Comparison of 5-fluorouracil pharmacokinetics in whole blood, plasma, and red blood cells in patients with colorectal cancer

STUDY OBJECTIVE

To compare 5-fluorouracil (5-FU) pharmacokinetics in whole blood, plasma, and red blood cells in patients with colorectal cancer.

DESIGN

Prospective, unblinded observational study in consecutive patients.

SETTING

Large regional teaching hospital.

PATIENTS

Five patients with colorectal cancer.

INTERVENTIONS

Patients received folinic acid 200 mg/m2 intravenously over 2 hours, followed by 5-FU 600 mg/m2 intravenous bolus over 30 minutes, then 5-FU 600 mg/m2 intravenous infusion over 22 hours, administered on days 1 and 2. This 48-hour cycle was repeated every 14 days.

MEASUREMENTS AND MAIN RESULTS

Concentrations of 5-FU in whole blood, plasma, and red blood cells were determined by high-performance liquid chromatography. ADAPT II was used for pharmacokinetic computations. The optimum model was determined for each matrix by calculating Akaike's information criteria values. Concentrations of 5-FU in whole blood were 106-115% of simultaneous plasma concentrations (median 112%), and packed red blood cell levels were 5-17% of plasma concentrations (median 11%). The drug's concentration-time profile was similar in the three matrices. The drug is reported to be unstable in whole blood, and red blood cell 5-FU concentrations were near the limit of detection (10 ng/ml), supporting plasma as the preferred matrix for therapeutic drug monitoring studies. Six pharmacokinetic models were fitted to the 5-FU individual data sets to determine the best curve fit. The optimal model for whole blood and plasma data sets was one compartment with both linear and nonlinear elimination models; a one-compartment model with nonlinear elimination provided the best curve fit for 5-FU in red blood cells. A two-compartment model with nonlinear elimination gave a similar degree of curve fit for plasma 5-FU as the one-compartment model with both linear and nonlinear elimination.

CONCLUSIONS

These pharmacokinetic results provide the basis for further investigation into the ability to correlate 5-FU systemic exposure with clinical drug activity.

High-performance liquid chromatographic assay of 5-fluorouracil in human erythrocytes, plasma and whole blood

A HPLC assay method was modified and validated for the determination of 5-fluorouracil in human red blood cells, plasma and whole blood with a two-fold increased sensitivity (detection limit=10 ng/ml). The assay was linear from 25 to 1500 ng/ml and the accuracy ranged from 96.7 to 103.2% at 25 ng/ml, 94.8 to 99.4% at 500 ng/ml, and 98.9 to 99.5% at 1500 ng/ml. Intra-assay and inter-assay coefficients of variation were less than 8% over the range of concentrations and less than 8% over 10 days of analysis. After intravenous bolus and infusion of 5-fluorouracil in patients with colorectal cancer, the concentrations of 5-fluorouracil in whole blood were 108-111% of plasma concentrations, while packed red blood cells levels were 8-15% of plasma concentrations in the five patients studied. By utilising basic analytical hardware, this represents an accurate, precise, reproducible and affordable method for 5-fluorouracil pharmacokinetics investigation and therapeutic drug monitoring.

Medicare/Medicaid restructuring. Challenges and opportunities of managed care

The restructuring of the Medicare and Medicaid programs poses significant operational, legislative, and mission challenges for the Catholic health ministry. This report highlights meetings held in Chicago and Philadelphia in November and December 1996 to prepare healthcare leaders for the changes that are coming. The meetings were two of seven held across the country last fall. Cosponsored by the National Coalition on Catholic Health Care Ministry, the Catholic Health Care Association (CHA), and Consolidated Catholic Health Care, these regional conferences were part of New Covenant, a process to strengthen the Catholic presence in healthcare through regional and national collaborative strategies. The meetings blended operational and mission concerns. On the first day, speakers reinforced mission as the ministry's foundation and market advantage, and they defined opportunities and strategic responses to the restructuring of the Medicare and Medicaid programs. The second day's sessions moved into collaborative strategies for dealing with Medicare and Medicaid changes. The day concluded with CHA's public policy proposals related to these programs' restructuring.

EO9 phase II study in advanced breast, gastric, pancreatic and colorectal carcinoma by the EORTC Early Clinical Studies Group

In a phase II trial, the activity of EO9, a new bioreductive alkylating agent, was assessed. EO9 was used as second-line chemotherapy in breast cancer patients and as first-line chemotherapy for patients with gastric, pancreatic and colorectal cancer. EO9 was given as a 5 min i.v. infusion at a weekly dose of 12 mg/m2. 92 patients were entered; 22 with breast cancer, 26 with colon cancer, 24 with pancreatic cancer and 20 with gastric cancer. In general, the drug was well tolerated with nausea and vomiting occurring in 26.42 and 13.3% of courses, respectively. Reversible proteinuria was the main toxicity occurring in 45% of courses. Antitumour activity was not observed. At this dose and schedule, EO9 is not an active drug in the type of tumour studied.

Preoperative assessment of the ambulatory patient

Whenever the human body is subjected to anesthesia and an invasive surgical procedure, the potential for complications exists. A goal of perioperative care is to minimize that risk while providing the safest care available for the patient. Initial steps toward accomplishing this goal include (1) conducting a thorough preoperative assessment of the patient's medical, surgical, and anesthetic history; (2) performing a physical examination; and (3) procuring and interpreting the results of necessary diagnostic procedures and laboratory evaluations. The increased use of ambulatory surgical services, coupled with changes in health care economics, dictates reform in patient evaluation before surgery. The evaluative process must be cost-effective and efficient without compromising reliability. This article familiarizes and updates the perianesthesia nurse on management issues for the surgical patient.

Mature results of a randomized trial of two doses of cisplatin for the treatment of ovarian cancer. Scottish Gynecology Cancer Trials Group

PURPOSE

In 1992, we reported the first results of a randomized study in ovarian cancer, comprising two doses of cisplatin and indicated a significant difference (P = .0008) in median survival. Four years later, we now describe the results of this trial.

PATIENTS AND METHODS

After a median follow-up of 4 years and 9 months, 115 of 159 cases of advanced ovarian cancer, originally randomized to receive six cycles of cyclophosphamide 750 mg/m2 and either a high dose (HD) of 100 mg/m2 cisplatin or a low dose (LD) of 50 mg/m2 (LD) cisplatin, have now died.

RESULTS

The overall survival for HD and LD patients is 32.4% and 26.6%, respectively, and the overall relative death rate is 0.68 (P = .043). This represents a reduction in overall benefit with longer follow-up compared with the first 2 years (relative death rate of 0.52). Toxicity, particularly neurotoxicity, is still evident in the fourth year (10/31 on HD compared with 1/24 on LD).

CONCLUSION

Our recommended dose of cisplatin in combination schedule is therefore 75 mg/m2, representing the optimal balance between efficacy and toxicity.