Phase I pharmacokinetic and pharmacodynamic study of recombinant human endostatin in patients with advanced solid tumors.

PURPOSE: Endostatin is the first endogenous angiogenesis inhibitor to enter clinical trials. Laboratory investigations with endostatin have indicated broad antitumor activity coupled with remarkably low toxicity. A phase I trial of recombinant human endostatin was designed to evaluate toxicity and explore biologic effectiveness in patients with refractory solid tumors. PATIENTS AND METHODS: Endostatin was administered as a 1-hour intravenous infusion given daily for a 28-day cycle. A starting dose of 30 mg/m2 was explored with subsequent dose escalations of 60, 100, 150, 225, and 300 mg/m2. Assessment of serum pharmacokinetics was performed on all 21 patients. Western blot assay and mass spectroscopy were employed to evaluate endostatin metabolism. Circulating levels of endogenous proangiogenic growth factors were examined. Tumor and tumor blood supply were imaged by dynamic computed tomography (CT), magnetic resonance imaging, ultrasound, and positron emission tomography. RESULTS: Endostatin given on this schedule was essentially free of significant drug-related toxicity. Two transient episodes of grade 1 rash were observed. No clinical responses were observed. Endostatin pharmacokinetics were linear with dose, and serum concentrations were achieved that are associated with antitumor activity in preclinical models. No aggregate effect on circulating proangiogenic growth factors were seen, although several patients exhibited persistent declines in vascular endothelial growth factor levels while enrolled in the study. A few patients demonstrated changes in their dynamic CT scans suggestive of a decline in microvessel density, although overall, no consistent effect of endostatin on tumor vasculature was seen. CONCLUSION: Endostatin given daily as a 1-hour intravenous infusion was well tolerated without dose-limiting toxicity at doses up to 300 mg/m2.

Phase I and pharmacokinetic study of a micronized formulation of carboxyamidotriazole, a calcium signal transduction inhibitor: toxicity, bioavailability and the effect of food.

PURPOSE: This Phase I study was conducted to evaluate the toxicity profile and determine the maximum tolerated dose (MTD) of an oral micronized formulation of the signal transduction inhibitor carboxyamidotriazole (CAI). Bioavailability of the micronized formulation relative to a gelatin capsule (gelcap) formulation was assessed. The effects of food intake and timing on CAI steady-state plasma concentrations (C(ss)) were also investigated. EXPERIMENTAL DESIGN: Patients received continuous daily CAI (28-day cycles). Starting dose was 150 mg/m(2) daily and escalations were by 50 mg/m(2) increments. The first three patients enrolled were given test doses of the original gelcap formulation and two different micronized formulations to determine relative bioavailability. Toxicity and pharmacokinetic assessments were performed weekly. Additional cohorts were added after MTD determination to assess the effect of food intake and duration of fast on CAI C(ss). RESULTS: The micronized formulation was absorbed more slowly than the gelcap formulation. Twenty-nine patients were enrolled in the dose-escalation portion of the study. After dose escalation to 300 mg/m(2), dose-limiting neurotoxicities occurred including reversible vision loss in two patients. Other toxicities were mild. The final MTD was 150 mg/m(2). Pharmacokinetics appeared linear with significant inter- and intrapatient variability. Patients with C(ss) of > or = 4.0 mg/liter were more likely to have neurotoxicity. Nine patients with renal cell cancer and one with hepatocellular cancer had prolonged stable disease. CAI plasma concentrations were higher when taken with food. CONCLUSIONS: Micronized CAI was well tolerated at the MTD of 150 mg/m(2). Higher doses were limited by significant neurotoxicity. The variability in CAI pharmacokinetics may be partially attributable to concomitant food intake and timing of the dose.

A phase I trial of perillyl alcohol administered four times daily for 14 days out of 28 days.

PURPOSE: Perillyl alcohol (POH) has been shown to have both chemopreventative and chemotherapeutic activities in preclinical studies. The underlying mechanism(s) of action of POH have yet to be delineated but may involve effects on the transforming growth factor beta (TGFbeta) and/or the Ras signaling pathways. A phase I study of POH for 14 days out of every 28 days in subjects with advanced malignancies was performed to evaluate dose escalation, toxicity, pharmacokinetics, and effects on TGFbeta and Ras. METHODS: POH was administered orally (500 mg capsules containing 250 mg POH) to 20 patients four times a day on a continuous basis for 14 days followed by a 14-day rest period, for up to three courses. The starting dose was 1200 mg/m(2) per dose. A minimum of three patients were treated and evaluated at each escalating POH dose. Pharmacokinetic analysis was performed on days 1 and 14 of course 1 and day 1 of selected later courses. Plasma TGFbeta levels were measured on days 1 and 14. Peripheral blood lymphocyte (PBLs) Ras levels were assayed on days 1 and 2 of the first course. RESULTS: The 20 patients, of whom 15 were evaluable, received doses between 1200 and 2000 mg/m(2) per dose for a total of 43 courses. The most common observed toxicities were nausea, gastrointestinal distress, and fatigue. Other toxicities included diarrhea or constipation, hypokalemia, and one incidence of acute pancreatitis. Due to these toxicities, four of the patients declined further treatment either during or after the second course. While POH was not detected in plasma, perillic acid (PA) and dihydroperillic acid (DHPA) were detected in plasma, and the peak levels at 2000 mg/m(2) per dose were approximately 600 micro M (PA) and 50 micro M (DHPA). There was some evidence for linearity in the peak plasma levels and area under the concentration-time curve of the metabolites from the starting dose to the highest dose. Metabolite pharmacokinetics were not significantly affected by ingestion in the fed or fasting state, or repeated exposure to POH. No evidence for an effect of POH on plasma TGFbeta or PBL Ras protein was observed. No objective responses were observed. CONCLUSIONS: In adults with advanced malignancies, an interrupted administration schedule of POH did not reveal significant advantages over continuous dosing schedules.

Gemcitabine, Paclitaxel, and piritrexim: a phase I study.

Piritrexim is a new antifolate that has shown activity in methotrexate-resistant tumors. Gemcitabine is an antimetabolite similar in structure to cytosine arabinoside with early studies demonstrating activity in a variety of cancers. It also has apparent synergistic activity with antifolates from initial work in tumor models. Paclitaxel is an antimicrotubule agent that has a wide spectrum of activity against a variety of solid tumors. The combination of gemcitabine, paclitaxel, and piritrexim was assessed in this phase I trial. Thirty patients were enrolled. The starting doses were piritrexim 25 mg orally twice daily (days 1-4, 15-18), paclitaxel 75 mg/m2 (days 1, 15), and gemcitabine 750 mg/m2 (days 1, 15), which then was escalated in a stepwise fashion. Four patients achieved stable disease while on study, whereas one patient with a poorly differentiated neuroendocrine tumor achieved a partial response. The main toxicity was myelosuppression. The maximum tolerated dose was thought to be piritrexim 25 mg orally three times daily (days 1-4), paclitaxel 150 to 175 mg/m2 (days 1, 15), and gemcitabine 1,000 mg/m2 (days 1, 15). The combination of these new antifolates with paclitaxel and gemcitabine appears safe and should be considered for phase II trials in known responsive tumors such as transitional cell carcinomas.

Phase I study of eniluracil, oral 5-fluororacil and gemcitabine in patients with advanced malignancy.

PURPOSE: The objectives of this trial were to assess the maximal tolerated dose and toxicity of the combination of oral eniluracil and 5-fluorouracil and intravenous gemcitabine. PATIENTS AND METHODS: Patients with histologically confirmed, incurable malignancy (solid tumor or lymphoma) refractory to standard therapy or for which no standard therapy exists were enrolled. The treatment plan consisted of weekly gemcitabine for three weeks with twice daily dosing of 5-FU and eniluracil for 21 days beginning on day one of gemcitabine. Cycles repeated on an every four week schedule. The initial cohort received gemcitabine 800 mg/m2, oral 5-FU 0.6 mg/m2 and eniluracil 6.0 mg/m2. RESULTS: Twenty-six patients were enrolled. Eight patients received less than 2 cycles of therapy. Hematologic and gastrointestinal toxicity predominated, with 48% of courses resulted in grade one or two neutropenia. Hematologic toxicity was dose limiting. One treatment related death occurred. CONCLUSIONS: The combination of eniluracil, 5-fluorouracil and gemcitabine offers an oral alternative for 5-FU administration. The recommended phase II dose is gemcitabine 1000 mg/m2, 5FU 1.2 mg/m2 and eniluracil 12 mg/m2.