the CD13-positive HUVECs demonstrating the advantages of NGR targeting in vitro. The antitumor activity of TVT-DOX was tested in nude mice bearing human prostate-cancer xenografts (PC3). A significant growth inhibition (up to 60%) of PC3 tumors in vivo was observed. Reduction of tumor vasculature following treatment with TVT-DOX was also apparent. We further compared the efficacies of TVT-DOX and free doxorubicin in the DOX-resistant colon-cancer model, HCT-116, and observed the more pronounced antitumor effects of the TVT-DOX formulation over free DOX. The potential utility of TVT-DOX in a variety of vascularized solid tumors is promising.

Animal models of complement-mediated hypersensitivity reactions to liposomes and other lipid-based nanoparticles

Intravenous injection of some liposomal drugs, diagnostic agents, micelles and other lipid-based nanoparticles can cause acute hypersensitivity reactions (HSRs) in a high percentage (up to 45%) of patients, with hemodynamic, respiratory and cutaneous manifestations. The phenomenon can be explained with activation of the complement (C) system on the surface of lipid particles, leading to anaphylatoxin (C5a and C3a) liberation and subsequent release reactions of mast cells, basophils and possibly other inflammatory cells in blood. These reactions can be reproduced and studied in pigs, dogs and rats, animal models which differ from each other in sensitivity and spectrum of symptoms. In the most sensitive pig model, a few miligrams of liposome (phospholipid) can cause anaphylactoid shock, characterized by pulmonary hypertension, systemic hypotension, decreased cardiac output and major cardiac arrhythmias. Pigs also display cutaneous symptoms, such as flushing and rash. The sensitivity of dogs to hemodynamic changes is close to that of pigs, but unlike pigs, dogs also react to micellar lipids (such as Cremophor EL) and their response includes pronounced blood cell and vegetative neural changes (e.g., leukopenia followed by leukocytosis, thrombocytopenia, fluid excretions). Rats are relatively insensitive inasmuch as hypotension, their most prominent response to liposomes, is induced only by one or two orders of magnitude higher phospholipid doses (based on body weight) compared to the reactogenic dose in pigs and dogs. It is suggested that the porcine and dog models are applicable for measuring and predicting the (pseudo)allergic activity of particulate "nanodrugs".

Phase 1 European Organisation for Research and Treatment of Cancer study determining safety of pegylated liposomal doxorubicin (Caelyx®) in combination with ifosfamide in previously untreated adult patients with advanced or metastatic soft tissue sarcomas

This phase I study evaluated the toxicity of first-line combined pegylated liposomal doxorubicin (Caelyx) and ifosfamide in patients with advanced and/or metastatic soft tissue sarcomas. Five dose levels (L) were studied: Caelyx 30 mg/m2 (L1-4) or 40 mg/m2 (L5) 1-h infusion d 1 q 3 weeks + ifosfamide and mesna at X g/m2/4 h d 1-3 q 3 weeks at five doses: L1: X = 1.7 g; L2: X = 2 g; L3: X = 2.5 g; L4 and L5: X = 3 g. Cohorts of 3 patients were entered at each level unless a dose-limiting toxicity (DLT) occurred. In case of DLT in 1 of 3 patients a new cohort was added. Toxicity was evaluated by Common Toxicity Criteria (CTC). A total of 28 patients was included: 4 at dose L1, 8 at L2, 3 at L3, 6 at L4, and 7 at L5. Median age was 60 years (range 29-69 years). Male/female ratio was 12/16. Seventy-five percent of patients had a performance status of 1.0 and 36% had leiomyosarcomas. No DLT was observed at dose L1-4. Six patients developed a DLT at dose L5, and thus the recommended dose is level 4 (i.e. Caelyx 30 mg/m2/1 h d 1+ifosfamide at 3 g/m2/4 h d 1-3 q 3 weeks). Few haematological and biochemical events were observed and the principal toxicities were granulocytopaenia and leucopaenia. Five patients discontinued therapy because of toxicity, 4 of them at dose level 5. Non-haematological toxicities > grade 2 were also few. Palmar-plantar erythrodysesthesia (PPE) > grade 1 was not seen. Two patients obtained partial response (PR) and 13 stable disease (SD). Median overall survival (OS) was 333 d and median progression-free survival (PFS) 174 d. In conclusion, this seems to be a feasible combination in patients with advanced soft tissue sarcomas, allowing ifosfamide to be given in a dosage similar to that used when given alone. The recommended dose for future studies is Caelyx 30 mg/m2/1 h d 1+ifosfamide 3 g/m2/4 h d 1-3 q 3 weeks.

Systemic treatment of AIDS-related Kaposi sarcoma: current status and perspectives

Kaposi's sarcoma (KS) is the most frequent type of cancer in patients with Acquired Immune Deficiency Syndrome (AIDS). In the western world, its incidence decreased dramatically in the era of highly active anti-retroviral therapy (HAART). In contrast, the incidence of KS has been steadily climbing in parallel with the AIDS epidemic in Africa over the past 10-15 years, being the most common cancer in adult men in countries like Uganda and Zimbabwe. AIDS-KS can be diagnosed at any stage of HIV infection, although it more commonly occurs in the setting of severe immune suppression, especially with an elevated viral load. Up to now, AIDS-KS is still an incurable disease. Its clinical course is variable, ranging from very indolent cases, requiring no or minimal therapy, to a rapidly progressive disease. Various local therapies are available to control small and asymptomatic lesions, while cytotoxic, immunological and biological therapies can be considered for more aggressive disease. The primary goal of therapy in most of the cases is to provide safe and effective palliation, in order to quality of life. Optimal anti-retroviral therapy is a key component of AIDS-KS management. There are still many questions to be answered in the management of patients with AIDS-KS, such as (1) What are the therapeutic agents that should be used in this disease, and in which sequence? and (2) What are the benefits and risks expected with each treatment option? The aim of this review is to discuss the systemic management of AIDS-KS, with special focus on the above mentioned questions.

Randomized Phase II Trial of Matrix Metalloproteinase Inhibitor COL-3 in AIDS-Related Kaposi's Sarcoma: An AIDS Malignancy Consortium Study

Purpose

Matrix metalloproteinases (MMPs) are involved in tumor metastasis and are overexpressed in Kaposi's sarcoma (KS) cells. In a phase I trial of the MMP inhibitor COL-3 in patients with AIDS-related KS, the drug was well tolerated, KS regression was observed, and MMP-2 levels decreased significantly in responders compared with nonresponders. The aim of this trial was to extend these initial observations.

Patients and Methods

This was a randomized, parallel-group, phase II study. COL-3 was administered orally once daily at one of two doses (group A received 50 mg and group B received 100 mg) to patients with AIDS-related KS. Antiretroviral therapy was permitted but not required. Serial tumor assessments and plasma levels of MMPs were obtained. Study end points were progressive KS and recurrent dose-limiting toxicity.

Results

Seventy-five patients received COL-3: 37 in group A and 38 in group B. Fifty-seven patients (76%) had received prior KS therapy. Thirty-three patients (44%) had more than 50 KS lesions. The response rate in group A was 41%, which was significantly greater than the prespecified target rate of 20% (95% CI, 25% to 58%; P = .003); the response rate of group B was 29% (P = not significant). There were significant declines in MMP-2 and MMP-9 plasma levels from baseline to minimum value with treatment (MMP-2, P < .001; MMP-9, P = .001). The most common adverse events were photosensitivity and rash.

Conclusion

COL-3, when administered as 50 mg/d, is both active and well tolerated in the treatment of AIDS-related KS. COL-3 is a promising agent for the treatment of this opportunistic neoplasm of AIDS.

Liposomal pegylated doxorubicin versus low-dose recombinant interferon Alfa-2a in the treatment of advanced classic Kaposi's sarcoma; retrospective analysis of three German centers

BACKGROUND

Classic Kaposi's sarcoma (KS) is a rare neoplasm, predominantly occurring in older subjects of Eastern Europe or Mediterranean descent. While single lesions may be treated by simple excision, laser therapy, cryotherapy, or intralesional therapy, advanced or disseminated disease requires systemic treatment. Several studies reported the effectiveness of pegylated liposomal doxorubicin (PLD) and low-dose recombinant interferon alfa-2a (IFNalpha) in the treatment of AIDS-associated KS.

OBJECTIVE

The aim of this retrospective analysis of three German centers was to compare the effectiveness and tolerability of PLD with IFNalpha in patients with advanced classic KS.

METHODS

Retrospective analysis of 18 Caucasian patients who had been treated for histologically proven classic KS, with either with PLD or IFNalpha was performed. Twelve patients received 20 mg/m2 of PLD monthly, and the number of cycles was adapted to the clinical response. Dose reduction or increased cycle length was conducted if toxicity intervened. In 6 patients, 3 million U of IFNalpha was injected subcutaneously 3 times a week. IFNalpha -therapy was adapted according to the clinical response.

RESULTS

In the 12 KS patients treated with PLD, complete response (CR) was achieved in 8 (67 percent), major response (MR) in 3 (25 percent), and minor response (mR) in 1 (8 percent). Stable disease (SD) or progression of disease (PD) was not observed. An initial response was noted after 4-16 weeks of treatment (mean 8.6 weeks), the mean cumulative dose of PLD was 571.5 mg/m2 (range, 40 to 1496 mg/m2), and the mean follow-up was 13 months. Neutropenia (33 percent) related to PLD was the most common adverse event (4/12). Vomiting occurred in 3 (25 percent) patients; none of these were severe. Six patients were treated with IFNalpha. MR was achieved in 1 (17 percent), mR in 4 (67 percent) and SD in 1 of 6 patients (17 percent), neither had CR or PD. An initial response was observed after 8-17 weeks of treatment (mean 12.7 weeks). Fever occurred in 4 patients (67 percent). Flu-like symptoms in 3 patients (50 percent) related to IFNalpha were the most common adverse events. Mean follow-up was 6.3 months. The differences in response to treatment between PLD and IFNalpha, in general, were significant with p < 0.05 (T-test for independent samples). Comparing weeks to respond and treatment efficiency data were significant with p < 0.001 (Fisher's exact): response to PLD was up to one-third faster than IFNalpha. Calculating different stages of response (MR, CR, etc.), PLD also was clearly superior (p = 0.018) to IFNalpha (Fisher's exact).

CONCLUSION

This retrospective analysis of patients with classic KS confirms the efficacy and safety of PLD. The benefits of PLD, including the monthly application, the high response even after previous treatments have failed, and the low rate of side effects even in elderly individuals, outweigh the risks. PLD is superior to IFNalpha and should be considered as an promising option in the treatment of advanced classic KS.

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.

Gastrointestinal and cutaneous AIDS-related Kaposi's sarcoma: different activity of liposomal doxorubicin according to location of lesions

Kaposi's sarcoma (KS) continues to be a frequent neoplasm in third world AIDS patients. We carried out a prospective study to evaluate the effectiveness of liposomal doxorubicin (LD) in gastrointestinal KS patients as well as its differential clinical activity depending on the location of the lesions. The study included 15 male AIDS patients aged between 25 and 35 years (mean: 27 years) with more than 25 cutaneous lesions and extensive gastrointestinal KS. They were treated with LD, 20 mg/m(2) every 21 days, for six cycles. Eleven (73%) of the patients obtained a complete response of the gastrointestinal KS lesions and four (27%) a partial response. Regarding cutaneous lesions, only two (13%) of the patients reached a complete response, six (40%) a partial response and seven (47%) stabilized their disease. By applying Fisher's test we found a significant difference (P < 0.00035) when comparing the effectiveness of LD in gastrointestinal lesions in relation to cutaneous lesions. We conclude that LD is more effective in gastrointestinal KS and can be recommended in patients in third world countries with extensive gastrointestinal lesions.