C2 Levels Research Articles

Early Cyclosporine C0 and C2 Monitoring in De Novo Kidney Transplant Patients: A Prospective Randomized Single-Center Pilot Study

C2 monitoring of cyclosporine (CsA) has been promoted as improving the results of organ transplantation. No randomized, controlled studies in de novo kidney transplant recipients are available. Between June 2003 and August 2004, 160 consecutive cadaveric kidney recipients allocated to CsA, mycophenolate and steroids were randomized to either C0 or C2 monitoring of CsA for the first 3 weeks posttransplant. Both levels were measured, keeping the other level blinded until 3 weeks. Altogether, 1451 double measurements were done. The target C0 was 200-300 microg/L and C2 1500-2000 microg/L. From the fourth week on, only C0 monitoring was used. Median follow up time was 505 days. The overall 3-month rejection rate was 7.5% in Group C0 vs. 10.8% in Group C2 and the one-year graft survival rates were 92.5% vs. 94.6% (NS). Rate of delayed graft function was similar in the groups. Plasma creatinine tended to be higher in group C2 at 3 weeks, but not thereafter. During the first three weeks posttransplant, the mean CsA dose was 57%, mean C2 levels were 55%, and mean C0 levels were 98% higher in group C2 than in group C0 (P < 0.00001). This pilot study showed no advantages of C2 monitoring but led to significantly higher CsA doses and blood levels than C0 monitoring.

Cyclosporine drug monitoring with C0 and C2 concentrations in children with stable renal allograft function

Cyclosporin A (CsA) has a narrow therapeutic window and necessitates monitoring of blood concentration. We aimed to evaluate trough (C0) and second hour (C2) level after ingestion of drug monitoring in renal allograft recipients. In this retrospective study, 12 children eight boys and four girls; mean age at transplantation 14.6 +/- 3.7 yr (ranges: 7.0-19.0), mean age post-transplant 17.8 +/- 4.9 yr (ranges: 9.0-24.0) who were transplanted >6 months were enrolled in this evaluation. Ten were recipients of a living related donor and two deceased donor grafts. While six children were receiving CsA, steroids and azathioprine, the other six received CsA, steroids and mycophenolate mofetil. Clinical course, blood pressure, renal and liver function tests were recorded. Mean C0 and C2 were 96.2 +/- 59.5 and 504 +/- 305.4 ng/mL respectively. Mean serum creatinine level was 1.2 +/- 0.45 mg/dL and mean creatinine clearance (CrCl) was 89.2 +/- 36.8 mL/min/1.73 m2. There was a correlation between serum creatinine level, CsA dose and C2 levels,whereas,there was no correlation between age, blood pressure, CrCl and C2 levels. However, no correlation was found between C0 levels and any of the above parameters. In conclusion, our data suggest that C2 levels are correlated better with dose and serum creatinine level.

Effect of Obesity and Overweight on Cyclosporine Blood Levels and Renal Functions in Renal Adolescent Recipients

Introduction The impact of obesity, a frequent problem after renal transplantation, which has been associated with poor graft and patient survival, was evaluated on renal function and cyclosporine (CsA) blood levels. Patients We retrospectively evaluated the data of adolescent renal recipients between 1994 and 2004. Patients with serum creatinine ≥ 2.5 mg/dL were excluded. We grouped the data with regard to the body mass index (BMI) percentiles as group I (BMI > 95th), group II (BMI < 95th), group III (BMI > 85th), group IV (BMI < 85th). We compared the clinical and laboratory findings between groups I and II and between groups III and IV. Results We evaluated 778 visits of 27 patients (M/F: 19/8). There were 30 visits in the obesity period (group I) and 72 visits after the overweight periods were added (group III). Serum creatinine levels were significantly higher and glomerular filtration rate levels significantly lower among obese and/or overweight than lean periods ( P < .05). Proteinuria levels were similar in groups I and II, but significantly higher in group III than group IV ( P = .356 and .000, respectively). CsA mg/bw, CsA mg/bmi, and CsA mg/bsa levels were significantly lower in group I than group II and in group III than group IV ( P < .05), while C0 and C2 levels were similar ( P > .05). Conclusion Weight gain is associated with worse renal functions but not greater proteinuria in our patients. Smaller CsA doses were sufficient to maintain C0 and C2 levels similar to the lean patients, results that were parallel to those of adult renal recipients.

Abnormal liver enzymes 2-3 months after liver transplantation in a patient with hepatitis C: Report of a case

A 50-year-old man, paraplegic from a motor vehicle accident in 1973, contracted hepatitis C virus (HCV) through multiple blood transfusions at the time of his severe injuries relating to his accident. He was diagnosed with HCV when he sought care for fatigue in 2003. In August 2004, he developed ascites and peripheral edema and was treated locally for several months. He had no variceal bleeding, no encephalopathy, and no other evidence of decompensated liver disease. He was otherwise healthy. He had never smoked and only drank 1-2 alcoholic beverages at a time every 4-8 weeks. He was an active individual who used a manual wheelchair, performed mechanical work with moderate lifting, and drove all-terrain vehicles. He was listed for a liver transplant in May 2005. He was a blood group A and was stable on diuretics and sodium restriction, with no other evidence of further decompensation through his follow-up on the waiting list. On October 17, 2005, the patient underwent a cadaveric liver transplantation without major complications. His preoperative Model for End-Stage Liver Disease score was 15. Both the donor and recipient were negative for cytomegalovirus. A duct-to-duct anastomosis was performed. The immunosuppression protocol at our institution consists of basiliximab 20 mg intraoperatively, then repeated on day 4 of the postoperative course; cyclosporine A (CyA) intravenously, changed to oral administration when the patient is eating well with a goal of cyclosporine blood level 2 hours after dose (C2) between 1000 to 1200 g/L; and mycophenolate mofetil (MMF) started when eating well. Corticosteroids are not used to treat our patients with hepatitis B and C. This patient received intravenous CyA for 4 days, and changed to oral dose on day 5. At that time, he also initiated MMF treatment. He spent a total of 3 uneventful days in the intensive care unit and was transferred to the ward. Postoperatively, his transaminases peaked on day 2 with an alanine aminotransferase (ALT) 1646 U/L (normal [N] 54) and an aspartate aminotransferase (AST) 1358 U/L (N 41). His bilirubin peaked on day 5 at 105 mol/L (6.2 mg/dL), as did his alkaline phosphatase (AP) at 208 U/L (N 92) and his gammaglutamyl transferase (GGT) at 239 U/L (N 50). The only complications throughout his postoperative course were mild fluid overload during early postoperative days 2-5, which was easily managed with diuretics; a urinary tract infection; and a superficial heel ulcer. His renal function remained stable throughout his posttransplantation course. His transaminases normalized by day 13 after transplant (ALT 18 U/L, AST 24 U/L; Table 1). At that time, his bilirubin continued to be mildly abnormal at 68 mol/L (4 mg/dL) and his alkaline phosphatase 129 U/L, but he steadily improved over the next few weeks. His creatinine was 60-90 mol/L (0.8-1 mg/ dL) and CyA C2 levels were 1000-1500 g/L. He was discharged from the hospital on November 9, 2005, with cyclosporine 450 mg twice a day (bid), MMF 1 g bid, acyclovir 400 mg bid, dapsone 100 mg daily, aspirin, and Prilosec 20 mg daily. On November 30, 2005 (1 month after transplantation), he underwent blood work, the results of which were as follows: ALT 222 U/L, AST 112 U/L, AP 97 U/L, GGT 48 U/L, bilirubin 29 mol/L, and CyA 1800-2300 g/L. Doppler ultrasonography revealed nothing abnormal. His CyA and MMF doses were decreased, and his liver biochemistry improved over the next few weeks to the following: ALT 153 U/L, AST 65 U/L, AP 91 U/L, GGT 39 U/L, and bilirubin 22 mol/L (1.3 mg/dL). On December 28, 2005 (2 months after transplanta-

Association Between Cyclosporine Concentrations at 2 Hours Post-dose and Clinical Outcomes in De Novo Lung Transplant Recipients

The objective of this study was to investigate the relationship between cyclosporine (CsA) pharmacokinetic parameters and clinical outcomes after lung transplantation. Data from 48 lung or heart/lung transplant recipients originally recruited to a randomized, prospective clinical trial of Sandimmune vs Neoral and followed for 12 months were included in this study. CsA dosing was based on the trough concentration. CsA concentrations at 0 (C0), 2 (C2), and 6 (C6) hours post-dosing were obtained at 1, 2, 3, 4, 13, 26, 39, and 52 post-operative weeks. Based on their average C2 levels in the first post-transplant month, patients were stratified retrospectively into Low C2 (<1,000 microg/liter, n = 18), Intermediate C2 (1,000-1,500 microg/liter, n = 16) and High C2 (>1,500 microg/liter, n = 14) Groups. Cyclosporine C2 was the best single-point determinant (r2 = 0.934) for area-under-the-concentration-time curve (AUC(0-6 hours)) compared with C0 (r2 = 0.267) or C6 (r2 = 0.304). The mean +/- SD values of CsA C2 and AUC(0 to 6 hours) in the first year post-transplant were significantly lower in patients with >2 rejection episodes compared with those with < or =2 rejection episodes (C2: 875 +/- 546 microg/liter vs 1,114 +/- 633 microg/liter, p = 0.01; AUC(0-6 hours): 4,036 +/- 1,904 microg x hour/liter vs 4,870 +/- 2,182 microg x hour/liter; p = 0.01) whereas C0 and C6 did not differ. Patients in the Intermediate C2 Group were free from rejection episodes for a significantly longer duration (p < 0.001) and had significantly higher predicted forced expiratory volume in 1 second (%) values (p < 0.001) compared with the Low and High C2 Groups. The percentage of increase in serum creatinine concentration by the end of first month post-transplant was significantly higher in the Intermediate C2 Group (p < 0.003). CsA C2 concentrations correlated better with the incidence of multiple rejections after lung transplantation than did C0 or C6. C2 concentrations between 1,000 and 1,500 microg/liter within the first post-operative month may be associated with better graft outcomes and improved pulmonary function and worsened renal function.

Comparison of Cyclosporine Concentrations 2 Hours Post-Dose Determined Using 3 Different Methods and Trough Level in Pediatric Renal Transplantation

Immunosuppression has been one of the great challenges in pediatric recipients of kidney allografts. Cyclosporine (CsA) has evolved during the past 25 years of transplantation. It requires frequent blood level monitoring because of its narrow therapeutic window and interpatient and intrapatient variability. Neoral (Novartis) is no exception. Ideally, monitoring of blood levels should also include determination of the area under the time-concentration curve (AUC) to better target the therapeutic window, thus avoiding underdosing or overdosing, especially in pediatric patients. A single blood concentration measurement 2 hours after Neoral administration (C2) has been shown to be a more for accurate predictor of drug exposure than trough levels (C0). Therefore, its use may lead to reduction in the incidence and severity of cellular rejection and of CsA toxicity. Some studies have shown that the metabolites/CsA ratio is substantially lower using C2 than C0, however, the between-assay differences for C2 monitoring have not been considered. The purpose of this study was to evaluate CsA C0 and C2 levels, determined using monoclonal fluorescence polarization immunoassay (FPIA)/TDx and enzyme multiplied immunoassay (EMIT). CsA levels were determined using a radioimmunoassay (RIA) in 30 pediatric transplant recipients with stable renal function within 42.7 mean months follow-up. Mean age was 13.4 years; 15 children were girls; 23 patients were recipients of cadaveric kidneys. The mean CsA microemulsion dose was 5.7 mg/kg/d. The 3 methods showed a high correlation between C0 and C2 ( r ≥ 0.97). A linear regression slope was significantly higher for C0 than C2 ( P < .001). The CsA concentrations both at C0 and C2 were significantly higher with FPIA than with RIA ( P < .009) but no differences were found for EMITT ( P = .2). The mean C0 level for FPIA was 22% and 26% higher than RIA and EMIT, respectively. The mean C2, for FPIA was 7% and 12% higher than RIA and EMIT, respectively. In conclusion, CsA levels determined using RIA or EMIT are better than using FPIA/Tx; also, C2 CsA levels are more accurate than C0 in pediatric transplantation patients.

A Multicenter, Prospective Study of C2-Monitored Cyclosporine Microemulsion in a U.S. Population of De Novo Renal Transplant Recipients

Monitoring cyclosporine microemulsion (CsA-ME; Neoral) exposure 2 hours postdose (C2) has been reported to optimize the efficacy and safety of CsA-ME therapy. The addition of induction therapy to a maintenance regimen including CsA-ME C2 monitoring has not been evaluated. In all, 123 adult renal transplant recipients were recruited at 14 U.S. centers for this 6-month study. CsA-ME dose was to be titrated to attain C2 targets of 1700 and 1500 ng/ml during posttransplant months 1 and 2, respectively. After 2 months, patients were randomized to one of two groups with different, decreasing C2 targets. Basiliximab, mycophenolate mofetil, and corticosteroids completed the study immunosuppression. Of the 119 evaluable patients, 76% were male, 22% African American, and 66% deceased donor recipients. Biopsy-proven acute rejection occurred in 10 patients (9.3%); there were two failed grafts and one death. Serum creatinine and calculated GFR values suggest good renal function, with month 6 medians of 1.5 ng/ml and 67 ml/min/1.73 m. Safety and tolerability assessments revealed no unexpected outcomes. Observed C2 levels were generally lower than protocol targets, particularly in the first weeks posttransplantation. The striking efficacy and outcomes may have been achieved in this study with lower C2 levels of CsA-ME because of the addition of basiliximab induction.

Clinical outcome after cyclosporine dose reduction based on C2 levels in long-term liver transplant patients

Recent studies suggest that cyclosporine dose adjustment based on C2 levels results in improvement of renal function. This study investigates the effect on renal function after dose reduction based on the C2 levels in long-term liver transplant patients. In 60 patients (>1 yr after transplantation), C2 levels were assessed (target 600 ng/mL +/- 20%). Dose reduction was performed when C2 >720 ng/mL. Serum creatinine concentrations were measured and creatinine clearance was calculated. Twenty-three patients (38%) had C2 values >720 ng/mL. After dose reduction, mean cyclosporine dose decreased by 25% (p < 0.01). Mean C2 value decreased by 42% (p < 0.01). Serum creatinine concentrations remained stable. After dose reduction two patients experienced recurrence of PBC, in one patient AIH recurred and rejection was diagnosed in one patient. Cyclosporine C2 concentrations above 720 ng/mL are common in long-term liver transplant patients. Dose reduction of 25% did not improve kidney function and was accompanied by immune activation.

Standardization of a dilution method for cyclosporin (C2) estimation in renal transplant patients

Accurate monitoring of blood cyclosporin C2 levels is vital to prevent over immunosuppression and acute renal toxicity in patients who receive organ transplant. The matrix used to dilute patients' C2 samples prior to the assay affected the final measured values. Hence there was a need to develop a method of dilution that would accurately estimate C2 levels when cyclosporin levels were beyond the calibration range of the method employed. Whole blood, cyclosporin free hemolysate and cell and protein free supernatant obtained after pretreatment of normal blood were used to dilute patients' C2 samples. C2 was measured in 188 patients using the supernatant method of dilution. C2 was correlated with Co and dose of cyclosporin received by the patient. The use of cell and protein free supernatant obtained after pretreatment of normal blood as a C2 diluent detected higher levels of C2 in the sample. Measured C2 correlated significantly with Co and the cyclosporin dose received by the patient. The uniformly aqueous cell and protein free supernatant ensures uniform dilution of the patients' C2 sample and measures higher cyclosporin levels.

Cyclosporine dose reduction in stable renal transplant patients with high C2 level: simplified method of single C2 measurement and individualization of C0 target

It is recommended that cyclosporine dosing should be based on the whole blood level 2 h after a dose (C2), not the trough level (C0). Initial studies did not however establish the outcome of dosing according to C2 levels in long-term patients previously managed by C0 levels. C0 and C2 were measured in 152 stable patients receiving Neoral therapy, mean 86.9 months after transplantation. This showed that 38 (25%) had C2 levels above a target range of 700-900 microg/l. Higher C2 levels were associated with higher cholesterol levels (P = 0.0058) and higher diastolic blood pressure (P = 0.0163). Cyclosporine dose reduction was undertaken in 32 patients with high C2 levels. For logistical reasons, C2 was not performed regularly, but an individualized C0 level was set for each patient. A 16% reduction in mean cyclosporine dose was achieved, associated with a 28% fall in mean C0, from 212 to 153 microg/l, and a 25% fall in mean C2, from 1075 to 820 microg/l. There was no excess in adverse events in the dose reduction cohort, compared with patients with initial C2 levels <900 microg/l. Over a mean 15 month follow-up period in the dose reduction cohort, there was a 4.4% reduction in mean diastolic blood pressure, from 84.9 (SEM 2.1) to 80.2 (1.9) mmHg, P = 0.023; and a 10.4% reduction in mean cholesterol, from 5.71 (0.27) to 5.11 (0.25), P = 0.005 (patients starting on statin during follow-up excluded). In patients with initial C2 <900 microg/l, blood pressure did not fall and the cholesterol fell by 3.9%, from 5.27 (0.14) to 5.07 (0.15) mmol/l (P = 0.0405). In conclusion, cyclosporine dose reduction was safe in stable long-term renal allograft recipients with high C2 levels. There was an improvement cholesterol levels and a small improvement in blood pressure after cyclosporine dose reduction.

Vertebral Artery Laceration Mimicking Elder Abuse

Elder abuse was first described almost 30 years ago. Today, approximately 1 in 25 elders is abused each year in the United States. A newly described form of domestic violence, the incidence of elder abuse will surely increase as the elderly population grows. Physical abuse/inflicted trauma is generally considered the most extreme form of elder mistreatment and includes blunt trauma, sexual assault, traumatic alopecia, and burns. Elder homicide is usually due to gunshot wounds, blunt trauma, stab wounds, or asphyxia. However, the difficult aspect of assessing the possible elder abuse homicide victim is delineating such inflicted trauma from accidental trauma. We report the case of a 94-year-old "demented" male, who reportedly fell out of his wheelchair. He was transported to a local emergency room, where he became unresponsive during examination. He experienced respiratory distress and was pronounced dead shortly thereafter. At autopsy, he had periorbital contusions and a midline abrasion between the eyes, with underlying supraorbital contusion. The skull, brain, and spinal cord were unremarkable for signs of trauma. The major traumatic finding was in the neck region. Neck dissection revealed hemorrhage extending from the base of the skull to the level of T-1 and anteriorly about the soft tissues, strap muscles, and vasculature. The strap muscles were individually examined and were free of hemorrhage. The carotid arteries and jugular veins were unremarkable. The larynx, hyoid, and thyroid were intact, with only surrounding hemorrhage. Further examination revealed a horizontal fracture of the C5 vertebral body and a medial laceration of the left vertebral artery at the C5 level; subarachnoid hemorrhage was absent. What initially appeared to be trauma to the neck, worrisome for strangulation or blunt force trauma, was a large retropharyngeal hematoma from the left vertebral artery laceration. Traumatic rupture of the vertebral artery usually occurs at the C1 and C2 levels, with resultant subarachnoid hemorrhage. This is an especially vulnerable location since it is where the artery turns and then enters the skull. Associated injuries include spinal cord transection or contusion, brachial plexus injury, pharyngoesophageal injury, and vertebral fractures. Retropharyngeal hemorrhage may result from deep neck infection, tumor, and trauma. Hemorrhage associated with trauma often involves flexion of the cervical spine, followed by hyperextension. The accumulation of blood slowly impinges on the pharynx/larynx and vasculature structures. The exact injuries and etiology of the hemorrhage must be determined to distinguish strangulation from blunt force trauma. The presentation of signs and symptoms can be helpful in assessing the decedent; however, in the practice of forensic pathology such a history is more often lacking.

Preprandial C2 monitoring of cyclosporine treatment in children with nephrotic syndrome

Sirs, We read with great interest the article by Rinaldi et al. [1] regarding cyclosporin (CsA) monitoring by use of abbreviated area under the curve (AUC) in nephrotic syndrome (NS). Although dose monitoring based on CsA trough levels (C0) has been widely used, it has been reported to be poor predictor of clinical outcome [2]. Recently, monitoring of 2-h post-dose CsA levels (C2) has been reported to be useful in adult transplant recipients [3], although the best way to monitor the blood levels remains unclear in children. Rinaldi et al. stated that mean CsA blood levels correlate with AUC better than C0 or C2 levels [1]. Though abbreviated AUC using this measure may be helpful in children with long-lasting NS and result in a low incidence and less toxicity, it is impractical to collect several blood samples and is more expensive. We are currently investigating the usefulness of single measurement of blood concentration 2 h after preprandial CsA (Neoral oral formulation, Novartis) administration. So far, 12 children (mean age 9.6 years) with steroiddependent (N=8) or steroid-resistant NS (N=4) in remission were enrolled in the study. Renal biopsy was performed on all patients before commencement of CsA treatment; this revealed minimal change disease in 11, focal segmental glomerulosclerosis in 1. CsA level had been initially monitored by C0 level for 6 months (C0 period) and subsequently converted to C2 level (6 months: C2 period). Oral dose of CsA was started from 2.5–5 mg kg 1 daily in two divided doses and was adjusted to target levels: C0 of 50–100 ng mL 1 by postprandial administration and C2 of 400–600 ng mL 1 by preprandial administration. It is postulated that high variability of intra-individual or inter-individual CsA blood level during the absorption phase [4] results in low reproducibility. Therefore, we used preprandial C2 level for monitoring because this may improve the variability [5]. With regard to steroids during the study period, predonisone (PSL) was used only until achieving remission when patients relapsed: then it was tapered off over 3 to 6 months. Clinical and laboratory data during the study period are summarized in Table 1: whereas the average number of relapses was not significantly different between the C0 period and the C2 period, the mean dose of CsA in the C2 period was significantly lower than that in C0 period (P<0.01) and the mean dose of PSL in the C2 period was nearly two-thirds that in C0 period. Because clearance of CsA is more rapid in children than in adults [6], C0 might be lower than the corresponding AUC, resulting in a larger dose of CsA. Taken together, we believe that CsA monitoring using the preprandial C2 level is closer to the AUC than that using C0, and is more simple and less expensive than that of mean concentrations. S. Fujinaga ()) · M. Takada · Y. Ohtomo · S. Akashi Division of Nephrology, Saitama Children’s Medical Center, Shuichiro 2100, Magome Iwatsuki City, Saitama 339, 8551 Iwatsuki, Japan e-mail: f_shuich@d2.dion.ne.jp Tel.: +81-48-758-1811 Fax: +81-48-758-1818

Monitoring of Cyclosporine 2-Hour Post-Dose Levels in Heart Transplantation: Improvement in Clinical Outcomes

Cyclosporine 2-hour post-dose (C2) monitoring is predictive of outcomes in solid-organ transplants. The purpose of this study was to determine C2 levels at various time points after heart transplantation and determine whether trough (C0) or C2 better predicts clinical outcomes. This was a 2-phase prospective study with paired determinations of cyclosporine levels at C0 and C2 in 58 heart transplant patients (46 men; mean age, 56 years). Phase I (6-month follow-up): cyclosporine monitored according to C0 levels (C2 blinded). Phase II (6-month follow-up): cyclosporine monitored according to C2 levels (C0 blinded). Clinical outcomes assessed were severe infections, rejection score, and renal dysfunction. No differences were observed in renal function between the phases. In Phase I, 8 infections (4 severe) and in Phase II, 6 infections (2 severe) were detected. During Phase I, the C0 levels did not correlate (p = .96) with the presence (195 +/- 121 ng/ml) or not (197 +/- 100 ng/ml) of rejection. During Phase II, C0 levels did not correlate (p = .88) with the presence (204 +/- 85 ng/ml) or not (209 +/- 138 ng/ml) of rejection. During Phase I, C2 levels did correlate (p = 0.022) with the presence (777 +/- 326 ng/ml) or not (1,015 +/- 422 ng/ml) of rejection. During Phase II, higher C2 levels showed a significant correlation (p = 0.03) with no rejection (967 +/- 470 ng/ml vs 765 +/- 297 ng/ml, no rejection vs rejection, respectively). High C2 levels were associated with less episodes of acute cellular rejection in patients post-heart transplantation. Monitoring with C2 levels is feasible and safe in terms of preservation of renal function and infection rates.

Best Single Time Points to Predict the Area-Under-the-Curve in Long-Term Heart Transplant Patients Taking Mycophenolate Mofetil in Combination with Cyclosporine or Tacrolimus

The use of C2 levels for therapeutic drug monitoring (TDM) of cyclosporine microemulsion (CsA) has been clinically validated. Routine TDM of tacrolimus and mycophenolate mofetil (MMF) is based on trough (C0) levels and side effects, respectively. The purpose of the present study was to determine the best single time points to assess the area-under-the-curve (AUC(0-12 hours)) in long-term heart transplant patients being treated with MMF in combination with CsA or tacrolimus. We studied the AUC(0-12 hours) in long-term (>1 year), adult heart transplant patients being treated with CsA and MMF (14 patients) and with tacrolimus and MMF (9 patients). C2 is the best surrogate (r2 = 0.87) of CsA AUC(0-12 hours). Tacrolimus C1 (r2 = 0.78), C2 (r2 = 0.83), C3 (r2 = 0.89) and C4 (r2 = 0.92) correlate better than C0 (r2 = 0.51) with the AUC(0-12 hours). When MMF is combined with CsA, there is poor correlation (r2) of MPA at all measured time points (C0 = 0.49, C2 = 0.09, C3 = 0.23, C4 = 0.44, and C6 = 0.60). When MMF is combined with tacrolimus, MPA C2 (r2 = 0.72), C4 (r2 = 0.86), C6 (r2 = 0.85), and C8 (r2 = 0.93) are better surrogates of the AUC(0-12 hours) compared with C0 (r2 = 0.69). Our results suggest that in long-term heart transplant patients, the calcineurin inhibitor used in combination with MMF affects the correlation between MPA single time points and the AUC(0-12 hours). Future studies should determine the clinical benefit of TDM of tacrolimus and MPA with C2 or C4 compared with C0 and determine the therapeutic ranges. As for CsA-treated patients, CsA TDM should be performed with C2, and the TDM of MMF may be clinically irrelevant.

Clinical outcomes and C2 cyclosporin monitoring in maintenance renal transplant recipients: 1 year follow-up study

Cyclosporin A (CsA) concentration monitoring with 2 h post-dosing levels (C2) correlates with the incidence of rejection and graft outcome in de novo renal transplant patients. The advantages of this policy beyond the first 12 months remain a matter of debate. The purpose of the present work was to evaluate the C2 target ranges on CsA monitoring after the first year in stable kidney transplant patients. We studied 142 patients, 94 on CsA-steroids and 48 on triple therapy (CsA-azathioprin-steroids), transplanted for 104+/-42 months and with a serum creatinine of 1.53+/-0.52 mg/dl. C2 and C0 measurements were performed at baseline and at least twice more during the year of follow-up. The mean annual C2 blood levels in double therapy patients showed C2 in 23 (24.5%) of <600 ng/ml; in 53 (56.4%) of between 600 and 850 ng/ml; and in 18 patients (19.1%) of >850 ng/ml. In the triple therapy group, C2 in 12 (25%) was <500 ng/ml, in 24 (50%) between 500 and 700 ng/ml and in 12 patients (25%) >700 ng/ml. In both groups, higher C2 levels were associated with a better absorption of the drug measured by the ratio C2/C0 and C2/dose. There were no differences in incidence of infections, need for hospitalization and the presence of hypertension, hyperuricaemia, hypercholesterolaemia or diabetes between patients with low and high C2 blood levels. However, serum creatinine was higher in triple therapy patients with lower C0 levels (P = 0.004). In 135 patients (90 on double and 45 on triple therapy), renal function remained stable during follow-up and 120 of them (89%) had C2 values under the recommended ranges. C2 monitoring in maintenance patients enabled us to identify overexposure to CsA. Target levels of C2 should be adjusted according to the immunosuppressive regime. C2 levels between 600 and 800 ng/ml in double therapy patients and between 500 and 700 ng/ml in triple therapy patients are sufficient to give an adequate immunosuppression. The superiority of C2 with respect to C0 levels could not be demonstrated.

The V-Twin system (Dade Behring Laboratories): A useful tool for immunosuppressive drug monitoring

The predose trough cyclosporine (CsA) level (C0) was widely used to assess the possibility of drug nephrotoxicity. Owing to its potential limitation as an indicator of total drug exposure, 2-hour postdose (C2) monitoring has been considered to be a more accurate marker. The V-Twin analyzer (Vital SC, Netherlands) conceived for EMIT technologies (Dade Behring Laboratories) is proposed herein to determine CsA levels using a specific calibrator without any dilution, as well as tacrolimus (FK) and mycophenolate mofetil (MMF) levels. Both CsA (C0: n = 133 and C2: n = 55) and FK (n = 121) EMIT assays were compared to the RIA CsA assay (DiaSorin Laboratory) and to the MEIA tacrolimus assay (Abbott Laboratory), respectively. In addition, the feasibility of MMF EMIT assay was evaluated. Overall, 309 transplant patients were included in this study. For all parameters tested, total imprecision studies were lower than 10%, and the coefficient of linearity was r 2 > .99. For the CsA kit, the range of linearity was between 25 and 500 ng/mL for the C0 and 400 and 2000 ng/mL for the C2 assay. The values obtained were highly correlated with the RIA for the C0 levels (EMIT = 0.9 RIA+3.66; r = .97) and for the C2 levels (EMIT = 0.89 RIA-14.2; r = .956). Similar results were obtained with the EK EMIT kit, with a linearity range between 3 and 30 ng/mL, and a high concordance with the MEIA test (EMIT = 0.98 RIA+1.09; r = .96). Preliminary MMF results in 59 sera, containing from 0.1 to 30 μg/mL, showed that this examination could be included as a routine. The V-twin system is a useful tool for routine monitoring with a single method for C0 and C2 cyclosporine, tacrolimus, and mycophenolate levels.

C2 is superior to C0 as predictor of renal toxicity and rejection risk profile in stable heart transplant recipients

To assess whether cyclosporine A (CsA) 2-h peak (C2) is superior to trough levels (C0) for Neoral dose monitoring in heart transplantation (HT), we studied 928 C0-C2 paired determinations from 313 stable HT patients (257 male, aged 50 +/- 14 years at HT, follow-up 6.9 +/- 4 years), on a C0-based regimen. Our target C0 levels (ng/ml) were 150-400 (first 3 months), 150-300 (4-12 months), 100-250 (>12 months). Mean C0 and C2 levels were 268 +/- 80 and 1031 +/- 386, respectively (first 3 months); 230 +/- 49 and 955 +/- 239 (4-12 months); 157 +/- 53 and 745 +/- 236 (>12 months). For patients within the target C0, the corresponding C2 were 600-1500 (first 3 months), 600-1300 (4-12 months), 400-1100 (>12 months). C2 correlated with C0 (r = 0.64, P = 0.0001). C2 correlated better with CsA dose than C0 (r = 0.41, P = 0.0001 vs. r = 0.33, P = 0.0001). Between patients, CsA dose varied by a factor of 9.3; the C/dose ratio varied by a factor of 8.5 for C2 and of 15.6 for C0. Patients with higher C2 (>740) had higher severe rejection score at 2 years (P = 0.02) than patients with lower C2. This did not apply to C0. Both C2 and C0 correlated with blood urea (r = -0.18, P = 0.0001; r = -0.12, P = 0.0002) and creatinine (r = -0.19, P = 0.0004; r = -0.19, P = 0.0001 respectively). By logistic regression higher C2 (>740) was associated with higher total severe rejection score at 2 years (P = 0.006). C2 showed better correlation with CsA dose, renal function, rejection profile and less variability between patients than C0. C2 may improve CsA-based immunosuppression in HT.

Comparison Between C0 And C2 Monitoring in De Novo Renal Transplant Recipients: Retrospective Analysis of a Single-Center Experience

Monitoring immunosuppression with cyclosporine microemulsion formulation (CsA-MEF) by using 2-hour CsA blood levels (C2) has been strongly recommended after kidney transplantation. The aim of our study was to evaluate the impact of C2 monitoring on the clinical outcome early after transplantation in a single-center setting. Nonsensitized, consecutive, de novo cadaveric kidney-transplant recipients were treated with CsA-MEF, mycophenolate mofetil, and steroids. Patients receiving transplants after January 2002 (n=89) were prospectively monitored by C2 levels (target: 1,500+/-200 ng/mL [fluorescence-polarization immunoassay]). They were retrospectively compared with the patients receiving transplants during 2001 (n=88) who had been monitored by C0 levels (target: 250+/-50 ng/mL). In the intention-to-treat analysis, 40 (45.4%) patients in the C0 group and 25 (28.1%) patients in the C2 group received treatment for rejection (P=0.017). The incidence of histologically verified rejection of Banff grade I or higher was 20.45% in the C0 group and 13.48% in the C2 group (P=0.235). In the per-protocol analysis, incidence of treated rejection was 24.7%, and incidence of histologically verified rejection of Banff grade I or higher was 12.35% in the C2 group (P=0.004 and 0.160, respectively, vs. C0). Mean CsA-MEF doses were 1.7 to 2 times higher in the C2 group than in the C0 group throughout follow-up (P=0.019). In the C2 group, target C2 levels were achieved on average 4 days after transplantation, and there was no significant difference in C2 levels between patients who rejected and patients who did not reject. Kidney-transplant recipients monitored by C2 levels receive significantly higher doses of CsA-MEF and have a lower incidence of early acute allograft rejection than patients monitored by C0 levels. In C2 monitored patients, C2 levels are not predictive for the incidence of early allograft rejection.

C2 is an age-independent parameter for optimal cyclosporine exposure in long-term kidney transplant recipients

The argument for therapeutic drug monitoring (TDM) of cyclosporine (Cya) has been discussed for the last two decades. So far, a generalized consensus has been reached for TDM of Cya microemulsion in adult transplant recipients, being Cya blood levels obtained 2 hours after the administration (C2), the most reliable in reflecting the overall Cya exposure. However, clear guidelines are not available for the pediatric population because of the distinct metabolism of the drug in this patient population. Therefore, adult data do not necessarily apply to children. In this retrospective analysis, the authors sought to define a universal parameter for pharmacokinetic clinical monitoring of Cya in long-term kidney transplant recipients, regardless of their age. Lower C2 levels were observed in all patients, adult and pediatric, who eventually developed chronic allograft dysfunction (CRAD) compared with patients who maintained stable kidney function throughout the entire follow-up (pediatric CRAD, 933 ± 455 ng/mL; vs Stable, 1236 ± 347 ng/mL, P = .0001; and adult CRAD, 781 ± 518 ng/mL; vs Stable, 1088 ± 452 ng/mL, P = .009). On the other hand, the risk of Cya underexposure was not highlighted by trough level monitoring (C0) because all patients have been maintained steadily on therapeutical C0 levels for the entire follow-up. In conclusion, for Cya maintenance therapy, C2 appears to be a superior strategy to C0 monitoring in both adult and pediatric kidney transplant recipients

Cyclosporine Minimization and Cost Reduction in Renal Transplant Recipients Receiving a C2-Monitored, Cyclosporine-Based Quadruple Immunosuppressive Regimen

Targeting 2-hr postdose cyclosporine (C2) levels to 1,000 to 1,700 mg/dL during the first 6 months after renal transplantation is recommended for triple immunosuppressive regimens. This trial determines whether lower C2 levels could be targeted safely in de novo kidney transplant recipients under a quadruple regimen compared with a similar cohort monitored with trough (C0) levels. This single-center, sequential, cohort-designed trial included patients who received Thymoglobulin, corticosteroids, an antimetabolite, and cyclosporine monitored by C2 (n=50) or C0 (n=50). Cyclosporine was tapered to maintain the C2 between 1,000 and 1,200 ng/mL months 0 to 3 and between 600 and 1,000 ng/mL thereafter and C0 between 250 and 350 ng/mL months 0 to 3 and between 100 and 250 ng/mL thereafter. Baseline patient and donor characteristics were similar. There were no differences in graft survival (100% C2 vs. 100% C0), acute rejection (4% C2 vs. 6% C0), allograft function, or adverse events at 6 months. C2 levels were lower than the suggested guidelines throughout the study (33% lower at 1 month and 48% lower at 6 months). Lower cyclosporine doses were achieved in the C2 arm compared with the C0 arm by 1 month and were sustained throughout the trial, which translated into an average cyclosporine cost savings of USD $773 in the C2 arm during the 6-month period (P<0.001). With a quadruple immunosuppressive regimen and lower C2 targets than recommended for triple therapy, safe and effective cyclosporine minimization was achieved. Lower cyclosporine doses were achieved in C2-monitored patients compared with C0-monitored patients, translating into lower immunosuppressive costs.