Phase I clinical and pharmacologic study of intraperitoneal cisplatin and fluorouracil in patients with advanced intraabdominal cancer.

Fluorouracil (5-FU) and cisplatin display marked therapeutic synergy in preclinical models and are effective in the treatment of a number of solid tumors when combined and administered intravenously (IV). Each drug has also been administered intraperitoneally (IP) and displays a favorable pharmacologic profile and acceptable clinical toxicity. We therefore undertook a phase I study to determine the feasibility and toxicity of combination IP chemotherapy with these agents. Thirty-one patients with histologically documented malignancy confined to the peritoneal space were treated with cisplatin 90 mg/m2 mixed with 5-FU in 2 L of lactated Ringer's solution and given IP for 4 hours every 28 days. Cohorts of at least three patients received starting 5-FU concentrations ranging from 5 mmol/L (1,300 mg in 2 L) to 20 mmol/L. The dose-limiting toxicity was neutropenia with a median granulocyte nadir of 156 cells per microliter occurring at a 5-FU dose of 20 mmol/L. Intrapatient escalation of the 5-FU dose was permitted and 15 cycles of chemotherapy were delivered at 5-FU concentrations greater than 20 mmol/L, the highest concentration being 30.7 mmol/L (8 g of 5-FU in 2L). Other toxicities included mild to moderate nausea during all cycles of therapy, vomiting in 54% of cycles, and diarrhea in 15% of cycles. Abdominal pain, renal dysfunction, peripheral neuropathy, and oral mucositis occurred infrequently and were not related to the 5-FU dose. Peritoneal fluid and plasma 5-FU concentrations were measured by high-performance liquid chromatography (HPLC) in selected patients. Mean peak plasma 5-FU concentrations ranged from 6.19 mumol/L to greater than 60 mumol/L, and peritoneal fluid to plasma 5-FU area under the curve (AUC) ratios ranged from 85 to 1,150. Nine of 15 patients with nonbulky disease had resolution of malignant ascites or at least a 50% reduction of peritoneal studding by tumor at repeat laparotomy. We conclude that combination IP chemotherapy with cisplatin and 5-FU is technically feasible and has acceptable clinical toxicity and a favorable pharmacologic profile. The recommended starting 5-FU dose for phase II trials is 3,900 mg mixed with 90 mg/m2 of cisplatin in 2 L of isotonic fluid.

Plasma pharmacokinetics of high-dose oral melphalan in patients treated with trialkylator chemotherapy and autologous bone marrow reinfusion.

The pharmacokinetics of melphalan following high-dose p.o. administration were determined in 17 patients with various malignancies for the purpose of assessing interpatient and intrapatient pharmacokinetic variability. All patients underwent bone marrow harvest on day -8 (relative to bone marrow reinfusion). On days -7, -6, and -5, melphalan was given p.o. and the dose was escalated on each cohort consisting of at least 3 patients (beginning at 0.75 mg/kg). On days -6, -4, and -2, cyclophosphamide at 2.5 g/m2 and thiotepa at 225 mg/m2 were given i.v. On day -7 the peak melphalan concentration was 1.64 +/- 0.89 (SD) microM with a terminal half-life of 1.56 +/- 0.86 h. The area under the plasma concentration time curve (AUC) and oral clearance were 217.9 +/- 115.1 microM/min and 30.2 +/- 14.2 ml/min/kg. There was only a moderate correlation between the melphalan dose and both the peak concentration (r = 0.50, P less than 0.05) and AUC (r = 0.64, P less than 0.01) over the dosage range of 0.75-2.5 mg/kg. There was a trend towards greater interpatient variability in peak concentration, AUC, and oral clearance observed at the higher doses of melphalan. Analysis of intrapatient pharmacokinetic variability in 8 patients showed a significant difference between the doses given on days -7 and -5 in the peak concentration (2.09 versus 1.07 microM, P = 0.02), AUC (264.9 versus 134.8 microM/min, P = 0.01), and oral clearance (25.1 versus 53.1 ml/min/kg, P = 0.05) but no significant difference in the time to peak and terminal half-life. We conclude that there is marked interpatient and intrapatient variability in melphalan pharmacokinetics following high-dose p.o. administration. The data are consistent with saturable absorptive pathways for melphalan, which might be especially sensitive to concurrent high-dose chemotherapy.

High-dose, multiple-alkylator chemotherapy with autologous bone marrow reinfusion in patients with advanced non-small cell lung cancer.

Fifteen patients with Stage IV lung cancer both untreated and previously treated were enrolled into a high-dose chemotherapy program with multiple alkylating agents and autologous bone marrow reinfusion. Eight patients received cyclophosphamide at 7.5 gm/m2 over 3 days with thiotepa escalated from levels of 1.8 mg/kg to 6.0 mg/kg over 3 days. Seven patients received the above dose of cyclophosphamide plus thiotepa at 675 mg/m2 and oral melphalan escalated from levels of 0.75 mg/kg to 2.5 mg/kg over 3 days. Both regimens are part of larger Phase I-II clinical studies. The median time to recovery of more than 500 granulocytes and more than 50,000 platelets per microliter was 16 and 27 days, respectively. Two patients died as a consequence of severe, overwhelming infections during their period of aplasia. Of the 13 evaluable patients, no patients achieved a complete response and seven patients (47%) obtained a partial response. The median duration of response was 12 weeks. Other nonhematologic toxicities included nausea/vomiting, diarrhea, mucositis, skin rash, hemorrhagic cystitis, and cardiomyopathy. Since there are substantial toxicities associated with high-dose chemotherapy and responses of such brief duration, further investigation with these drug combinations is not warranted.

Photosynthesis and Photorespiration in Typha latifolia.

Photosynthetic rates of Typha latifolia, the broad-leaved cattail, are the equivalent of rates reported in tropical grasses and other plants which assimilate carbon by the phosphopyruvate carboxylase reaction, but photosynthesis in T. latifolia proceeds by a typical Calvin cycle. Glycolate oxidase, the photorespiratory enzyme, is present in high concentration in this species, but only minor quantities of the assimilated carbon pass through the photorespiratory pathway. However, continued operation of the pathway is apparently essential in the maintenance of assimilatory capacity. Glycolate oxidase function is not closely coupled to stomatal operation in T. latifolia.