cemadotin and Neoplasms

To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetic profile of the dolastatin 15 analog LU103793 when administered daily for 5 days every 3 weeks.. Fifty-six courses of LU103793 at doses of 0.5 to 3.0 mg/m2 were administered to 26 patients with advanced solid malignancies. Pharmacokinetic studies were performed on days 1 and 5 of course one. Pharmacokinetic variables were related to the principal toxicities.. Neutropenia, peripheral edema, and liver function test abnormalities were dose-limiting at doses greater than 2.5 mg/m2 per day. Four of six patients developed DLT at 3.0 mg/m2 per day, whereas two of 12 patients treated at 2.5 mg/m2 per day developed DLT. Pharmacokinetic parameters were independent of dose and similar on days 1 and 5. Volume of distribution at steady-state (Vss) was 7.6 +/- 2.0 L/m2, clearance 0.49 +/- 0.18 L/h/m2, and elimination half-life (t1/2) 12.3 +/- 3.8 hours. Peak concentrations (Cmax) on day 1 related to mean percentage decrement in neutrophils (sigmoid maximum effect (Emax) model). Patients who experienced dose-limiting neutropenia had significantly higher Cmax values than patients who did not, whereas nonhematologic DLTs were more related to dose.. The recommended dose for phase II evaluations of LU103793 daily for 5 days every 3 weeks is 2.5 mg/m2 per day. The lack of prohibitive cardiovascular effects and the generally acceptable toxicity profile support the rationale for performing disease-directed evaluations of LU103793 on the schedule evaluated in this study.

Topics: Adult; Aged; Antineoplastic Agents; Female; Humans; Male; Middle Aged; Neoplasms; Oligopeptides

To determine the maximum tolerable dose (MTD), principal toxicity, and pharmacologic behaviour of Cemadotin-HCl, a novel antimitotic peptide.. Cemadotin-HCl (10.0 to 27.5 mg/m2/day every three weeks) was administered as a 24-hour intravenous (i.v.) continuous infusion to patients with advanced cancer. Pharmacokinetic analyses were performed during the first treatment cycle. Blood samples were taken over 48 hours and analyzed by radioimmunoassay.. Hypertension was the dose-limiting toxicity (DLT). This type of toxicity was observed at all dose levels, but grade 3 (CTC) was observed only at dose levels 20.0, 25.0 and 27.5 mg/m2. This effect was reversible but in three patients associated with signs of cardiac ischemia. Other significant toxic effects were neutropenia, asthenia, tumor pain and transient liver enzyme elevation. A linear pharmacokinetics was observed. The best curve fit was obtained with a two-compartment model with a terminal half-life of approximately 10 hours at each dose level, a volume of distribution at steady state of approximately 9 l/m2 and a total clearance of approximately 0.6 l/hour/m2. Neither partial nor complete responses were observed although minor tumor regressions were seen in a patient with carcinoma of unknown primary (CUP) and in another patient with liver metastases from a colon cancer.. Hypertension was the dose-limiting toxicity of Cemadotin-HCl administered as a continuous 24-hour infusion. The recommended dose for further evaluation of its anticancer efficacy in disease-oriented phase II studies with this schedule is 15.0 mg/m2. The nature of the principal cardiovascular toxicity remains unclear. The observed toxicities appeared to be significant but manageable.

Topics: Adult; Aged; Antineoplastic Agents; Area Under Curve; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Gastrointestinal Diseases; Growth Inhibitors; Humans; Hypertension; Infusions, Intravenous; Male; Middle Aged; Mitosis; Myocardial Ischemia; Neoplasms; Neutropenia; Oligopeptides; Pain; Survival Analysis; Treatment Outcome

LU103793 (NSC D-669356) is a new synthetic derivative of Dolastatin 15, an antiproliferative compound which was isolated from the mollusk Dolabella auricularia. Like Dolastatin 15, LU103793 is highly cytotoxic in vitro (IC50 = 0.1 nM). To investigate the mechanism of action of LU103793, we used a combination of biochemical and cellular methods. Turbidity assays with bovine brain microtubules demonstrated that LU103793 inhibits microtubule polymerization in a concentration-dependent manner (IC50 = 7 microM). Treatment with this compound also induced depolymerization of preassembled microtubules. Cell cycle analysis of tumor cell lines treated with LU103793 indicated a block in the G2-M phase. At the cellular level, it induced depolymerization of microtubules in interphase cells and development of abnormal spindles and chromosome distribution in mitotic cells. Although these effects are very similar to the cellular alterations caused by vinblastine, LU103793 does not inhibit vinblastine binding to unpolymerized tubulin in vitro. Our results suggest that LU103793 exerts its cytotoxic activity primarily through disruption of microtubule organization.

Topics: Adenocarcinoma; Amino Acid Sequence; Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Division; Chromosomes, Human; Colonic Neoplasms; Drug Interactions; Guanosine Triphosphate; HeLa Cells; Humans; Hydrolysis; Microtubules; Mitosis; Molecular Sequence Data; Neoplasms; Oligopeptides; Tubulin; Tumor Cells, Cultured; Vinblastine