Clinical Cancer Research Folkman
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cabanes, A.
Right arrow Articles by Gabizon, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cabanes, A.
Right arrow Articles by Gabizon, A.
Clinical Cancer Research Vol. 5, 687-693, March 1999
© 1999 American Association for Cancer Research

Experimental Therapeutics, Preclinical Pharmacology

Enhancement of Antitumor Activity of Polyethylene Glycol-coated Liposomal Doxorubicin with Soluble and Liposomal Interleukin 21

Anna Cabanes, Simcha Even-Chen, Jacqueline Zimberoff, Yechezkel Barenholz, Eli Kedar and Alberto Gabizon2

Sharet Institute of Oncology, Hadassah Hebrew University Medical Center [A. C., J. Z., A. G.], and Department of Biochemistry [S. E-C., Y. B.] and Lautenberg Center for General and Tumor Immunology [J. Z., E. K.], Hebrew University-Hadassah Medical School, Jerusalem, Israel 91.120


   ABSTRACT
Top
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Polyethylene glycol-coated liposomal doxorubicin (Doxil) has a sustained release profile and a mild myelosuppressive effect that may enable a beneficial interaction with lymphocyte-activating cytokines, such as interleukin 2 (IL-2). Previous studies have shown that liposome entrapment of IL-2 potentiates its immunomodulatory effects and reduces the need for frequent dosing. We assessed the therapeutic effect of Doxil (8 mg/kg) followed by free or liposomal IL-2 (50,000 Cetus Units x3) in mice bearing M109 lung adenocarcinoma transplanted i.v. or i.p. Doxil was always administered i.v., whereas IL-2 was given i.v. in the i.v. M109 model and i.p. in the i.p. M109 model. The optimal combined treatment was significantly more effective than liposomal chemotherapy alone, producing tumor-free, long-term survivors in 100% (i.v. M109) and 94% (i.p. M109) of the mice, compared with 50% and 56%, respectively, for Doxil alone. The efficacy boost of IL-2 appeared to be formulation dependent, with free IL-2 and IL-2 in small unilamellar vesicles most active in the i.v. tumor model, and IL-2 in multilamellar vesicles most active in the i.p. tumor model. The combination of Doxil with free or liposomal IL-2 was devoid of any conspicuous toxicity. Cytokine treatment without chemotherapy was completely ineffective. Liposome-based chemoimmunotherapy is a synergistic and highly efficacious approach to eradicate metastatic and regionally spread tumors.


   INTRODUCTION
Top
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Previous studies with liposomal anthracyclines have shown that stable encapsulation of doxorubicin in PEGylated3 liposomes modifies the pharmacological profile of the drug, resulting in prolonged circulation half-life, slow drug release, and changes in tissue distribution with increased deposition in tumors and reduced cardiotoxicity (1, 2, 3, 4, 5, 6) . This results in a substantial improvement in the therapeutic efficacy in animal tumor systems (reviewed in Ref. 7 ). Furthermore, the pharmacokinetics in humans of a pharmaceutical formulation of PEGylated liposomal doxorubicin known as Doxil4 has been found to be consistent with the preclinical observations (8) .

Despite these improved results with liposome delivery of anthracyclines, the goal of achieving cures with chemotherapy as a single modality remains elusive. In most instances, liposomal doxorubicin prolongs median survival more than Free-Dox, but the number of cured animals (tumor-free, long-term survivors) in models of disseminated cancer is very small. The failure is often due to the regrowth of a small fraction of tumor cells that are relatively resistant to chemotherapy due to intrinsic or cell kinetic factors or are located in underexposed, sanctuary anatomical sites.

The concept of activating the host immune mechanisms to destroy residual tumor cells after chemotherapy has long been proposed. IL-2, used as a single agent, has shown activity both preclinically and clinically against a wide spectrum of tumors (9, 10, 11, 12, 13) . However, due to the rapid clearance of IL-2, high and frequent doses must be administered to achieve significant antitumor activity, leading to serious side effects, including capillary leakage, cardiac toxicity, and hypotension (11, 12, 13) . Combined treatment with doxorubicin and IL-2 has been shown to be effective against a variety of murine tumors, such as renal cell carcinoma (14) , colon and mammary adenocarcinoma (15) , and EL4 lymphoma (16) . Despite these encouraging preclinical results, clinical trials using this combination have been limited (17) due to major problems related to the high toxicity of IL-2 therapy at the dose required to augment peripheral blood mononuclear cell toxicity.

To improve the therapeutic index of IL-2, Kedar et al. (18, 19, 20) have used liposomes aimed at improving the cytokine pharmacokinetics and its immunomodulatory activity and at reducing its toxicity. These experiments in normal, immunosuppressed, and tumor-bearing mice demonstrated that liposome-entrapped IL-2 is far more potent and less toxic than the soluble, free form. In the current studies, IL-2 has been successfully formulated in various liposome formulations. The purpose of this study was to examine the antitumor activity of a combined treatment comprising Doxil followed by the administration of either free or liposome-associated IL-2. Two liposome formulations [PEGylated SUVs (PEG-SUV-IL-2) and dimyristoyl-phosphatidylcholine/dimyristoyl- phosphatidylglycerol MLV-IL-2,]were used, which differ substantially in pharmacokinetic properties (21) .


   MATERIALS AND METHODS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Drugs
Doxorubicin.
Free-Dox was obtained from Farmitalia-Carlo Erba (Milan, Italy) and diluted in physiological saline before injection.

Doxil.
The PEGylated liposome preparation containing doxorubicin was kindly provided by Sequus Pharmaceuticals, Inc. (Menlo Park, CA). Doxil has the following lipid com-position (expressed as a mole ratio): hydrogenated soybean phosphatidylcholine (56.2%); cholesterol (38.3%); and methoxy-PEG (Mr 2000)-derivatized distearoyl-phosphatidyl-ethanolamine (5.3%). Doxorubicin is encapsulated in the intraliposomal aqueous space by remote loading under a 250 mM ammonium sulfate gradient (22) to achieve a drug:phospholipid ratio of approximately 150 µg/µmol. More than 95% of the drug is in the encapsulated form. The Gaussian mean vesicle size as measured by dynamic laser light scattering is in the range of 80–100 nm. The Doxil dose is measured and expressed on the basis of its doxorubicin content.

IL-2.
Purified (>97%) recombinant human IL-2 was kindly supplied by Chiron (Emeryville, CA) in 18 x 106 IU lyophilized vials (3 x 106 CU = 1 mg). After the addition of 1.2 ml of double-distilled water, the solution contained 1 mg/ml IL-2, 50 mg of mannitol and 0.2 mg of SDS buffered with sodium phosphate to pH 7.5. IL-2 was further diluted in PBS (pH 7.4) or in HBSS before use.

Liposomal IL-2.
MLV-IL-2:dimyristoyl-phosphatidylcholine (Lipoid KG, Ludwigshafen, Germany) and dimyristoyl-phosphatidylglycerol (Lipoid KG or Avanti Polar Lipids, Pelham, AL; molar ratio, 9:1) were dissolved in 5 ml of tertiary butanol. The mixture was sonicated in a bath sonicator until clear, frozen in liquid nitrogen, and lyophilized overnight. Subsequently, the dried lipid cake was hydrated by adding IL-2 solution (1 mg IL-2/100 mg lipid) and shaking for 15 min at room temperature, resulting in the formation of MLVs containing more than 90% of the IL-2. IL-2 associated to liposomes was separated from free IL-2 by centrifugation (18) and quantified by high-performance liquid chromatography as described elsewhere (23) as well as by the fluorescamine assay (24) . Similar values of IL-2 entrapment in liposomes have been obtained using an in vitro bioassay (18) . The mean size of the vesicles was 750 nm (N4-SD Submicron Particle Analyzer; Coulter Electronics Ltd).

PEG-SUV-IL-2:egg phosphatidylcholine (Lipoid KG; 450 mg), cholesterol (Sigma, St. Louis, MO; 117 mg), methoxy-PEG-distearoyl-phosphatidylethanolamine (PEG 1900-DSPE; kindly provided by Sequus Pharmaceuticals, Inc.; 105 mg), and D-{alpha}-tocopherol succinate (Sigma; 18 mg; molar ratio, 54:40:5:1) were dissolved in 9 ml of tertiary butanol. The mixture was sonicated for 20 min in a sonication bath (Transsonic 460/H; Elma, Austria) at 37°C, after which IL-2 (9 x 106 CU in 9 ml of HBSS preheated to 37°C) was added. The lipid/IL-2 mixture was then sonicated briefly until clear, frozen in liquid nitrogen, and lyophilized overnight. Subsequently, the dried lipid/IL-2 cake was hydrated by adding 9 ml of double-distilled water and immediately shaking for 15–30 min at room temperature, resulting in the formation of multilamellar vesicles. The liposomes were diluted in HBSS and 0.1% BSA to a final volume of 35 ml. Downsizing of the liposomes to form SUVs (mean diameter, 65 nm) was carried out by homogenization for 5–6 min at 46–48°C under high pressure (10,000 psi) using the Rannie Minilab 8.30H High Pressure Homogenizer (APV Rannie). The IL-2 liposomes were sterilized by filtration through 0.2 µm Nucleopore polycarbonate filters (Nucleopore, Pleasanton, CA). Gel exclusion chromatography through a Sepharose-6B CL (Pharmacia) column indicated that >=95% of the cytokine was associated with the liposome fraction (18) .

Mice
Female 8–12-week-old BALB/c mice were obtained from the Animal Breeding House of the Hebrew University-Hadassah Medical School (Jerusalem, Israel). Animals were housed at 5–10 mice/cage in a specific pathogen-free facility at Hadassah Medical Center with food and water ad libitum and a 12-h light cycle. The experimental procedures were in accordance with the standards required by the Institutional Animal Care and Use Committee of the Hebrew University and Hadassah Medical Organization.

Therapeutic Studies
M109 lung carcinoma cells (25) were used in this study. Cells obtained from frozen tumor cell vials were grown in vitro. For in vivo inoculation, M109 tumor cells were suspended in serum-free PBS and injected i.v. or i.p. into BALB/c mice (106 cells in a volume of 0.2 ml). As described previously (26) , i.v. inoculation results in widespread lung metastases, whereas i.p. inoculation results in multiple i.p. masses. The mice were treated with either Free-Dox, Doxil, or Doxil combined with soluble IL-2 or liposomal IL-2 according to different protocols, as described in "Results. " Control mice were left untreated. All experimental groups consisted of 8–16 mice.

Statistics
Survival times were recorded for a total of 100 days after treatment. Median survival times and the statistical significance of differences in survival curves were calculated by means of the log-rank test using Prism Software (GraphPad, San Diego, CA). Fisher’s exact test was used to analyze the differences in the final cure rate. Differences were considered significant at P < 0.05. Each experiment was done twice. The results were pooled for analysis and presentation.


   RESULTS
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Systemic Chemoimmunotherapy of Lung Metastases.
Mice were injected i.v. with 106M109 tumor cells on day 0 and received i.v. chemotherapy (8 mg/kg doxorubicin or 8 mg/kg Doxil) on day 7 after tumor inoculation; free or liposomal IL-2 (50,000 CU/dose) was administered i.v. on days 10, 13, and 16. This tumor provides a model of an epithelial tumor with the ability to metastasize to the lungs, which represents the most lethal and common form of cancer in humans. Fig. 1, a and bCitation , shows the survival curves obtained, and Table 1Citation presents the treatment groups and median survival times. The results clearly indicate an advantage for the combined chemoimmunological treatment over chemotherapy alone. Doxil was more effective than Free-Dox, although the trend was not statistically significant in these experiments. Soluble IL-2 and liposomal IL-2 used as single agents were completely ineffective. The combined treatment with Doxil and IL-2, either free or associated with PEG-SUV liposomes, was significantly more effective than treatment with doxorubicin or Doxil alone. The combination of Doxil with MLV-IL-2 liposomes did not enhance the antitumor activity of Doxil against M109 pulmonary metastases at a statistically significant level, although there was a trend for improved survival. Perhaps the most striking advantage of chemoimmunotherapy over chemotherapy alone is the sharp increase in the overall cure rate (from 32–50% for Free-Dox and Doxil to 93–100% for Doxil with either free IL-2 or PEG-SUV-IL-2; P < 0.001–0.016, Fisher’s exact test).



View larger version (24K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 1. Systemic chemoimmunotherapy of BALB/c mice carrying M109 pulmonary metastases. a, survival after treatment with single agents. b, survival of the combined therapy groups in relation to single agent Doxil. For other experimental details and statistical analysis, see Table 1Citation .

 

View this table:
[in this window]
[in a new window]

  		Table 1 Chemoimmunotherapy of BALB/c mice with M109 pulmonary metastasesa

 
A s.c. rechallenge of surviving animals with M109 tumor cells (106 cells) on day 120 resulted in tumor growths in most of the animals, suggesting that cure was not correlated with an immune state against this tumor.

Systemic Chemotherapy and Regional Immunotherapy of i.p. Tumors.
Mice were injected i.p. with 106M109 tumor cells on day 0 and received i.v. chemotherapy at a dose of 8 mg/kg Free-Dox or Doxil on day 10. Soluble or liposomal IL-2 (50,000 CU/dose) was administered i.p. (regional therapy) on days 13, 16, and 19 after tumor inoculation. Fig. 2, a and bCitation , shows the survival curves, and Table 2Citation summarizes the treatment groups and median survival times obtained. In this regional therapy model, the combined treatment of Doxil and MLV-IL-2 was the most effective one, achieving a statistically significant advantage over chemotherapy alone and a very high and significantly increased cure rate (94% versus 56% for Doxil alone; P = 0.037, Fisher’s exact test). The Doxil and soluble IL-2 combination and the Doxil and PEG-SUV-IL-2 combination improved survival slightly but not significantly over treatment with Doxil alone. As seen in previous studies (26) , Free-Dox was inferior to Doxil in this tumor model and had no significant advantage over the control group. Given the reduced antitumor effect and greater toxicity of Free-Dox when compared to Doxil (7) , in addition to preliminary observations from our laboratory indicating that combining Free-Dox with free or liposomal IL-2 tends to worsen toxicity, we did not pursue the investigation of combinations of free drug with IL-2 formulations. Interestingly, i.p. therapy with IL-2 (soluble or liposomal) as a single agent was not only ineffective but also caused several toxic deaths (Table 2Citation , footnote e), which did not occur when the cytokine was administered after Doxil or when the cytokine was administered to tumor-free mice at the same dose and schedule (data not shown).



View larger version (25K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 2. Systemic chemotherapy and regional immunotherapy of BALB/c mice carrying M109 i.p. tumors. a, survival after treatment with single agents. b, survival of the combined therapy groups in relation to single agent Doxil. For other experimental details and statistical analysis, see Table 2Citation .

 

View this table:
[in this window]
[in a new window]

  		Table 2 Chemoimmunotherapy of BALB/c mice with intraperitoneal M109 tumora

 
In both i.v. and i.p. models, mice surviving at the end of the experiment were dissected and found to be macroscopically tumor free, except for the site of a s.c. rechallenge, thus confirming that the final survival rate and the cure rate are equivalent.


   DISCUSSION
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Much of the work on liposomal drug delivery has focused on cancer treatment because conventionally delivered cancer chemotherapy has been far from satisfactory. Major problems with conventional chemotherapy are the inability of the drug to reach the tumor site at pharmacologically active concentrations, intrinsic as well as acquired cross-resistance to multiple chemotherapeutic agents, and toxicity that contributes to many of the treatment failures.

Doxorubicin encapsulated in long-circulating, PEGylated liposomes has proven to be more effective than the free drug in several tumor models, including murine tumors and human tumor xenografts, regardless of tumor type and site of implantation (27) . In all of the experiments conducted, the liposomal preparation clearly performed better than Free-Dox, and the peak tumor drug levels obtained by liposome delivery were at least 3-fold greater. Notable differences in toxicity between free drug and liposomal drug have also been observed, including decreased cardiotoxicity, nephrotoxicity, dermal toxicity, and myelotoxicity with liposome-based therapy. The fact that myelosuppression was found to be less severe in liposome-treated animals (28) and relatively mild in humans (29) pointed at Doxil, a pharmaceutical preparation of PEGylated liposomal doxorubicin, as a promising agent for combination with lymphocyte-activating cytokines such as IL-2. This is an important consideration in chemoimmunotherapy because many of the conventional chemotherapeutic agents (due to their severe bone marrow toxicity) deplete the pool of myeloid and lymphoid cells, thereby reducing the magnitude of the immunostimulatory and antitumor effects of cytokines precisely at a crucial time when tumor cells are maximally inhibited by chemotherapy. Our results suggest that the combination of Doxil with IL-2 is synergistic and has significant potential with regard to tumor eradication and cure, a feature seldom fulfilled with conventional chemotherapy in metastatic cancer.

In the experiments reported here, IL-2 as single agent, in free or liposomal form, was inactive after i.v. or i.p. injection when treatment was started 10–13 days after tumor inoculation. This observation underscores the limited potential of immunotherapy when facing a large, established tumor burden and the need for prior cytoreductive chemotherapy. Indeed, several preclinical models indicate that the sequence of chemotherapy followed by immunotherapy appears to be the most effective way of combining both treatment modalities (19 , 30) .

Several studies have shown slow release, extended circulation time, modified distribution, and reduced systemic toxicity of IL-2 when administered in association with liposomes. In addition, the antitumor and immunomodulatory activities of different liposomal formulations of IL-2 were found to be superior to those of the soluble agent (19 , 20 , 30, 31, 32) . Studies carried out in animals with s.c. or ascitic tumors and pulmonary or hepatic metastases demonstrated that IL-2 delivered in liposomes was mainly effective when administered locally, intracavitarily, or regionally (32, 33, 34, 35, 36) . However, as found here, liposome formulation also has a significant impact on the antitumor activity of IL-2. Small (diameter < 100 nm) PEGylated liposomes as vehicles for IL-2 for systemic treatment of metastatic lung disease boosted the antitumor effect of Doxil to the same level achieved with soluble IL-2. In comparison, the combination of Doxil and MLV-IL-2 appeared to be less efficacious, probably due to the large size of the MLVs that are cleared rapidly from circulation by reticuloendothelial system phagocytes after i.v. administration. In contrast, in the regional model, the most effective combination was Doxil with MLV-IL-2 liposomes. A tentative explanation for this observation is the retention and slow release of IL-2 in the peritoneal cavity due to the inability of MLVs to enter the circulatory system or the draining lymph vessels, whereas IL-2 in small liposomes or in soluble form escapes rapidly from the peritoneal cavity. Another possibility is that enhanced immunostimulation results from the avid uptake of MLV-IL-2 by peritoneal macrophages as opposed to the stealth properties of PEGylated SUV-IL-2. In line with this hypothesis, recent results from one of our laboratories point to greatly enhanced activation of peritoneal cells, including lymphokine-activated killer cell activity, when MLV preparations are used to deliver IL-2 i.p. (21) . Recent studies lending support to the regional/intracavitary approach with IL-2 include: (a) a clinical study in patients with recurrent ovarian cancer treated i.p. with IL-2 after maximal cytoreductive chemotherapy pointing at some remarkably long-term, disease-free survivors (37) ; (b) intrapleural infusion of IL-2 in patients with mesothelioma (38) ; and (c) aerosol therapy studies with free IL-2 in humans (39) and liposomal IL-2 in dogs (40) that demonstrate efficacy and minimal toxicity.

In conclusion, the combined treatment with Doxil and IL-2 is more effective than the expected additive effects of both agents. At the dose and schedule used in our experiments, soluble IL-2 and IL-2 encapsulated in small unilamellar PEGylated liposomes in combination with Doxil showed the same efficacy against M109 pulmonary metastases. With regard to the regional M109 i.p. model, IL-2 in large multilamellar liposomes appears to be the most effective synergist with Doxil chemotherapy. Enhancement of Doxil activity with IL-2 or liposomal IL-2 is a promising approach to cancer therapy with direct and immediate clinical applications.


   FOOTNOTES
 
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1 Supported in part by Yissum Co. and Hadasit, Ltd. Back

2 To whom requests for reprints should be addressed, at Hadassah Medical Center, Oncology Department, P. O. Box 12000, Kiryat Hadassah, Jerusalem, il-91120, Israel. Fax: 972-2-643-0622; E-mail: alberto{at}md2.huji.ac.il Back

3 The abbreviations used are: PEGylated, polyethylene glycol-coated; PEG, polyethylene glycol; Free-Dox, free doxorubicin; IL-2, interleukin 2; CU, Cetus Units (for IL-2); MLV, multilamellar large vesicle; SUV, small unilamellar vesicle. Back

4 Doxil (also known as Caelyx) and Stealth liposomes are registered trademark names of Sequus Pharmaceuticals, Inc. Back

Received 9/ 8/98; revised 12/14/98; accepted 12/15/98.


   REFERENCES
Top
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Papahadjopoulos D., Allen T., Gabizon A., Mayhew E., Matthay K., Huang S. K., Lee K. D., Woodle M. C., Lasic D. D., Redemann C., Martin F. J. Sterically stabilized liposomes: improvements in pharmacokinetics and anti-tumor therapeutic efficacy. Proc. Natl. Acad. Sci. USA, 88: 11460-11464, 1991.[Abstract/Free Full Text]
  2. Gabizon A., Barenholz Y., Bialer M. Prolongation of the circulation time of doxorubicin encapsulated in liposomes containing a polyethylene glycol-derivatized phospholipid: pharmacokinetic studies in rodents and dogs. Pharm. Res., 10: 703-708, 1993.[Medline]
  3. Working P. K., Newman M. S., Huang S. K., Mayhew E., Vaage J., Lasic D. D. Pharmacokinetics, biodistribution and therapeutic efficacy of doxorubicin encapsulated in Stealth liposomes (Doxil). J. Liposome Res., 4: 667-687, 1994.
  4. Unezaki S., Maruyama K., Ishida O., Suginaka A., Hosoda J., Iwatsuru M. Enhanced tumor targeting and improved anti-tumor activity of doxorubicin by long-circulating liposomes containing amphipathic poly(ethylene glycol). Int. J. Pharm. (Amst.), 126: 41-48, 1995.
  5. Gabizon A., Goren D., Horowitz A. T., Tzemach D., Lossos A., Siegal T. Long-circulating liposomes for drug delivery in cancer therapy: a review of biodistribution studies in tumor-bearing animals. Adv. Drug Delivery Rev., 24: 337-344, 1996.
  6. Vaage J., Donovan D., Uster P., Working P. Tumor uptake of doxorubicin in polyethylene glycol-coated liposomes and therapeutic effect against a xenografted human pancreatic carcinoma. Br. J. Cancer, 75: 482-486, 1997.[Medline]
  7. Gabizon A., Barenholz Y. Liposomal doxorubicin: from basics to clinical approval Janoff A. eds. . Liposomes: Rational Design, : 343-362, Marcel Dekker New York 1999.
  8. Gabizon A., Catane R., Uziely B., Kaufman B., Safra T., Cohen R., Martin F., Huang A., Barenholz Y. Prolonged circulation time and enhanced accumulation in malignant exudates of doxorubicin encapsulated in polyethylene-glycol coated liposomes. Cancer Res., 54: 987-992, 1994.[Abstract/Free Full Text]
  9. Ettinghausen S. E., Rosenberg S. A. Immunotherapy of murine sarcomas using lymphokine-activated killer cells: optimization of the schedule and route of administration of recombinant interleukin-2. Cancer Res., 46: 2784-2792, 1986.[Abstract/Free Full Text]
  10. Talmadge J. E., Philips H., Schindler J., Tribble H., Pennington R. Systematic preclinical study on the therapeutic properties of recombinant human recombinant interleukin-2 for the treatment of metastatic disease. Cancer Res., 47: 5725-5732, 1987.[Abstract/Free Full Text]
  11. Rosenberg S. A., Lotze M. T., Muul L. M., Leitman S., Chang A. E., Ettinghausen S. E., Matory Y. L., Shibber J. M., Shiloni E., Vetto J. T., Seipp C. A., Simpson C., Reichert C. M. Observations on the systemic administration of autologous lymphokine-activated killer cells and recombinant interleukin-2 to patients with metastatic cancer. N. Engl. J. Med., 313: 1485-1492, 1985.[Abstract]
  12. Negrier S., Mercatello A., Bret M., Theisse P., Blay J. Y., Corobnel B., Merrouche Y., Oskam R., Franks C. R., Clavel M., Moskovtchenko J. F., Philip T. Intravenous interleukin-2 in patients over 65 with metastatic renal carcinoma. Br. J. Cancer, 65: 723-726, 1992.[Medline]
  13. Rosenberg S. A., Yang J. C., Topalian S. L., Schwartzentruber D. J., Weber J. S., Parkinson D. R., Seipp C. A., Einhorn J. H., White D. E. Treatment of 283 consecutive patients with metastatic melanoma or renal cell cancer using high dose bolus interleukin-2. J. Am. Med. Assoc., 271: 907-913, 1994.[Abstract]
  14. Gautam S. C., Chikkala N. F., Ganapathi R., Hamilton T. A. Combination therapy with Adriamycin and interleukin 2 augments immunity against murine renal cell carcinoma. Cancer Res., 51: 6133-6137, 1991.[Abstract/Free Full Text]
  15. LoRusso P. M., Aukerman S. L., Polin L., Redman B. G., Valdivieso M., Biernat L., Corbett T. H. Antitumor efficacy of interleukin-2 alone and in combination with Adriamycin and dacarbazine in murine solid tumor systems. Cancer Res., 50: 5876-5882, 1992.[Abstract/Free Full Text]
  16. Ehrke M. J., Versovsek S., Zaleskis G., Ho R. L. X., Ujhazy P., Maccubbin D. L., Mihich E. Specific anti-EL4-lymphoma immunity in mice cured 2 years earlier with doxorubicin and interleukin-2. Cancer Immunol. Immunother., 42: 221-230, 1996.[Medline]
  17. Paciucci P. A., Bekesi G., Ryder J. S., Odchimar R., Chahinian P. A., Holland J. F. Immunotherapy with IL2 by constant infusion and weekly doxorubicin. Am. J. Clin. Oncol., 14: 341-348, 1991.[Medline]
  18. Kedar E., Rutkowski Y., Braun E., Emanuel N., Barenholz Y. Delivery of cytokines by liposomes. I. Preparation and characterization of interleukin-2 encapsulated in long-circulating sterically stabilized liposomes. J. Immunother., 16: 47-59, 1994.
  19. Kedar E., Braun E., Rutkowski Y., Emanuel N., Barenholz Y. Delivery of cytokines by liposomes. II. Interleukin-2 encapsulated in long-circulating sterically stabilized liposomes: immunomodulatory and anti-tumor activity in mice. J. Immunother., 16: 115-124, 1994.
  20. Kedar E., Barenholz Y. Delivery of cytokines by liposomes: a means of improving their immunomodulatory and antitumor activity Chouaib S. eds. . The Biotherapy of Cancers: From Immunotherapy to Gene Therapy, : 333-362, INSERM Paris 1998.
  21. Kedar, E., Gur, H., Babai, I., Samira, S., Even-Chen, S., Barenholz, Y. Delivery of cytokines by liposomes. IV. Hematopoietic and immunomodulatory activity of interleukin-2 encapsulated in conventional liposomes and in long-circulating liposomes. J. Immunother., in press, 1999.
  22. Haran G., Cohen R., Bar L. K., Barenholz Y. Transmembrane ammonium sulfate gradients in liposomes produce efficient and stable entrapment of amphipathic weak bases. Biochim. Biophys. Acta, 1151: 201-215, 1993.[Medline]
  23. Koppenhagen F. J., Visser A. J., Herron J. N., Storm G., Crommelin D. J. Interaction of recombinant interleukin-2 with liposomal bilayers. J. Pharm. Sci., 87: 707-714, 1998.[Medline]
  24. Udenfriend S., Stein S., Bohlen P., Dairman W., Leimbruger W., Weigel M. Fluorescamine: a reagent for assay of amino acids, peptides, proteins, and primary amines in the picomole range. Science (Washington DC), 178: 871-872, 1972.[Abstract/Free Full Text]
  25. Marks T. A., Woodman R. J., Geran R. I., Billups L. H., Madison R. M. Characterization and responsiveness of the Madison 109 lung carcinoma to various antitumor agents. Cancer Treat. Rep., 61: 1459-1470, 1977.[Medline]
  26. Gabizon A., Chemla M., Tzemach D., Horowitz A. T., Goren D. Liposome longevity and stability in circulation: effects on the in vivo delivery to tumors and therapeutic efficacy of encapsulated antracyclines. J. Drug Targeting, 3: 391-398, 1996.[Medline]
  27. Gabizon A., Martin F. Polyethylene glycol-coated (pegylated) liposomal doxorubicin: rationale for use in solid tumours. Drugs, 54 (Suppl. 4): 15-21, 1997.
  28. Working P. M., Dayan A. D. Pharmacological-toxicological expert report-CAELYXTM (Stealth® liposomal doxorubicin HCl). Hum. Exp. Toxicol., 15: 752-785, 1996.[Free Full Text]
  29. Uziely B., Jeffers S., Isacson R., Kutsch K., Wei-Tsao D., Yehoshua Z., Muggia F. M., Gabizon A. Liposomal doxorubicin: antitumor activity and unique toxicities during two complementary Phase I studies. J. Clin. Oncol., 13: 1777-1785, 1995.[Abstract/Free Full Text]
  30. Kedar E., Klein E. Cancer immunotherapy: are the results discouraging? Can they be improved?. Adv. Cancer Res., 59: 245-322, 1992.[Medline]
  31. Anderson P. M., Katsanis E., Sencer S. F., Hasz D., Ochoa A. C., Bostrom B. Depot characteristics and biodistribution of interleukin-2 liposomes: importance of route of administration. J. Immunother., 12: 19-31, 1992.
  32. Anderson P. M., Sorenson M. A. Effects of route and formulation on clinical pharmacokinetics of interleukin-2. Clin. Pharmacokinet., 27: 19-31, 1994.[Medline]
  33. Anderson P. M., Katsanis E., Leonard A. S., Schow D., Loeffler C. M., Goldstein M. B., Ochoa A. C. Increased local antitumor effects of interleukin 2 liposomes in mice with MCA sarcoma pulmonary metastases. Cancer Res., 50: 1853-1856, 1990.[Abstract/Free Full Text]
  34. Konno H., Yamashita A., Tadakuma T., Sakaguchi S. Inhibition of growth of rat hepatoma by local injection of liposomes containing recombinant interleukin-2. Biotherapy, 3: 211-218, 1991.[Medline]
  35. Den Otter W., De Groot J. W., Bernsen M. R., Heintz P. M., Maas R., Hordijk G. J., Hill F. G., Klein W. R., Ruitenberg E. J., Rutten V. P. Optimal regimes for local IL-2 tumor therapy. Int. J. Cancer, 66: 400-403, 1996.[Medline]
  36. Koppenhagen F. J. Liposomes as delivery system for recombinant interleukin-2 in anticancer immunotherapy (thesis) Utrecht University Utrecht, The Netherlands 1997.
  37. Edwards R. P., Gooding W., Lembersky B. C., Colonello K., Hammond R., Paradise C., Kowal C. D., Kunschner A. J., Baldisseri M., Kirkwood J. M., Herberman R. B. Comparison of toxicity and survival following intraperitoneal recombinant interleukin-2 for persistent ovarian cancer after platinum: 24-hour versus 7-day infusion. J. Clin. Oncol., 15: 3399-2407, 1997.[Abstract/Free Full Text]
  38. Goey S. H., Eggermont A. M., Punt C. J., Slingerland R., Gratama J. W., Oosterom R., Oskam R., Bolhuis R. L., Stoter G. Intrapleural administration of interleukin 2 in pleural mesothelioma: a Phase I-II study. Br. J. Cancer, 72: 1283-1288, 1995.[Medline]
  39. Huland E., Heinzer H., Mir T., Huland H. Inhaled interleukin-2 therapy in pulmonary metastatic renal cell carcinoma: six years of experience. Cancer J. Sci. Am., 3: 1-8, 1997.
  40. Khanna C., Anderson P. M., Hasz D. E., Katsanis E., Neville M., Klausner J. S. Interleukin-2 liposome inhalation therapy is safe and effective for dogs with spontaneous pulmonary metastases. Cancer (Phila.), 79: 1409-1421, 1997.[Medline]



This article has been cited by other articles:


Home page
 Ann. Surg. Oncol.Home page
L. E. Harrison, M. Bryan, L. Pliner, and T. Saunders
Phase I Trial of Pegylated Liposomal Doxorubicin with Hyperthermic Intraperitoneal Chemotherapy in Patients Undergoing Cytoreduction for Advanced Intra-abdominal Malignancy
Ann. Surg. Oncol., May 1, 2008; 15(5): 1407 - 1413.
[Abstract] [Full Text] [PDF]

Home page
 Pharmacol. Rev.Home page
S. M. Moghimi, A. C. Hunter, and J. C. Murray
Long-Circulating and Target-Specific Nanoparticles: Theory to Practice
Pharmacol. Rev., June 1, 2001; 53(2): 283 - 318.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cabanes, A.
Right arrow Articles by Gabizon, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cabanes, A.
Right arrow Articles by Gabizon, A.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online