α4-integrin receptor desaturation and disease activity return after natalizumab cessation.

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. CLINICALTRIALSGOV IDENTIFIER: NCT01499667.

Everolimus for the treatment of lymphangioleiomyomatosis: a phase II study.

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.

mTOR inhibition improves immune function in the elderly.

Inhibition of the mammalian target of rapamycin (mTOR) pathway extends life span in all species studied to date, and in mice delays the onset of age-related diseases and comorbidities. However, it is unknown if mTOR inhibition affects aging or its consequences in humans. To begin to assess the effects of mTOR inhibition on human aging-related conditions, we evaluated whether the mTOR inhibitor RAD001 ameliorated immunosenescence (the decline in immune function during aging) in elderly volunteers, as assessed by their response to influenza vaccination. RAD001 enhanced the response to the influenza vaccine by about 20% at doses that were relatively well tolerated. RAD001 also reduced the percentage of CD4 and CD8 T lymphocytes expressing the programmed death-1 (PD-1) receptor, which inhibits T cell signaling and is more highly expressed with age. These results raise the possibility that mTOR inhibition may have beneficial effects on immunosenescence in the elderly.

The pharmacokinetics of everolimus in de novo kidney transplant patients receiving tacrolimus: an analysis from the randomized ASSET study.

BACKGROUND: Pharmacokinetic data regarding a drug-drug interaction between everolimus and tacrolimus are sparse. MATERIAL AND 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 (C0), peak concentration (Cmax), and AUC0-12 in the very low tacrolimus group were approximately half that in the low tacrolimus group, but everolimus dose, C0, Cmax, and AUC0-12 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 C0, Cmax and AUC0-12 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.

Validation of a liquid chromatography/tandem mass spectrometry method for the simultaneous quantification of Sotrastaurin and its metabolite N-desmethyl-sotrastaurin in human blood.

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 C18 (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 K3EDTA 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.

Clinical pharmacokinetics of fingolimod.

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-ß-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 of >90%, 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.

Lung deposition of inhaled tobramycin with eFlow rapid/LC Plus jet nebuliser in healthy and cystic fibrosis subjects.

BACKGROUND: Reducing nebulisation times for tobramycin solution for inhalation in cystic fibrosis (CF) may improve compliance. METHODS: In 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. RESULTS: In 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<0.05). Lung deposition in healthy subjects was comparable between both devices. CONCLUSIONS: eFlow rapid reduces the nebulisation time of tobramycin and can potentially improved compliance in patients with CF.

Pharmacokinetics of sotrastaurin combined with tacrolimus or mycophenolic acid in de novo kidney transplant recipients.

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<0.0001). Sotrastaurin increased tacrolimus concentrations by a pharmacokinetic interaction inasmuch as the tacrolimus dose needed to achieve a given C0 was up to 47% lower when combined with sotrastaurin versus with MPA. CONCLUSIONS: Sotrastaurin pharmacokinetics were similar when combined with reduced-exposure or standard-exposure tacrolimus or with MPA. Tacrolimus exposure was significantly increased by sotrastaurin in the initial weeks posttransplant by a pharmacokinetic interaction.

Sotrastaurin single-dose pharmacokinetics in de novo liver transplant recipients.

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 < 0.0001). There was minor excretion of sotrastaurin in drained bile (1% of dose) consistent with the fact that sotrastaurin is extensively metabolized leaving little unchanged drug to excrete. In the first week after liver transplantation, sotrastaurin is bioavailable after oral administration. However, patients with elevated α1-acid glycoprotein levels may have lower free drug concentrations. Whether a higher dose of sotrastaurin is needed to compensate for this in the short-term after surgery will be addressed in future clinical trials.

Overview of sotrastaurin clinical pharmacokinetics.

Sotrastaurin (AEB071) is an investigational immunosuppressant that blocks T-lymphocyte activation through protein kinase C inhibition. It is currently in Phase II of clinical development for the prevention of acute rejection after solid organ transplantation. In renal transplant clinical trials, sotrastaurin has been administered at doses of 200 to 300 mg twice daily. Using a validated liquid chromatography method with tandem mass spectrometry, steady-state predose blood concentrations averaged approximately 600 and 900 ng/mL at these dose levels, respectively. Sotrastaurin is primarily metabolized through CYP3A4. There is one active metabolite, N-desmethyl-sotrastaurin, that is present at low blood concentrations (less than 5% of the parent exposure). The elimination half-life of sotrastaurin averages 6 hours. Clinical drug interaction studies to date have demonstrated that sotrastaurin increases the area under the concentration-time curve of everolimus 1.2-fold and of tacrolimus twofold. Conversely, sotrastaurin area under the concentration-time curve is increased up to 1.8-fold by cyclosporine and 4.6-fold by ketoconazole. Blood samples from renal transplant patients receiving sotrastaurin were stimulated ex vivo by protein kinase C-dependent pathways. Inhibition of cytokine production, expression of CD69, and thymidine uptake served as biomarkers that demonstrated the ability of sotrastaurin to inhibit T-cell activation and proliferation at the doses used in these studies. Phase II trials have paired sotrastaurin with tacrolimus, mycophenolic acid, or everolimus. The clinical and pharmacokinetic results of these and upcoming trials will determine the optimal immunosuppressive regimen to benefit from sotrastaurin's novel mechanism of action and whether therapeutic drug monitoring will be beneficial.

Sotrastaurin and cyclosporine drug interaction study in healthy subjects.

INTRODUCTION: Sotrastaurin is an immunosuppressant that inhibits protein kinase C and blocks T-lymphocyte activation. The authors determined the effect of combining sotrastaurin with the calcineurin inhibitor cyclosporine on the pharmacokinetics and biomarker responses to both drugs. METHODS: This was a randomized, 4-period, crossover study in 20 healthy subjects who received single oral doses of (1) sotrastaurin 100 mg, (2) cyclosporine 400 mg, (3) 100 mg sotrastaurin with 100 mg cyclosporine and (4) 100 mg sotrastaurin with 400 mg cyclosporine. Blood samples were collected to measure drug levels and biomarkers of T-lymphocyte activation (interleukin-2 and tumor necrosis factor producing T-cells and interleukin-2 messenger RNA levels) and of T-lymphocyte proliferation (thymidine uptake). RESULTS: Sotrastaurin did not alter cyclosporine AUC; however, low-dose and high-dose cyclosporine increased sotrastaurin AUC by 1.2-fold [90% confidence interval, 1.1-1.4] and 1.8-fold [1.6-2.1], respectively. Adding high-dose cyclosporine to a low-therapeutic dose of sotrastaurin significantly enhanced the inhibition of cytokine production by 31% [95% confidence interval, 25-36%], of interleukin-2 messenger RNA levels by 13% [7-19%], and of thymidine uptake by 37% [32-42%] compared with sotrastaurin alone. Addition of low-dose cyclosporine elicited slightly lower enhancements in inhibition by 21% [14-28%], 6% [-4-16%], and 26% [21-30%], respectively, compared with sotrastaurin alone. CONCLUSIONS: Sotrastaurin did not alter the pharmacokinetics of cyclosporine, but cyclosporine increased sotrastaurin AUC up to 1.8-fold. The combined drugs elicited a significantly greater inhibition of T-cell activation and proliferation than sotrastaurin alone.

Sotrastaurin and tacrolimus coadministration: effects on pharmacokinetics and biomarker responses.

Sotrastaurin is an immunosuppressant that inhibits protein kinase C. In the prevention of acute rejection in organ transplantation, sotrastaurin might be combined with tacrolimus. A drug interaction study was performed in 18 healthy subjects who received single oral doses of sotrastaurin 400 mg, tacrolimus 7 mg, and the drug combination. Drug blood levels and lymphocyte activation and proliferation were measured. Tacrolimus did not alter the pharmacokinetics of sotrastaurin; however, sotrastaurin increased tacrolimus area under the concentration-time curve by 2.0-fold (90% confidence interval, 1.8-2.1). Production of interleukin-2 and tumor necrosis factor by T cells activated via calcium-independent pathways was inhibited by 75% ± 22% from baseline by sotrastaurin. Interleukin-2 messenger RNA levels were decreased by 90% ± 9% from baseline by sotrastaurin. Addition of tacrolimus to sotrastaurin had minimal or no effect on these biomarkers, consistent with tacrolimus' mechanism of action. Lymphocyte proliferation induced via calcium-dependent pathways was decreased from baseline by 82% ± 9% by sotrastaurin, 76% ± 11% by tacrolimus, and 96% ± 2% for the drug combination. How sotrastaurin and tacrolimus could be partnered in an immunosuppressive regimen will need to be established in the context of controlled clinical trials in organ transplant patients, taking into account the pharmacokinetic interaction on tacrolimus and the potentially enhanced immunosuppressive activity of this drug combination.

The effect on sotrastaurin pharmacokinetics of strong CYP3A inhibition by ketoconazole.

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 C(max) 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.

Pharmacokinetics and safety of tobramycin administered by the PARI eFlow rapid nebulizer in cystic fibrosis.

BACKGROUND: Nebulization times have been identified as an issue in patient compliance with tobramycin solution for inhalation (TSI) therapy in cystic fibrosis (CF). METHODS: In this randomized, open-label, multicentre, two-period, crossover study, patients (n=25) with CF and chronic pulmonary pseudomonal infection received TSI for 15 days via eFlow rapid or LC PLUS nebulizer. Nebulization times and sputum/serum tobramycin concentrations were determined, and safety evaluated. RESULTS: Nebulization times were significantly shorter for eFlow rapid versus LC PLUS on Day 1 (least squares mean estimate of the difference -10.5 min, 95% confidence intervals [CI] -12.6, -8.3, p<0.0001) and Day 15 (difference -7.7 min, 95% CI -9.0, -6.5, p<0.0001). Broadly comparable sputum/systemic exposure to tobramycin was observed and the incidence of adverse events was similar for both nebulizers. CONCLUSION: Use of the eFlow rapid nebulizer reduced TSI nebulization time. The systemic exposure to tobramycin appeared to be broadly similar in this exploratory study.

Ketoconazole increases fingolimod blood levels in a drug interaction via CYP4F2 inhibition.

The sphingosine-1-phosphate receptor modulator fingolimod is predominantly hydroxylated by cytochrome CYP4F2. In vitro experiments showed that ketoconazole significantly inhibited the oxidative metabolism of fingolimod by human liver microsomes and by recombinant CYP4F2. The authors used ketoconazole as a putative CYP4F2 inhibitor to quantify its influence on fingolimod pharmacokinetics in healthy subjects. In a 2-period, single-sequence, crossover study, 22 healthy subjects received a single 5-mg dose of fingolimod in period 1. In period 2, subjects received ketoconazole 200 mg twice daily for 9 days and a single 5-mg dose of fingolimod coadministered on the 4th day of ketoconazole treatment. Ketoconazole did not affect fingolimod t(max) or half-life, but there was a weak average increase in C(max) of 1.22-fold (90% confidence interval, 1.15-1.30). The AUC over the 5 days of ketoconazole coadministration increased 1.40-fold (1.31-1.50), and the full AUC to infinity increased 1.71-fold (1.53-1.91). The AUC of the active metabolite fingolimod-phosphate was increased to a similar extent by 1.67-fold (1.50-1.85). Ketoconazole predose plasma levels were not altered by fingolimod. The magnitude of this interaction suggests that a proactive dose reduction of fingolimod is not necessary when adding ketoconazole to a fingolimod regimen. The clinician, however, should be aware of this interaction and bear in mind the possibility of a fingolimod dose reduction based on clinical monitoring.

Pharmacokinetics and immunodynamics of basiliximab in pediatric renal transplant recipients on mycophenolate mofetil comedication.

BACKGROUND: The aim of this substudy within a prospective, multicenter, placebo-controlled trial was to assess the pharmacokinetics and immunodynamics of basiliximab in pediatric renal transplant recipients on comedication with mycophenolate mofetil (MMF). METHODS: Eighty-two patients aged 3 to 18 years, receiving cyclosporine microemulsion, MMF, corticosteroids, and basiliximab or placebo were investigated. Basiliximab serum concentrations were determined by ELISA, CD25+, and CD122+ T lymphocytes by flow cytometry. RESULTS: Basiliximab clearance adjusted to body surface area was significantly (P<0.05) greater in children versus adults, but the relatively higher basiliximab dose given to children yielded similar exposure compared with adolescents. A cross-study comparison revealed that MMF reduced basiliximab clearance and prolonged CD25 saturation duration from approximately 5 weeks in the absence of MMF to 10 weeks in the presence of MMF. Basiliximab led to a marked reduction of CD25+ T-cell fraction during the first 8 to 10 weeks posttransplant, but did not specifically affect CD122+ T cells. The majority of biopsy-proven acute rejection episodes (BPAR) were observed after interleukin (IL) 2-R desaturation, whereas about a quarter of BPARs occurred despite adequate IL2-R blockade. CONCLUSIONS: The currently recommended basiliximab dose for pediatric patients, when used with cyclosporine microemulsion and corticosteroids, yielded adequate drug exposure in children and adolescents also under MMF comedication. The observation that about a quarter of BPARs occurred despite adequate IL2-R blockade suggests that another T-cell activation pathway independent of the IL-2/IL-2R pathway is operative, for example, the IL-15 signaling pathway.

The ability of atropine to prevent and reverse the negative chronotropic effect of fingolimod in healthy subjects.

AIMS: The authors determined whether intravenous atropine can prevent or counteract the negative chronotropic effect of the immunomodulator fingolimod. METHODS: In this randomized, placebo-controlled, two-period, crossover study, 12 healthy subjects received 5 mg fingolimod orally concurrently with intravenous atropine (titrated to a heart rate of 110-120 beats min(-1)) or intravenous placebo. A second group of 12 subjects received atropine/placebo 4 h after the fingolimod dose. Continuous telemetry measurements were made for 24 h after each fingolimod dose. RESULTS: Fingolimod administration alone yielded a heart rate nadir of 51 +/- 5 beats min(-1) at a median 4 h postdose with heart rate remaining depressed at 51-64 beats min(-1) over the rest of the day. Concurrent administration of fingolimod and atropine yielded a nadir of 66 +/- 6 beats min(-1) resulting in an atropine: placebo ratio (90% confidence interval) of 1.30 (1.22, 1.36). When atropine was administered at the time of the nadir, it was able to reverse the negative chronotropic effect of fingolimod from a heart rate of 56 +/- 9 beats min(-1) (placebo) to 64 +/- 8 beats min(-1) (atropine) resulting in an atropine: placebo ratio of 1.15 (1.04, 1.26). Atropine had no influence on the pharmacokinetics of fingolimod. CONCLUSIONS: Atropine administered concurrently with fingolimod prevented the heart rate nadir that typically occurs 4 h postdose. Atropine administered at the time of the heart rate nadir was able to reverse the negative chronotropic effect of fingolimod.

Identifying optimal biologic doses of everolimus (RAD001) in patients with cancer based on the modeling of preclinical and clinical pharmacokinetic and pharmacodynamic data.

PURPOSE: To 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 METHODS: Inhibition 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. RESULTS: Time- 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. CONCLUSION: A 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.

Phase I pharmacokinetic and pharmacodynamic study of the oral mammalian target of rapamycin inhibitor everolimus in patients with advanced solid tumors.

PURPOSE: To identify the optimal regimen and dosage of the oral mammalian target of rapamycin inhibitor everolimus (RAD001). METHODS: We 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. RESULTS: Ninety-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 >or= 20 mg/wk. Area under the curve increased proportional to dose, but maximum serum concentration increased less than proportionally at doses >or= 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 >or= 6 months, including five of 10 patients with renal cell carcinoma. CONCLUSION: Everolimus 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 effect on heart rate of combining single-dose fingolimod with steady-state atenolol or diltiazem in healthy subjects.

OBJECTIVE: The sphingosine-1-phosphate receptor modulator fingolimod (FTY720) is known to elicit a negative chronotropic effect at treatment initiation that attenuates over time with continued dosing. The authors determined the effect of combining a single dose of fingolimod with steady-state atenolol or diltiazem on heart rate and mean arterial pressure. METHODS: In a partially randomized, single-blind, placebo-controlled, three-period, crossover study, 25 healthy subjects received (1) a single oral 5-mg dose of fingolimod, (2) either 50 mg atenolol or 240 mg diltiazem once daily for 5 days, and (3) the antihypertensive for 5 days and a single dose of fingolimod on day 5. Telemetry and pharmacokinetic data were collected. RESULTS: The daytime mean heart rate nadir was 15% lower when fingolimod was combined with atenolol (42 +/- 7 bpm) compared with fingolimod alone (51 +/- 9 bpm) yielding a combination/monotherapy ratio of 0.85 (90%CI, 0.79-0.92). The daytime mean heart rate nadir from fingolimod alone (55 +/- 5 bpm) was not altered when combined with diltiazem (56 +/- 8 bpm) yielding a ratio of 0.99 (0.94-1.05). There was no clinically relevant change in mean arterial pressure when fingolimod was administered with atenolol or diltiazem compared with administration of the drugs alone in normotensive subjects. The pharmacokinetics of the drugs were not altered during coadministration. CONCLUSION: Adding fingolimod to a beta-blocker such as atenolol resulted in a moderately lower mean heart rate nadir compared with fingolimod alone. However, subjects who had a stronger negative chronotropic response to fingolimod alone (nadir < 50 bpm) had minimal or no further reduction in heart rate with the drug combination. Adding fingolimod to a calcium channel blocker such as diltiazem did not further lower the heart rate compared to fingolimod alone.