Phase II trial of liposomal doxorubicin (Doxil) in advanced soft tissue sarcomas

Combination Treatment with Liposomal Doxorubicin and Inductive Moderate Hyperthermia for Sarcoma Saos-2 Cells

Despite efforts in osteosarcoma (OS) research, the role of inductive moderate hyperthermia (IMH) in delivering and enhancing the antitumor effect of liposomal doxorubicin formulations (LDOX) remains unresolved. This study investigated the effect of a combination treatment with LDOX and IMH on Saos-2 human OS cells. We compared cell viability using a trypan blue assay, apoptosis and reactive oxygen species (ROS) measured by flow cytometry and pro-apoptotic Bax protein expression examined by immunocytochemistry in response to IMH (42 MHz frequency, 15 W power for 30 min), LDOX (0.4 μg/mL), and LDOX plus IMH. The lower IC50 value of LDOX at 72 h indicated increased accumulation of the drug in the OS cells. LDOX plus IMH resulted in a 61% lower cell viability compared to no treatment. Moreover, IMH potentiated the LDOX action on the Saos-2 cells by promoting ROS production at temperatures of <42 °C. There was a 12% increase in cell populations undergoing early apoptosis with a less heterogeneous distribution of Bax after combination treatment compared to those treated with LDOX (p < 0.05). Therefore, we determined that IMH could enhance LDOX delivery and its antitumor effect via altered membrane permeabilization, ROS generation, and a lower level of visualized Bax heterogeneity in the Saos-2 cells, suggesting the potential translation of these findings into in vivo studies.

An Integrative Bioorthogonal Nanoengineering Strategy for Dynamically Constructing Heterogenous Tumor Spheroids

Although tumor models have revolutionized perspectives on cancer aetiology and treatment, current cell culture methods remain challenges in constructing organotypic tumor with in vivo-like complexity, especially native characteristics, leading to unpredictable results for in vivo responses. Herein, the bioorthogonal nanoengineering strategy (BONE) for building photothermal dynamic tumor spheroids is developed. In this process, biosynthetic machinery incorporated bioorthogonal azide reporters into cell surface glycoconjugates, followed by reacting with multivalent click ligand (ClickRod) that is composed of hyaluronic acid-functionalized gold nanorod carrying dibenzocyclooctyne moieties, resulting in rapid construction of tumor spheroids. BONE can effectively assemble different cancer cells and immune cells together to construct heterogenous tumor spheroids is identified. Particularly, ClickRod exhibited favorable photothermal activity, which precisely promoted cell activity and shaped physiological microenvironment, leading to formation of dynamic features of original tumor, such as heterogeneous cell population and pluripotency, different maturation levels, and physiological gradients. Importantly, BONE not only offered a promising platform for investigating tumorigenesis and therapeutic response, but also improved establishment of subcutaneous xenograft model under mild photo-stimulation, thereby significantly advancing cancer research. Therefore, the first bioorthogonal nanoengineering strategy for developing dynamic tumor models, which have the potential for bridging gaps between in vitro and in vivo research is presented.

Gold cluster encapsulated liposomes: theranostic agent with stimulus triggered release capability

Cancer is a major cause of death worldwide. Cancer-resistant to chemo or radiotherapy treatment is a challenge that could be overcome by a nanotechnology approach. Providing a theranostic nano-platform for different cancer treatment strategies could be revolutionary. Here we introduce a multifunctional theranostic nanostructure which has the capacity for improving cancer diagnosis and treatment through better chemo and radiotherapy and current x-ray imaging systems through co-encapsulation of a small gold cluster and anticancer drug doxorubicin. 2 nm gold clusters represent good heating under radio frequency electric field (RF-EF) exposure and have been used for in vitro hyperthermia treatment of cancerous cells. Liposomal doxorubicin (169 ± 19.8 nm) with gold clusters encapsulation efficiency of 13.2 ± 3.0% and doxorubicin encapsulation efficiency of 64.7 ± 0.7% were prepared and studied as a theranostic agent with a high potential in different cancer treatment modalities. Exposure to a radiofrequency electric field on prepared formulation caused 20.2 ± 2.1% drug release and twice decreasing of IC50 on colorectal carcinoma cells. X-ray attenuation efficiency of the liposomal gold cluster was better than commercial iohexol and free gold clusters in different concentrations. Finally, treatment of gold clusters on cancerous cells results in a significant decrease in the viability of irradiated cells to cobalt-60 beam. Based on these experiments, we concluded that the conventional liposomal formulation of doxorubicin that has been co-encapsulated with small gold clusters could be a suitable theranostic nanostructure for cancer treatment and merits further investigation.

The emerging role of cancer nanotechnology in the panorama of sarcoma

In the field of nanomedicine a multitude of nanovectors have been developed for cancer application. In this regard, a less exploited target is represented by connective tissue. Sarcoma lesions encompass a wide range of rare entities of mesenchymal origin affecting connective tissues. The extraordinary diversity and rarity of these mesenchymal tumors is reflected in their classification, grading and management which are still challenging. Although they include more than 70 histologic subtypes, the first line-treatment for advanced and metastatic sarcoma has remained unchanged in the last fifty years, excluding specific histotypes in which targeted therapy has emerged. The role of chemotherapy has not been completely elucidated and the outcomes are still very limited. At the beginning of the century, nano-sized particles clinically approved for other solid lesions were tested in these neoplasms but the results were anecdotal and the clinical benefit was not substantial. Recently, a new nanosystem formulation NBTXR3 for the treatment of sarcoma has landed in a phase 2-3 trial. The preliminary results are encouraging and could open new avenues for research in nanotechnology. This review provides an update on the recent advancements in the field of nanomedicine for sarcoma. In this regard, preclinical evidence especially focusing on the development of smart materials and drug delivery systems will be summarized. Moreover, the sarcoma patient management exploiting nanotechnology products will be summed up. Finally, an overlook on future perspectives will be provided.

Optimal Clinical Management and the Molecular Biology of Angiosarcomas

Angiosarcomas comprise less than 3% of all soft tissue sarcomas but have a poor prognosis. Most angiosarcomas occur without obvious risk factors but secondary angiosarcoma could arise after radiotherapy or chronic lymphedema. Surgery remains the standard treatment for localized angiosarcoma but neoadjuvant systemic treatment may improve the curability. For advanced angiosarcoma, anthracyclines and taxanes are the main chemotherapy options. Anti-angiogenic agents have a substantial role but the failure of a randomized phase 3 trial of pazopanib with or without an anti-endoglin antibody brings a challenge to future trials in angiosarcomas. Immune checkpoint inhibitors as single agents or in combination with oncolytic virus may play an important role but the optimal duration remains to be investigated. We also report the current understanding of the molecular pathways involved in angiosarcoma pathogenesis including MYC amplification, activation of angiogenic pathways and different molecular alterations that are associated with angiosarcomas of different aetiology. The success of the patient-partnered Angiosarcoma Project (ASCProject) has provided not only detailed insights into the molecular features of angiosarcomas of different origins but also offers a template for future fruitful collaborations between patients, physicians, and researchers. Lastly, we provide our perspective of future developments in optimizing the clinical management of angiosarcomas.

Spotlight on aldoxorubicin (INNO-206) and its potential in the treatment of soft tissue sarcomas: evidence to date

Anthracyclines, and doxorubicin in particular, remain a mainstay of sarcoma therapy. Despite modest activity and significant toxicities, no cytotoxic monotherapy has yet yielded superior overall survival over doxorubicin for therapy of advanced soft tissue sarcomas in a randomized trial. Similarly, combination regimens have also been unable to overcome doxorubicin in terms of overall survival. Strategies to ameliorate the most prominent side effect of doxorubicin, cardiotoxicity, are available, but their use in sarcoma patients has been limited. Aldoxorubicin is a prodrug consisting of doxorubicin with a covalent linker. It binds rapidly after intravenous infusion to cysteine-34 of human serum albumin. The drug-albumin conjugate is preferentially retained in tumor tissue, with uptake into tumoral cells. At physiologic pH, the complex is stable. Hydrolysis can occur under the acidic conditions of the endocytic lysosome, releasing doxorubicin. Doxorubicin then distributes to various cellular compartments, including Golgi, mitochondrion, and nucleus, with subsequent cytotoxic effects. Aldoxorubicin has demonstrated in vitro and in vivo activities in both cancer model systems and human xenografts. Preclinical models also support its decreased cardiac effects vs doxorubicin, although such promising results require formal comparison at efficacy equivalent doses of the two drugs. Phase I studies confirmed the tolerability of aldoxorubicin in humans. Clinical cardiotoxicity was not observed, but molecular and subclinical cardiac effects could be demonstrated. A Phase II study in treatment-naïve, advanced sarcoma patients demonstrated improved progression-free survival and response rate over doxorubicin, although no survival benefit was evident. A Phase III study of aldoxorubicin vs investigator's choice from a panel of chemotherapy regimens in the salvage setting was unable to demonstrate a benefit in progression-free or overall survival in the entire population. Progression-free survival in L-sarcomas (leiomyosarcomas and liposarcomas) was documented. While evidence of subclinical cardiac effects was seen in a small proportion of aldoxorubicin-treated patients, data from both the Phase II and III studies indicated a favorable cardiotoxicity profile vs doxorubicin. Despite the negative results from this Phase III study, the importance of anthracycline therapy in sarcoma management merits further investigation of the potential role of aldoxorubicin in this indication. Other avenues for progress include identification of sensitive histologies and biomarkers of activity, exploration of clinical niches without proven standard therapies, and exploration of alternate dosing strategies.

Aldoxorubicin: a tumor-targeted doxorubicin conjugate for relapsed or refractory soft tissue sarcomas

Despite available therapies after initial systemic therapy, prognosis remains poor in relapsed or refractory soft tissue sarcomas (STS). The rational and clinical development of novel agents to improve outcomes in this area of high unmet need is desperately warranted. Aldoxorubicin is a prodrug of doxorubicin that binds to serum albumin immediately after administration through an acid-sensitive hydrazone linker and is subsequently transported to tumor tissues where the acidic environment cleaves the linker and facilitates delivery of a tumor-targeted drug payload. In clinical studies to date, there has been evidence of efficacy and mitigated cardiac toxicity. In this review, we comprehensively detail the clinical development of aldoxorubicin in STS to date. Specifically, we highlight available data on the pharmacokinetics and efficacy from Phase I, Phase II, and Phase III trials in advanced or metastatic STS. We conclude with considerations for future directions of investigation for this promising antitumor agent.

Systemic therapy for advanced soft tissue sarcomas: highlighting novel therapies and treatment approaches

Soft tissue sarcomas (STS) are a rare, heterogeneous group of solid tumors in need of improved therapeutic options. First-line chemotherapy is considered the current standard of care for patients with advanced, symptomatic STS, but the median survival is only 8 to 12 months. Efforts to increase response rates by using combination or dose-dense regimens have largely failed to improve patient outcomes. However, increasing evidence supports the use of specific treatments for certain histological subtypes of STS, and novel therapies, including tyrosine kinase and mammalian target of rapamycin inhibitors, are currently under active investigation. In addition, novel treatment approaches (such as maintenance therapy) designed to prolong the duration of response to chemotherapy and delay disease progression are being explored. This article provides an overview of current systemic therapies for patients with advanced STS and discusses ongoing efforts designed to improve patient outcomes through the use of novel therapeutic agents and treatment strategies.

Systematic therapy for unresectable or metastatic soft-tissue sarcomas: past, present, and future

Unresectable or metastatic disease occurs in 40% to 60% of soft-tissue sarcoma (STS) patients and portends a poor prognosis. For decades, doxorubicin has formed the backbone of systemic treatment, with response rates of approximately 26%. Patients progressing following first-line therapy were left with few proven options. No other cytotoxic chemotherapy agent or combination has demonstrated superiority to doxorubicin. Advances in targeted therapy of STS have been hindered by STS heterogeneity and poorly understood disease biology. Despite challenges, progress has been made in specific STS subtypes. Here, we highlight the challenges, progress, and lessons learned from STS trials published in the last 20 to 25 years.

Primary cardiac angiosarcoma

Primary cardiac sarcoma is a rare clinical entity, with an incidence of 0.0001% in collected autopsy series. The majority of the literature describes a uniformly dismal prognosis with a median survival of only 6 months for these aggressive tumors. Standard surgery, adjuvant chemotherapy, and radiotherapy have been consistently unsuccessful. Early heart transplantation and novel radiation therapy approaches may offer a survival benefit in nonmetastatic tumors, but up to 80% of the patients present with systemic metastasis at diagnosis. Though several chemotherapeutic regimens have been tried, the role of chemotherapy is not well established and outcome data available is minimal. Liposomal doxorubicin (PLD) has been shown to be useful in the treatment of soft tissue sarcomas, and our case supports its use in cardiac angiosarcoma.

Phase II Clinical Trial With Pegylated Liposomal Doxorubicin (CAELYX(R)/Doxil(R)) and Quality of Life Evaluation (EORTC QLQ-C30) in Adult Patients With Advanced Soft Tissue Sarcomas: A study of the Spanish Group for Research in Sarcomas (GEIS)

BACKGROUND

Pegylated liposomal doxorubicin (PLD), a formulation with pharmacokinetic differences with respect to doxorubicin (DXR), might benefit patients with advanced soft tissue sarcoma (STS) pretreated with DXR.

PATIENTS AND METHODS

Patients with measurable and progressive STS received PLD at 35 mg/(2) every 3 weeks. Quality of life before and during treatment was assessed with EORTC QLQ-C30.

RESULTS

Twenty-eight patients, 22 DXR-pretreated, were given 140 cycles (median 3, range 1-18). Activity in 27 patients (5 GIST): one complete and one partial remission (both non-GIST and without prior DXR), 12 stabilizations and 13 progressions (response rate 7.4%, 95% CI: 0-17%). Grade 3 toxicity: palmar-plantar erythrodysesthesia (19% of patients), stomatitis (4%) or cutaneous (4%). Neutropenia grade>/=3 was detected in 16% of patients. Median relative dose intensity was 95%. Progression-free rate at 3 and 6 months was, respectively, 48 and 22%, median progression-free survival 5.8 months and median overall survival 8.7 months. QLQ-C30 at baseline and at weeks 6-11 in 23 and 13 patients, respectively, showed good reliability and validity. Quality of life did not seem to worsen during therapy.

CONCLUSIONS

PLD did not induce objective remissions in 22 STS patients pretreated with DXR, but progression-free rate figures support the use of this agent in patients who have not progressed under a DXR-containing regimen. The toxicity observed was comparable to that of other PLD schedules.

An imaging-driven model for liposomal stability and circulation

Simultaneous labeling of the drug compartment and shell of delivery vehicles with optical and positron emission tomography (PET) probes is developed and employed to inform a hybrid physiologically based pharmacokinetic model. Based on time-dependent estimates of the concentration of these tracers within the blood pool, reticuloendothelial system (RES) and tumor interstitium, we compare the stability and circulation of long-circulating and temperature-sensitive liposomes. We find that rates of transport to the RES for long-circulating and temperature-sensitive particles are 0.046 and 0.19 h(-1), respectively. Without the application of exogenous heat, the rates of release from the long-circulating and temperature-sensitive particles circulating within the blood pool are 0.003 and 0.2 h(-1), respectively. Prolonged lifetime in circulation and slow drug release from liposomes result in a significantly greater drug area under the curve for the long-circulating particles. Future studies will couple these intrinsic parameters with exogenous heat-based release. Finally, we develop a transport constant for the transport of liposomes from the blood pool to the tumor interstitium, which is on the order of 0.01 h(-1) for the Met-1 tumor system.

Novel therapeutic agents for osteosarcoma

Osteosarcoma is the most common malignant primary bone tumor in childhood. Despite multiagent chemotherapy and aggressive surgical resection, 30% of patients with localized disease and 80% of patients with metastatic disease at diagnosis will relapse. Survival for these patients has remained unchanged over the past 20 years. A number of novel agents in various stages of development hold promise for improving therapy for patients with osteosarcoma. This article will focus on novel therapeutic approaches, including agents targeting signal-transduction pathways, inhibitors of the tumor microenvironment and immunomodulatory agents, as well as overcoming resistance mechanisms and the use of novel delivery mechanisms.

Therapy for osteosarcoma: where do we go from here?

Osteosarcoma is the most common malignant primary bone tumor in children and adolescents. Current optimal treatment for osteosarcoma consists of multi-agent chemotherapy and aggressive surgical resection of all sites of disease involvement. The current national and international cooperative trial for patients with newly diagnosed osteosarcoma builds upon the backbone of cisplatin, doxorubicin, and methotrexate. This protocol is designed to clarify whether (i) the addition of ifosfamide and etoposide to postoperative chemotherapy with cisplatin, doxorubicin, and methotrexate improves the event-free survival and overall survival for patients with resectable osteosarcoma and a poor histologic response to 10 weeks of preoperative chemotherapy; and (ii) the addition of pegylated interferon-alpha-2b as maintenance therapy after postoperative chemotherapy with cisplatin, doxorubicin, and methotrexate improves the event-free survival and overall survival for patients with resectable osteosarcoma and a good histologic response to 10 weeks of preoperative chemotherapy. However, the optimal treatment strategy (or strategies) for patients with relapsed or metastatic disease has yet to be defined. This remains one of the persistent challenges in the treatment of osteosarcoma. Recent therapeutic advances have focused on circumventing chemotherapy resistance mechanisms, incorporation of non-classical agents into upfront therapy, targeting of the tumor micro-environment, and investigating the role of novel delivery mechanisms. In patients with localized disease the 5-year survival rate is at least 70%; patients with metastatic or recurrent disease have <20% chance of long-term survival despite aggressive therapies. These figures have changed little in the past 2 decades. This review focuses on the current therapy for osteosarcoma, and highlights emerging strategies that will hopefully change the outlook for patients with this disease.

[Accelerated blood clearance (ABC) phenomenon induced by administration of PEGylated liposome]

PEGylated liposomes (approximately 100 nm in diameter) lose their long-circulating characteristic upon repeated injection at certain intervals in the same animal (referred to as the "accelerated blood clearance (ABC) phenomenon"), as described by our group and by researchers in the Netherlands. Recently, it was demonstrated by our group that anti-PEG IgM, induced by the first dose of PEGylated liposomes, is responsible for the ABC phenomenon. The IgM produced in this manner then selectively bound to the surface of subsequently injected PEGylated liposomes, leading to substantial complement activation. It is generally believed that nanocarriers coated with a polymer, such as PEG, have no immunogenicity. However, unexpected immune responses occurred even in response to polymer-coated liposomes. This immunogenicity to PEGylated liposomes presents a serious concern in the development and clinical use of liposomal formulations. In this review, we demonstrate our recent observations regarding with the ABC phenomenon against liposomes.

Tuftsin augments antitumor efficacy of liposomized etoposide against fibrosarcoma in Swiss albino mice

Anticancer drugs are generally plagued by toxic manifestations at doses necessary for control of various forms of cancer. Incorporating such drugs into liposomes not only reduces toxicity but also enhances the therapeutic index. Some antioxidants and potent immunomodulators have also been shown to impart significant antitumor activity presumably by nonspecific activation of the host immune system. In the present study, we evaluated augmentation of the antitumor activity of etoposide (ETP) by the immunomodulator tuftsin in Swiss albino mice with fibrosarcoma. The efficacies of the free form of ETP, liposomized ETP (Lip-ETP), and tuftsin-bearing liposomized ETP (Tuft-Lip-ETP) formulations were evaluated on the basis of tumor regression, effect on expression level of p53wt and p53mut, and survival of the treated animals. Tuft-Lip-ETP, when administered at a dosage of 10 mg/kg body weight/day for five days, significantly reduced tumor volume, delayed tumor growth, and also up-regulated the expression of p53wt. In contrast, although Lip-ETP delayed tumor growth, it did not decrease tumor size. The results of the present study suggest that tuftsin incorporation in drug-loaded liposomes is a promising treatment strategy for various forms of cancers, including fibrosarcoma.

Tuftsin augments antitumor efficacy of liposomized etoposide against fibrosarcoma in Swiss albino mice

Anticancer drugs are generally plagued by toxic manifestations at doses necessary for control of various forms of cancer. Incorporating such drugs into liposomes not only reduces toxicity but also enhances the therapeutic index. Some antioxidants and potent immunomodulators have also been shown to impart significant antitumor activity presumably by nonspecific activation of the host immune system. In the present study, we evaluated augmentation of the antitumor activity of etoposide (ETP) by the immunomodulator tuftsin in Swiss albino mice with fibrosarcoma. The efficacies of the free form of ETP, liposomized ETP (Lip-ETP), and tuftsin-bearing liposomized ETP (Tuft-Lip-ETP) formulations were evaluated on the basis of tumor regression, effect on expression level of p53wt and p53mut, and survival of the treated animals. Tuft-Lip-ETP, when administered at a dosage of 10 mg/kg body weight/day for five days, significantly reduced tumor volume, delayed tumor growth, and also up-regulated the expression of p53wt. In contrast, although Lip-ETP delayed tumor growth, it did not decrease tumor size. The results of the present study suggest that tuftsin incorporation in drug-loaded liposomes is a promising treatment strategy for various forms of cancers, including fibrosarcoma.

Phase II multicenter open-label study of carboplatin and pegylated liposomal doxorubicin in uterine and cervical malignancies

The results of a multicenter phase II study investigating carboplatin and pegylated liposomal doxorubicin (PLD) in patients with recurrent/metastatic uterine and cervical malignancies (UCM) are presented here. Fifty-three subjects with measurable, untreated, advanced UCM were enrolled. Fifty-one were evaluable for response. Prior combined-modality treatment was permitted if a component of primary therapy. Patients received carboplatin AUC = 5 with PLD 35 mg/m(2) intravenously once every 4 weeks. Overall response rate was 33% (35% stable disease). Overall survival (OS) at six months was 86% (95% CI 76%-96%). Six-month progression-free survival (PFS) was 43% (95% CI 30%-57%). Median PFS was 22.9 weeks (range 16.0-35.3) and median OS was 49.1 weeks (range 41.4-75.1). The most frequent grade 3-4 nonhematological adverse events were: abdominal pain (n = 7), fatigue (4), vomiting (4), nausea (3), and shortness of breath (3). There was 1 report of grade 3 hand-foot syndrome and none of grade 4. Twelve patients had first infusion reactions with only 1 discontinuing treatment. Grade 3-4 neutropenia occurred in 26/230 cycles (11.3%). There were no treatment-related deaths. The combination of carboplatin and PLD is well tolerated with sufficient activity to justify additional evaluation in clinical trials and might be suited to the addition of a taxane.

Emerging treatments for soft tissue sarcoma of adults

Soft tissue sarcomas are a heterogeneous group of malignancies arising from mesenchymal tissues. Patients can present with a localised tumour (primary or local recurrence) at different sites (e.g., extremity, abdomen) or metastatic disease, which may require different treatment strategies. Is the surgical resection of a localised sarcoma enough or is it better to give an additional treatment like adjuvant and/or preoperative radiotherapy and/or chemotherapy? Which chemotherapy should be selected in the first or second line situation? Do new treatment options exist, such as targeted therapies? This review provides answers to some of these questions. To decide on consecutive treatment steps, it is important to know as many relevant factors as possible at first presentation. Therefore, the first part of this review discusses the specific characteristics and prognostic factors of importance for treatment planning. A short summary of current therapy strategies and existing standards is then given. The main body of the review summarises information on new and emerging clinical compounds for patients with soft tissue sarcoma of adults, including recent developments of targeted therapy.

Combination of pegylated liposomal doxorubicin (PLD) and paclitaxel in patients with advanced soft tissue sarcoma: a phase II study of the Hellenic Cooperative Oncology Group

Patients with soft tissue sarcoma (STS), even after complete local disease control, often relapse locally or with distant metastases. This multicenter phase II study was conducted to evaluate the safety and efficacy of the combination of pegylated liposomal doxorubicin (PLD) and paclitaxel, as first-line treatment in patients with advanced STS. In all, 42 patients with locally advanced or metastatic STS, median age 54 years and median Eastern Cooperative Oncology Group performance status (PS) 1 were treated with PLD 45 mg m⁻² and paclitaxel 150 mg m⁻², every 28 days for a total of six cycles. Histological types included mainly leiomyosarcomas (43%), malignant fibrous histiocytomas (14%) and liposarcomas (12%). At study entry, 69% of patients had distant metastases. Overall response rate was 16%, including one complete (CR 2%) and six partial responses (PRs 14%), while an additional 14 patients had disease stabilization (SD 33%). At median follow-up 41.5 months, median time to progression (TTP) was 5.7 months with median overall survival (OS) 13.2 months. Grade 3–4 toxicities included neutropenia (17%), anaemia (15%), neurotoxicity (5%) and palmar–plantar erythrodysesthesia (9%). There were no treatment-related deaths. The combination of PLD and paclitaxel is a safe and well-tolerated regimen demonstrating modest efficacy as first-line treatment in patients with advanced STS.

Efficacy and safety of liposomal anthracyclines in Phase I/II clinical trials

Preclinical studies have established the pharmacologic advantages of liposomal anthracyclines, including pharmacokinetic profiles after bolus dosing that resemble continuous infusion of conventional anthracyclines, increased drug concentrations in tumor cells compared with the surrounding tissues, and reduced toxicity relative to conventional anthracycline treatment. Based on these studies, many phase I and phase II clinical trials were conducted to assess the safety and potential activity of liposomal anthracyclines in the management of both solid and hematologic tumors. These studies provided valuable insight into the safety of pegylated liposomal doxorubicin (Doxil/Caelyx [PLD]), nonpegylated liposomal doxorubicin (Myocet [NPLD]), and liposomal daunorubicin (DaunoXome [DNX]) over a range of doses, either as single-agent therapy or in combination with other cytotoxic agents. Other liposomal anthracyclines in development may be well tolerated but their activity remains to be elucidated by clinical trials. The available data also suggest that liposomal anthracyclines have activity not only against tumor types with known sensitivity to conventional anthracyclines, but also potentially for tumors that are typically anthracycline-resistant. Despite the availability of clinical data from a wide variety of tumor types and patient populations, further studies of liposomal anthracycline therapy are needed to fully establish their safety, efficacy, and dosing in the treatment of these patients.

Phase II trial of pegylated-liposomal doxorubicin (Doxil) in sarcoma

Pegylated-liposomal doxorubicin (Doxil) is a unique form of liposomal doxorubicin in which the liposomes are coated with methoxypoly (ethylene glycol), resulting in a diminished uptake by the reticuloendothelial system, leading to a longer half-life in blood and a different toxicity profile than nonpegylated liposomes. We performed a phase II study of Doxil in sarcoma. The patient population was primarily previously treated or had diagnoses considered unresponsive to chemotherapy. The initial dose per course was 55 mg/m2 every four weeks with dose modification based on mucositis and hand-foot syndrome (the main limiting toxicities). Treatment was generally well tolerated. Of 214 evaluable treatment courses in 47 patients, toxicities were mild and similar to previous reports, but dose reduction was common. No definite cardiac toxicity was observed. There were: 6 osteosarcomas, 3 Ewings, 1 extraosseous osteosarcoma, 1 chondrosarcoma, 2 alveolar soft part sarcomas, 15 gastrointestinal stromal cell tumors (GIST), and 19 other soft tissue sarcomas. Three of the 47 patients received a CR or PR, although 15 of the 47 patients were felt to have derived clinical benefit from the treatment. Some responses were delayed. These data suggest that pegylated-liposomal doxorubicin has activity in this population of poor prognosis sarcoma and that this treatment is associated with modest toxicity.

The use of chemotherapy in soft-tissue sarcomas

The treatment of advanced soft-tissue sarcomas is often palliative, although a subset of patients may be cured or have a long disease-free interval. This paper reviews the historical data over 30 years of treatment that has led to the use of ifosfamide and doxorubicin as the mainstay in the treatment of metastatic disease. These treatments have a high toxicity, relative to other chemotherapeutic regimens, with median response durations on the order of months. Agents developed in the last few years, whose role in the treatment of sarcomas is still evolving, are discussed as well. Finally, we discuss the role of chemotherapy in combination with surgery and radiation in the adjuvant and neoadjuvant settings.

Translocation of liposomes into cancer cells by cell-penetrating peptides penetratin and tat: a kinetic and efficacy study

Unlike conventional liposomes, sterically stabilized liposomes, with their smaller volume of distribution and reduced clearance, preferentially convey encapsulated drugs into tumor sites. Despite these improvements, intracellular delivery is hampered by the stable drug retention of the liposomes, which diminishes the efficacy of the liposomal drug. To facilitate uptake of liposomal drugs into cells, two cell-penetrating peptides, penetratin (PEN) and TAT, derived from the HIV-1 TAT protein, were studied. In contrast to control peptides, both TAT and PEN enhanced the translocation efficiency of liposomes in proportion to the number of peptides attached to the liposomal surface. A peptide number of as few as five could enhance the intracellular delivery of liposomes. The kinetics of uptake was peptide- and cell-type dependent. Intracellular accumulation of TAT-liposomes increased with incubation time, but PEN-liposomes peaked at 1 h and then declined gradually. After treatment with 1 microg/ml doxorubicin equivalents of liposome for 2 h, TAT increased the doxorubicin uptake of A431 cells by 12-fold. However, the improvement of uptake of liposomal doxorubicin was not reflected by cytotoxicity in vitro or tumor control in vivo. Our results demonstrated that merely adding CPP to a liposome encapsulating anticancer drug was inadequate in improving its antitumor activity. An additional approach to enhance the intracellular release of the encapsulated drug is obviously necessary.

Docetaxel as rescue medication in anthracycline- and ifosfamide-resistant locally advanced or metastatic soft tissue sarcoma: results of a phase II trial

BACKGROUND

Metastatic soft tissue sarcoma not amenable to curative surgery has a dismal prognosis. Aggressive treatment with anthracyclines and ifosfamide represents the current therapeutic mainstay in these patients, most of whom succumb to relapses. Thus, the efficacy of subsequent therapeutic approaches has to be weighed against toxicity caused by palliative treatment.

PATIENTS AND METHODS

Patients with locally advanced or metastatic soft tissue sarcoma refractory to treatment with anthracyclines and ifosfamide were enrolled into the present phase II study. Patients were assigned to receive docetaxel at 100 mg/m2 every three weeks. In case of severe toxicity, patients were switched to a weekly schedule of docetaxel (40 mg/m2).

RESULTS

A total of 106 cycles (80% at the scheduled 100 mg/m2 dose level) were administered in 27 patients. Partial response was observed in 4 (15%) patients and 4 (15%) patients experienced disease stabilization. Median progression free survival and overall survival were 2.4 (range: 0.9-23.9) and 7.7 (range: 1.0-44.3) months, respectively. Upon renewed progression, three patients initially responsive to treatment with docetaxel were successfully reinduced by treatment with docetaxel. The safety profile of docetaxel was tolerable and the administration mostly manageable on an outpatient basis.

CONCLUSIONS

Our results suggest that docetaxel represents an efficacious and tolerable treatment in a minority of patients refractory to standard treatment. There is a need for better identification of patients most likely to benefit from salvage treatment with docetaxel.