Gemcitabine and oxaliplatin in patients with metastatic breast cancer resistant to or pretreated with both anthracyclines and taxanes: clinical and pharmacokinetic data.

Objectives: To evaluate the efficacy, the toxicity and the pharmacokinetics of a gemcitabine (GEM) and oxaliplatin (OXA) combination in metastatic breast cancer patients (MBC), previously treated with anthracycline and taxanes.

Methods: A total of 40 women were enrolled; 37 patients had visceral metastases as dominant site of disease, including 20 patients with liver metastases and 14 with multiple visceral metastases. Three patients received neo-adjuvant chemotherapy, 13 patients adjuvant chemotherapy alone, 24 patients chemotherapy for MBC alone.

Pharmacokinetic evaluation of gemcitabine and 2',2'-difluorodeoxycytidine-5'-triphosphate after prolonged infusion in patients affected by different solid tumors.

Background: The study determined pharmacokinetic parameters, toxicity profile and preliminary clinical activity of gemcitabine administered i.v. at different infusion rates in patients with a range of solid tumors.

Pharmacokinetics of cisplatin in semi-closed hyperthermic peritoneal perfusion (HPP) for treatment of peritoneal carcinomatosis.

Background: This study investigates the pharmacokinetics and toxicity of cisplatin, admininistered by a new semi-closed hyperthermic peritoneal perfusion (HPP) technique to patients with peritoneal carcinomatosis.

Materials And Methods: After surgical cytoreduction, 12 patients were given cisplatin 100 mg/m2 (CDDP), introduced into the HPP circuit for 60 min at 41.7 degrees C and 1200 ml/min flow rate.

A preliminary pharmacokinetic study of docetaxel, carboplatin and concurrent radiotherapy for regionally advanced squamous cell carcinoma of the head and neck.

This work investigates the pharmacokinetics and toxicity resulting from the concomitant use of low dose carboplatin (CBCA)/docetaxel (DTX) plus concurrent radiotherapy in patients with head and neck cancer. The study comprised 11 patients with stage III-IV head and neck cancer. All patients received 2 Gy radiotherapy daily, 5 fractions per week, up to a planned total of 70 Gy over 7 weeks.

2,3,4,5-tetrahydroxy-5-(4-hydroxyphenyl)valeric acid: a new cleavable monofunctional reagent for monoclonal antibody labeling.

The synthesis and preliminary biological assays of a new monofunctional reagent to reversible derivatize monoclonal antibodies is described. This compound, comprising a 1,4-polyiol moiety, is cleavable by means of sodium periodate in mild conditions; moreover it also contains a phenolic residue suitable for 125I labelling and a carboxylic group for reaction with epsilon-lysyl amino group of antibodies. These features are suitable to study the monoclonal antibodies cell-internalization process and antigen expression on cell surface.

Pharmacokinetics of an antibody-ricin conjugate administered intraperitoneally to mice.

Immunotoxins have been extensively studied for the treatment of neoplasias; their intracavitary administration could be useful for the therapy of tumors confined to the pleural or peritoneum spaces. To study the feasibility of this "locoregional" treatment, a pharmacokinetic study of immunotoxins delivery is necessary. Ricin, a plant toxin extracted from the seeds of Ricinus communis, has often been used in immunoconjugates for its high activity; nevertheless, appropriate strategies have been necessary to limit the aspecific toxicity.

A new approach in the synthesis of immunotoxins: ribosome inactivating protein noncovalently bound to monoclonal antibody.

This study describes the synthesis of a new generation of immunotoxins made by a noncovalent interaction between a monoclonal antibody derivatized with a dichlorotriazinic dye and the ribosomal inhibitor protein gelonin. The scheme of preparation has several advantages with respect to the traditional methods, which used heterobifunctional cross-linkers, such as a higher overall yield of production and the homogeneity of the obtained conjugate. Moreover, because no chemical derivatization of the gelonin was required, the unconjugated ribosome inactivating protein was recovered unaltered and therefore can be reused in other synthetic processes.

Toxin-targeted design for anticancer therapy. II: Preparation and biological comparison of different chemically linked gelonin-antibody conjugates.

To obtain more potent immunotoxins for anticancer therapy a gelonin-AR3 antibody immunoconjugate was prepared with different new linkers and coupling procedures. The gelonin was derivatized with the heterobifunctional thioimidate linkers ethyl-acetyl-3-mercaptopropionthioimidate (AMPT) and 3-(4-carboxamidophenyldithio)propionthioimidate (CDPT), and with the succinimidyl type reagents N-succinimidyl-3-(4-carboxamidophenyldithio)propionate (SCDP) and N-succinimidyl-S-acetyl thiolacetate (SATA). The biological activity of gelonin modified with different linkers (AMPT, CDPT, SCDP, SATA) was determined by a rabbit reticulocyte assay.

Toxin-targeted design for anticancer therapy. I: Synthesis and biological evaluation of new thioimidate heterobifunctional reagents.

In an effort to obtain a more potent and specific immunotoxin for cancer therapy, we designed a series of heterobifunctional linkers characterized by a thioimidate group linked to a S-acetyl thiol (4, 5) or substituted aryldithio group (6-10). These ligands were synthesized by a Pinner-type process from the corresponding nitrile derivatives obtained by thiol-disulphide exchange reaction, reaction with substituted benzene-sulphenyl chloride, or other known procedures. To check the reagent of choice for immunoconjugate preparation, we studied thioldisulphide exchange kinetics between the intermediate nitrile derivatives and cysteine.

A new 'solid phase' procedure to synthesize immunotoxins (antibody-ribosome inactivating protein conjugates).

A method to produce immunotoxins (conjugates comprising of a monoclonal antibody and toxin) using ribosome inactivating protein anchored on an affinity gel derivatized with triazinic dye is described. The adsorbed toxins were activated with 2-imino-thiolane and then conjugated to monoclonal antibody activated by SPDP. The "heterogeneous phase" system offered several advantages, reducing the usually required purification steps and opening a way to automatize the conjugation procedure.

Antitumour activity of a sterically blocked ricin immunotoxin on a human colorectal adenocarcinoma grafted subcutaneously in nude mice.

We prepared a ricin-antibody conjugate, lacking the ability to bind the galactosidic residues of Sepharose 6B, a so-called blocked immunotoxin. The monoclonal antibody AR-3 was cross-linked to ricin through a thioether bond. Further studies showed that the immunoconjugate suppressed the tumour growth of HT-29 cells in intraperitoneally grafted nude mice, without showing any undesirable ricin toxicity.

Comparison of blocked and non-blocked ricin-antibody immunotoxins against human gastric carcinoma and colorectal adenocarcinoma cell lines.

To avoid non-specific binding of intact ricin-antibody conjugates, we prepared a new blocked thioether-linked ricin-antibody IT, in which the galactose binding site of ricin had lost the ability to bind to galactosidic residues of Sepharose 6B gel. As carrier agent, the monoclonal antibody AR-3, which defines the CAR-3 tumour-associated antigenic determinant expressed selectively on different human carcinoma cell lines, was used. Purification of the new conjugate was performed in three sequential steps: (1) by HPLC gel filtration on TSK G3000SW to remove the unconjugated ricin: (2) by affinity chromatography on Affi-Gel Blue to separate the free antibody from the conjugate and (3) by affinity chromatography on Sepharose 6B to separate the galactose-binding IT from the non-binding moiety.

The squalene-2,3-epoxide cyclase as a model for the development of new drugs.

The 2,3-oxido squalene (SO) cyclases represent a group of enzymes which convert SO into polycyclic triterpenoids such as lanosterol, cycloartenol, cucurbitadienol and beta-amyrin. Taking into account the postulated model of the enzymatic cyclization of SO, we have investigated the possibility of designing compounds that would be selective and potent inhibitors of SO cyclases. Due to the fundamental role of sterols in animal, higher plant and fungal tissues, these inhibitors might behave as very selective (ipocholesterolemic, antifungal or phytotoxic) drugs.

In vitro inhibition of animal and higher plants 2,3-oxidosqualene-sterol cyclases by 2-aza-2,3-dihydrosqualene and derivatives, and by other ammonium-containing molecules.

2-Aza-2,3-dihydrosqualene and related molecules, a series of new compounds designed as analogues of the transient carbocationic high energy intermediate, occurring in the oxirane ring opening during the cyclization of 2,3-oxidosqualene, were tested in vitro as inhibitors of the microsomal 2,3-oxidosqualene cyclase of animals (rat liver) and of higher plants (maize, pea). These molecules proved to be good and specific inhibitors for the cyclases of both phyla. The inhibition is due to positively charged species and is sensitive to the steric hindrance around the nitrogen-atom.

Biosynthesis of Sterols and Triterpenoids in Tissue Cultures of Cucurbita maxima.

The biosynthesis of sterols and triterpenoids in CUCURBITA MAXIMA was studied by analysis of unsaponifiable fraction of tissues from different development stages of the plant (seeds, seedlings, adult plant and tissue culture) and by feeding germinating seeds and tissue cultures with [2- (14)C]-acetate. Synthesis of cucurbitacins does not occur in callus tissues of CUCURBITA MAXIMA, whereas a wide variety of 4,4-dimethylsterols present in these tissues testifies of a high level of squaleneoxide cyclase activity in growing callus. The peculiarity of Cucurbitaceae among the higher plants is also discussed comparing the side chain biosynthesis of sterols in CUCURBITA MAXIMA to that operating in other higher plants.

Side chain degradation and microbial reduction of different steroids by Aspergillus auroefulgens.

The Aspergillus aureofulgens ability to cleave the side chain of progesterone (I) and the related C-21 steroids was studied. The enzymic system responsible for the progesterone side chain degradation was demonstrated to be adaptative and to operate by a Baeyer-Villiger mechanism. The cleavage of the side chain of the progesterone and of the related compounds was followed by the stereospecific reduction of the formed androst-4-ene-3,17-dione(II) to the 5 beta-androstan derivatives.