Stephen J. Tomlanovich

The effects of ketoconazole on the intestinal metabolism and bioavailability of cyclosporine.

The pharmacokinetics of cyclosporine were studied in the blood of five normal healthy volunteers (two men and three women) after each received oral and intravenous cyclosporine alone and with concomitant oral ketoconazole. Administration of ketoconazole caused a significant decrease in intravenous cyclosporine clearance (0.18 ± 0.05 L/kg/hr versus 0.32 ± 0.09 L/hr/kg) and a significant increase in cyclosporine oral bioavailability (56.4% ± 11.7% versus 22.4% ± 4.8%) compared with values before ketoconazole administration. Steady‐state volume of distribution for intravenously administered cyclosporine was unchanged (1.26 ± 0.44 L/kg versus 1.10 ± 0.27 L/kg). Hepatic bioavailability (1 — hepatic extraction ratio) calculated for intravenous cyclosporine increased by 11% in the presence of ketoconazole (86.3% ± 3.7% versus 75.2% ± 6.6% without ketoconazole), which accounts for only one third of the observed increase in cyclosporine oral bioavailability. Because it is unlikely that ketoconazole had a significant effect on either cyclosporine absorption or hepatic blood flow, the increase in cyclosporine bioavailability observed in this study is most likely explained by inhibition of gastrointestinal cytochrome P450 enzymes.

Recurrent focal glomerulosclerosis: Natural history and response to therapy

PURPOSE Recurrent focal glomerulosclerosis (FGS) has been well documented since it was first reported in 1972. However, the course of the disease after transplantation and the optimal treatment regimen have not been well defined since the introduction of newer treatment modalities. PATIENTS AND METHODS We reviewed all the charts of patients with biospy-proven FGS who received renal transplants at our institution from January 1980 through December 1990. Case histories consistent with diagnoses other than primary FGS (such as reflux nephropathy or intravenous drug use) were eliminated from the study. During this time period, 78 allografts were received by 71 patients with FGS. Independent variables that were analyzed included sex, race, time in months between the diagnosis of FGS and end-stage disease (dialysis or transplantation), age at time of transplantation, type of dialysis, source of allograft (cadaveric or living related), haplotype matching, donor-specific transfusions, age and sex of the donor, post-transplantation acute tubular necrosis, rejection episodes, immunosuppression regimen, use of plasmapheresis and angiotensin converting enzyme (ACE) inhibitors, and outcome. RESULTS FGS recurred in 25 allografts (32%) of 21 patients. Biopsy-proven diagnosis of recurrence was made a mean of 7.5 months (range: 0.5 to 44 months) after transplantation. Patients who had rapid progression to end-stage disease tended to experience more frequent recurrences. Of seven patients who received a second transplant, five patients lost the first graft to recurrent FGS, and four of those patients (80%) had a recurrence in the second allograft. Recurrent disease developed in 34% of patients concurrently treated with cyclosporine and in 28% of those treated with prednisone and azathioprine alone (NS). Patients with recurrent FGS who were treated with ACE inhibitors benefited from a significant reduction of proteinuria. Six patients underwent plasmapheresis after diagnosis of the recurrence. Three of five patients in whom the diagnosis was made early in the course of the disease and in whom plasmapheresis was initiated immediately had reversal of epithelial foot process effacement and remission of proteinuria. End-stage disease eventually developed in 14 allografts (56%) an average of 23.7 months (range: 1 to 65 months) after diagnosis of recurrent disease. The cause of failure was chronic rejection in four allografts and recurrent disease in the remaining 10 allografts. CONCLUSIONS FGS recurs in approximately 30% of allografts and causes graft loss in half of these. Patients who have lost a first allograft to recurrent FGS are at high risk for developing recurrent disease in a second allograft. Prolonged allograft survival is possible in patients with recurrent FGS and may best be obtained with a combination of treatment modalities including cyclosporine (perhaps in higher dosages than are routinely used in clinical renal transplantation), ACE inhibitors, and early use of plasmapheresis. The efficacy of these modalities supports the notion that recurrent FGS is caused by a circulating humoral mediator.

Kidney and liver transplantation in human immunodeficiency virus-infected patients: a pilot safety and efficacy study.

Background. Human immunodeficiency virus (HIV)-infected patients have historically been excluded from consideration for transplantation out of concern for the effects of immunosuppression on the progression of HIV disease. Improvements in HIV-related morbidity and mortality with the use of highly active antiretroviral therapy (HAART) have prompted a reevaluation of transplantation as a treatment option for HIV-infected patients with end-stage kidney and liver disease. Methods. Eligible patients met standard transplant criteria. They had undetectable plasma HIV-1 RNA levels (viral load) for 3 months (kidney) or were predicted to achieve viral load suppression posttransplantation if unable to tolerate HAART (liver); a CD4+ T-cell count of more than 200 cells/&mgr;L (kidney) or more than 100 cells/&mgr;L (liver) for 6 months; and no history of opportunistic infections and neoplasm. Standard immunosuppression included prednisone, mycophenolate mofetil (CellCept, Roche Pharmaceuticals, Basel, Switzerland), and cyclosporine (Neoral, Novartis, East Hanover, NJ). Results. Fourteen patients received transplants (10 kidney transplants, mean follow-up 480 days; four liver transplants, mean follow-up 380 days). All of the kidney transplant recipients (100%) are alive and with functioning grafts, and three of four liver transplant patients (75%) are alive and well with functioning grafts (all liver transplant patients with normal liver function tests). The one death occurred 445 days posttransplantation in a liver recipient coinfected with hepatitis C virus, who died as the result of its rapid reoccurrence. Rejection occurred in 5 of 10 kidney transplant recipients but did not occur in any of the four liver transplant recipients. HIV viral loads have remained undetectable in all patients maintained with HAART. CD4 counts have remained stable in patients not treated for rejection. Patients receiving protease inhibitors require 25% of the dose of cyclosporine compared with patients receiving nonnucleoside reverse transcriptase inhibitors. Conclusions. There has been no evidence of significant HIV progression and no adverse effect of HIV on allograft function. Rejection is a concern in kidney transplant recipients, as is the possible poor outcome in hepatitis C virus-coinfected liver transplant recipients. Preliminary data are encouraging and indicate that transplantation should be a treatment option for individuals with well-controlled HIV disease.

Sirolimus Prolongs Recovery from Delayed Graft Function After Cadaveric Renal Transplantation

Sirolimus, lacking known nephrotoxicity, appeared to be an ideal immunosuppressive agent in the setting of delayed graft function (DGF) after renal transplantation. Coincident with our use of sirolimus however, we noticed prolongation of DGF. To investigate possible causes of prolonged DGF, extensive donor, recipient, transplant, and post‐transplant data were collected on 132 consecutive cases of DGF at the University of California, San Francisco between 1/1/97 and 6/30/01. Cox proportional hazards analysis of time to graft function was used in univariate and multivariate models to identify factors that prolong DGF. Sirolimus had a large and highly significant effect on time to graft function (hazard ratio 0.48, p = 0.0007). The hazard ratio indicates that a recipient on sirolimus is half as likely to resolve DGF or twice as likely to remain on dialysis as a recipient without sirolimus. Two other factors had less potent but still significant association with DGF duration: recipient sensitization (hazard ratio 0.66, p = 0.037), and Novartis score (hazard ratio 0.93 per 1.0 increase; p = 0.034). Sirolimus retained its profound negative association with time to graft function in all multivariate models. Because sirolimus appears to prolong DGF, it may not be the optimal immunosuppressive choice in the DGF setting.

Cytokine and T cell receptor gene expression at the site of allograft rejection

Intragraft cytokine and T cell receptor gene expression was analyzed in rejecting renal allografts by polymerase chain reaction (PCR). Message for IL-1β, IL-6, and TNF-α was detected in nephrectomy tissue with pathological evidence of acute or chronic rejection. Similarly, mRNA for both IL-6 and TNF-α was present in renal biopsies from acute rejecting kidneys. IL-2R, IL-4, and IL-5 mRNA was present in both rejecting and rejected kidney allografts, indicating that these cytokines may play a role in ongoing renal allograft rejection. Conversely, IL-2, IL-7, and IFN-γ message was detected infrequently. In order to address the diversity of T cells in rejecting kidneys, we have analyzed the clonality of the TcR present within the allograft tissue. Rearranged TcR genes were identified in all allografts examined (n=16) indicating the presence of T cells bearing the α/β TcR. We have determined that there is a heterogeneous infiltration of T cells in the rejected allograft with TcR representing x=7.47±2.4 families rearranged in samples obtained from nephrectomies, whereas x=5.33±0.58 families were detected in samples obtained from biopsy tissue. These data indicate that (1) cytokines are produced locally which may contribute to graft cell destruction, (2) the heterogeneity of intragraft T cells during kidney allograft rejection may exist because nonspecific lymphocytes have been recruited to the site by locally produced cytokines or because T cells are responding to multiple epitopes or multiple donor antigens. Detection of intragraft cytokines and TcR may prove useful in elucidating the mechanism of rejection and therefore lead to improved immunosuppression.

Effect of Food on the Pharmacokinetics of Cyclosporine in Healthy Subjects Following Oral and Intravenous Administration

The pharmacokinetics of cyclosporine were studied in healthy subjects following administration of cyclosporine both orally (10 mg kg−1) and intravenously (4 mg kg−1) without and with high fat meals. Both blood and plasma samples (separated at 37°C) were analyzed for cyclosporine concentration. Blood and plasma clearances of cyclosporine were calculated to be 0.36 and 0.47 L hr−1 Kg−1, respectively, and volume of distribution at steady state was calculated to be 1.21 L Kg−1, when cyclosporine was administered without a high fat meal. Using plasma analysis, the oral bioavailability of cyclosporine was estimated to be 21 and 79%, when administered without and with a high fat meal, respectively. When cyclosporine was administered intravenously together with a high fat meal, both clearance and volume of distribution increased significantly. Blood and plasma clearances of cyclosporine were 0.44 and 0.70 L hr−1 Kg−1, respectively, when cyclosporine was administered along with a high fat meal. We conclude that food not only enhances the absorption of cyclosporine but also enhances its clearance and volume of distribution. The observed variability in clearance, bioavailability, and volume of distribution values for cyclosporine across various pharmacokinetic studies can be partially accounted by the type of food administered and the sampling matrix used for analysis.

Intravenous mycophenolate mofetil: safety, tolerability, and pharmacokinetics

An intravenous (i.v.) formulation of mycophenolate mofetil (MMF; CellCept®, Roche Pharmaceuticals, Inc., Palo Alto, CA) that will enable its administration to patients unable to tolerate oral medication is available. Two separate studies, an open‐labeled pharmacokinetic (PK) study and a double‐blind safety study, were performed. Within 24 h after transplant, 153 (safety study) and 45 (PK study) first or second renal transplant recipients were started on i.v. MMF 1 g Q12h or placebo (used in the safety study only, 2:1 MMF:placebo), given over 2 h via a dedicated peripheral venous catheter. In the safety study, per os (p.o.) MMF (1g Q12h) or placebo was administered, starting within 72 h after transplant, whereas in the PK study, p.o. MMF was started on the evening of day 5. Sequential blood samples obtained on study days 5 (i.v. MMF) and 6 (p.o. MMF) before and up to 12 h after the AM dose were analyzed for mycophenolic acid (MPA) and MPA glucuronide (MPAG) concentrations by high‐performance liquid chromatography. The area under the concentration curve (AUC) was calculated using the linear trapezoidal rule. The MPA AUC0–12 was higher for i.v. MMF than p.o. MMF (40.8±11.4 μg·h/mL vs. 32.9±15, p<0.001). There were no other significant PK differences for plasma MPA or MPAG. In the safety study (n=98 i.v. MMF vs. n=55 placebo), 11 patients (11%, i.v. MMF) and 4 patients (7%, placebo) discontinued their use of the drug because of an adverse event (AE). Overall, AEs were similar between i.v. MMF and placebo. Injection site phlebitis (4%) and thrombosis (4%) were observed only with i.v. MMF. MMF i.v. 1 g twice daily (b.i.d.) should provide efficacy at least equivalent to p.o. MMF without increased toxicity, and it provides an acceptable alternative dose form in the immediate period after transplant.

Histopathological concordance of paired renal allograft biopsy cores : effect on the diagnosis and management of acute rejection

To assess the effect of sampling error on renal allograft biopsies, we determined the concordance of diagnoses between 2 biopsy samples from the same renal allograft and the frequency with which 1 biopsy sample would underdiagnose or lead to the under-treatment of acute rejection. Two core samples from the same allograft biopsy procedure were labeled as core A and core B and presented to both unblinded and blinded pathologists, and each pathologist independently assigned an acute and a chronic rejection grade. A set of clinical data with pertinent prebiopsy information was combined with either the core A or core B histopathological diagnosis and presented to 3 transplant nephrologists who made treatment recommendations for each combination. Two cores were obtained in 79 allograft biopsies. Core pairs differed by

Improvement in 3-Month Patient-Reported Gastrointestinal Symptoms After Conversion From Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Renal Transplant Patients

gEl grade of acute rejection in 30% and 50% of cases for unblinded and blinded pathologist readings, respectively. Moderate or severe acute rejection would have been missed with a 1 core in 9.5% of cases, increasing to 25.6% if only biopsy pairs containing at least 1 reading of moderate or severe acute rejection are included. Therapy would have failed to be increased with a single core in 7.5% of cases, increasing to 10.5% if only pairs containing at least one recommendation of an increase in therapy are included. The use of 2 cores of renal allograft tissue provides better diagnostic information and thereby leads to appropriate increases in antirejection therapy without increasing the complication rate of the procedure.

Immunologic and patient selection strategies for successful utilization of less than 15 kg pediatric donor kidneys-long term experiences with 40 transplants

Background. The benefit of conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) in terms of gastrointestinal symptom burden has been evaluated previously using patient-reported outcomes. However, data are lacking concerning the sustained effect of conversion over time, and the potential impact of concomitant calcineurin inhibitor. Methods. In this 3-month, prospective, multicenter, longitudinal, open-label trial, MMF-treated renal transplant patients with gastrointestinal symptoms receiving cyclosporine or tacrolimus were converted to equimolar doses of EC-MPS. Change in gastrointestinal symptom burden was evaluated using a validated Gastrointestinal Symptom Rating Scale (GSRS). Results. A significant improvement in GSRS score was observed from baseline (2.61, 95% CI 2.54–2.68) to month 1 (1.87, 95% CI 1.81–1.93) after conversion to EC-MPS and was sustained to month 3 (1.81, 95% CI 1.74–188; both P<0.0001 versus baseline). The mean change in overall GSRS score from baseline to month 1 was −0.74 overall (cyclosporine: −0.73 and tacrolimus: −0.74; all P<0.0001 versus baseline), with a slight further improvement (−0.79) at month 3 (cyclosporine: −0.82 and tacrolimus: −0.78; all P<0.0001 versus baseline). A significant improvement in GSRS subscale scores was also observed in the total population regardless of calcineurin inhibitor at month 1, sustained to month 3 (all P<0.0001 versus baseline). The improvement in GSRS score postconversion was similar in African-American and non-African-American patients, and in diabetic and nondiabetic patients. Conclusions. This exploratory study in 728 patients demonstrates that following conversion from MMF to EC-MPS, regardless of concomitant calcineurin inhibitor, GSRS is improved and sustained over 3 months.