st-1481 and Ovarian-Neoplasms

A prospective phase II study was conducted to evaluate the efficacy and toxicity of oral gimatecan in patients with recurrent epithelial ovarian, fallopian tube or peritoneal cancer.. Patients had a maximum of three prior chemotherapy lines with no more than two prior platinum-containing regimens and a progression-free interval after the last dose of platinum <12 months. A total dose of 4 mg/m(2)/cycle (0.8 mg/m(2)/day from day 1 to day 5) was administered, repeated every 28 days.. From June 2005 to December 2005, 69 assessable patients were enrolled. The best overall response to study treatment by combined CA-125 and RECIST criteria was partial response in 17 patients (24.6%) and disease stabilization in 22 patients (31.9%). The median time to progression and overall survival were 3.8 and 16.2 months, respectively. A total of 312 cycles were administered. Neutropenia grade 4 and thrombocytopenia grade 4 occurred in 17.4% and 7.2% of patients, respectively. Diarrhea grade 4 was never observed. Asthenia and fatigue were reported by 36.2% and 18.8% of patients, but were all grade 2 or less.. Gimatecan is a new active agent in previously treated ovarian cancer with myelosuppression as main toxicity.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Chemotherapy, Adjuvant; Fallopian Tube Neoplasms; Female; Humans; Middle Aged; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Peritoneal Neoplasms; Platinum; Recurrence; Taxoids

To determine the pharmacokinetics of gimatecan, a camptothecin with a lipophilic substitution in position 7, given orally to patients participating in the phase I study.. Pharmacokinetics was evaluated in 78 patients after oral daily dose for 5 days a week for 1, 2 or 3 weeks by HPLC with a fluorescence detector.. Gimatecan was mainly present in plasma as lactone (>85%), the active form as DNA-topoisomerase I poison. The AUC(0-24) on the first day of treatment normalised per daily dose (mg/m(2)), ranged from 194 to 2909 ng h/mL/mg/m(2). The half-life was 77.1+/-29.6h, consequently C(max) and AUC rose 3-6-fold after multiple dosing. Multivariate analysis indicated the daily dose (p<0.0001) and the alpha(1)-acid glycoprotein (AGP) plasma levels (p<0.0001) as main predictors of gimatecan AUC(0-24). In the overall analysis, daily dose and AGP plasma levels explained 85% of the deviance. The hydroxy metabolite ST1698 was present in plasma at low levels with AUC values of 5-15% of gimatecan. In mice, orally treated with gimatecan, plasma and tissue levels were 2-fold higher after treatment with a pro-inflammatory agent causing AGP induction.. Gimatecan is orally absorbed and its variable plasma levels seem to be related to AGP plasma concentrations. Data obtained in mice, together with the fact that AGP levels largely exceeded gimatecan plasma concentrations, suggest that the increased gimatecan levels in patients with high AGP levels are not related to the binding of the drug to AGP with consequent reduced tissue drug distribution, but possibly to other mechanism associated with inflammation being AGP simply a marker of the inflammation process.

Topics: Administration, Oral; Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antineoplastic Agents, Phytogenic; Blood Specimen Collection; Camptothecin; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Half-Life; Humans; Mice; Mice, Nude; Middle Aged; Orosomucoid; Ovarian Neoplasms; Xenograft Model Antitumor Assays; Young Adult

Oxidized form of avidin, named AvidinOX, provides stable fixation of biotinylated molecules in tissues thus representing a breakthrough in topical treatment of cancer. AvidinOX proved to be a stable receptor for radiolabeled biotin, biotinylated antibodies and cells. In order to expand applicability of the AvidinOX-based delivery platform, in the present study we investigated the possibility to hold biotinylated chemotherapeutics in AvidinOX-treated sites. A novel biotinylated gimatecan-derived camptothecin, coded ST8161AA1, was injected at suboptimal doses into human tumors xenografted in mice alone or pre-complexed to AvidinOX. Significantly higher growth inhibition was observed when the drug was anchored to AvidinOX suggesting the potential utility of this delivery modality for the local treatment of inoperable tumors.

Topics: Animals; Antineoplastic Agents; Avidin; Biotin; Camptothecin; Carcinoma; Cell Line, Tumor; Cell Proliferation; Female; Humans; Mice; Ovarian Neoplasms; Protein Binding

Gimatecan, a novel oral lipophilic camptothecin characterized by favorable features at molecular/cellular level and by a promising profile of preclinical activity, is currently in clinical phase I/II. The aim of the study was to additionally investigate the therapeutic potential of the drug in human tumor xenografts growing in different organs as models representative of tumor growth in the clinical setting.. The models include two orthotopic central nervous system tumors, two melanomas growing intracranially, and an ovarian carcinoma growing i.p. In addition, gimatecan was tested against experimental lung metastases of two tumor types (lung and ovarian carcinomas). Gimatecan was delivered by oral gavage according to various schedules (daily or intermittent). The time (in days) mice required to show evident signs of disease was used as end point for drug efficacy.. Gimatecan was highly effective in delaying disease manifestations in all tumor systems investigated. In the intracranially growing tumors, a significant time increase (versus control mice) was achieved by the drug administered according to all of the schedules. In addition, almost all treated mice were alive and tumor-free at the end of the experiment in the metastatic models and in the ascitic ovarian tumor. The daily prolonged treatment schedule was the best one.. In all tumor systems investigated, including orthotopic tumor growth models and lung metastases, the oral administration of gimatecan showed a therapeutic benefit in terms of survival increase. The good oral availability allowed a prolonged daily treatment regimen, which seems the most promising to exploit the therapeutic potential of the drug.

Topics: Animals; Brain; Camptothecin; Female; Humans; Melanoma; Mice; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Nervous System Neoplasms; Ovarian Neoplasms; Time Factors; Xenograft Model Antitumor Assays

Relevant drawbacks of the molecular structure and mechanism of the action of camptothecins are the instability of the E ring lactone and the reversibility of drug-target interaction. Such features are expected to limit the clinical efficacy of conventional camptothecins. In an attempt to overcome these limitations and to improve the pharmacological profile of camptothecins, a novel series of seven modified lipophilic analogues was synthesized based on the hypothesis that lipophilicity could promote a rapid cellular accumulation and stabilization of drug-target interaction. A novel analogue (ST1481) of the series, characterized by a potent antitopoisomerase and cytotoxic activity, was selected for preclinical development. A detailed preclinical study of ST1481 was performed in the H460 non-small cell lung tumor model using oral administration and various treatment schedules. Under all of the conditions, ST1481 exhibited an impressive efficacy in terms of tumor growth inhibition (tumor volume inhibition percentage > 99%), log(10) cell kill, rate of complete responses (including "cures"), and an improvement of the therapeutic index compared with topotecan (used as the reference drug). The cytotoxic potency was also reflected by the in vivo potency, because the drug activity was observed at doses as low as 0.25 mg/kg with the daily schedule. In contrast to topotecan, no cross-resistance to ST1481 was found in ovarian carcinoma cells overexpressing P-glycoprotein (A2780/DX). A similar trend in the improvement of activity was also observed in the same tumor model growing in vivo with a 100% rate of complete tumor regressions. A rapid intestinal absorption and good oral bioavailability were supported by in vivo distribution studies, because the peak values of drug accumulation were found from 1 to 2 h after administration. The relevant liver accumulation may account for a marked effect of ST1481 against liver metastases induced by the ovarian carcinoma IGROV-1. In conclusion, the results support the hypothesis that a potent lipophilic camptothecin with a proper substituent at the position 7 may have therapeutic advantages likely related to a rapid intracellular uptake and tissue distribution, stabilization of the drug-target complex, and good oral bioavailability. Overall, the results support the preclinical interest of ST1481 in terms of efficacy, potency, toxicity profile, and ability to overcome multidrug resistance.

Topics: Administration, Oral; Animals; Antineoplastic Agents, Phytogenic; Camptothecin; Carcinoma, Non-Small-Cell Lung; Doxorubicin; Drug Administration Schedule; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Female; Humans; Liver Neoplasms, Experimental; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Ovarian Neoplasms; Tissue Distribution; Tumor Cells, Cultured; Xenograft Model Antitumor Assays