Feasibility, phase I, and pharmacological study of aerosolized liposomal 9-nitro-20(S)-camptothecin in patients with advanced malignancies in the lungs

Liposomes for Inhalation

Inhalation of liposomes formulated with phospholipids similar to endogenous lung surfactants and lipids offers biocompatibility and versatility within the pulmonary medicine field to treat a range of diseases such as lung cancer, cystic fibrosis and lung infections. Manipulation of the physicochemical properties of liposomes enables innovative design of the carrier to meet specific delivery, release and targeting requirements. This delivery system offers several benefits: improved pharmacokinetics with reduced toxicity, enhanced therapeutic efficacy, increased delivery of poorly soluble drugs, taste masking, biopharmaceutics degradation protection and targeted cellular therapy. This section provides an overview of liposomal formulation and delivery, together with their applications for different disease states in the lung.

Integration of In Vitro and In Vivo Models to Predict Cellular and Tissue Dosimetry of Nanomaterials Using Physiologically Based Pharmacokinetic Modeling

Nanomaterials (NMs) have been increasingly used in a number of areas, including consumer products and nanomedicine. Target tissue dosimetry is important in the evaluation of safety, efficacy, and potential toxicity of NMs. Current evaluation of NM efficacy and safety involves the time-consuming collection of pharmacokinetic and toxicity data in animals and is usually completed one material at a time. This traditional approach no longer meets the demand of the explosive growth of NM-based products. There is an emerging need to develop methods that can help design safe and effective NMs in an efficient manner. In this review article, we critically evaluate existing studies on in vivo pharmacokinetic properties, in vitro cellular uptake and release and kinetic modeling, and whole-body physiologically based pharmacokinetic (PBPK) modeling studies of different NMs. Methods on how to simulate in vitro cellular uptake and release kinetics and how to extrapolate cellular and tissue dosimetry of NMs from in vitro to in vivo via PBPK modeling are discussed. We also share our perspectives on the current challenges and future directions of in vivo pharmacokinetic studies, in vitro cellular uptake and kinetic modeling, and whole-body PBPK modeling studies for NMs. Finally, we propose a nanomaterial in vitro to in vivo extrapolation via physiologically based pharmacokinetic modeling (Nano-IVIVE-PBPK) framework for high-throughput screening of target cellular and tissue dosimetry as well as potential toxicity of different NMs in order to meet the demand of efficient evaluation of the safety, efficacy, and potential toxicity of a rapidly increasing number of NM-based products.

Inhaled cytotoxic chemotherapy: clinical challenges, recent developments, and future prospects

INTRODUCTION

Since 1968, inhaled chemotherapy has been evaluated and has shown promising results up to phase II but has not yet reached the market. This is due to technological and clinical challenges that require to be overcome with the aim of optimizing the efficacy and the tolerance of drug to re-open new developments in this field. Moreover, recent changes in the therapeutic standard of care for treating the patient with lung cancer also open new opportunities to combine inhaled chemotherapy with standard treatments.

AREAS COVERED

Clinical and technological concerns are highlighted from the reported clinical trials made with inhaled cytotoxic chemotherapies. This work then focuses on new pharmaceutical developments using dry powder inhalers as inhalation devices and on formulation strategies based on controlled drug release and with sustained lung retention or based on nanomedicine. Finally, new clinical strategies are described in regard to the impact of the immunotherapy on the patient's standard of care.

EXPERT OPINION

The choice of the drug, inhalation device, and formulation strategy as well as the position of inhaled chemotherapy in the patient's clinical care are crucial factors in optimizing local tolerance and efficacy as well as in its scalability and applicability in clinical practice.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

The potential to treat lung cancer via inhalation of repurposed drugs

Lung cancer is a highly invasive and prevalent disease with ineffective first-line treatment and remains the leading cause of cancer death in men and women. Despite the improvements in diagnosis and therapy, the prognosis and outcome of lung cancer patients is still poor. This could be associated with the lack of effective first-line oncology drugs, formation of resistant tumors and non-optimal administration route. Therefore, the repurposing of existing drugs currently used for different indications and the introduction of a different method of drug administration could be investigated as an alternative to improve lung cancer therapy. This review describes the rationale and development of repositioning of drugs for lung cancer treatment with emphasis on inhalation. The review includes the current progress of repurposing non-cancer drugs, as well as current chemotherapeutics for lung malignancies via inhalation. Several potential non-cancer drugs such as statins, itraconazole and clarithromycin, that have demonstrated preclinical anti-cancer activity, are also presented. Furthermore, the potential challenges and limitations that might hamper the clinical translation of repurposed oncology drugs are described.

Biologically active quinoline and quinazoline alkaloids part I

Quinoline and quinazoline alkaloids, two important classes of N-based heterocyclic compounds, have attracted tremendous attention from researchers worldwide since the 19th century. Over the past 200 years, many compounds from these two classes were isolated from natural sources, and most of them and their modified analogs possess significant bioactivities. Quinine and camptothecin are two of the most famous and important quinoline alkaloids, and their discoveries opened new areas in antimalarial and anticancer drug development, respectively. In this review, we survey the literature on bioactive alkaloids from these two classes and highlight research achievements prior to the year 2008 (Part I). Over 200 molecules with a broad range of bioactivities, including antitumor, antimalarial, antibacterial and antifungal, antiparasitic and insecticidal, antiviral, antiplatelet, anti-inflammatory, herbicidal, antioxidant and other activities, were reviewed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.

Camptothecin-based nanodrug delivery systems

The drug camptothecin has a wide range of antitumor effects in cancers including gastric cancer, rectal and colon cancer, liver cancer, and lung cancer. Camptothecin-based drugs inhibit topoisomerase 1 (Topo 1), leading to destruction of DNA, and are currently being used as important chemotherapeutic agents in clinical antitumor treatment. However, the main obstacle associated with cancer therapy is represented by systemic toxicity of conventional anticancer drugs and their low accumulation at the tumor site. In addition, low bioavailability, poor water solubility, and other shortcomings hinder their anticancer activity. Different from traditional pharmaceutical preparations, nanotechnology-dependent nanopharmaceutical preparations have become one of the main strategies for different countries worldwide to overcome drug development problems. In this review, we summarized the current hotspots and discussed a variety of camptothecin-based nanodrugs for cancer therapy. We hope that through this review, more efficient drug delivery systems could be designed with potential applications in clinical cancer therapy.

Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications

This is a critical review on research conducted in the field of pulmonary delivery of liposomes. Issues relating to the mechanism of nebulisation and liposome composition were appraised and correlated with literature reports of liposome formulations used in clinical trials to understand the role of liposome size and composition on therapeutic outcome. A major highlight was liposome inhalation for the treatment of lung cancers. Many in vivo studies that explored the potential of liposomes as anticancer carrier systems were evaluated, including animal studies and clinical trials. Liposomes can entrap anticancer drugs and localise their action in the lung following pulmonary delivery. The safety of inhaled liposomes incorporating anticancer drugs depends on the anticancer agent used and the amount of drug delivered to the target cancer in the lung. The difficulty of efficient targeting of liposomal anticancer aerosols to the cancerous tissues within the lung may result in low doses reaching the target site. Overall, following the success of liposomes as inhalable carriers in the treatment of lung infections, it is expected that more focus from research and development will be given to designing inhalable liposome carriers for the treatment of other lung diseases, including pulmonary cancers. The successful development of anticancer liposomes for inhalation may depend on the future development of effective aerosolisation devices and better targeted liposomes to maximise the benefit of therapy and reduce the potential for local and systemic adverse effects.

Perspectives on biologically active camptothecin derivatives

Camptothecins (CPTs) are cytotoxic natural alkaloids that specifically target DNA topoisomerase I. Research on CPTs has undergone a significant evolution from the initial discovery of CPT in the late 1960s through the study of synthetic small-molecule derivatives to investigation of macromolecular constructs and formulations. Over the past years, intensive medicinal chemistry efforts have generated numerous CPT derivatives. Three derivatives, topotecan, irinotecan, and belotecan, are currently prescribed as anticancer drugs, and several related compounds are now in clinical trials. Interest in other biological effects, besides anticancer activity, of CPTs is also growing exponentially, as indicated by the large number of publications on the subject during the last decades. Therefore, the main focus of the present review is to provide an ample but condensed overview on various biological activities of CPT derivatives, in addition to continued up-to-date coverage of anticancer effects.

Nanomedicine in cancer therapy: challenges, opportunities, and clinical applications

Cancer is a leading cause of death worldwide. Currently available therapies are inadequate and spur demand for improved technologies. Rapid growth in nanotechnology towards the development of nanomedicine products holds great promise to improve therapeutic strategies against cancer. Nanomedicine products represent an opportunity to achieve sophisticated targeting strategies and multi-functionality. They can improve the pharmacokinetic and pharmacodynamic profiles of conventional therapeutics and may thus optimize the efficacy of existing anti-cancer compounds. In this review, we discuss state-of-the-art nanoparticles and targeted systems that have been investigated in clinical studies. We emphasize the challenges faced in using nanomedicine products and translating them from a preclinical level to the clinical setting. Additionally, we cover aspects of nanocarrier engineering that may open up new opportunities for nanomedicine products in the clinic.

Lipid-based carriers for pulmonary products: preclinical development and case studies in humans

A number of lipid-based technologies have been applied to pharmaceuticals to modify their drug release characteristics, and additionally, to improve the drug loading for poorly soluble drugs. These technologies, including solid-state lipid microparticles, many of which are porous in nature, liposomes, solid lipid nanoparticles and nanostructured lipid carriers, are increasingly being developed for inhalation applications. This article provides a review of the rationale for the use of these technologies in the pulmonary delivery of drugs, and summarizes the manufacturing processes and their limitations, the in vitro and in vivo performance of these systems, the safety of these lipid-based systems in the lung, and their promise for commercialization.

Liposomal formulations for inhalation

No marketed inhaled products currently use sustained release formulations such as liposomes to enhance drug disposition in the lung, but that may soon change. This review focuses on the interaction between liposomal formulations and the inhalation technology used to deliver them as aerosols. There have been a number of dated reviews evaluating nebulization of liposomes. While the information they shared is still accurate, this paper incorporates data from more recent publications to review the factors that affect aerosol performance. Recent reviews have comprehensively covered the development of dry powder liposomes for aerosolization and only the key aspects of those technologies will be summarized. There are now at least two inhaled liposomal products in late-stage clinical development: ARIKACE® (Insmed, NJ, USA), a liposomal amikacin, and Pulmaquin™ (Aradigm Corp., CA, USA), a liposomal ciprofloxacin, both of which treat a variety of patient populations with lung infections. This review also highlights the safety of inhaled liposomes and summarizes the clinical experience with liposomal formulations for pulmonary application.

Anti-tumor activity of CpG-ODN aerosol in mouse lung metastases

Studies in preclinical models have demonstrated the superior anti-tumor effect of CpG oligodeoxynucleotides (CpG-ODN) when administered at the tumor site rather than systemically. We evaluated the effect of aerosolized CpG-ODN on lung metastases in mice injected with immunogenic N202.1A mammary carcinoma cells or weakly immunogenic B16 melanoma cells. Upon reaching the bronchoalveolar space, aerosolized CpG-ODN activated a local immune response, as indicated by production of IL-12p40, IFN-γ and IL-1β and by recruitment and maturation of DC cells in bronchoalveolar lavage fluid of mice. Treatment with aerosolized CpG-ODN induced an expansion of CD4+ cells in lung and was more efficacious than systemic i.p. administration against experimental lung metastases of immunogenic N202.1A mammary carcinoma cells, whereas only i.p. delivery of CpG-ODN provided anti-tumor activity, which correlated with NK cell expansion in the lung, against lung metastases of the poorly immunogenic B16 melanoma. The inefficacy of aerosol therapy to induce NK expansion was related to the presence of immunosuppressive macrophages in B16 tumor-bearing lungs, as mice depleted of these cells by clodronate treatment responded to aerosol CpG-ODN through expansion of the NK cell population and significantly reduced numbers of lung metastases. Our results indicate that tumor immunogenicity and the tumor-induced immunosuppressive environment are critical factors to the success of CpG therapy in the lung, and point to the value of routine sampling of the lung immune environment in defining an optimal immunotherapeutic strategy.

Targeted delivery of transferrin-conjugated liposomes to an orthotopic model of lung cancer in nude rats

BACKGROUND

Lung cancer is the leading cause of cancer death worldwide. Pulmonary anticancer therapy might offer several advantages over systemic delivery, leading to an increased exposure of the lung tumor to the drug, while minimizing side effects, due to regional containment. Here, we studied if a combination of inhalation therapy and drug targeting holds potential as an even more efficient lung cancer therapy.

METHODS

Transferrin (Tf )-conjugated PEG liposomes loaded with doxorubicin (DOX) were administered using an intracorporeal nebulizing catheter to an orthotopic lung cancer model established in athymic Rowett nude rats. Different DOX formulations and doses (0.2 and 0.4 mg/kg) were tested and the influence on tumor progression and life span of rats was evaluated in comparison with the i.v. administration of Tf-PEG-liposomes loaded with DOX at a therapeutic dose of 2 mg/kg.

RESULTS

Rats in the untreated control group showed significant weight loss 2 weeks after tumor induction and died between days 19 and 29. Lungs of these animals showed multiple foci of neoplastic deposits, ranging up to 20 mm replacing the entire lobe. Empty Tf-liposomes showed a significant effect on survival time. This might be caused by the secondary cytotoxicity via stimulation of pulmonary macrophages. All animal treated intravenously also perished before the end of the study. No significant (p<0.05) improvement in survival was observed between the groups treated with aerosols of free drug, DOX encapsulated in plain and in Tf-modified liposomes. However, more animals survived in the Tf-liposome groups than in the other treatment regimes, and their lung tissue generally had fewer and smaller tumors. Nevertheless, the size of the groups, and the duration of the trial render it impossible to come to a definite conclusion.

CONCLUSIONS

Drug targeting demonstrated potential for improving the aerosol treatment of lung cancer.

Aerosolized gemcitabine in patients with carcinoma of the lung: feasibility and safety study

BACKGROUND

We investigated the biodistribution, pharmacokinetics, safety profile, and feasibility of aerosolized gemcitabine (GCB) in patients with lung carcinoma.

METHOD

Eleven patients with carcinoma localized in the lungs were studied in a dose escalation study of aerosolized GCB administered 1 day/week for 9 consecutive weeks. Safety data, scintigraphic assessment of the delivered dose and pharmacokinetic monitoring were analyzed. Patients were treated with doses of between 1 mg/kg and 4 mg/kg (dose in the nebulizer), using a new inhaler device (Aeroneb Pro with an Idehaler Chamber).

RESULTS AND CONCLUSIONS

The total dose of GCB delivered to the patient's lung was 42±16% of the initial amount of dose in the nebulizer. Safety data showed no hematologic toxicity, nephrotoxicity or neurotoxicity. At 4 mg/kg, one patient experienced grade 4 pulmonary toxicity (bronchospasm), which was the dose-limiting toxicity. Grade 2 and 3 toxic effects included fatigue, vomiting, dyspnea, and cough. Overall response: minor response in one patient, stable disease in four patients, progressive disease in four patients. Pharmacokinetic data showed very low plasma GCB levels. Maximal plasma concentration was observed at the end of nebulization. Aerosolized gemcitabin was safe, with minimal toxicity, for patients with lung carcinoma.

The role of Fas/FasL in the metastatic potential of osteosarcoma and targeting this pathway for the treatment of osteosarcoma lung metastases

Pulmonary metastases remain the main cause of death in patients with Osteosarcoma (OS). In order to identify new targets for treatment, our laboratory has focused on understanding the biological properties of the tumor microenvironment that contribute to or interfere with metastasis. Dysfunction of the Fas/FasL signaling pathway has been implicated in tumor development, and progression. Here we describe the status of Fas expression in murine nonmetastatic K7 and metastatic K7M2 cells and human nonmetastatic SAOS and LM2 and metastatic LM6 OS cells. We demonstrated that Fas expression correlates inversely with metastatic potential. Pulmonary metastases from patients were uniformly Fas- supporting the importance of Fas expression to the metastatic potential. Since FasL is constitutively expressed in the lung, our data suggests that Fas+ tumor cells undergo apoptosis and are cleared from the lung. By contrast, Fas- tumor cells evade this host defense mechanism and form lung metastases. We confirmed these findings by blocking the Fas pathway using Fas Associated Death Domain Dominant-Negative (FDN). Fas+ cells transfected with FDN were not sensitive to FasL, showed delayed clearance and formed lung metastases. Fas+ cells were also able to form lung metastases in FasL-deficient mice. Using our mouse model systems, we demonstrated that aerosol treatment with liposomal 9-Nitrocamptothecin and Gemcitabine (chemotherapeutic agents known to upregulate Fas expression) increased Fas expression and induced tumor regression in wild type mice. Lung metastases in FasL deficient mice did not respond to the treatment. We conclude that Fas is an early defense mechanism responsible for clearing invading Fas+ tumor cells from the lung. Fas- cells or cells with a nonfunctional Fas pathway evade this defense mechanism and form lung metastases. Therapy that induces Fas expression may therefore be effective in patients with established OS lung metastases. Aerosol delivery of these agents is an ideal way to target treatment to the lung.

Disease guided optimization of the respiratory delivery of microparticulate formulations

BACKGROUND

Inhalation of microparticulate dosage forms can be effectively used in the treatment of respiratory and systemic diseases.

OBJECTIVE

Disease states investigated for treatment by inhalation of microparticles were reviewed along with the drugs' pharmacological, pharmacokinetic and physical chemical properties to identify the advantages of microparticulate inhalation formulations and to identify areas for further improvement.

METHODS

Microbial infections of the lung, asthma, diabetes, lung transplantation and lung cancer were examined, with a focus on those systems intended to provide a sustained release.

CONCLUSION

In developing microparticulate formulations for inhalation in the lung, there is a need to understand the pharmacology of the drug as the key to revealing the optimal concentration time profile, the disease state, and the pharmacokinetic properties of the pure drug as determined by IV administration and inhalation. Finally, in vitro release studies will allow better identification of the best dosing strategy to be used in efficacy and safety studies.

Phase I study of aerosolized SLIT cisplatin in the treatment of patients with carcinoma of the lung

PURPOSE

To investigate the safety and pharmacokinetics of aerosolized Sustained Release Lipid Inhalation Targeting (SLIT) Cisplatin in patients with lung carcinoma.

EXPERIMENTAL DESIGN

Phase I, dose-escalating study of SLIT Cisplatin given in two sessions daily. Safety data, including laboratory variables, adverse events, pulmonary function tests, and radiographic imaging, were collected and analyzed for all patients to determine toxicity. Pharmacokinetic monitoring was done during the first course.

RESULTS

Seventeen patients and one tracheostomy patient on compassionate use received treatment. Aerosolized cisplatin was well tolerated. No dose-limiting toxicity was observed at the maximum delivered dose. Safety data showed no hematologic toxicity, nephrotoxicity, ototoxicity, or neurotoxicity. Most common adverse events were nausea (64.7%), vomiting (47.1%), dyspnea (64.7%), fatigue (64.7%), and hoarseness (47.1%). Pharmacokinetic data showed very low plasma platinum levels only with the longest repeated inhalations. Common Toxicity Criteria grade 2 decrease in forced expiratory volume in one second and diffusing lung capacity for carbon monoxide after one course occurred both in two patients and grade one decrease in forced expiratory volume in one second and diffusing lung capacity for carbon monoxide in six and five patients, respectively. Direct airway deposition via the tracheostomy resulted in clinical deterioration after two cycles best described as bronchitis, completely reversible within days. Overall response: stable disease in 12 patients and progressive disease in 4 patients (one patient received one cycle).

CONCLUSIONS

Aerosolized liposomal cisplatin was found to be feasible and safe.

p53 Aerosol Formulation with Low Toxicity and High Efficiency for Early Lung Cancer Treatment

PURPOSE

To develop an optimal nonviral aerosol formulation for locoregional treatment of early lung cancer.

EXPERIMENTAL DESIGN

The formulation was made of polylysine/protamine combination (AND) as the carrier and p53 gene (p53sm) as therapeutic agent. To estimate the aerosol deposition, the aerodynamic size of the AND-p53sm was measured with extrusion-precipitation method. To accurately determine the dose, the aerosol efficiency in mice was measured with a fluorescent dye. The transfection efficiency and DNA protection function of the aerosolized formulation in cultured cells and mouse lungs were detected with reporter gene assays and/or reverse transcription-PCR. The preclinical safety and efficacy of AND-p53sm were studied in healthy mice and mice bearing orthotopic human non-small-cell lung cancer (NSCLC) xenograft.

RESULTS

After aerosolization, AND is 3- to 17-fold more effective than commonly used PEI or cationic lipid formulations in transfecting the NSCLC cells (relative light units, 1,494 versus 534 and 86; P < 0.003). Aerodynamic size of AND-p53sm ranged 0.2 to 3 mum is the optimal aerosol droplets for deposition in the entire human respiratory tract. Significant gene expression was detected in the lungs of mice given aerosolized AND-p53sm and AND-luciferase. Aerosolized AND-p53sm significantly prolonged the life of mice bearing orthotopic human NSCLC xenografts, and it was more effective than an optimal i.v. cisplatin chemotherapy (increased life span, 93% versus 25%; P = 0.014). Inhalation of AND produced low and reversible pulmonary toxicity and no systemic toxicity.

CONCLUSIONS

This optimal formulation is suitable for delivering biological materials to human lung with aerosol administration. This therapeutic strategy is an option for patients with early lung cancer and bronchoalveolar carcinoma.

Carboplatin nanocapsules: a highly cytotoxic, phospholipid-based formulation of carboplatin

Platinum-based drugs are widely used in cancer chemotherapy. However, their clinical use is limited by systemic toxicity, rapid blood clearance, and the occurrence of resistance. Our research is aimed at increasing the therapeutic index of these drugs by encapsulation in a lipid formulation. Previously, we developed a method for efficient encapsulation of cisplatin in a lipid formulation, yielding cisplatin nanocapsules. Here, we show that carboplatin, a cisplatin-derived anticancer drug with different chemical properties, can be efficiently encapsulated in a lipid formulation by a similar method. The carboplatin nanocapsules exhibit a very high cytotoxicity in vitro: the IC(50) value of carboplatin nanocapsules is up to a 1,000-fold lower than that of conventional carboplatin when tested on a panel of carcinoma cell lines. Cellular platinum content analysis and confocal fluorescent imaging of the interaction of the carboplatin nanocapsules with IGROV-1 cells indicate that the improved cytotoxicity is due to increased platinum accumulation in the cells, resulting from uptake of the formulation by endocytosis.

Alternative administration of camptothecin analogues

In order to improve the therapeutic index of camptothecin (CPT) analogues, alternative administration of CPT analogues is being evaluated. Topotecan, irinotecan, rubitecan, lurtotecan and 9-aminocamptothecin have been administered orally with response rates equivalent to that seen after intravenous administration, where applicable. Oral availability and administration of some of the newer CPT analogues, including diflomotecan (BN80915) and grimatecan (ST1481), have also shown promising results. Aerosolisation of liposomal 9-nitrocamptothecin has been studied in patients with advanced malignancies involving the lung, demonstrating systemic antitumour activity. Intrathecal administration of topotecan has been studied in children with refractory neoplastic meningitis. It is well tolerated and associated with some antitumour activity. Intraperitoneal administration of topotecan as consolidation therapy in patients with ovarian cancer has shown promising results. Transdermal administration of rubitecan has been studied in mice. So far, no CPT has been approved for an alternative route of administration.

Liposomal irinotecan: formulation development and therapeutic assessment in murine xenograft models of colorectal cancer

PURPOSE

The purpose is to demonstrate whether an appropriately designed liposomal formulation of irinotecan is effective in treating mice with liver-localized colorectal carcinomas.

EXPERIMENTAL DESIGN

Irinotecan was encapsulated in 1,2-distearoyl-sn-glycero-3-phosphocholine/cholesterol (55:45 molar ratio) liposomes using an ionophore (A23187)-generated transmembrane proton gradient. This formulation was evaluated in vivo by measuring plasma elimination of liposomal lipid and drug after i.v. administration. Therapeutic activity was determined in SCID/Rag-2M mice bearing s.c. LS180 tumors or orthotopic LS174T colorectal metastases.

RESULTS

Drug elimination from the plasma was significantly reduced when irinotecan was administered in the liposomal formulation. At 1 hour after i.v. administration, circulating levels of the liposomal drug were 100-fold greater than that of irinotecan given at the same dose. High-performance liquid chromatographic analysis of plasma samples indicated that liposomal irinotecan was protected from inactivating hydrolysis to the carboxylate form. This formulation exhibited substantially improved therapeutic effects. For the LS180 solid tumor model, it was shown that after a single injection of liposomal irinotecan at 50 mg/kg, the time to progress to a 400-mg tumor was 34 days (as compared with 22 days for animals treated with free drug at an equivalent dose). In the model of colorectal liver metastases (LS174T), a median survival time of 79 days was observed after treatment with liposomal irinotecan (50 mg/kg, given every 4 days for a total of three doses). Saline and free drug treated mice survived for 34 and 53 days, respectively.

CONCLUSIONS

These results illustrate that liposomal encapsulation can substantially enhance the therapeutic activity of irinotecan and emphasize the potential for using liposomal irinotecan to treat liver metastases.

Pharmacokinetic studies of 9-nitrocamptothecin on intermittent and continuous schedules of administration in patients with solid tumors

PURPOSE

Oral administration of 9-nitrocamptothecin (9NC), and the formation of its metabolite 9-aminocamptothecin (9AC), may be associated with high interpatient and intrapatient variability. Therefore, we evaluated the plasma pharmacokinetics and urine recovery of 9NC administered on three different schedules as part of phase I and phase II studies.

EXPERIMENTAL DESIGN

In phase I schedule A, 9NC was administered orally daily for 5 days per week for 2 weeks repeated every 4 weeks. On phase I schedule B, 9NC was administered daily for 14 days repeated every 4 weeks. In Phase II, 9NC was administered daily for 5 days during 8 weeks (one cycle). Serial blood samples were obtained on day 1 and day 10 or 11 for phase I studies, and day 1 and day 50 for the phase II study. Recovery of 9NC and 9AC in urine was evaluated on day 1 and day 10 or 11 in the phase I study. Area under the 9NC and 9AC plasma concentration vs time curves from 0 to 24 h (AUC0-24 h) were calculated using compartmental analysis.

RESULTS

The mean+/-SD 9NC lactone AUC0-24 h values on day 1 at the maximum tolerated dose of schedules A and B (2.43 and 1.70 mg/m2, respectively) and the phase II dose (1.5 mg/m2) were 78.9+/-54.4, 155.7+/-112.8, and 48.3+/-17.5 ng/ml.h, respectively. The mean+/-SD 9AC lactone AUC0-24 h values at these same doses of 9NC were 17.3+/-17.9, 41.3+/-16.6, and 31.3+/-12.8 ng/ml h, respectively. The ratios of 9NC lactone AUC0-24 h on day 10 or 11 to day 1 on phase I A and B were 1.27+/-0.68 and 1.73+/-1.56, respectively, and the ratios 9AC lactone AUC0-24 h on day 10 or 11 to day 1 on phase I A and B were 2.23+/-1.02 and 1.65+/-0.97, respectively. The recovery of 9NC and 9AC in the urine was <15%.

CONCLUSIONS

There was significant interpatient and intrapatient variability in the disposition of 9NC and 9AC. 9NC and 9AC undergo primarily nonrenal elimination.

Novel vitamin E analogue and 9-nitro-camptothecin administered as liposome aerosols decrease syngeneic mouse mammary tumor burden and inhibit metastasis

PURPOSE

To test the anticancer properties of a nonhydrolyzable ether-linked acetic acid analogue of vitamin E, 2,5,7,8-tetramethyl-2R-(4R,8R, 12-trimethyltridecyl)chroman-6-yloxyacetic acid (alpha-TEA), and a derivative of camptothecin, 9-nitrocamptothecin (9-NC)singly and in combination against mouse mammary tumor cells (line 66 clone 4 stably transfected with green fluorescent protein; 66cl-4-GFP) cultured in vitro or transplanted subcutaneously into the inguinal region of female BALB/c mice to form established tumors.

METHODS

Following in vitro treatment of 66cl-4-GFP cells with alpha-TEA and suboptimal concentrations of 9-NC, singly or in combination, apoptosis was measured by morphological evaluation of nuclei stained with 4',6-diamidino-2-phenylindole (DAPI), and DNA synthesis arrest was measured by tritiated thymidine uptake. For in vivo analyses alpha-TEA and 9-NC, both water-insoluble compounds, were formulated into liposomes using dil-auroylphosphatidylcholine and administered by aerosol to deliver doses calculated to be 36 and 0.4 microg/mouse per day, respectively, (singly or each separately for combined treatments) 7 days per week.

RESULTS

Treatment of 66cl-4-GFP cells in culture for 3 days with a combination of alpha-TEA (10 microg/ml; singly produces 38% apoptosis), and suboptimal concentrations of 9-NC(15.6, 31.3, 62.5, or 125 ng/ml; singly produce 2-7% apoptosis), produced 47%, 58%, 64%, and 69% apoptosis. Likewise, combinations of alpha-TEA 9-NC inhibited DNA synthesis more than either agent administered singly. A significant reduction (P< 0.001)in growth of subcutaneous transplanted tumors was observed with liposome-formulated and aerosolized delivery of alpha-TEA + 9-NC to BALB/c mice. The incidence of macroscopic lung metastasis was 83% in control vs 8 % in alpha-TEA-, 9-NC-, or combination-treated mice. Fluorescence microscopic examination of lungs and axillary and brachial lymph nodes showed a statistically significant decrease in metastasis observed in alpha-TEA-,9-NC-, and combination- vs control-treated animals. Analyses of primary tumor tissue for proliferation and apoptosis showed treatment groups to have lower Ki-67 and higher terminal deoxynucleotidyl transferase-mediated nick end labeling, respectively. Treatments showed no measurable effects on two angiogenesis parameters,namely intratumoral blood volume as assessed by hemoglobin content and intratumoral blood vessel density as assessed with CD31 staining.

CONCLUSIONS

Combination treatments enhanced antiproliferative and proapoptotic activities in cell culture, and when formulated in liposomes and delivered via aerosolization to treat an aggressive and metastatic syngeneic murine mammary tumor, the combination treatment showed a significant reduction in tumor volume in comparison to either treatment alone. Mechanistically, it appears that neither enhanced apoptosis, reduced cell proliferation,nor reduced blood vessel density can fully account for the enhanced effects of the combination treatment.

Clinical Evaluation of the Delivery and Safety of Aerosolized Liposomal 9-Nitro-20(S)-Camptothecin in Patients with Advanced Pulmonary Malignancies

PURPOSE

The purpose is to evaluate the feasibility and safety of aerosol administration of the topoisomerase I inhibitor, 9-nitrocamptothecin, in a liposome formulation, and to recommend a dosage for a Phase II trial for an 8-week daily treatment schedule.

EXPERIMENTAL DESIGN

Patients with primary or metastatic lung cancer received aerosolized liposomal 9-nitrocamptothecin for 5 consecutive days/week for 1, 2, 4, or 6 weeks followed by 2 weeks of rest to determine feasibility. For the Phase I part, the dose was increased stepwise from 6.7 up to 26.6 micro g/kg/day Monday to Friday for 8 weeks followed by 2 weeks of rest.

RESULTS

Twenty-five patients received treatment. The mean baseline forced expiratory volume in 1 second for all patients was 85% of predicted. A dose-limiting toxicity was chemical pharyngitis seen after 1 week in 2 of 2 patients at 26.6 micro g/kg/day. At 20.0 micro g/kg/day, grade 2 and 3 fatigue prompting a dose reduction was seen after 4 weeks in 2 of 4 patients. Grade 2 toxic effects included nausea/vomiting (9 patients), cough and bronchial irritation (6 patients), fatigue (5 patients), anemia (4 patients), neutropenia (2 patients), anorexia (1 patient), and skin rash around the face mask (1 patient). 9-Nitro-20(S)-camptothecin (9NC) was absorbed systemically. Partial remissions were observed in 2 patients with uterine cancer, and stabilization occurred in 3 patients with primary lung cancer.

CONCLUSIONS

Aerosol administration of liposomal 9NC was found to be feasible and safe. 9NC delivered as an aerosol was detected in patient's plasma shortly after the start of treatment. The recommended dose for Phase II studies is 13.3 micro g/kg/day (equivalent to 0.5 mg/m(2)/day), which constitutes two consecutive 30-min nebulizations/day from a nebulizer reservoir with 4 mg of 9NC in 10 ml of sterile water, Monday to Friday for 8 weeks every 10 weeks.

Transport characteristics of 9-nitrocamptothecin in the human intestinal cell line Caco-2 and everted gut sacs

The intestinal absorptive characteristics and the efflux mechanisms of 9-nitrocamptothecin (9-NC), a novel water-insoluble camptothecin (CPT) derivative, were investigated. The Caco-2 cells and the everted gut sacs were used as models of the intestinal mucosa to assess transepithelial transport of 9-NC. The determination of 9-NC was performed by HPLC. In the Caco-2 cells, the absorptive transport of 9-NC was pH dependent and the transport was enhanced at weakly acidic pH on the apical side. No concentration dependence and saturation were observed for the absorptive transport of 9-NC at concentrations up to 250 microM, while secretory transport were concentration dependent and saturable process (K(m) was 49.8 +/- 1.2 microM, V(max) was 38.28 +/- 0.8 ng/cm(2)/min). In the presence of verapamil (100 microM) and CsA (10 microM), potent inhibitors of P-glyprotein (P-gp)/MRP2 (cMOAT), the P(appBL-AP)/P(appAP-BL) ratio was decreased from 3.4 to 1.4 and 1.3, respectively, and permeation of apical to basolateral was enhanced approximately two-fold. In the everted gut sacs, the absorption of 9-NC was passive diffusion and had no significant difference in different gut regions. Adding verapamil in the everted gut sacs over a concentration ranging from 10 to 100 microM, the absorption of 9-NC was significantly enhanced, especially more markedly in lower small intestine (P < 0.05). Overall, the current study suggests that pH and efflux transporters are capable of mediating the absorption and efflux of 9-NC, and they may play significant roles in limiting the oral absorption of 9-NC.

Cyclosporin A Aerosol Improves the Anticancer Effect of Paclitaxel Aerosol in Mice

The objective of this study was to assess the effect of cyclosporin A liposome aerosol on the anticancer activity of paclitaxel (PTX) liposome aerosol against renal cell carcinoma (Renca) pulmonary metastases in mice. Cyclosporin A (CsA) was administered as a liposome aerosol for one-half hour before starting one-half hour treatment with PTX liposome aerosol (CsA/PTX), and in a second groups of animals cyclosporin A liposome aerosol was given before PTX for one-half hour and also later by mixing a second dose of cyclosporin A aerosol with PTX aerosol and extending the treatment period to one hour (CsA/PTX + CsA). In one experiment, PTX and CsA/PTX aerosols were significantly more effective compared to untreated controls against renal cell cancer as measured by lung weights and tumor surface areas. CsA/PTX was significantly better that PTX alone as measured by lung weights and tumor area. In a second experiment, tumor areas of PTX and CsA/PTX treated mice were significantly reduced compared to untreated controls and CsA/PTX treated mice had significantly smaller tumor areas than PTX treated mice. In contrast, tumor numbers were not significantly fewer than controls in either therapeutic group. In a third experiment, tumor numbers and tumor areas were significantly fewer in mice treated with CsA/PTX and CsA/PTX + CsA compared to untreated controls. Mice treated with CsA/PTX + CsA had significantly fewer tumors and less tumor area than mice receiving CsA/PTX. While PTX treated mice were not different than untreated controls with respect to tumor numbers or tumor volumes, PTX treated mice had significantly greater tumor numbers and tumor areas than CsA/PTX and CsA/PTX + CsA treated mice. Co-administration of CsA with PTX demonstrated significant dose dependent anticancer effects against renal cell pulmonary metastases in mice. Toxicity manifested by weight loss was associated with the highest dose of CsA.

Liposomally targeted cytotoxic drugs for the treatment of cancer

Phospholipid spherules composed of lipid bilayer membranes entrapping a central aqueous core were first described more than 30 years ago (Bangham et al 1965). The term liposome was coined in 1968 (Sessa & Weissmann 1968) and the first suggestions that these vesicles might have potential as vehicles for targeted drug delivery for a range of diseases, including cancer, appeared shortly afterwards (Gregoriades et al 1974; Gregoriades 1976a, b). However, the process of turning this expectation into a clinical reality has suffered a number of setbacks and has taken more than a quarter of a century. In the process, new types of liposomes with favourable in-vivo pharmacokinetics and biodistribution patterns have been generated (Lasic & Papahadjopoulos 1995). Many of these preparations have been subjected to extensive examination and an increasing number of agents have entered clinical trials. In this review, we will trace the development of those liposomes that are currently undergoing (or are about to undergo) clinical evaluation.

Camptothecins

Camptothecin analogues and derivatives appear to exert their antitumour activity by binding to topoisomerase I and have shown significant activity against a broad range of tumours. In general, camptothecins are not substrates for either the multidrug-resistance P-glycoprotein or the multidrug-resistance-associated protein (MRP). Because of manageable toxicity and encouraging activity against solid tumours, camptothecins offer promise in the clinical management of human tumours. This review illustrates the proposed mechanism(s) of action of camptothecins and presents a concise overview of current camptothecin therapy, including irinotecan and topotecan, and novel analogues undergoing clinical trails, such as exatecan (DX-8951f), IDEC-132 (9-aminocamptothecin), rubitecan (9-nitrocamptothecin), lurtotecan (GI-147211C), and the recently developed homocamptothecins diflomotecan (BN-80915) and BN-80927.