Pharmacokinetics of neoral in stable renal transplant recipients with long-term diabetes mellitus

Therapeutic drug monitoring (TDM) of Neoral has been studied widely and C2 monitoring has been shown to be superior to C0 monitoring in predicting outcomes. However, data are scarce in diabetic renal transplant recipients who may have gastroparesis. We studied 0 to 8 hour pharmacokinetic profiles (AUC(0-8h)) of Neoral on 3 consecutive days in 18 diabetic adults who had stable renal function for at least 6 months after transplantation and no overt symptoms of diabetic gastroparesis. All patients had diabetes mellitus (DM) for at least 5 years. Intrapatient variability of C2 levels was 28% (range, 6%-68%); it was < or =20% in 9 patients (50%) and >60% in 2 patients. Correlation coefficients between AUC(0-8h) and AUC(0-4h), between C2 and AUC(0-8h), and between C0 and AUC(0-8h) were 0.95, 0.86, and 0.77, respectively. Exposure phase (85% of AUC(0-8h)) was longer than 4 hours in all completed (48/54; 89%) profiles; it was longer than 6 hours in 20 profiles. C4 levels had good correlation with AUC(0-8h) (0.86) and low intrapatient variability (16% +/- 11%; range, 2%-39%). Thirteen of 18 patients (72%) had intrapatient variability of C4 < or = 20%. We conclude that the exposure phase of Neoral is prolonged more than 4 hours in adult renal transplant recipients with long-term diabetes, even in the absence of symptoms of gastroparesis. Because of very high intrapatient variability in this group of patients, C2 levels may not be reliable for TDM of Neoral despite high correlation with AUC(0-8h). C4 level may be a valid alternative for these patients.     

Pharmacodynamics, pharmacokinetics, and safety of multiple doses of FTY720 in stable renal transplant patients: a multicenter, randomized, placebo-controlled, phase I study

BACKGROUND: FTY720, a novel immunomodulator, displays potent immunosuppressive activity in a variety of preclinical transplant models. This study examined the safety, pharmacodynamics, and pharmacokinetics of multiple doses of FTY720 in stable renal transplant patients. METHODS: This randomized, multicenter, double-blind, placebo-controlled, phase I study included adults who had been maintained on a regimen of cyclosporine A (CsA) microemulsion and prednisone (or its equivalent) for at least 1 year after renal transplantation. Patients received once-daily doses of 0.125, 0.25, 0.5, 1.0, 2.5, or 5.0 mg FTY720, or placebo for 28 days. After completion of study drug administration, the patients were monitored until day 56 by serial laboratory tests, clinical examinations, and recording of adverse events. The study includes 76 treatment courses (61 FTY720 and 15 placebo), with 65 patients enrolled once and 11 reenrolled. RESULTS: FTY720 doses greater than or equal to 1.0 mg/day produced a significant reduction in peripheral blood lymphocyte count by up to 85%, which reversed within 3 days after discontinuation of study medication. Compared with placebo-treated patients, FTY720 subjects did not show a major increase in adverse events or a change in renal function. Pharmacokinetic measurements revealed that FTY720 displayed linear relations of doses and concentrations over a wide range, but had no effect on CsA exposure. CONCLUSIONS: At doses up to 5.0 mg/day for 28 days, stable renal transplant patients treated with FTY720 in combination with CsA and prednisone displayed a dose-dependent, reversible decline in peripheral blood lymphocytes without an enhanced incidence of collateral toxicities, except possibly bradycardia.     

No gender-associated differences of cyclosporine pharmacokinetics in stable renal transplant patients treated with diltiazem

Cytochrome-P450 enzymes metabolize cyclosporine both in the liver and in the intestinal wall. Diltiazem, by competitive inhibition of these enzymes, may increase the absorption and the bioavailability of cyclosporine. Some evidence points to a higher activity of some specific enzymes in women, such as CYP3A, that may influence differences in cyclosporine pharmacokinetics. We examined possible gender-associated differences in pharmacokinetic profiles of cyclosporine in 19 stable renal transplant recipients cotreated with diltiazem. Ten women and nine men, chronically using diltiazem associated with cyclosporine, azathioprine, and prednisone were randomly assigned to an 8-week period of continued controlled treatment with diltiazem (10 patients) or a wash-out period discontinuing diltiazem (nine patients). At the end of this period, the time-concentration curves of cyclosporine in the first 4 hours were performed after a single dose of cyclosporine. Thereafter, a cross-over between groups was performed, and time-concentration curves repeated. A specific RIA was used to measure cyclosporine concentrations. Comparisons between male and female patients in doses of cyclosporine and other pharmacokinetics parameters (C(0), C(2), AUC(0-4)), with or without diltiazem, did not show any difference related to gender. The association of diltiazem allowed a similar degree of reduction in Neoral dosage in male and female patients (21%). No changes in serum creatinine, blood urea nitrogen, potassium, uric acid, or blood pressure, or other adverse event were observed during the study. In these groups of patients, gender was not an important factor to be considered when diltiazem is added to cyclosporine therapy.     

Six-month clinical outcome of cyclosporine microemulsion formulation (Sigmasporin Microral) in stable renal transplant patients previously maintained on sandimmun neoral

The trial objective was to investigate the feasibility and safety of conversion to a generic microemulsion cyclosporine in stable renal transplant patients premaintained on Neoral. We enrolled 75 patients from seven centers in five Middle Eastern countries monitored them for 6 months after conversion to Sigmasporin Microral. Readings at 0, 0.5, 1, 2, 3, 4.5, and 6 months included cyclosporine blood level, serum creatinine, liver enzymes, lipid profile, blood sugar, blood pressure and adverse events. Patients included 54 men and 21 women of mean age 38.9 +/- 10.7 years at 30.3 +/- 29.3 months post-transplantation maintained on Sigmasporin Microral dose of 2.8 +/- 1.0 mg/kg per day; they were observed to be stable throughout the study period as reflected by the therapeutic blood C(0) level of 181.6 +/- 102.1 and C(2) of 759.2 +/- 384.4. Their absorption profile as represented by C(2)/C(0) was 4.9 +/- 2.8, and C(2)/cyclosporine dose of 282.3 +/- 128.8. An average serum creatinine level of 116.1 +/- 29.5 mumol/L denoted stable graft function and their liver enzymes did not change during the study. No new-onset cases of hypertension, diabetes mellitus, or hyperlipidemia were reported among the patients. Graft function was stable for all patients, except for two incidences of mild acute rejection and two of mild cyclosporine nephrotoxicity; graft and patient survival rates were both 100%. Results of this 6-month study showed that Sigmasporin Microral was effective to maintain stable renal function in kidney transplant patients converted from Neoral with similar safety and tolerability profiles as those reported in the literature.     

The effects of FK778 in combination with tacrolimus and steroids: a phase II multicenter study in renal transplant patients

BACKGROUND: In animal and in vitro models, FK778 inhibits acute rejection, modifies vasculopathy, and shows anti-viral activity. We report first efficacy and safety data of FK778 in human kidney transplant recipients at two concentration-controlled ranges. METHODS: In a double-blind manner, 149 patients were randomized to a 12-week treatment with FK778 in combination with tacrolimus (Tac) and corticosteroids (S). Of the high-level group (H), 49 patients received 2 x 600 mg/day FK778 and continued on 150 mg/day, 54 patients of the low-level group (L) got 1 x 600 mg/day followed by 75 mg/day, and 46 patients received placebo (P). Subsequent FK778 doses were adjusted to trough levels of 100-200 microg/mL (H) and 10-100 microg/mL (L). The primary endpoint was the incidence of biopsy proven acute rejection (AR). RESULTS: In 93% of the patients in group L, targeted plasma trough levels were reached by Day 3; in half of the patients in group H, the targeted levels were reached by Day 9. Graft survival at week 16 was 89.7%, 88.8%, and 91.3%, and the incidences of AR were 26.5%, 25.9%, and 39.1% for groups H, L, and P. For the subgroup of patients in which target levels were reached by week 2, incidences were 7.7%, 27.1%, and 39.1%, respectively. Anemia, the most frequently reported adverse event especially in group H, was reversible. Mean total cholesterol and LDL-cholesterol levels were reduced during FK778 treatment compared with group P. CONCLUSION: FK778 is pharmacologically active, well-tolerated, and safe. To fully benefit from this promising new drug, FK778 dosing will be optimized in subsequent studies.     

Conversion to tacrolimus once-daily from ciclosporin in stable kidney transplant recipients: a multicenter study

This 24-week, open, single-arm, prospective, multicenter study evaluated the effects of conversion from ciclosporin to Tacrolimus QD in adult kidney transplant patients. Stable patients receiving ciclosporin were converted to Tacrolimus QD at 0.1mg/kg/day. Relative change in renal function (primary endpoint) was assessed using estimated creatinine clearance (eCrCl) with a noninferiority margin set at -10%. A total of 346 patients were enrolled; and 301 patients were treated per protocol (PPS) in the hyperlipidemia (n=42), hypertrichosis (n=106), hypertension (n=77) and gingival hyperplasia (n=76) groups. Relative change in eCrCl was -0.6% in all PPS patients (95% CI, -2.2; 0.9) and -5.3% in the hyperlipidemia (CI, -9.59; -0.97), 0.9% in the hypertrichosis (CI, -2.59; 4.45), -0.1% in the hypertension (CI, -3.8; 3.68), and -1% in the gingival hyperplasia groups (CI, -4.63; 2.65) (PPS), meeting noninferiority criteria. There was no acute rejection. Decreases in serum lipids and blood pressure were moderate but without meaningful change in the number of treatment medications. Substantial decreases in severity of ciclosporin-related cosmetic side effects were evident from investigator and patient self-report of symptoms. Renal function remained stable after conversion to Tacrolimus QD. The effect of conversion on cardiovascular parameters was not clinically meaningful, however, marked improvement in ciclosporin-related cosmetic side effects was observed. (ClinicalTrials.gov number: NCT00481481).     

Population pharmacokinetics of propofol: a multicenter study

BACKGROUND: Target-controlled infusion is an increasingly common type of administration for propofol. This method requires accurate knowledge of pharmacokinetics, including the effects of age and weight. The authors performed a multicenter population analysis to quantitate the effects of covariates. METHODS: The authors analyzed 4,112 samples of 270 individuals (150 men, 120 women, aged 2-88 yr, weighing 12-100 kg). Population pharmacokinetic modeling was performed using NONMEM (NONMEM Project Group, University of California, San Francisco, CA). Inter- and intraindividual variability was estimated for clearances and volumes. The effects of age, weight, type of administration and sampling site were investigated. RESULTS: The pharmacokinetics of propofol were best described by a three-compartment model. Weight was found to be a significant covariate for elimination clearance, the two intercompartmental clearances, and the volumes of the central compartment, the shallow peripheral compartment, and the deep peripheral compartment; power functions with exponents smaller than 1 yielded the best results. The estimates of these parameters for a 70-kg adult were 1.44 l/min, 2.25 l/min, 0.92 l/min, 9.3 l, 44.2 l, and 266 l, respectively. For patients older than 60 yr the elimination clearance decreased linearly. The volume of the central compartment decreased with age. For children, all parameters were increased when normalized to body weight. Venous data showed a decreased elimination clearance; bolus data were characterized by increases in the volumes of the central and shallow peripheral compartments and in the rapid distribution clearance (Cl2) and a decrease in the slow distribution clearance (Cl3). CONCLUSIONS: Pharmacokinetics of propofol can be well described by a three-compartment model. Inclusion of age and weight as covariates significantly improved the model. Adjusting pharmacokinetics to the individual patient should improve the precision of target-controlled infusion and may help to broaden the field of application for target-controlled infusion systems.     

Comparison of generic cyclosporine microemulsion versus neoral in de novo renal transplant recipients managed by 2-hour postdose monitoring

INTRODUCTION: The bioequivalence of generic formulations is established by measuring pharmacokinetic parameters in healthy volunteers. Cyclosporine (CsA) absorption and exposure is known to differ between healthy volunteers and transplant recipients. Therefore bioequivalence testing may be inadequate to ensure therapeutic equivalence. We sought to compare the efficacy of generic cyclosporine (ArpimuneME, RPG Life Sciences) versus Sandimmune Neoral in de novo renal transplant recipients. METHODS: A prospective single-center, open-label study enrolled 20 de novo renal transplant patients (group 1: mean age 30.55 +/- 9.81 years, M:F 19:1, mean donor age 43.4 +/- 10.8). All patients received ArpimuneME along with azathioprine and prednisolone. The results were compared with 17 matched controls (group 2: mean age 28.1 +/- 9.5 years, M:F 13:4, mean donor age 47.8 +/- 6.8) who received Neoral and were transplanted during the same period. C(2) levels were monitored by the cloned enzyme donor immunoassay (CEDIA). RESULTS: Patient and graft survivals were 100% and 100% and 100% and 92.8% in groups 1 and 2, respectively (P = NS). Six patients (30%) experienced rejection in group 1 as compared eight patients (47.1%) in group 2. Mean CsA levels (ng/mL) during the first month were 1419.1 +/- 213.6 and 1460.5 +/- 290.7 and at 3 months, 1296.3 +/- 227.8 and 1342.4 +/- 303.4 in the two groups, respectively (P = NS). The mean serum creatinine levels (mg%) in group 1 and group 2 were 1.6 +/- 0.8 and 2.0 +/- 1.4 at discharge and 1.5 +/- 0.4 and 1.5 +/- 0.8 at 6 months, respectively (P = NS). CONCLUSION: Use of a generic microemulsion form of CsA provided safe and effective immunosuppression compared with Sandimmune Neoral when drug monitoring was performed by C(2) levels.