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A liquid chromatography/tandem mass spectrometry (HPLC–MS/MS) method was validated for the quantification of Sotrastaurin (AEB071) and N-desmethyl-sotrastaurin in human blood. The validation of the analytical procedure was performed according to the latest Food and Drug Administration (FDA) “Guidance for Industry, Bioanalytical Method Validation”. Chromatographic separation was performed using an RP C 18 (50 mm × 4.6 mm, 5 μm) column at 40 ± 3.0 °C with a mobile phase consisted of 2 mM ammonium acetate in water (pH 4.5):methanol:acetonitrile (25:15:60, v/v) of a flow rate of 1 mL/min followed by quantification with tandem mass spectrometer, operated in electrospray ionization (ESI) positive ion mode and applying multiple reaction monitoring (MRM). The validated method described in this paper presents high absolute recovery, with a sensitivity of 3.00 ng/mL as lower limit of quantitation using a sample volume of 300 μL, low inter-run bias and variability (for Sotrastaurin, −4.4 to 0.4% and 1.8 to 2.5% and for N-desmethyl-sotrastaurin, ranged from 1.6 to 2.3% and 2.7 to 3.9%, respectively) with a short runtime of 3.5 min. The method was validated using K 3 EDTA as specific anticoagulant and cross-validated using Li-Heparin and Na-Heparin. The method was specific for Sotrastaurin and N-desmethyl-sotrastaurin within the given criteria of acceptance (apparent peak area for Sotrastaurin and N-desmethyl-sotrastaurin in zero samples ≤20% of mean peak area at LLOQ) in human blood. The method was fully validated for the quantitative determination of Sotrastaurin and its metabolite N-desmethyl-sotrastaurin in human blood between the range of 3.00 ng/mL and 1200 ng/mL.

Oral fingolimod signals the sphingosine 1-phosphate receptor and this in turn mediates immunomodulatory activity. No data of fingolimod in any pediatric population existed before this study. We put our study results in perspective against data from adult renal transplant patients. We investigated pharmacokinetics and pharmacodynamics of single-dose fingolimod (0.07 mg/kg) and its effects on lymphocytes and heart rate in seven adolescents (14.1 ± 1.6 yr) with stable renal transplants. Blood samples for pharmacokinetics and lymphocytes were collected at screening, baseline, and up to 28 days post-dosing. Cardiac monitoring included 12-lead ECG, 24-h Holter monitoring, and echocardiography. A fingolimod dose of 0.07 mg/kg resulted in mean AUC of 731 ± 240 ng·h/mL and C(max) of 3.6 ± 0.6 ng/mL. Drug exposure was nearly identical to adults receiving the same dose. Absolute lymphocyte count decreased 85% from baseline; average nadir occurred by six h post-dose. Heart rate decreased from 74 bpm (predose mean) to 53 bpm (nadir) three h post-dose. Mean heart rates recovered by Day 14 (75 bpm). Weight-adjusted doses of fingolimod in adolescents resulted in drug exposure similar to adults. Adolescents and adults shared comparable negative chronotropic effects and decreased lymphocyte count. Recovery trajectories of these parameters back to baseline were similar between age groups.

BACKGROUND Sotrastaurin is a protein kinase C inhibitor in the development for prevention of organ rejection after renal transplantation. METHODS In a multicenter phase 2 trial, 216 de novo renal transplant recipients were randomized to mycophenolic acid (MPA) with standard-exposure tacrolimus (treatment A, n=74), 200 mg sotrastaurin twice daily with standard-exposure tacrolimus (treatment B, n=76), or 200 mg sotrastaurin twice daily with reduced-exposure tacrolimus (treatment C, n=66). After month 3, tacrolimus was replaced with MPA in arms B and C. The longitudinal pharmacokinetics of sotrastaurin and tacrolimus were prospectively evaluated through month 6. RESULTS Sotrastaurin predose drug concentration (C0) was 0.6±0.4 μg/mL and did not differ when combined with standard-exposure versus reduced-exposure tacrolimus (P=0.99) nor when tacrolimus was replaced by MPA (P=0.11). Sotrastaurin peak concentration was 1.6±0.6 μg/mL, and area under the drug concentration-time curve over a dosing interval (AUC) was 12.2±4.2 μg hr/mL. Intersubject variability in AUC was 27% and not significantly influenced by age (18-67 years), weight (47-121 kg), sex, or creatinine clearance (36-173 mL/min). Sotrastaurin C0 was positively correlated with AUC (r=0.62, P

BackgroundReducing nebulisation times for tobramycin solution for inhalation in cystic fibrosis (CF) may improve compliance.MethodsIn this single-dose, open-label, two-way crossover study, 13 subjects (7 CF, 6 healthy) were randomised to receive tobramycin via eFlow rapid or LC Plus jet nebuliser. Drug deposition in the lung using gamma scintigraphic imaging, nebulisation times, pharmacokinetics, and safety were evaluated.ResultsIn CF patients, whole-lung deposition was 40% less with the eFlow rapid compared with LC Plus nebulisers was (8.9±0.8%, and 15.1±6.0%, p>0.05). Nebulisation time was shorter with eFlow rapid compared to LC Plus (7.0min versus 20.0min, p

Summary Sotrastaurin is a protein kinase C inhibitor in development for prevention of rejection after liver transplantation. In a pharmacokinetic study, 13 de novo liver transplant recipients received 100 mg sotrastaurin once between days 1–3 and once between days 5–8 post-transplant. Sotrastaurin absorption based on the area under the concentration-time curve (AUC) of total drug in blood (3544 ± 1434 ng·h/ml) was similar to that of healthy subjects in a previous study (4531 ± 1650 ng·h/ml). However, the sotrastaurin binding protein, α1-acid glycoprotein, was nominally higher in patients (1.07 ± 0.28 vs. 0.87 ± 0.16 g/l, P = 0.13) yielding a 60% lower AUC based on free drug versus that in healthy subjects (27 ± 13 vs. 62 ± 15 ng·h/ml, P

INTRODUCTION Sotrastaurin is an immunosuppressant that blocks T-lymphocyte activation via protein kinase C inhibition. The authors determined whether a pharmacokinetic interaction occurs between sotrastaurin and everolimus, both of which are substrates and inhibitors of CYP3A4. METHODS This was a randomized, three-period, crossover study in 18 healthy subjects. They received single oral doses of (1) 100 mg sotrastaurin, (2) 2 mg everolimus, and (3) the drug combination. Clinical and pharmacokinetic data were collected to Day 5 after each treatment. RESULTS Coadministration of everolimus decreased sotrastaurin C(max) from 638 +/- 295 to 539 +/- 211 ng/ml yielding a combination/ monotherapy ratio (90% confidence interval) of 0.87 (0.76 - 1.00). Sotrastaurin total AUC was not altered by everolimus with values of 3660 +/- 1853 versus 3630 +/- 2006 ng*h/ml and a ratio of 1.00 (0.88 - 1.13). Sotrastaurin increased everolimus C(max) from 15 +/- 6 to 16 +/- 6 ng/ml yielding a ratio of 1.15 (0.99 - 1.33) and increased everolimus total AUC from 114 +/- 50 to 137 +/- 56 ng*h/ml yielding a ratio of 1.20 (1.05 - 1.37). The possibility that a higher dose of sotrastaurin than used in this study might further increase everolimus blood levels cannot be excluded. CONCLUSIONS Coadministration of a single 100 mg dose sotrastaurin with a single 2 mg dose everolimus did not alter sotrastaurin pharmacokinetics to a clinically relevant extent. Everolimus AUC was increased 20% by sotrastaurin.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT? • Sotrastaurin is an investigational protein kinase C inhibitor. This represents a new mechanism of action for immunosuppression to prevent acute rejection after organ transplantation. In vitro experiments indicate that sotrastaurin is a substrate of CYP3A4. WHAT THIS STUDY ADDS • This study provides clinical pharmacokinetic information to quantify the effect of the strong CYP3A4 inhibitor ketoconazole on sotrastaurin. The susceptibility of sotrastaurin to CYP3A4-related drug interactions is placed in the context of similar information about calcineurin inhibitors (tacrolimus, ciclosporin) and T-cell proliferation inhibitors (everolimus, sirolimus). AIMS Sotrastaurin is an immunosuppressant that reduces T-lymphocyte activation via protein kinase C inhibition. The effect of CYP3A4 inhibition by ketoconazole on the pharmacokinetics of sotrastaurin, a CYP3A4 substrate, was investigated. METHODS This was a two-period, single-sequence crossover study in 18 healthy subjects. They received a single 50 mg oral dose of sotrastaurin in period 1 followed by a 14-day inter-treatment phase. In period 2 they received ketoconazole 200 mg twice daily for 6 days and a single 50 mg dose of sotrastaurin on the fourth day of ketoconazole administration. RESULTS Co-administration of single-dose sotrastaurin during steady-state ketoconazole increased sotrastaurin Cmax by 2.5-fold (90% confidence interval 2.2, 2.9) from 285 ± 128 to 678 ± 189 ng ml−1 and increased AUC by 4.6-fold (4.1, 5.2) from 1666 ± 808 to 7378 ± 3011 ng ml−1 h. Sotrastaurin half-life was nearly doubled from 5.9 ± 1.7 to 10.6 ± 2.5 h. The AUC of the active metabolite N-desmethyl-sotrastaurin was increased by 6.8-fold. Sotrastaurin did not alter ketoconazole steady-state predose plasma concentrations. CONCLUSIONS The strong CYP3A4 inhibitor ketoconazole increased sotrastaurin AUC by 4.6-fold. A compensatory reduction in the dose of sotrastaurin is warranted when strong CYP3A4 inhibitors are co-administered.

PurposeTo use preclinical and clinical pharmacokinetic (PK)/pharmacodynamic (PD) modeling to predict optimal clinical regimens of everolimus, a novel oral mammalian target of rapamycin (mTOR) inhibitor, to carry forward to expanded phase I with tumor biopsy studies in cancer patients.Patients and MethodsInhibition of S6 kinase 1 (S6K1), a molecular marker of mTOR signaling, was selected for PD analysis in peripheral blood mononuclear cells (PBMCs) in a phase I clinical trial. PK and PD were measured up to 11 days after the fourth weekly dose. A PK/PD model was used to describe the relationship between everolimus concentrations and S6K1 inhibition in PBMCs of cancer patients and in PBMCs and tumors of everolimus-treated CA20948 pancreatic tumor-bearing rats.ResultsTime- and dose-dependent S6K1 inhibition was demonstrated in human PBMCs. In the rat model, a relationship was shown between S6K1 inhibition in tumors or PBMCs and antitumor effect. This allowed development of a direct-link PK/PD model that predicted PBMC S6K1 inhibition-time profiles in patients. Comparison of rat and human profiles simulated by the model suggested that a weekly 20- to 30-mg dose of everolimus would be associated with an antitumor effect in an everolimus-sensitive tumor and that daily administration would exert a greater effect than weekly administration at higher doses.ConclusionA direct-link PK/PD model predicting the time course of S6K1 inhibition during weekly and daily everolimus administration allowed extrapolation from preclinical studies and first clinical results to select optimal doses and regimens of everolimus to explore in future clinical trials.

PurposeTo identify the optimal regimen and dosage of the oral mammalian target of rapamycin inhibitor everolimus (RAD001).MethodsWe performed a dose-escalation study in advanced cancer patients administering oral everolimus 5 to 30 mg/wk, with pharmacokinetic (PK) and pharmacodynamic (PD) studies. PD data prompted investigation of 50 and 70 mg weekly and daily dosing at 5 and 10 mg.ResultsNinety-two patients were treated. Dose-limiting toxicity was seen in one patient each at 50 mg/wk (stomatitis and fatigue) and 10 mg/d (hyperglycemia); hence, the maximum-tolerated dose was not reached. S6 kinase 1 activity in peripheral-blood mononuclear cells was inhibited for at least 7 days at doses ≥ 20 mg/wk. Area under the curve increased proportional to dose, but maximum serum concentration increased less than proportionally at doses ≥ 20 mg/wk. Terminal half-life was 30 hours (range, 26 to 38 hours). Partial responses were observed in four patients, and 12 patients remained progression free for ≥ 6 months, including five of 10 patients with renal cell carcinoma.ConclusionEverolimus was satisfactorily tolerated at dosages up to 70 mg/wk and 10 mg/d with predictable PK. Antitumor activity and PD in tumors require further clinical investigation. Doses of 20 mg/wk and 5 mg/d are recommended as appropriate starting doses for these studies.

The sphingosine-1-phosphate receptor modulator fingolimod (FTY720) elicits a negative chronotropic effect at treatment initiation that attenuates thereafter. The authors determined whether isoproterenol can counteract this effect. In this randomized, crossover study, 14 healthy subjects received 5 infusions of isoproterenol (titrated to increase heart rate to 100-120 bpm) or intravenous placebo. The first infusion was 2 hours before and the other 4 infusions were between 3 and 6 hours after a 5-mg oral dose of fingolimod. Telemetry and pharmacokinetic data were collected for 24 hours. During isoproterenol infusion 1 (before fingolimod administration), heart rate was increased 80% from preinfusion 68 +/- 9 bpm to a maximum 122 +/- 15 bpm. Administration of fingolimod decreased heart rate from 73 +/- 11 bpm predose to a nadir of 57 +/- 8 bpm. The subsequent isoproterenol infusion 2 in the presence of fingolimod increased mean heart rate by 85% to a maximum 105 +/- 21 bpm. A 41% higher total isoproterenol dose was needed to increase heart rate to the target range with fingolimod (97 +/- 6 mcg) compared with isoproterenol alone (69 +/- 27 mcg). Isoproterenol infusions 3 to 5 had similar effects on heart rate as infusion 2. Fingolimod had no significant influence on blood pressure responses to isoproterenol. Isoproterenol did not alter the pharmacokinetics of fingolimod. The pure beta-agonist isoproterenol can reverse the heart rate reduction that occurs transiently after initiating fingolimod treatment.

OBJECTIVE The authors compared the pharmacokinetics and pharmacological effects of the immunomodulator fingolimod in healthy white and Asian subjects for potential ethnic differences. METHODS White and Asian (Japanese) healthy subjects were demographically matched for sex, age and weight. Subjects received single 1.25 mg doses of fingolimod (6 ethnic pairs), 2.5 mg (7 pairs), 5 mg (6 pairs) or 5 mg/day for 7 days (6 pairs). The pharmacokinetics of fingolimod, major metabolites, peripheral blood lymphocyte counts and heart rate were characterized over 1 month after single-dose and 2 months after multiple-dose administration. RESULTS There were no clinically relevant differences in the fingolimod dose Cmax or dose AUC relationships between Asian subjects (slopes 0.84 and 1.05) versus white subjects (slopes 1.13 and 1.26) after single-dose administration. During multiple-dose administration, there were no clinically relevant interethnic differences in fingolimod accumulation ratios (6.6 +/- 0.4 for whites, 7.0 +/- 0.7 for Asians), area under the concentration-time curve (390 +/- 73 versus 382 +/- 106 ng x h/ml), or elimination half-life (7.4 +/- 0.8 versus 7.9 +/- 2.0 days). The acute decrease in lymphocyte counts after single- and multiple-dose fingolimod were similar in the two ethnic groups. The lymphocyte recovery rate to baseline after a 5 mg single dose and 5 mg/day multiple dose was reduced by 36 and 15% in Asian subjects compared with white subjects. The transient, acute decrease in heart rate after the first dose of fingolimod and the subsequent return to baseline was similar in the two ethnic groups. CONCLUSION There were no marked differences between healthy white and Asian subjects in fingolimod single-dose and multiple-dose pharmacokinetics, lymphocyte trafficking and heart rate responses.

Objective. The pharmacokinetics and lymphocyte responses to the immunomodulator fingolimod (FTY720) were characterized after oral and intravenous administration. Methods. In this randomized, two-period crossover study 11 evaluable healthy subjects received single doses of fingolimod 1.25 mg orally and 1 mg intravenously infused over 2 h. The pharmacokinetics of fingolimod, blood lymphocyte counts and heart rate were characterized for 28 days after each dose. Results. After oral administration, Cmax was 1.1±0.2 ng/ml occurring at 12 h postdose and the AUC was 201±31 ng.h/ml. After intravenous infusion, Cmax was 4.9±0.8 ng/ml, AUC was 175±50 ng. h/ml, clearance was 6.3±2.3 l/h and distribution volume was 1199±260 l. The oral/intravenous ratio of dose-normalized AUCs was 0.94 (95%CI: 0.78–1.12). The pharmacologically active metabolite fingolimod-phosphate was quantifiable near its peak after oral administration but not after intravenous administration. The mean lymphocyte nadir occurred on day 1 and was 35% lower after oral (0.74 × 109/l) than after intravenous (1.15 × 109/l) administration. Lymphocytes recovered to the normal range by day 15 for both treatments. The mean heart rate nadir occurred 3–4 h postdose and was 11% lower after oral administration (47 bpm) versus intravenous administration (53 bpm). Conclusions. Average systemic exposure to fingolimod was similar after oral and intravenous administration. However, the acute decrease in lymphocyte counts was weaker after intravenous administration, likely because of lower blood levels of the active metabolite fingolimod-phosphate compared with oral administration. Copyright © 2007 John Wiley & Sons, Ltd.

The purpose of this double-blind, placebo-controlled study was to measure the effects of FTY720, a novel immunomodulator, on heart rate and rhythm in healthy volunteers. Subjects (n = 66) were randomized to FTY720 1.25 mg or 5 mg or placebo administered once daily for 7 days. Continuous telemetry revealed an acute, dose-dependent decrease in mean heart rate (10-bpm decrease vs placebo) following the first dose of FTY720, with a nadir generally 4 hours postdose. Although a persistent FTY720-related decrease in heart rate was measured from day 2 to day 7, additional doses of FTY720 after day 2 resulted in no further incremental decreases. Mean PR interval increased by approximately 8 to 10 msec in FTY720-treated subjects on day 1. FTY720 did not increase the QRS or QT interval. These results confirm that the first dose of FTY720 has a mild to moderate negative chronotropic effect.

Aims We sought to define the influence of verapamil, an inhibitor of CYP3A and P-glycoprotein, on the pharmacokinetics of everolimus, a substrate of this enzyme and transporter. Methods This was a two-period, single-sequence, crossover study in 16 healthy subjects. In period 1 subjects received a single 2 mg oral dose of everolimus. In period 2 they received verapamil 80 mg three times daily for a total of 6 days and a single 2 mg dose of everolimus co-administered on the second day of verapamil therapy. Results During verapamil co-administration, everolimus Cmax increased 2.3-fold (90% CI, 1.9, 2.7) from 21 ± 8 to 47 ± 18 ng ml−1 and AUC increased 3.5-fold (90% CI, 3.1, 3.9) from 115 ± 45 to 392 ± 142 ng ml−1 h. Everolimus half-life was only prolonged to a minor extent (32 ± 6 vs. 37 ± 6 h). Verapamil predose concentrations doubled from 32 ± 16 to 74 ± 42 ng ml−1 after single dose administration of everolimus. Conclusions Multiple dosing with verapamil increased blood concentrations of everolimus after a single dose by an average 3.5-fold. During verapamil treatment, dose reduction for everolimus should be made guided by blood monitoring and for verapamil by blood pressure monitoring.

The aims of the current study were to determine whether therapeutic drug monitoring (TDM) might benefit kidney transplant recipients receiving everolimus, and to establish dosage recommendations when everolimus is used in combination with cyclosporine and corticosteroids. The analysis was based on data from 779 patients enrolled in two 12-month trials. Everolimus trough concentrations >/=3 ng/mL were associated with a reduced incidence in biopsy-proven acute rejection (BPAR) in the first month (p = 0.0001) and the first 6 months (p = 0.0001), and reduced graft loss compared with lower concentrations (4% vs. 20%, respectively). By contrast, cyclosporine in the standard concentration range had no impact on BPAR within the same timeframes. Most patients receiving everolimus 1.5 or 3 mg/d achieved trough concentrations above the therapeutic threshold of 3 ng/mL, regardless of reductions in cyclosporine dose. TDM simulation showed that just two dose adjustments would achieve median everolimus trough values >/=3 ng/mL in 95% of patients during the first 6 months. This investigation indicates that improved efficacy is likely when TDM is considered as an integral component of the immunosuppressive strategy of everolimus.

We sought to quantify the influence of the CYP3A inhibitor erythromycin on the pharmacokinetics of everolimus, a CYP3A substrate.This was a two-period, single-sequence, crossover study in 16 healthy subjects. In period 1, subjects received the reference treatment of a single 2-mg dose of everolimus. In period 2, they received the test treatment of erythromycin 500 mg three times daily for a total of 9 days and a single 2-mg dose of everolimus coadministered on the fifth day of erythromycin therapy. The test/reference ratio and 90% confidence interval (CI) were derived for everolimus C (max) and AUC.During erythromycin coadministration, everolimus C (max) increased 2.0-fold (90% CI, 1.8-2.3) from 20+/-5 ng/ml to 40+/-10 ng/ml. Everolimus AUC increased 4.4-fold (90% CI, 3.5-5.4) from 116+/-37 ng h/ml to 524+/-225 ng h/ml. Everolimus half-life was prolonged by 39% from 32+/-6 h to 44+/-6 h. Erythromycin predose concentrations were not changed after single-dose administration of everolimus.Multiple-dose erythromycin increased single-dose everolimus blood levels by an average 4.4-fold (range, 2.0-12.6). During erythromycin treatment, a compensatory everolimus dose reduction should be made guided by everolimus therapeutic drug monitoring.

Everolimus, a proliferation signal inhibitor, is an immunosuppressant that targets the primary causes of progressive allograft dysfunction, thus improving the long-term outcome after heart transplantation. The present study investigated whether therapeutic drug monitoring (TDM) of everolimus would benefit heart transplant patients. Data from a twelve-month phase III trial comparing everolimus (1.5 or 3 mg daily) with azathioprine were used to evaluate everolimus pharmacokinetics, exposure-efficacy/safety and TDM prognostic simulations. Everolimus trough levels were stable in the first year post-transplant and averaged 5.2 +/- 3.8 and 9.4 +/- 6.3 ng/mL in patients treated with 1.5 and 3 mg/day, respectively. Cyclosporine trough levels were similar in all treatment groups. Biopsy-proven acute rejection (BPAR) was reduced with everolimus trough levels > or =3 ng/mL. Intravascular ultrasound (IVUS) analysis showed evidence of reduced vasculopathy at 12 months with increasing everolimus exposure. Unlike cyclosporine, increasing everolimus exposure was not related to a higher rate of renal dysfunction. The TDM simulation, which was based on two everolimus dose adjustments and an initial starting dose of 1.5 mg/day, showed that the simulated BPAR rate (with TDM) was 21% versus 26% in the group with fixed dosing. Therefore, TDM in heart transplantation could optimize immunosuppressive efficacy and reduce treatment-related toxicity.

FTY720 is a sphingosine-1-phosphate receptor agonist being developed as an immunomodulator for acute rejection prophylaxis after organ transplantation. This study was performed to characterize the pharmacokinetics of and lymphocyte response to multiple-dose FTY720. In this randomized, double-blind study, three groups of 20 healthy subjects each received either placebo, 1.25 mg/day FTY720, or 5 mg/day FTY720 for 7 consecutive days. FTY720 blood concentrations and lymphocyte counts were assessed over the weeklong treatment phase and over a month-long washout phase. The relationship between FTY720 blood concentrations and lymphocyte counts was explored by an inhibitory E(max) model. First-dose exposure was consistent with dose proportionality between the low- and high-dose groups. Blood levels accumulated fivefold over the treatment period. Exposure on day 7 was dose proportional for C(max) (5.0 +/- 1.0 vs. 18.2 +/- 4.1 ng/mL) and for AUC (109 +/- 24 vs. 399 +/- 85 ng.h/mL). Washout pharmacokinetics after the last dose indicated an elimination half-life averaging 8 days. Lymphocyte counts decreased by 80% in subjects receiving the lower dose to a nadir of 0.4 +/- 0.1 x 10(9)/L and by 88% in subjects receiving the upper dose to a nadir of 0.2 +/- 0.1 x 10(9)/L. Descriptive exposure-response modeling estimated that the lymphocyte response at 5 mg/day is near the maximal response achievable. By the end-of-study evaluation on day 35, lymphocyte counts had recovered to within 75% and 50% of baseline in the low- and high-dose groups, respectively. In summary, systemic exposure to FTY720 was consistent with dose-proportionality after both single- and multiple-dose administration. Total lymphocyte counts decreased from baseline by 80% and 88% at regimens of 1.25 and 5 mg/day, respectively. Exposure-response modeling provided evidence that 5 mg/day FTY720 resulted in a near-maximal dynamic effect of this drug on lymphocytes.

Aims FTY720 is a sphingosine-1-phosphate receptor agonist that redirects lymphocytes from the circulation to lymph nodes without impairing lymphocyte function. It is being developed as an immunomodulator for the prevention of acute rejection after organ transplantation. This study was performed to provide guidance on administration with respect to meals and to measure pharmacologic responses in healthy subjects. Methods In this randomized, two-period, crossover study, 14 healthy subjects received placebo on day −1 of each period with baseline circadian measurements of lymphocyte count and heart rate. Subjects subsequently received a single 1 mg oral dose of FTY720 on day 1 under fasting conditions and after a high fat meal. Blood FTY720 concentrations, lymphocyte count, and supine heart rate were assessed over an 8 day period after each FTY720 dose. The effect of food on FTY720 pharmacokinetics was assessed by standard bioequivalence testing. Results Both the peak concentration (0.65 ± 0.17 vs 0.64 ± 0.18 ng ml−1) and total exposure (AUC 149 ± 65 vs 139 ± 43 ng ml−1 h) did not differ significantly between fasting and fed states, respectively. The corresponding fed/fasting ratios and 90% confidence intervals were 1.00 (0.86, 1.17) for Cmax and 0.98 (0.86, 1.11) for AUC. Under both treatment conditions peripheral blood lymphocyte count decreased from baseline by 38 ± 9% over the first 2 days postdose and then increased towards predose values over the subsequent week. Whereas a circadian rhythm in supine heart rate was preserved in the presence of FTY720, the heart rate vs time curve was shifted downwards by 10% over the first day postdose and then recovered to prestudy values by days 3–5 postdose. These changes were asymptomatic. Conclusions Single 1 mg doses of FTY720 were well tolerated in healthy subjects and elicited a moderate decrease in peripheral blood lymphocyte count and a transient decrease in heart rate consistent with its pharmacological mode of action. FTY720 may be administered without regard to the timing of meals or their fat content.

Cyclosporine absorption profiling uses either the area under the concentration curve in the first 4 h post dose, AUC(0–4), or the concentration 2 h post dose (C2) to optimize immunosuppression in adult kidney and liver transplantation. We characterized C2 versus AUC(0–4) relationships over time after transplant and across transplant indications in 56 pediatric transplant patients. There were 36 kidney transplant patients aged 9.7±3.9 years. Nineteen of these patients were studied in the de novo period on day 7 post transplant and 17 in the maintenance phase more than 1 year post transplant. In addition, 20 liver transplant patients aged 8.9±4.2 years were studied in the maintenance phase. All patients had five blood samples collected over the 12-h dose interval that were analyzed by validated assay methods at a central laboratory. Pediatric C2 values were 1,463±658 ng/ml for de novo kidney, 954±322 ng/ml for maintenance kidney, and 619±339 ng/ml for maintenance liver transplant patients. C2 was a strong predictor of AUC(0–4) in all three pediatric groups, with coefficients of determination (r 2) ranging from 0.861 to 0.936. Although data were limited from the de novo period, the C2 versus AUC(0–4) regression was consistent over time after transplant and between transplant indications, with a regression slope of 2.50 in de novo kidney, 2.54 in maintenance kidney, and 2.76 in maintenance liver transplant recipients. These slopes were also comparable to that in adult maintenance kidney transplant patients (2.60). In conclusion, C2 versus AUC(0–4) relationships demonstrated consistency over time (de novo vs. maintenance phase), between transplant indications (kidney vs. liver), and across age groups (pediatric vs. adult patients). Average C2 values achieved with current pediatric cyclosporine dosing practices cluster around the target C2 ranges recommended for adults.

We evaluated exposure, safety, and efficacy data from an international Phase 3 trial of everolimus in de novo heart transplantation to characterize the longitudinal pharmacokinetics of everolimus and cyclosporine and to identify a therapeutic concentration range for everolimus. We randomized 634 patients to receive either 0.75 mg everolimus twice daily, 1.5 mg everolimus twice daily, or azathioprine in addition to corticosteroids and cyclosporine. At 8 visits during the first 6 months after transplantation, we obtained 2,328 everolimus trough levels (Cmin) and 129 area-under-the-curve (AUC) profiles over the dosing interval in patients treated with everolimus; we collected 3,258 cyclosporine trough concentrations and 174 profiles in all 3 treatment arms. We used median-effect analysis to characterize exposure-response associations between everolimus average Cmin vs freedom from biopsy-confirmed acute rejection; maximum cholesterol, low density lipoprotein, triglyceride, and creatinine levels; and minimum leukocyte and platelet counts. Everolimus Cmins averaged 5.2 +/- 3.8 ng/ml and 9.4 +/- 6.3 ng/ml at the lower and upper dose levels. A 17% underproportionality was noted in Cmins; however, peak exposure and AUC were consistent with dose proportionality. Everolimus exposure was stable during the 6-month period. Interindividual variability was 37% for AUC and 40% for Cmin. The latter parameter was not influenced to a clinically relevant extent by sex, age, or weight. The Cmin was well correlated with AUC (r2 = 0.81). Everolimus Cmin was significantly related to freedom from rejection (p = 0.02) with 3 ng/ml being an informative lower threshold for efficacy. Thrombocytopenia, defined as

BACKGROUND In cystic fibrosis (CF), absorption of cyclosporine A (CsA) through the gastrointestinal tract is often impaired because of fat malabsorption. The aim of this study was to compare the steady-state pharmacokinetics of CsA and the inter- and intrasubject variability of CsA exposure in stable lung transplant recipients with and without CF and to determine the best single-time predictors of the area under the curve (AUC). METHODS Ten lung transplant recipients without CF and 10 lung transplant recipients with CF were studied. All patients received Neoral twice daily. Blood samples were obtained predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, and 12 h postdose on three separate days within a 5-day period. RESULTS CsA exposure and pharmacokinetic variables were similar in the two groups, although exposure-per-milligram-per-dose was approximately 25% lower in CF patients. Coefficients of intersubject variability were numerically higher in CF patients, but the difference between groups did not reach significance. On the other hand, the maximum concentration (Cmax), the concentration 2 hours after administration (C2), AUC0-12, and AUC0-4 showed a twofold greater intrasubject variability in CF patients. CsA trough concentration did not predict accurately the AUC, but C2 was a good predictor of the AUC0-4 in both CF (r2=0.90) and non-CF (r2=0.78) patients. CONCLUSION Compared to patients without CF, patients with CF show a lower bioavailability of CsA and a greater intrasubject variability of Cmax, C2, and AUC. C2 is the best single-point predictor of the AUC0-4 in lung transplant recipients with and without CF.

Background The steady-state pharmacokinetics of everolimus were longitudinally assessed in pediatric de novo kidney allograft recipients during a 6-month period. Methods. Nineteen patients received everolimus 0.8 mg/m 2 (maximum 1.5 mg) twice daily as a dispersible tablet in water in addition to cyclosporine and corticosteroids. Everolimus and cyclosporine trough concentrations were obtained on days 3, 5, 6, and 7 and at months 1, 2, 3, and 6; an everolimus pharmacokinetic profile was obtained on day 7 and month 3. Results. There were 9 boys and 10 girls with a median age of 9.9 (range, 1-16) years. Steady-state pharmacokinetic parameters were as follows (median, range): C min (trough level), 4.7 (2.3- 9.5) ng/mL; peak concentration, 13.5 (5.9-22.2) ng/mL; area under the concentration-time curve (AUC), 77 (53-147) ng.hr/mL; and apparent oral clearance, 10.2 (5.5-15.6) L/hr/m 2 . Clearance (unadjusted for demographic factors) was positively correlated with age (r=0.66), body surface area (r=0.68), and weight (r=0.67). There were no trends in C min or AUC versus patient age when everolimus was dosed on a mg/m 2 basis. Everolimus C min were stable over time with median values of 3.9, 3.4, and 3.1 ng/mL at months 1, 3, and 6, respectively. Intraand interpatient variability in AUC was 29% and 35%, similar to that in adults. During the observation period, eight patients maintained stable AUCs and nine patients had increases or decreases, generally between 30% and 50% compared with the AUC at week 1. The concurrent median cyclosporine C min were generally at the lower end of conventional target ranges: 156, 83, and 69 ng/mL at months 1, 3, and 6, respectively. There were no graft losses and only three mild or moderate, reversible rejection episodes occurred. Everolimus was generally safe and well tolerated. Conclusions. These data support the use of body surface area-adjusted dosing for everolimus in pediatric patients. Although exposure is generally stable over time with moderate variability in AUC, therapeutic monitoring would be a helpful adjunct for individualizing everolimus exposure, assessing regimen adherence, and adjusting doses as the child matures.

Background. The pharmacokinetics and immunodynamics of basiliximab were assessed in 39 pediatric de novo kidney allograft recipients to rationally chose a dose regimen for this age group. Methods. In study part 1, patients were given 12 mg/m 2 of basiliximab by bolus intravenous injection before surgery and on day 4. An interim pharmacokinetic evaluation supported a fixed-dose approach for study part 2 in which infants and children received two 10-mg doses and adolescents received two 20-mg doses. Blood samples were collected over a 12-week period for analysis of basiliximab and soluble interleukin-2 receptor concentrations, flow cytometry, and screening for anti-idiotype antibodies. Results. Basiliximab clearance in infants and children (n=25) was reduced by approximately half compared with adults from a previous study and was independent of age (1-11 years), weight (9-37 kg), and body surface area (0.44-1.20 m 2 ). Clearance in adolescents (12-16 years, n=14) approached or reached adult values. CD25-saturating basiliximab concentrations were maintained for 31±12 days in study part 1 with mg/m 2 dosing and for 36±14 days in study part 2 based on the fixed-dose regimen (P=0.31). A single patient experienced a rejection episode during CD25 saturation. The duration of CD25 saturation in patients who experienced a rejection episode after desaturation did not differ from those who remained rejection-free for the full 6-month period: 34±6 days (n=6) vs. 35±14 days (n=33 patients); P=0.74. Anti-idiotype antibodies were detected in two patients; however, this did not influence the clearance of basiliximab or the duration of CD25 saturation. Conclusions. To achieve similar basiliximab exposure as is efficacious in adults, pediatric patients

A non-microemulsion cyclosporine oral solution was recently recalled from the market because of the lack of bioequivalence when administered with apple juice compared with water as the diluent. This open-label, randomized, two-period, crossover study assessed the effect of apple juice on Neoral, a microemulsion cyclosporine oral solution. The study enrolled 34 subjects who received 180 mg Neoral oral solution diluted in 200 mL tap water or apple juice. Cyclosporine was measured in whole blood by a liquid chromatography method. Pharmacokinetic parameters were compared by standard bioequivalence tests. With water vs. apple juice, cyclosporine Cmax was 1263 +/- 203 vs. 1191 +/- 225 ng/mL and AUC was 4714 +/- 1117 vs. 4788 +/- 1320 ng h/mL, respectively. Bioequivalence was demonstrated for both parameters. These data were comparable with those from a previous study in which subjects received 180 mg Neoral oral solution with orange juice. Cyclosporine bioavailability is unaltered when Neoral is administered diluted in apple juice or orange juice compared with tap water which conforms to the cyclosporine product label.

OBJECTIVE: To assess the influence of the CYP3A4 enzyme inducer rifampin on the pharmacokinetics of the immunosuppressant everolimus to provide guidance for their coadministration. METHODS: In this open-label, single-sequence, crossover study, 12 healthy subjects received a single oral 4-mg dose of everolimus alone and again after an 8-day pretreatment with rifampin 600 mg/d. Urinary excretion of 6β-hydroxycortisol was measured at various time points during rifampin treatment as a marker of CYP3A4 induction. RESULTS: Urine excretion of 6β-hydroxycortisol was significantly elevated during treatment with rifampin compared with prestudy, indicating enzyme induction. When everolimus was coadministered during rifampin treatment, the apparent clearance of everolimus was significantly increased, on average by 172%. This was manifested as a decrease in maximum concentration in all subjects, on average by 58% (range 14–73%). The AUC remained unaffected in 1 subject (although 6β-hydroxycortisol indicated enzyme induction) and decreased in the other 11 subjects. The average decrease in AUC in the full study population was 63% (range 0–82%). Everolimus half-life was reduced significantly, from an average of 32 hours to 24 hours. CONCLUSIONS: In everolimus-treated patients for whom rifampin is indicated, alternative agents with less enzyme induction potential than rifampin could be considered. Alternatively, the dose of everolimus could be individually titrated based on everolimus therapeutic drug monitoring during rifampin therapy.

BACKGROUND Exposure, safety, and efficacy data from the two everolimus randomized, double-blind phase 3 trials were evaluated to identify a therapeutic concentration range applicable in de novo kidney transplantation. METHODS A total of 695 evaluable everolimus-treated patients received either 0.75 or 1.5 mg bid in addition to corticosteroids and cyclosporine (troughs 150-400 ng/ml in month 1 and 100-300 ng/ml thereafter). A total of 3355 everolimus trough levels (Cmin) were obtained in weeks 1 and 2 and months 1, 2, 3, and 6 after transplantation. Each patient's average Cmin was calculated and the values were divided into quintiles: 1.0-3.4, 3.5-4.5, 4.6-5.7, 5.8-7.7, 7.8-15.0 ng/ml (139 patients per quintile). Efficacy was freedom from biopsy-confirmed acute rejection. Safety measures were maximum total cholesterol and triglyceride levels and minimum leukocyte and platelet counts. A sigmoid exposure-response model was used to test the significance of these Cmin-efficacy and Cmin-safety relationships. RESULTS Freedom from acute rejection was significantly related to Cmin with an incidence of 68% at 1.0-3.4 ng/ml, 81-86% at 3.5-7.7 ng/ml, and 91% at 7.8-15.0 ng/ml (P=0.03). The incidence of hypercholesterolemia, defined as >6.5 mmol/liter, ranged from 76 to 87% over the exposure range without a significant relation to Cmin (P=0.37). The incidence of hypertriglyceridemia, defined as >2.9 mmol/liter, rose from 59 to 77% across the exposure groups (P=0.02). Leukocytopenia, defined as

Study Objective. To quantify the influence of a high-fat meal on the oral bioavailability of the immunosuppressant everolimus in a single-dose study in healthy subjects and to confirm the results in a small food-effect screening assessment in patients with renal transplants who were receiving multiple-dose everolimus. Design. Randomized, open-label, crossover, single-dose study and confirmatory screening. Setting. Phase 1 unit for the single-dose study and two German hospitals for the patient screening. Subjects. Twenty-four healthy male volunteers; six clinically stable patients with renal transplants who were originally part of a phase I dose-escalation study. Intervention. The 24 healthy men received everolimus 2 mg orally under fasting conditions and after a high-fat meal. The six patients received everolimus 2.5 mg/day orally, in addition to cyclosporine and prednisone. On two occasions, a pharmacokinetic profile was obtained over the dosing interval after drug administration under fasting conditions and after a high-fat meal in a randomized sequence. Measurements and Main Results. In the single-dose study in healthy subjects, a high-fat meal delayed everolimus time to maximum concentration (Tmax) by a median 1.25 hours, reduced peak blood concentration (Cmax) by 60%, and reduced area under the concentration-time curve (AUC) by 16%. In the multiple-dose screening in patients with renal transplants, a high-fat meal delayed (Tmax by a median 1.75 hours and reduced Cmax by 53% and AUC by 21%. Everolimus trough levels showed no food effect, whereas the peak-trough fluctuation was dampened by 52%. Conclusions. A high-fat meal modestly reduced everolimus AUC. To minimize longitudinal variability in exposure, everolimus should be administered consistently either with food or without food.

Everolimus is an immunosuppressant intended for use with cyclosporine in acute-rejection prophylaxis following organ transplantation. The possibility of a drug interaction of cyclosporine on everolimus was assessed. In this randomized, two-period, crossover study, 24 healthy subjects received a single oral dose of 2 mg everolimus alone and with one of two cyclosporine formulations: either 175 mg Neoral or 300 mg Sandimmune. The single doses of Neoral and Sandimmune were chosen to yield similar average areas under the concentration-time curve (AUC). Treatments were separated by a 14-day washout period. Cyclosporine AUCs were similar for both formulations (p = 0.53), whereas the peak concentration (Cmax) was significantly higher for Neoral (p = 0.02). Simultaneous administration of Neoral with everolimus increased everolimus Cmax and AUC by 82% and 168%, respectively (p = 0.0001). Coadministration of Sandimmune with everolimus did not affect everolimus Cmax (p = 0.59) but increased everolimus AUC by 74% on average (p = 0.0001). Everolimus elimination half-lives were unchanged in the presence of both cyclosporine formulations. The everolimus AUC increase with Neoral coadministration was significantly greater than the AUC increase with Sandimmune (p = 0.008). However, there was no apparent association between cyclosporine Cmax and the change in everolimus AUC with cyclosporine coadministration. If Neoral or Sandimmune is removed from an everolimus-cyclosporine immunosuppressive regimen, a two- to three-fold decrease in everolimus exposure is expected. Therapeutic monitoring of everolimus concentrations would be helpful after the removal of cyclosporine to individually titrate everolimus exposure.

Objective:To describe the time course of α4-integrin receptor desaturation and disease activity return in patients with relapsing-remitting MS who discontinued natalizumab and to investigate baseline and on-study predictors for the recurrence of disease activity.Methods:In the course of TOFINGO, a 32-week, patient- and rater-blinded multicenter, parallel-group study, we performed MRI, counted relapses, and measured α4-integrin receptor occupancy (RO) at baseline and 8, 12, 16, 20, and 24 weeks. The relationship between RO and total number of new T1 gadolinium-enhancing (Gd+) lesions was modeled using Poisson linear regression.Results:Patients (N = 142) were randomized (1:1:1) to 8-, 12-, or 16-week washout (WO) groups. At randomization, the median RO in the 8-, 12-, and 16-week WO groups was 94.5%, 92.4%, and 90.9%, which declined to 79.8%, 30.7%, and 8.7% after 8, 12, and 16 weeks of WO, respectively. The percentage of patients with new T1 Gd+ lesions increased with longer WO period before commencing fingolimod: 2.1% (8 weeks), 9.1% (12 weeks), and 50.0% (16 weeks). Overall, 71% of patients with first relapse between weeks 6 and 18 had RO values below the time-matched population median. Higher T2 lesion volume (LV) at baseline predicted a higher number of new T1 Gd+ lesions.Conclusions:A faster decline in natalizumab RO, longer WO period, and higher T2 LV at baseline were associated with an increased risk for return of inflammatory disease activity. These results provide a mechanistic rationale and, together with the main outcomes of the TOFINGO study, support initiation of fingolimod within 8 weeks of natalizumab discontinuation.ClinicalTrials.gov identifier:NCT01499667.

Lymphangioleiomyomatosis is a rare, progressive cystic lung disorder characterised by dysregulated activation of mammalian target of rapamycin (mTOR) signalling.This was a phase IIa, multicentre, open-label study of the mTOR inhibitor everolimus (2.5 mg·day−1 escalated to 10 mg·day−1) in 24 women with lymphangioleiomyomatosis. Primary endpoints were safety, pharmacokinetics and serum vascular endothelial growth factor-D (VEGF-D) levels; secondary endpoints were measures of lung function.Following 26 weeks of everolimus treatment, forced vital capacity exhibited stability, while forced expiration volume in 1 s improved from baseline, with mean changes (95% confidence interval) of 10 mL (−111–132) and 114 mL (11–217), respectively; 6-min walk distance improved by 47 m. Median VEGF-D and collagen IV levels decreased from baseline, from 1730 pg·mL−1 to 934.5 pg·mL−1, and 103 ng·mL−1 to 80.5 ng·mL−1, respectively. Adverse events were mostly grade 1−2; mouth ulceration, headache, nausea, stomatitis and fatigue were common. Serious adverse events suspected to be treatment related included peripheral oedema, pneumonia, cardiac failure and Pneumocystis jirovecii infection. Everolimus blood levels increased dose proportionally.In this study, everolimus improved some measures of lung function and exercise capacity and reduced serum VEGF-D and collagen IV. Side effects were generally consistent with known toxicities of mTOR inhibitors, although some were severe.

Background: Pharmacokinetic data regarding a drug-drug interaction between everolimus and tacrolimus are sparse. Material/Methods: In a pharmacokinetic substudy of the randomized ASSET trial, 46 de novo kidney transplant patients receiving very low (1.5-3 ng/mL) or low (4-7 ng/mL) tacrolimus exposure after month 3, both with everolimus and steroids, provided area under the curve (AUC) concentration profiles at day 5 and months 1, 3, and 12. Results: At month 12, mean values for tacrolimus trough concentration (C-0), peak concentration (C-max), and AUC(0-12) in the very low tacrolimus group were approximately half that in the low tacrolimus group, but everolimus dose, C-0, C-max, and AUC(0-12) were virtually identical in both groups. In a cross-study comparison with data at months 1 and 3 from the pharmacokinetic substudy of the A2307 trial, in which patients received cyclosporine, mean values for everolimus C-0, C-max and AUC(0-12) were similar to those in the ASSET trial but the everolimus dose needed to achieve similar exposure was 1.5- to 2-fold higher with concomitant tacrolimus versus cyclosporine. Conclusions: Everolimus exposure is unaffected when tacrolimus exposure is down-titrated within the trough concentration range of 1.5-7 ng/mL. Higher doses of everolimus are needed to achieve a given exposure when combined with tacrolimus versus cyclosporine.

Background Everolimus is a macrolide immunosuppressant intended for acute rejection prophylaxis after kidney transplantation. Methods A total of 5260 blood samples were collected in the context of two randomized, double-blind, multicenter efficacy trials in 673 patients over a 6-month period after kidney transplantation. The data were evaluated in a nonlinear mixed-effects model. The influence of demographic characteristics (age, weight, sex, and ethnicity) and of comedications on everolimus exposure was explored. Results For a reference 44-year-old, 71-kg Caucasian kidney allograft recipient receiving everolimus as part of a cyclosporine (INN, ciclosporin)–prednisone immunosuppressive regimen, the absorption rate constant was 6.07 h−1 (standard error [SE], 0.70 h−1), the apparent clearance was 8.8 L/h (SE, 0.2 L/h), and the apparent central distribution volume was 110 L (SE, 5 L). There were no clinically relevant influences of age, weight, or sex on clearance. No significant difference in clearance was detected for Asian patients, whereas black patients had an average clearance that was 20% higher than that of nonblack patients. Patients concomitantly receiving erythromycin or azithromycin had an average 19% lower clearance. One patient receiving itraconazole had a 74% reduction in clearance. After we accounted for covariates, the remaining interindividual variability in clearance was 27% and the variability for distribution volume was 36%. The combined intraindividual and assay/measurement residual error in everolimus blood concentrations was 31%. Conclusions Dose adjustment of everolimus on the basis of weight does not appear necessary. Black patients may need a higher dose to achieve exposure that is similar to that of nonblack patients. Concomitant administration of potent inhibitors of the cytochrome P450 isozyme CYP3A may reduce everolimus clearance and increase its blood concentrations. Clinical Pharmacology & Therapeutics (2001) 70, 247–254; doi: 10.1067/mcp.2001.118022

Background RAD is a novel macrolide with potent immunosuppressive and antiproliferative activities. This study characterizes the safety, tolerability, and pharmacokinetics of two different single oral doses of RAD in stable lung and heart/lung transplant recipients with and without cystic fibrosis (CF). Methods This was a Phase I, multicenter, randomized, double-blind, two-period, two-sequence, crossover study. Single doses of RAD capsules at doses of 0.035 mg/kg (2.5 mg maximum) or 0.10 mg/kg (7.5 mg maximum) were administered with cyclosporine (Neoral [cyclosporine, USP] modified), steroids, and azathioprine on Day 1. The alternate dose was administered on Day 16. Laboratory assessments, vital signs, and adverse events were recorded throughout the study. RAD pharmacokinetic profiles were assessed over a 7-day period following each dose. Steady-state cyclosporine (CsA) profiles were assessed at baseline and with each RAD dose; RAD and CsA trough concentrations were obtained throughout the study period. Results Of the 20 patients randomized, 8 had CF and 12 did not. Single doses of RAD were safe and well tolerated. Headache was the most common side effect. RAD produced a mild, dose-dependent, reversible decrease in platelet and leukocyte counts. Cholesterol and triglycerides were minimally affected. At both doses, CF patients had significantly lower peak concentrations of RAD than did non-CF patients (p = 0.03); however, overall exposure (area under the curve/dose) was not different between the groups (p = 0.63). At the higher dose, there was a clinically minor under-proportionality in AUC, averaging −11%. Steady-state pharmacokinetics of CsA were not affected by RAD co-administration. Conclusions RAD was safe and well tolerated by stable lung and heart/lung transplant recipients with and without CF. The presence of CF did not influence the extent of RAD exposure. Single doses of RAD did not affect the pharmacokinetics of CsA. Ongoing studies are assessing the long-term safety and efficacy of RAD in lung and heart/lung transplantation.

Objective Our objective was to characterize the steady-state pharmacokinetics of everolimus and cyclosporine (INN, ciclosporin) when coadministered in de novo kidney allograft recipients during the first year after transplantation. Methods This study was a multicenter randomized double-blind study of 101 patients who were randomly assigned 1:1:1 to receive everolimus tablets at doses of 0.5 mg, 1 mg, or 2 mg twice daily with cyclosporine and prednisone. Blood sampling for the pharmacokinetics of everolimus and cyclosporine was performed on day 1, on weeks 1, 2, 3, and 4, and on months 2, 3, 6, 9, and 12. Everolimus dose-proportionality and stability over time were assessed in the context of linear regression and ANOVA models. Everolimus exposure-response relationships between area under the blood concentration-time curve (AUC) and changes in platelets, leukocytes, and lipids were explored with the median-effect model. Potential differences in cyclosporine dosing and pharmacokinetics at different levels of everolimus exposure were assessed in the context of ANOVA. Results Everolimus steady state was reached on or before day 7, with a median 3-fold accumulation of drug exposure compared with that after the first postoperative dose. Both steady-state maximum concentration and AUC were dose proportional over the full dose range when assessed on day 1, as well as for the full duration of the study at steady state. There was evidence for longitudinal stability in AUC of everolimus during the course of the study. The interindividual pharmacokinetic variability for AUC was 85.4% and intraindividual, interoccasion variability was 40.8%. Age (range, 17–69 years), weight (range, 49–106 kg), and sex (65 men and 36 women) were not significant contributors to variability. There was an increasing incidence of transient thrombocytopenia (≤100 × 109/L) with increasing everolimus AUC (P = .03). Cyclosporine doses, trough concentrations, and AUC exhibited similar temporal patterns during the course of the study regardless of the co-administered everolimus dose level (P = .13, .82, and .76, respectively). Conclusions Everolimus exhibited dose-proportional, stable exposure during the first post-transplant year. For a 4-fold range of everolimus doses there were no differential effects on cyclosporine dosing or pharmacokinetics. Clinical Pharmacology & Therapeutics (2001) 69, 48–56; doi: 10.1067/mcp.2001.112969

In this randomized, double-blind, parallel-group study, a commercially available human immunoglobulin-G product, IVIG, was compared with two test formulations: (1) IVIG-N, which is a nanofiltered formulation of IVIG, and (2) IVIG-L, which is a nanofiltered, liquid, ready-for-use IgG formulation containing nicotinamide, L-proline, and L-isoleucine as stabilizers. Three groups of 10 healthy subjects each received a single 0.6 g/kg dose of one of the formulations infused over 3.5 to 6.8 hours, depending on the total volume to be infused. Blood samples were obtained over a 6-week period to assess pharmacokinetics, immunogenicity, and the pharmacodynamic effects on leukocytes and TNF-alpha. A blood sample was taken at 6 months for a viral safety check. Administrations were generally well tolerated with only one reference IVIG infusion stopped prematurely due to headache. The IgG Cmax and AUC over the 6-week blood sampling period from both test formulations satisfied equivalence criteria compared with the reference formulation. In subjects receiving IVIG-L, peak concentrations of the stabilizer nicotinamide ranged from 0.34 to 0.47 mmol/L and of nicotinamide-N-oxide from 0.03 to 0.04 mmol/L, which are below those reported to cause adverse events. During the infusion of IVIG, leukocyte counts initially declined from a baseline of 5.7 +/- 1.1 x 10(9)/L to 3.7 +/- 0.8 x 10(9)/L at 2 to 4 hours and returned to baseline by 24 hours. TNF-alpha levels, reflecting activation of the monocyte-macrophage system by the infused IVIG, rose from a baseline of 13 +/- 4 pg/mL to a peak of 272 +/- 324 pg/mL at 2 to 4 hours and returned to baseline by 24 hours. These patterns were generally similar for the test formulations, with the exception that the increase in TNF-alpha levels was dampened for IVIG-N, although this was not statistically significant. There was no evidence of immunogenicity or viral transmission from any of the formulations. Hence, these three formulations were generally well tolerated, yielded similar systemic exposure to IgG over a 6-week period after administration, and did not give rise to immunogenicity or viral safety concerns.

BACKGROUND Basiliximab is an interleukin-2 receptor (CD25) chimeric monoclonal antibody used for acute rejection prophylaxis in renal transplants. In the context of a randomized, double-blind efficacy trial, its population pharmacokinetics and potential exposure-response relationships were explored in de novo kidney allograft recipients receiving 40 mg basiliximab (20 mg on days 0 and 4) in addition to baseline immunosuppressive therapy with cyclosporine microemulsion and corticosteroids. METHODS Serial blood samples (8.2+/-1.3 per patient) were collected over 12 weeks after transplant from 169 basiliximab-treated patients, and empirical Bayes estimates of each patient's disposition parameters were derived. The duration of CD25 saturation was estimated as the time over which serum basiliximab concentrations exceeded 0.2 microg/ml. The relationships between pharmacokinetic parameters and demographic-clinical covariates were explored by regression methods and unpaired t-tests. RESULTS Basiliximab clearance was 36.7+/-15.2 ml/hr, distribution volume 8.0+/-2.4 L, and half life 7.4+/-3.0 days. Patient weight (range, 44-131 kg) and age (range, 20-69 yrs) each contributed < or =6% to the variability in clearance and volume. Gender, ethnic group, and the presence of proteinuria had no clinically relevant influences on basiliximab disposition. Receptor-saturating basiliximab concentrations were maintained for 36+/-14 days (range, 12-91). There was no apparent relationship between the incidence or day of onset of acute rejection episodes during CD25 saturation and basiliximab concentration (range, 0.2-5.0 microg/ml). In patients who experienced a rejection episode after basiliximab was eliminated from serum (n=33), basiliximab had not been cleared faster than in their rejection-free peers (P=0.322) nor had CD25 been saturated for a shorter period of time (33+/-13 days vs. 37+/-14 days for rejection-free patients, P=0.162). CONCLUSIONS There were no demographic or clinical subpopulations not adequately treated with the standard basiliximab dosing regimen. Over the range of CD25 suppression durations observed in this study, extended periods of receptor blockade did not seem to confer an immunoprophylactic advantage compared with shorter periods of receptor suppression.

The recent introduction of a cyclosporine microemulsion demonstrating less pharmacokinetic variability than the conventional formulation offers the potential for accurately and precisely predicting area under the curve (AUC) with a limited-sampling monitoring strategy. This was studied based on the pharmacokinetic profiles from 55 stable patients with renal transplants who were observed on two occasions at steady state on both formulations. Multiple linear regression analyses were performed on a training dataset from 27 patients, in which combinations of cyclosporine concentrations drawn from 0 to 4 hours postdose were regressed against the full AUC over the dosing interval. Predictor regression equations used concentration combinations ranging from one-point (concentrations at 0, 1, 2, 3, or 4 hours) through five-points (all five concentrations 0 to 4 hours). The predictive performance of these equations was then assessed in the training group with data from a subsequent profiling occasion and in the remaining 28 patients who constituted an independent test group. Prediction bias (mean prediction error) and prediction precision (absolute prediction error) were quantified and compared between formulations. Correlations between predicted and actual AUC were consistently stronger for the microemulsion, suggesting the possibility of more accurate and precise predictions of exposure than from the conventional formulation. For both formulations, the one-point predictors rendered the lowest prediction precision, and predictive performance improved considerably when multiple-point predictors were used. Significantly higher precision and lower variability were observed with the microemulsion for most predictors in the both training and test groups. For the microemulsion, two-point (C0 + C1 or C0 + C2) and three-point (C0 + C1 + C2) predictors yielded relatively unbiased and precise exposure predictions, inasmuch as mean absolute prediction error was less than 10% and 5%, respectively. Hence, a two- or three-point method may provide a clinically important improvement over the use of trough levels in monitoring cyclosporine therapy in patients with renal transplants.

Background Basiliximab is an interleukin-2 receptor (IL-2R; CD25) chimeric monoclonal antibody for immunoprophylaxis against acute rejection in renal transplantation. Its pharmacokinetics were characterized in a multicenter open-label, prospective dose-escalation study to identify a single-dose regimen providing IL-2R-saturating serum concentrations in the critical first posttransplant month. Methods. Thirty-two recipients of primary, mismatched cadaver kidneys were enrolled: 20 men and 12 women, who were 47±11 years old and weighed 65±12 kg. The immunosuppression regimen consisted of steroids and azathioprine from day 0 and cyclosporine from day 10. Basiliximab was infused over 30 min as a single dose preoperatively. Results. Thirty patients were evaluable for basiliximab pharmacokinetics: 24 received 40 mg and 6 received 60 mg. Basiliximab was well tolerated without evidence of cytokine-release syndrome, hypersensitivity reactions, or anti-idiotype antibody response. Peak concentration and area under the concentration curve increased proportionally with dose. Postinfusion concentrations declined in a biphasic manner with a terminal half-life of 6.5±2.1 days. Weak, widely dispersed correlations were noted between body weight versus distribution volume (r=0.29) and versus clearance (r=0.45), suggesting no clinical relevance for weight-adjusted dosing. There were no apparent gender-related differences in basiliximab disposition. Previous phase II data indicated that serum concentrations in excess of 0.2 μg/ml are sufficient to saturate IL-2R epitopes on circulating T lymphocytes. Concentrations were above this threshold for 26±8 days (range 16 to 46) at the 40-mg dose level and for 32±11 days (range 22 to 51) at the 60-mg dose level. Conclusions. Total basiliximab doses of 40-60 mg were well tolerated, nonimmunogenic, and estimated to provide immunoprophylaxis to cover the first posttransplant month.

A randomized, sequential, bioreplication study was performed with 24 healthy volunteers to assess the pharmacokinetic variability of oral and intravenous administrations of valspodar, a multidrug resistance modulator for use as a chemotherapy adjunct. Subjects received 200 mg as a 2-hour intravenous infusion and 400 mg orally as microemulsion soft gelatin capsules each given on two separate occasions. Following replicate intravenous administrations, reproducibility in peak concentration and area-under-the-curve was demonstrated by interoccasion equivalence testing. Low to moderate inter- and intra-subject pharmacokinetic variability were observed with coefficients of variation ranged from 9% to 19%. Absolute bioavailability from the microemulsion formulation was 60%. Replicate oral administrations demonstrated uniform and repeatable absorption with interoccasion equivalence in peak concentration, time to reach the peak concentration, and area-under-the-curve. Coefficients of inter- and intra-subject variation for these parameters ranged from 10% to 20% indicating low to moderate pharmacokinetic variability. When variabilities were compared between the two routes of administration, the absence of differences indicated that the rate and extent of drug absorption from the microemulsion formulation was as uniform and repeatable as by intravenous infusion.

Current clinical difficulties in the use of cyclosporine in transplantation are in part due to its narrow therapeutic window between effective immunosuppression and adverse events and in part due to suboptimal absorption associated with wide pharmacokinetic variability. Under the assumption that the latter aspects are largely formulation-related, a clinical development program was undertaken to compare the conventional formulation (Sandimmun) with a new microemulsion preconcentrate (Neoral). After oral administration, Neoral immediately forms a microemulsion in aqueous gastrointestinal fluids yielding a homogeneous dispersion from which cyclosporine is more readily absorbed. Single-dose crossover studies in healthy subjects were initially performed to document improved bioavailability and dose linearity, lower intrasubject pharmacokinetic variability, and reduced food effect with Neoral. In a subsequent phase of the development program, questions that could only be assessed in transplant patients at steady state were addressed in small, open-label studies under a trough concentration-guided strategy. This approach was necessary to maintain effective immunosuppression while determining appropriate and safe guidelines for converting between formulations, assessing the trough : area under the curve correlation and exploring for potential differences in metabolism. Multicenter, double-blind, randomized investigations were then performed to compare the formulations in stable and de novo transplant populations. In this context, the conversion approach, the safety/tolerability profile, and the attendant pharmacokinetic advantages of the microemulsion formulation were confirmed in larger populations under clinical conditions. It is anticipated that the more precise pharmacokinetic control possible with Neoral will provide a firmer base from which to elucidate the relationship between cyclosporine exposure and graft survival to optimize cyclosporine-based immunosuppressive regimens.

A concentration-guided study was designed to maintain adequate immunosuppression and avoid excessive drug exposure while determining steady-state relative bioavailability of two cyclosporine G (CyG) oral formulations in stable renal transplant patients. In period I (week 1), 26 patients taking cyclosporine A (CyA)-based immunosuppressive regimens entered the study. Doses were titrated to maintain trough concentrations within a predefined range, as measured by fluorescence polarization immunoassay (FPIA). Patients were given an oral solution of CyG in period II (weeks 2-3), and a microemulsion capsule formulation of CyG in period III (weeks 4-5), with dose titration as necessary to achieve trough concentrations in a predefined range, as measured by FPIA. Full pharmacokinetic profiles were obtained on the last day of each study period. Treatment with CyA was reinitiated in period IV (week 6) at the same doses as at study entry. All blood samples were analyzed at the conclusion of the study using CyG- and CyA-specific high-performance liquid chromatography (HPLC). When changing from oral solution to capsule for CyG, an average 19% dose reduction was necessary to compensate for the elevated trough concentrations resulting from the increased bioavailability of the capsule formulation. The concentration-guided strategy was successful in avoiding over-exposure, and resulted in comparable values for area under the concentration-time curve (AUC) for both formulations of CyG. Dose normalization of the pharmacokinetic parameters subsequently allowed calculation of the relative bioavailability. Specifically, a faster rate and greater extent of CyG absorption from the capsule than the oral solution were manifested as a slightly earlier time to peak concentration (tmax), an average 44% increase in the maximum concentration (Cmax), and an average 29% increase in AUC. This experience demonstrated that a concentration-guided trial design allowed a drug development question for a compound with a narrow therapeutic index to be addressed safely and directly in the target patient population.

To evaluate the pharmacokinetic properties of the new microemulsion formulation of cyclosporine (Sandimmun Neoral), a double-blind, prospective study in stable renal transplant recipients was performed. The patients were randomized on a 4:1 basis either to receive Sandimmun Neoral (n = 45) or continue on regular Sandimmun (n = 12). Before randomization, a steady-state pharmacokinetic profile study was performed in all patients while they were still on regular Sandimmun. Pharmacokinetic assessments were then performed after 8 and 12 weeks and after 1 year. A milligram-to-milligram dose conversion was shown to be adequate to maintain the patients within a predefined target therapeutic window. Changes in pharmacokinetic parameters after conversion to Sandimmun Neoral were consistent with an increased rate and extent of cyclosporine absorption from the Neoral formulation. This was reflected by a shorter time to reach peak concentration and also by a mean increase in peak concentration by 67%, and an overall mean increase in drug exposure (area under the curve) by 34%. These findings were also confirmed 1 year after conversion. Furthermore, significantly reduced intraindividual variability in pharmacokinetic parameters was found, as well as improvements in the correlation between trough concentrations and area under the curve after conversion to Sandimmun Neoral. In conclusion, our results indicate an improved and consistent absorption of cyclosporine from the Neoral formulation, which should make clinical management easier and safer.

Potential differences in the acute effect of cyclosporin on renal function when dosed orally as the current market formulation or following a milligram-to-milligram conversion to a new microemulsion formulation were investigated in 14 stable kidney transplant patients. The study consisted of three sequential periods of 2 weeks duration each. Patients entered (period I) and completed (period III) the investigation with the market formulation and received the microemulsion formulation in period II; individualized cyclosporin doses remained unchanged throughout the study. Over one steady-state dosing interval at the end of each study period, whole blood cyclosprin pharmacokinetic profiles were assessed in parallel with endogenous creatinine clearances over sequential 1-to 2-h intervals. The rate and extent of cyclosporin absorption were significantly greater (P

A new microemulsion formulation of cyclosporine (Sandimmune Neoral) was compared to the commercially available formulation (Sandimmune) in 11 stable renal transplant patients with regard to the consistency in cyclosporine pharmacokinetics between a daytime fasting, and a nighttime nonfasting administration. Daily cyclosporine doses were individualized and administered in equal, divided doses every 12 h as soft gelatin capsules; doses were kept constant throughout the study. Serial blood samples were obtained over a 24-h period (two consecutive dosing intervals) at steady-state for each formulation, and cyclosporine concentrations were determined in whole blood by a specific radioimmunoassay method. Within-formulation consistency in pharmacokinetic parameters between the daytime and nighttime administrations was assessed in terms of bioequivalence criteria. Following the mg-to-mg conversion from the commercial to the microemulsion formulation, area under the curve (AUC) was increased on average by 30% due to absorption-related pharmacokinetic differences, while trough concentrations remained in the therapeutic range. Within each formulation, AUC was bioequivalent when comparing the daytime fasting to the nighttime nonfasting administration. For the commercial formulation, however, there was considerable variation in absorption rate, dampening of peak-trough fluctuation, and elevation of trough concentration following the nighttime nonfasting dose. By contrast, the microemulsion exhibited a more stable concentration-time profile over the two dosing intervals, with bioequivalence in peak-trough fluctuation and trough concentrations. Hence, the steady-state pharmacokinetics of cyclosporine from the microemulsion formulation exhibit greater within-day consistency compared to the commercial formulation in stable renal allograft recipients.

The steady-state pharmacokinetics and tolerability of a microemulsion formulation of cyclosporine (Sandimmune Neoral) were compared with Sandimmune in 18 clinically stable renal allograft recipients. In study period I (2 weeks duration), patients entered the study on a stable, individualized twice-daily dosage regimen of Sandimmune. Two approaches were assessed for changing patients over from Sandimmune to Sandimmune Neoral. In period II (2 weeks), doses were converted based on the area under the curve ratio derived from a relative bioavailability study comparing the two formulations in healthy volunteers. In period III (2 weeks), doses were titrated to provide comparable steady-state trough concentrations as at study entry. Sandimmune was reinstituted during period IV (2 weeks). Safety and tolerability were assessed at weekly clinic visits and the steady-state pharmacokinetics of cyclosporine in whole blood were characterized at the end of each study period. Dose conversion in period II based on the AUC ratio derived from healthy volunteers was inadequate for achieving comparable cyclosporine exposure as assessed by steady-state AUC and troughs. The concentration-controlled approach (period III) indicated that maintaining the same cyclosporine dose when changing between formulations yields comparable steady-state trough concentrations. Concomitant with this conversion, steady-state peak concentration and AUC increased on average by 39% and 15%, respectively, due to absorption-related differences between the formulations. These increases were not associated with adverse events or changes in blood pressure or clinical laboratory parameters. Furthermore, they were not detrimental to the transplanted kidney as monitored by ultrasound examination. The pharmacokinetic profiles from Sandimmune Neoral exhibited less variability and yielded a stronger correlation between trough concentration and systemic exposure (AUC) compared with Sandimmune.

The influence of a fat-rich meal on the pharmacokinetics of cyclosporine from a new oral formulation (Sandimmune Neoral) was compared in a randomized, four-way crossover study to the currently marketed formulation (Sandimmune) in 24 healthy male volunteers. Single oral doses of 300 mg Sandimmune and 180 mg Sandimmune Neoral were each administered once under fasting conditions and once 30 min after starting a high-fat meal. Serial blood samples were obtained over a 48-hr period after each administration, and whole-blood cyclosporine concentrations were determined by a specific monoclonal radioimmunoassay method. Food had a marked effect on cyclosporine absorption from Sandimmune manifested by a nearly doubled time to reach the peak concentration and a 37% increase in the area under the curve. This was associated with significant elevations in subsequent whole-blood cyclosporine concentrations compared to the fasting administration. For Sandimmune Neoral the influence was less pronounced. The maximum concentration was decreased by 26%, without a relevant change in the time to reach the peak; the area under the curve showed a slight reduction of 15%. The relatively minor influence of a fat-rich meal on the absorption of cyclosporine from Sandimmune Neoral is advantageous when individualizing a dosage regimen under clinical and out-patient administration conditions.

The pharmacokinetic dose proportionality and relative bioavailability of cyclosporine from a microemulsion formulation (Sandimmune Neoral) were compared to those of the commercial formulation (Sandimmune) over the dosage range 200 to 800 mg. Single oral administrations were given as soft gelatin capsules in an open randomized study with 48 healthy volunteers. Whole-blood cyclosporine concentrations were determined by a specific monoclonal radioimmunoassay. In comparison to Sandimmune, the absorption rate (maximum concentration) and systemic availability (area under the curve) of cyclosporine were greater for Sandimmune Neoral at all dose levels investigated. The area under the curve for Sandimmune increased in a less than proportional manner with respect to dose, whereas that for Sandimmune Neoral was consistent with linear pharmacokinetics. Because of this difference, no global assessment of relative bioavailability could be performed. The relative bioavailability of cyclosporine from Sandimmune Neoral ranged from 174 to 239% compared to Sandimmune, depending on the dose level. The improvements in oral bioavailability and dose linearity of cyclosporine exposure after administration as Sandimmune Neoral should facilitate more accurate dosage titration in the clinical setting.

Fingolimod (FTY720), a sphingosine 1-phosphate receptor modulator, is the first in a new class of therapeutic compounds and is the first oral therapy approved for the treatment of relapsing forms of multiple sclerosis (MS). Fingolimod is a structural analogue of endogenous sphingosine and undergoes phosphorylation to produce fingolimod phosphate, the active moiety. Fingolimod targets MS via effects on the immune system, and evidence from animal models indicates that it may also have actions in the central nervous system. In phase III studies in patients with relapsing-remitting MS, fingolimod has demonstrated efficacy superior to that of an approved first-line therapy, intramuscular interferon-β-1a, as well as placebo, with benefits extending across clinical and magnetic resonance imaging measures. The pharmacokinetic profiles of fingolimod and fingolimod phosphate have been extensively investigated in studies in healthy volunteers, renal transplant recipients (the indication for which fingolimod was initially under clinical development, but the development was subsequently discontinued) and MS patients. Results from these studies have demonstrated that fingolimod is efficiently absorbed, with an oral bioavailability of90%, and its absorption is unaffected by dietary intake, therefore it can be taken without regard to meals. Fingolimod and fingolimod phosphate have a half-life of 6-9 days, and steady-state pharmacokinetics are reached after 1-2 months of daily dosing. The long half-life of fingolimod, together with its slow absorption, means that fingolimod has a flat concentration profile over time with once-daily dosing. Fingolimod and fingolimod phosphate show dose-proportional exposure in single- and multiple-dose studies over a range of 0.125-5 mg; hence, there is a predictable relationship between dose and systemic exposure. Furthermore, fingolimod and fingolimod phosphate exhibit low to moderate intersubject pharmacokinetic variability. Fingolimod is extensively metabolized, with biotransformation occurring via three main pathways: (i) reversible phosphorylation to fingolimod phosphate; (ii) hydroxylation and oxidation to yield a series of inactive carboxylic acid metabolites; and (iii) formation of non-polar ceramides. Fingolimod is largely cleared through metabolism by cytochrome P450 (CYP) 4F2. Since few drugs are metabolized by CYP4F2, fingolimod would be expected to have a relatively low potential for drug-drug interactions. This is supported by data from in vitro studies indicating that fingolimod and fingolimod phosphate have little or no capacity to inhibit and no capacity to induce other major drug-metabolizing CYP enzymes at therapeutically relevant steady-state blood concentrations. Population pharmacokinetic evaluations indicate that CYP3A inhibitors and CYP3A inducers have no effect or only a weak effect on the pharmacokinetics of fingolimod and fingolimod phosphate. However, blood concentrations of fingolimod and fingolimod phosphate are increased moderately when fingolimod is coadministered with ketoconazole, an inhibitor of CYP4F2. The pharmacokinetics of fingolimod are unaffected by renal impairment or mild-to-moderate hepatic impairment. However, exposure to fingolimod is increased in patients with severe hepatic impairment. No clinically relevant effects of age, sex or ethnicity on the pharmacokinetics of fingolimod have been observed. Fingolimod is thus a promising new therapy for eligible patients with MS, with a predictable pharmacokinetic profile that allows effective once-daily oral dosing.