PURPOSE: In vivo efficacy and safety of HPMA-based copolymers armed with doxorubicin via a spacer containing pH-sensitive linkage that can be prepared within a broad range of attached drug contents (1) was tested in murine tumor models. METHODS: Mice bearing T cell lymphoma EL4 or B cell lymphoma 38C13 were treated with a single dose of the conjugate (15, 25, and 75 mg Dox eq./kg i.v.) in a therapeutic regime. Anti-tumor resistance of the cured animals was proved by a second challenge with a lethal dose of tumor cells without additional treatment. RESULTS: The content of drug bound to the polymer is an important parameter in relation to the conjugate therapeutic efficacy. The best anti-tumor effects were produced by conjugates with 10 - 13 wt% of bound doxorubicin. Free doxorubicin up to 4.6% relative to total drug content had no impact on the treatment efficacy and acute toxicity. The conjugates induced a complete cure of mice and regular treatment-dependent development of specific anti-tumor resistance. No myelosuppression or organ damage was observed. CONCLUSIONS: A well-defined HPMA copolymer-doxorubicin conjugate with pH-sensitive drug release is a good candidate for clinical trials as it has remarkable anti-tumor efficacy and a favorable safety profile.

• MeSH
• Doxorubicin analogs & derivatives   chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Immunomodulation drug effects   MeSH
• Hydrogen-Ion Concentration MeSH
• Polymethacrylic Acids chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Drug Carriers chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Polymers * chemical synthesis   pharmacokinetics   pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• Antibiotics, Antineoplastic pharmacokinetics   pharmacology   MeSH
• Xenograft Model Antitumor Assays MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Doxorubicin MeSH
• Polymethacrylic Acids MeSH
• Drug Carriers MeSH
• Polymers * MeSH
• Antibiotics, Antineoplastic MeSH

Linkage of doxorubicin (Dox) to a water-soluble synthetic N-(2-hydroxypropyl)methacrylamide copolymer (PHPMA) eliminates most of the systemic toxicity of the free drug. In EL-4 lymphoma-bearing C57BL/6 mice, a complete regression of pre-established tumours has been achieved upon treatment with Dox-PHPMA-HuIg conjugate. The treatment was effective using a range of regimens and dosages, ranging from 62.5 to 100% cured mice treated with a single dose of 10-20 mg of Dox eq./kg, respectively. Fractionated dosages producing lower levels of the conjugate for a prolonged time period had substantial curative capacity as well. The cured mice developed anti-tumour protection as they rejected subsequently re-transplanted original tumour. The proportion of tumour-protected mice inversely reflected the effectiveness of the primary treatment. The treatment protocol leading to 50% of cured mice produced only protected mice, while no mice treated with early treatment regimen (i.e. starting on day 1 after tumour transplantation) rejected the re-transplanted tumour. Exposure of the host to the cancer cells was a prerequisite for developing protection. The anti-tumour memory was long lasting and specific against the original tumour, as the cured mice did not reject another syngeneic tumour, melanoma B16-F10. The immunity was transferable to naïve recipients in in vivo neutralization assay by spleen cells or CD8(+) lymphocytes derived from cured animals. We propose an effective treatment strategy which eradicates tumours without harming the protective immune anti-cancer responses.

• MeSH
• Doxorubicin analogs & derivatives   therapeutic use   MeSH
• Immunoglobulins therapeutic use   MeSH
• Immune Tolerance * MeSH
• Polymethacrylic Acids therapeutic use   MeSH
• Humans MeSH
• Lymphoma, T-Cell drug therapy   immunology   prevention & control   MeSH
• Melanoma, Experimental drug therapy   immunology   metabolism   MeSH
• Survival Rate MeSH
• Mice, Inbred C57BL MeSH
• Mice, Nude MeSH
• Mice MeSH
• Tumor Cells, Cultured transplantation   MeSH
• Skin Neoplasms drug therapy   immunology   metabolism   MeSH
• Drug Carriers MeSH
• Antibiotics, Antineoplastic therapeutic use   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Doxorubicin MeSH
• Immunoglobulins MeSH
• Polymethacrylic Acids MeSH
• Drug Carriers MeSH
• Antibiotics, Antineoplastic MeSH

PURPOSE: Two different monoclonal antibody-targeted HPMA copolymer-doxorubicin conjugates, classic and starlike, were synthesized to be used for site-specific cancer therapy. The anti-mouse Thy-1.2 (IgG3) and two anti-human CD71/A (IgG1) and CD71/B (IgG2a) monoclonal antibodies were used as targeting structures. METHODS: Their binding and cytotoxic activity in vitro, body distribution, and anticancer activity in vivo were evaluated. RESULTS: The results of flow cytometric analysis showed comparable binding of classic and starlike conjugates to the target cells. The in vitro cytotoxic effect was 10-fold higher if cancer cells were exposed to the starlike conjugate compared to the classic one. Biodistribution studies showed that the starlike conjugate remained in a relatively high concentration in blood, whereas the classic conjugate was found in a 6.5-times lower amount. In contrast to the low antitumor activity of free doxorubicin and nontargeted HPMA copolymer-doxorubicin conjugate, both anti-Thy-1.2 targeted conjugates (classic and starlike) cured all mice bearing T-cell lymphoma EL4. On the other hand, starlike conjugates containing anti-CD71/A or anti-CD71/B monoclonals as targeting structures were more effective against human colorectal cancer SW 620 than the classic one. CONCLUSIONS: We have shown that the starlike conjugates are more effective systems for targeted drug delivery and cancer treatment than classic conjugates.

• MeSH
• Cell Division drug effects   MeSH
• Doxorubicin chemistry   pharmacokinetics   pharmacology   MeSH
• Colorectal Neoplasms drug therapy   MeSH
• Humans MeSH
• Lymphoma, T-Cell drug therapy   MeSH
• Methacrylates chemistry   pharmacology   MeSH
• Molecular Structure MeSH
• Antibodies, Monoclonal chemistry   metabolism   MeSH
• Mice, Inbred BALB C MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Prodrugs chemistry   pharmacology   MeSH
• Antibiotics, Antineoplastic chemistry   pharmacokinetics   pharmacology   MeSH
• In Vitro Techniques MeSH
• Tissue Distribution MeSH
• Neoplasm Transplantation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Doxorubicin MeSH
• hydroxypropyl methacrylate MeSH Browser
• Methacrylates MeSH
• Antibodies, Monoclonal MeSH
• Prodrugs MeSH
• Antibiotics, Antineoplastic MeSH

This study compares the toxic effects of native cyclosporia A (CyA) with those of targeted CyA that is conjugated with the anti-rat-thymocyte antibody of rabbit origin via the N-(2-hydroxypropyl)methacrylamide (HPMA) carrier bearing digestible, reactive oligopeptide side chains. Ten toxic doses of native CyA (50 mg/kg i.p.) given to young adult rats in the course of 14 d produced a severe renal lesion-diffuse microvacuolization of the proximal tubules in the deep cortex, and hypergranulation of juxtaglomerular regions. Severe atrophy of the thymic medulla was documented by morphometry. In the cortex the epithelial reticular (but not deep interdigitating) cells showed ultrastructural signs of severe degeneration and lysis. The immature CD4+8+ double-positive cortical lymphocytes were preserved whereas the single-positive medullary thymocytes were greatly depleted; there was also a restriction of MHC class II antigen expression in the medulla. The number of medullary B cells was increased. The cytokeratin net was focally shrunken in the cortex and almost negative in the medulla, with loss of Hassall's corpuscles. After ten corresponding doses of antibody-targeted conjugated CyA no damage to the renal tubules and arterioles appeared and the antiGBM or immune-complex deposition was absent. The thymus had a normal medulla with numerous mature thymocytes and the cortical epithelial reticulum remained well preserved. Thus, the main toxic effects of CyA could be eliminated by targeting. The T-cell-targeted drug was tested for preserved immunosuppressive properties and non-toxic character of HPMA copolymer carrier.

• MeSH
• Cyclosporine toxicity   MeSH
• Cyclosporins toxicity   MeSH
• Immunoconjugates toxicity   MeSH
• Immunosuppressive Agents toxicity   MeSH
• Rats MeSH
• Kidney drug effects   MeSH
• Drug Carriers toxicity   MeSH
• Rats, Wistar MeSH
• T-Lymphocytes drug effects   immunology   MeSH
• Thymus Gland drug effects   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Cyclosporine MeSH
• Cyclosporins MeSH
• Immunoconjugates MeSH
• Immunosuppressive Agents MeSH
• Drug Carriers MeSH

Drug targeting is an attractive new approach to killing cancer cells while leaving normal tissue unharmed. Recently we have developed a new generation of antibody-targeted immunosuppressive (cyclosporin A) and cytostatic (daunomycin, doxorubicin) drugs and photosensitizers (chlorin e6) effective in vitro and in vivo. The drugs and the targeting antibody (polyclonal and monoclonal) are conjugated to the oligopeptidic side chains of a water-soluble synthetic carrier, copolymer of N-(2-hydroxypropyl)methacrylamide. The composition of the side chains ensures the stability of the linkage between the drug and the polymeric carrier in the bloodstream and its intralysosomal degradability which is a prerequisite for the pharmacological activity of the preparation. Antibody-targeted polymer bound drugs show considerably decreased hepatotoxicity, cardiotoxicity, myelotoxicity and nephrotoxicity. Two adriamycin-HPMA copolymers are in Phase I/II clinical trials in United Kingdom.

• MeSH
• Acrylamides administration & dosage   adverse effects   chemistry   pharmacokinetics   MeSH
• Thy-1 Antigens immunology   MeSH
• Chlorophyllides MeSH
• Cyclosporine administration & dosage   adverse effects   pharmacokinetics   MeSH
• Daunorubicin therapeutic use   MeSH
• Doxorubicin analogs & derivatives   therapeutic use   MeSH
• Immunoconjugates * administration & dosage   adverse effects   chemistry   pharmacokinetics   MeSH
• Immunosuppressive Agents administration & dosage   adverse effects   chemistry   pharmacokinetics   MeSH
• Clinical Trials as Topic MeSH
• Polymethacrylic Acids therapeutic use   MeSH
• Humans MeSH
• Lysosomes metabolism   MeSH
• Histocompatibility Antigens Class II immunology   MeSH
• Antibodies, Monoclonal administration & dosage   chemistry   immunology   pharmacokinetics   MeSH
• Mice, Inbred BALB C MeSH
• Mice, Nude MeSH
• Mice MeSH
• Neoplasms drug therapy   MeSH
• Immune System Diseases drug therapy   MeSH
• Porphyrins administration & dosage   adverse effects   pharmacokinetics   MeSH
• Antibiotics, Antineoplastic administration & dosage   adverse effects   pharmacokinetics   MeSH
• Antineoplastic Agents administration & dosage   adverse effects   pharmacokinetics   MeSH
• Radiation-Sensitizing Agents administration & dosage   adverse effects   chemistry   pharmacokinetics   MeSH
• T-Lymphocyte Subsets immunology   MeSH
• Tissue Distribution MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Acrylamides MeSH
• Thy-1 Antigens MeSH
• Chlorophyllides MeSH
• Cyclosporine MeSH
• daunomycin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Daunorubicin MeSH
• doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate MeSH Browser
• Doxorubicin MeSH
• Immunoconjugates * MeSH
• Immunosuppressive Agents MeSH
• Polymethacrylic Acids MeSH
• Histocompatibility Antigens Class II MeSH
• Antibodies, Monoclonal MeSH
• N-(2-hydroxypropyl)methacrylamide MeSH Browser
• phytochlorin MeSH Browser
• Porphyrins MeSH
• Antibiotics, Antineoplastic MeSH
• Antineoplastic Agents MeSH
• Radiation-Sensitizing Agents MeSH