Concentration-QTc modeling of sitravatinib in patients with advanced solid malignancies.

Sitravatinib (MGCD516) is an orally available, small molecule, tyrosine kinase inhibitor that has been evaluated in patients with advanced solid tumors. Concentration-corrected QT interval (QTc; C-QTc) modeling was undertaken, using 767 matched concentration-ECG observations from 187 patients across two clinical studies in patients with advanced solid malignancies, across a dose range of 10-200 mg, via a linear mixed-effects (LME) model. The effect on heart rate (HR)-corrected QT interval via Fridericia's correction method (QTcF) at the steady-state maximum concentration (Cmax,ss) for the sitravatinib proposed therapeutic dosing regimen (100 mg malate once daily [q.d.]) without and with relevant intrinsic and extrinsic factors were predicted. No significant changes in HR from baseline were observed. Hysteresis between sitravatinib plasma concentration and change in QTcF from baseline (ΔQTcF) was not observed. There was no significant relationship between sitravatinib plasma concentration and ΔQTcF. The final C-QTc model predicted a mean (90% confidence interval [CI]) ΔQTcF of 3.92 (1.95-5.89) ms and 2.94 (0.23-6.10) ms at the proposed therapeutic dosing regimen in patients with normal organ function (best case scenario) and patients with hepatic impairment (worst-case scenario), respectively. The upper bounds of the 90% CIs were below the regulatory threshold of concern of 10 ms. The results of the described C-QTc analysis, along with corroborating results from nonclinical safety pharmacology studies, indicate that sitravatinib has a low risk of QTc interval prolongation at the proposed therapeutic dose of 100 mg malate q.d.

Absorption, Metabolism, and Excretion, In Vitro Pharmacology, and Clinical Pharmacokinetics of Ozanimod, a Novel Sphingosine 1-Phosphate Receptor Modulator.

Ozanimod is approved for the treatment of relapsing forms of multiple sclerosis. Absorption, metabolism, and excretion of ozanimod were investigated after a single oral dose of 1.0 mg [14C]ozanimod hydrochloride to six healthy subjects. In vitro experiments were conducted to understand the metabolic pathways and enzymes involved in the metabolism of ozanimod and its active metabolites. The total mean recovery of the administered radioactivity was ∼63%, with ∼26% and ∼37% recovered from urine and feces, respectively. Based on exposure, the major circulating components were active metabolite CC112273 and inactive metabolite RP101124, which together accounted for 50% of the circulating total radioactivity exposure, whereas ozanimod accounted for 6.7% of the total radioactive exposure. Ozanimod was extensively metabolized, with 14 metabolites identified, including two major active metabolites (CC112273 and CC1084037) and one major inactive metabolite (RP101124) in circulation. Ozanimod is metabolized by three primary pathways, including aldehyde dehydrogenase and alcohol dehydrogenase, cytochrome P450 isoforms 3A4 and 1A1, and reductive metabolism by gut microflora. The primary metabolite RP101075 is further metabolized to form major active metabolite CC112273 by monoamine oxidase B, which further undergoes reduction by carbonyl reductases to form CC1084037 or CYP2C8-mediated oxidation to form RP101509. CC1084037 is oxidized rapidly to form CC112273 by aldo-keto reductase 1C1/1C2 and/or 3ß- and 11ß-hydroxysteroid dehydrogenase, and this reversible oxidoreduction between two active metabolites favors CC112273. The ozanimod example illustrates the need for conducting timely radiolabeled human absorption, distribution, metabolism, and excretion studies for characterization of disproportionate metabolites and assessment of exposure coverage during drug development. SIGNIFICANCE STATEMENT: Absorption, metabolism, and excretion of ozanimod were characterized in humans, and the enzymes involved in complex metabolism were elucidated. Disproportionate metabolites were identified, and the activity of these metabolites was determined.

Concentration-QTc Modeling of Ozanimod's Major Active Metabolites in Adult Healthy Subjects.

Ozanimod, approved by regulatory agencies in multiple countries for the treatment of adults with relapsing multiple sclerosis, is a sphingosine 1-phosphate (S1P) receptor modulator, which binds with high affinity selectively to S1P receptor subtypes 1 and 5. The relationships between plasma concentrations of ozanimod and its major active metabolites, CC112273 and CC1084037, and the QTc interval (C-QTc) from a phase I multiple-dose study in healthy subjects were analyzed using nonlinear mixed effects modeling. QTc was modeled linearly as the sum of a sex-related fixed effect, baseline, and concentration-related random effects that incorporated interindividual and residual variability. Common linear, power, and maximum effect (Emax ) functions were assessed for characterizing the relationship of QTc with concentrations. Model goodness-of-fit and performance were evaluated by standard diagnostic tools, including a visual predictive check. The placebo-corrected change from baseline in QTc (ΔΔQTc) was estimated based on the developed C-QTc model using a nonparametric bootstrapping approach. QTc was better derived using a study-specific population formula (QTcP). Among the investigated functions, an Emax function most adequately described the relationship of QTcP with concentrations. Separate models for individual analytes characterized the C-QTcP relationship better than combined analytes models. Attributing QT prolongation independently to CC1084037 or CC112273, the upper bound of the 95% confidence interval of the predicted ΔΔQTcP was ~ 4 msec at the plateau of the Emax curves. Therefore, ΔΔQTcP is predicted to remain below 10 msec at the supratherapeutic concentrations of the major active metabolites.

Multiple-Dose Pharmacokinetics of Ozanimod and its Major Active Metabolites and the Pharmacodynamic and Pharmacokinetic Interactions with Pseudoephedrine, a Sympathomimetic Agent, in Healthy Subjects.

INTRODUCTION: The aims of this study were to characterize the multiple-dose pharmacokinetics (PK) of ozanimod's major active metabolites (CC112273 and CC1084037) and to evaluate the pharmacodynamic and PK interactions with pseudoephedrine (PSE). METHODS: In this phase 1, single-center, randomized, double-blind, placebo-controlled study, 56 healthy adult subjects were randomized to receive either placebo or ozanimod once daily for 30 days (0.23 mg on days 1-4, 0.46 mg on days 5-7, 0.92 mg on days 8-10, and 1.84 mg on days 11-30). On day 30, a single oral dose of PSE 60 mg was co-administered with placebo or ozanimod. Maximum time-matched change in systolic blood pressure (SBP) from baseline (day 29) following PSE administration on day 30 was calculated. Plasma PK parameters for ozanimod, CC112273, CC1084037, and PSE were estimated using noncompartmental methods. RESULTS: Fifty-two subjects (92.9%) completed the study. Following multiple dosing, approximately 94% of circulating total active drug exposure was represented by ozanimod (6%), CC112273 (73%), and CC1084037 (15%). Exposures of CC112273 and CC1084037 were highly correlated. Mean maximum time-matched change from baseline for SBP was not significantly different between ozanimod + PSE and placebo + PSE. Ozanimod also had no effect on the PK of PSE. Co-administration of ozanimod with a single dose of PSE in healthy subjects was generally well tolerated. While CC112273 and CC1084037 selectively inhibited monoamine oxidase (MAO)-B in vitro, both active metabolites do not inhibit platelet MAO-B activity in vivo. CONCLUSION: Concomitant administration of ozanimod with PSE, a sympathomimetic agent, did not potentiate the effects on blood pressure. TRIAL REGISTRATION: NCT03644576.

Single-Dose Pharmacokinetics of Ozanimod and its Major Active Metabolites Alone and in Combination with Gemfibrozil, Itraconazole, or Rifampin in Healthy Subjects: A Randomized, Parallel-Group, Open-Label Study.

INTRODUCTION: The aims of this study were to characterize the single-dose pharmacokinetics (PK) of the major active metabolites of ozanimod, CC112273 and CC1084037, and to evaluate the effect of gemfibrozil (a strong inhibitor of cytochrome P450 [CYP] 2C8), itraconazole (a strong inhibitor of CYP3A and P-glycoprotein [P-gp]), and rifampin (a strong inducer of CYP3A/P-gp and moderate inducer of CYP2C8) on the single-dose PK of ozanimod and its major active metabolites in healthy subjects. METHODS: This was a phase 1, randomized, parallel-group, open-label study with two parts. In part 1, 40 subjects were randomized to receive a single oral dose of ozanimod 0.46 mg (group A, n = 20) or oral doses of gemfibrozil 600 mg twice daily for 17 days with a single oral dose of ozanimod 0.46 mg on day 4 (group B, n = 20). In part 2, 60 subjects were randomized to receive a single oral dose of ozanimod 0.92 mg (group C, n = 20), oral doses of itraconazole 200 mg once daily for 17 days with a single oral dose of ozanimod 0.92 mg on day 4 (group D, n = 20), or oral doses of rifampin 600 mg once daily for 21 days with a single oral dose of ozanimod 0.92 mg on day 8 (group E, n = 20). Plasma PK parameters for ozanimod, CC112273, and CC1084037 were estimated using noncompartmental methods. RESULTS: Dose-proportional increases in maximum observed concentration (Cmax) and area under the concentration-time curve (AUC) were observed for ozanimod, CC112273, and CC1084037. The mean terminal elimination half-life (t1/2) for ozanimod was approximately 20-22 h while the mean t1/2 for CC112273 and CC1084037 were approximately 10 days. CC112273 and CC1084037 exposures were highly correlated with or without interacting drugs. Itraconazole increased ozanimod AUC by approximately 13% while rifampin reduced ozanimod AUC by approximately 24%, suggesting a minor role of CYP3A and P-gp in the overall disposition of ozanimod. Gemfibrozil increased the AUC for CC112273 and CC1084037 by approximately 47% and 69%, respectively. Rifampin reduced the AUC for CC112273 and CC1084037, primarily via CYP2C8 induction, by approximately 60% and 55%, respectively. CONCLUSIONS: Ozanimod's major active metabolites, CC112273 and CC1084037, exhibited similar single-dose PK properties and their exposures were highly correlated. CYP2C8 is one of the important enzymes in the overall disposition of CC112273 and subsequently its direct metabolite CC1084037. TRIAL REGISTRATION: Clinical trial: NCT03624959.

Effect of the sphingosine-1-phosphate receptor modulator ozanimod on leukocyte subtypes in relapsing MS.

OBJECTIVE: To better understand ozanimod's mechanism of action (MOA), we conducted exploratory analyses from a phase 1 study to characterize ozanimod's effect on circulating leukocyte subsets in patients with relapsing multiple sclerosis. METHODS: An open-label pharmacodynamic study randomized patients to oral ozanimod hydrochloride (HCl) 0.5 (n = 13) or 1 mg/d (n = 11) for ∼12 weeks (including 7-day dose escalation). Circulating leukocyte subsets were quantified using flow cytometry (days 28, 56, and 85) and epigenetic cell counting (days 2, 5, 28, 56, and 85) and compared with baseline (day 1) using descriptive statistics. RESULTS: Ozanimod caused dose-dependent reductions in absolute lymphocyte counts. Observed by both methodologies, circulating CD19+ B- and CD3+ T-cell counts were reduced by >50% with ozanimod HCl 0.5 mg and >75% with 1 mg at day 85. Based on flow cytometry, ozanimod HCl 1 mg showed greater decreases in CD4+ than CD8+ T cells, greater decreases in both CD4+ and CD8+ central memory vs effector memory T cells, and reductions in mean CD4+ and CD8+ naive T cells by ≥90% at day 85. In the flow cytometry analysis, changes in monocytes, natural killer, and natural killer T cells were minimal. Using epigenetic cell counting, greater reductions for Th17 than T regulatory cells were determined. CONCLUSION: Ozanimod induced dose-dependent reductions in circulating B- and T-cell counts and differential effects on naive and memory CD4+ and CD8+ T cells and CD19+ B cells. Data characterized with both a novel epigenetic cell-counting method and flow cytometry support ozanimod's MOA. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov NCT02797015.

Cardiac Safety of Ozanimod, a Novel Sphingosine-1-Phosphate Receptor Modulator: Results of a Thorough QT/QTc Study.

Ozanimod is a novel, selective, oral sphingosine-1-phosphate (1 and 5) receptor modulator in development for multiple sclerosis and inflammatory bowel disease. This randomized, double-blind, placebo-controlled, positive-controlled, parallel-group thorough QT study characterized the effects of ozanimod on cardiac repolarization in healthy subjects. Eligible subjects were randomized to 1 of 2 groups: ozanimod (escalated from 0.25 to 2 mg over 14 days) or placebo (for 14 days). A single dose of moxifloxacin 400 mg or placebo was administered on days 2 and 17. The primary end point was the time-matched, placebo-corrected, baseline-adjusted mean QTcF (ΔΔQTcF). A total of 113/124 (91.1%) subjects completed the study. The upper limits of the 2-sided 90% confidence intervals for ΔΔQTcF for both ozanimod 1 and 2 mg were below the 10-millisecond regulatory threshold. No QTcF >480 milliseconds or postdose change in QTcF of >60 milliseconds was observed. There was no evidence of a positive relationship between concentrations of ozanimod and its active metabolites and ΔΔQTcF. Although ozanimod blunted the observed diurnal increase in heart rate, excursions below predose heart rates were no greater than with placebo. Results demonstrate that ozanimod does not prolong the QTc interval or cause clinically significant bradycardia, supporting ozanimod's evolving favorable cardiac safety profile.

Effects of High- and Low-Fat Meals on the Pharmacokinetics of Ozanimod, a Novel Sphingosine-1-Phosphate Receptor Modulator.

Ozanimod (RPC1063) is an oral selective modulator of the sphingosine-1-phosphate 1 and 5 receptors under development for the treatment of relapsing multiple sclerosis and inflammatory bowel disease. The effects of high-fat and low-fat meals on the pharmacokinetics (PK) of a single oral dose of ozanimod were evaluated in 24 healthy volunteers in a randomized, open-label crossover trial. Each subject received a 1-mg dose of ozanimod hydrochloride under 3 meal conditions (fasted, high-fat, and low-fat), each separated by 7 days. Mean plasma concentration-time profiles for ozanimod and its active metabolites (RP101988 [major], RP101075 [minor]) were similar under all 3 conditions. Moreover, all PK parameters for ozanimod, RP101988, and RP101075 were similar under the 3 meal conditions. The 90% confidence intervals (CIs) for the ratios of geometric least-squares mean (fed/fasted) were within the equivalence limits of 0.80 to 1.25 for area under the concentration-time curve from time 0 to infinity (AUC0-∞ ) and maximum plasma concentration (Cmax ) for ozanimod, RP101988, and RP101075, except for the high-fat effect on RP101075 Cmax (90%CI, 0.76-0.88). Given this lack of a food effect on the exposure of ozanimod and its active metabolites, ozanimod can be taken without regard to meals.

Results From the First-in-Human Study With Ozanimod, a Novel, Selective Sphingosine-1-Phosphate Receptor Modulator.

The sphingosine-1-phosphate 1 receptor (S1P1R ) is expressed by lymphocytes, dendritic cells, and vascular endothelial cells and plays a role in the regulation of chronic inflammation and lymphocyte egress from peripheral lymphoid organs. Ozanimod is an oral selective modulator of S1P1R and S1P5R receptors in clinical development for the treatment of chronic immune-mediated, inflammatory diseases. This first-in-human study characterized the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of ozanimod in 88 healthy volunteers using a range of single and multiple doses (7 and 28 days) and a dose-escalation regimen. Ozanimod was generally well tolerated up to a maximum single dose of 3 mg and multiple doses of 2 mg/d, with no severe adverse events (AEs) and no dose-limiting toxicities. The most common ozanimod-related AEs included headache, somnolence, dizziness, nausea, and fatigue. Ozanimod exhibited linear PK, high steady-state volume of distribution (73-101 L/kg), moderate oral clearance (204-227 L/h), and an elimination half-life of approximately 17 to 21 hours. Ozanimod produced a robust dose-dependent reduction in total peripheral lymphocytes, with a median decrease of 65% to 68% observed after 28 days of dosing at 1 and 1.5 mg/d, respectively. Ozanimod selectivity affected lymphocyte subtypes, causing marked decreases in cells expressing CCR7 and variable decreases in subsets lacking CCR7. A dose-dependent negative chronotropic effect was observed following the first dose, with the dose-escalation regimen attenuating the first-dose negative chronotropic effect. Ozanimod safety, PK, and PD properties support the once-daily regimens under clinical investigation.

Population PK-PD analyses of CD25 occupancy, CD56bright NK cell expansion, and regulatory T cell reduction by daclizumab HYP in subjects with multiple sclerosis.

AIM: Daclizumab high yield process (HYP) is a humanized IgG1 monoclonal antibody that binds to the α-subunit of the interleukin-2 receptor and is being developed for treatment of multiple sclerosis (MS). This manuscript characterized the pharmacokinetic-pharmacodynamic (PK-PD) relationships of daclizumab HYP in subjects with MS. METHODS: Approximately 1400 subjects and 7000 PD measurements for each of three biomarkers [CD25 occupancy, CD56bright natural killer (NK) cell count, regulatory T cell (Treg) count] from four clinical trials were analyzed using non-linear mixed effects modelling. Evaluated regimens included 150 or 300 mg subcutaneous (s.c.) every 4 weeks. RESULTS: CD25 occupancy was characterized using a sigmoidal maximum response (Emax ) model. Upon daclizumab HYP treatment, CD25 saturation was rapid with complete saturation occurring after approximately 7 h and maintained when daclizumab HYP serum concentration was ≥5 mg l-1 . After the last 150 mg s.c. dose, unoccupied CD25 returned to baseline levels in approximately 24 weeks, with daclizumab HYP serum concentration approximately ≤1 mgl-1 1L. CD56bright NK cell expansion was characterized using an indirect response model. Following daclizumab HYP 150 mg s.c. every 4 weeks, expansion plateaus approximately at week 36, at which the average maximum expansion ratio is 5.2. After the last dose, CD56bright NK cells gradually declined to baseline levels within 24 weeks. Treg reduction was characterized by a sigmoidal Emax model. Average maximum reduction of 60% occurred approximately 4 days post 150 mg s.c. dose. After the last dose, Tregs were projected to return to baseline levels in approximately 20 weeks. CONCLUSIONS: Robust PK-PD models of CD25 occupancy, CD56bright NK cell expansion and Treg reduction by daclizumab HYP were developed to characterize its key pharmacodynamic effects in the target patient population.

Therapeutic protein-drug interaction assessment for daclizumab high-yield process in patients with multiple sclerosis using a cocktail approach.

AIMS: To characterize the potential effect of daclizumab high-yield process (DAC HYP), a monoclonal antibody that blocks the high-affinity interleukin-2 receptors for treatment of multiple sclerosis, on activity of cytochrome P450 (CYP) enzymes. METHODS: Twenty patients with multiple sclerosis received an oral cocktail of probe substrates of CYP1A2 (caffeine 200 mg), CYP2C9 (warfarin 10 mg/vitamin K 10 mg), CYP2C19 (omeprazole 40 mg), CYP2D6 (dextromethorphan 30 mg) and CYP3A (midazolam 5 mg) on two sequential occasions: 7 days before and 7 days after subcutaneous administration of DAC HYP 150 mg every 4 weeks for three doses. Serial pharmacokinetic blood samples up to 96 h post dose and 12-h urine samples were collected on both occasions. Area under the curve (AUC) for caffeine, S-warfarin, omeprazole and midazolam, and urine dextromethorphan to dextrorphan ratio were calculated. Statistical analyses were conducted on log-transformed parameters using a linear mixed-effects model. RESULTS: The 90% confidence intervals (CIs) for the geometric mean ratio (probe substrate with DAC HYP/probe substrate alone) for caffeine AUC from 0-12 h (0.93-1.15), S-warfarin AUC from 0 to infinity (AUC[0-inf]) (0.95-1.06), omeprazole AUC(0-inf) (0.88-1.13) and midazolam AUC(0-inf) (0.89-1.15) were within the no-effect boundary of 0.80-1.25. The geometric mean ratio for urine dextromethorphan to dextrorphan ratio was 1.01, with the 90% CI (0.76-1.34) extending slightly outside the no-effect boundary, likely due to high variability with urine collections and CYP2D6 activity. CONCLUSIONS: DAC HYP treatment in patients with multiple sclerosis had no effect on CYP 1A2, 2C9, 2C19, 2D6 and 3A activity.

Pharmacokinetics of daclizumab high-yield process with repeated administration of the clinical subcutaneous regimen in patients with relapsing-remitting multiple sclerosis.

BACKGROUND: Daclizumab high-yield process (DAC HYP), a humanized immunoglobulin G1 monoclonal antibody specific for the α subunit (CD25) of the high-affinity interleukin-2 receptor, has demonstrated efficacy for treatment of relapsing forms of multiple sclerosis in Phase II and III clinical trials. OBJECTIVE: To characterize the pharmacokinetics (PK) of DAC HYP following repeated administration of the 150 mg subcutaneous (SC) dose every 4 weeks (q4wk), the proposed clinical regimen in patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: Twenty-six patients with RRMS received DAC HYP 150 mg SC q4wk for a total of six doses. Serial PK blood samples were collected over the first and last dosing intervals and trough PK samples were collected between these doses. Blood samples for immunogenicity assessment were collected throughout the study. Serum DAC HYP levels and anti-DAC HYP antibodies were characterized using validated immunoassays. PK parameters were estimated using noncompartmental analysis. RESULTS: DAC HYP showed slow SC absorption with a median time to reach maximum observed concentration (Cmax) value of ~1 week. Steady state was reached by the fourth injection. At steady state, DAC HYP mean serum Cmax, minimum observed concentration (Cmin), and area under the concentration-time curve within a dosing interval (AUCtau) values were 29.1 µg/mL, 14.9 µg/mL, and 638 µg · day/mL, respectively, with intersubject variability of 35%-40%. The AUC accumulation ratio was ~2.5 at steady state. DAC HYP had a long elimination half-life of ~22 days and low apparent clearance (0.274 L/day). Nine patients tested positive for anti-DAC HYP antibodies, with no impact on DAC HYP clearance in this limited data set. CONCLUSION: The PK of DAC HYP in patients with RRMS are consistent with those previously reported in healthy volunteers. The half-life of ~3 weeks and the low fluctuations in peak and trough concentrations of serum DAC HYP support the once-monthly SC dosing regimen.

Population Pharmacokinetics of Daclizumab High-Yield Process in Healthy Volunteers and Subjects with Multiple Sclerosis: Analysis of Phase I-III Clinical Trials.

BACKGROUND AND OBJECTIVES: Daclizumab high-yield process (HYP) is a humanized IgG1 monoclonal antibody that binds to the α-subunit (CD25) of the interleukin-2 receptor. The present work characterized the population pharmacokinetics of daclizumab HYP in healthy volunteers (HVs) and subjects with relapsing-remitting multiple sclerosis (RRMS) and evaluated the effects of covariates on daclizumab HYP exposure. METHODS: Measurable serum concentrations (n = 17,139) from 1670 subjects in seven clinical studies (three phase I, one immunogenicity, one phase II with extension, and one phase III) were included in this pharmacokinetic analysis using non-linear mixed-effects modeling. The three phase I studies evaluated single or multiple doses that ranged from 50 to 400 mg with either intravenous or subcutaneous (SC) administration in HVs (n = 71). The phase II with extension studies evaluated doses of 150 or 300 mg SC every 4 weeks (n = 567), and the immunogenicity (n = 113) and the phase III (n = 919) studies evaluated 150 mg SC every 4 weeks, all in RRMS patients. RESULTS: A two-compartment model with first-order absorption and elimination adequately described daclizumab HYP pharmacokinetics. Clearance (CL) was 0.212 L/day and the central volume of distribution was 3.92 L, scaled by [body weight (kg)/68] with exponents of 0.87 and 1.12, respectively. The peripheral volume of distribution was 2.42 L. Absorption lag time, mean absorption time, and absolute bioavailability (100-300 mg SC) were 1.61 h, 7.2 days, and 88 %, respectively. The daclizumab HYP terminal half-life was 21 days. Baseline CD25, age, and sex did not influence daclizumab HYP pharmacokinetics. Body weight explained 37 and 27 % of the inter-individual variability for CL and central volume of distribution, respectively. Neutralizing antibody (NAb)-positive status (included as a time-varying covariate) increased daclizumab HYP CL by 19 %. CONCLUSIONS: Consistent with previous findings in HVs, this analysis including extensive data from RRMS patients demonstrates that daclizumab HYP is characterized by slow CL, linear pharmacokinetics at doses above 100 mg, and high SC bioavailability. The pharmacokinetics of daclizumab HYP were not influenced by age (range 18-66 years), the sex of adult subjects, or the baseline CD4+CD25+ T cells (target level). The impact of covariates (body weight, NAb) on daclizumab HYP pharmacokinetics is unlikely to be clinically relevant.

Blockade of the High-Affinity Interleukin-2 Receptors with Daclizumab High-Yield Process: Pharmacokinetic/Pharmacodynamic Analysis of Single- and Multiple-Dose Phase I Trials.

BACKGROUND AND OBJECTIVE: Daclizumab high-yield process (DAC HYP) is a humanized monoclonal antibody that selectively blocks the α-subunit (CD25) of the high-affinity interleukin-2 receptors, and has shown robust efficacy as a treatment for multiple sclerosis (MS). This work quantitatively characterized the relationship between DAC HYP serum concentrations and saturation of CD25 expressed on antigen-rich target T cells in blood. METHODS: Serial pharmacokinetic and 968 CD25 measurements from three double-blind, randomized, placebo-controlled, phase I studies of DAC HYP (50-300 mg subcutaneous and 200-400 mg intravenous doses or placebo) in healthy volunteers (n = 95) were analyzed using nonlinear mixed-effects modeling. CD25 occupancy was determined using flow cytometry and a fluorescently-labeled DAC HYP-competing antibody. RESULTS: CD25 occupancy was described using a direct inhibitory sigmoidal maximum effect (E max) model (where DAC HYP fully inhibited CD25 labeling with competing antibody). Two IC50 (serum concentration corresponding to 50 % of maximal inhibition) parameters were used to describe rapid CD25 saturation at initiation of dosing and apparently slower desaturation during DAC HYP washout. Parameter estimates (95 % bootstrap confidence intervals) were: baseline CD25 labeling, 47 % (45-48); DAC HYP IC50(saturation), 0.023 µg/mL (0.005-0.073); IC50(desaturation) 0.86 µg/mL (0.74-0.98); Hill coefficient 5.6 (4.3-6.8). CONCLUSIONS: Based on the developed model, the 150 mg monthly subcutaneous regimen of DAC HYP in subjects with MS is predicted to saturate CD25 on target effector T cells within a few hours of dosing and maintain CD25 saturation during the entire dosing interval. Free CD25 levels return to baseline within 4-6 months of the last DAC HYP dose.

Randomized phase I trials of the safety/tolerability of anti-LINGO-1 monoclonal antibody BIIB033.

OBJECTIVE: To evaluate the safety, tolerability, and pharmacokinetics (PK) of BIIB033 (anti-LINGO-1 monoclonal antibody) in healthy volunteers and participants with multiple sclerosis (MS). METHODS: In 2 separate randomized, placebo-controlled studies, single ascending doses (SAD; 0.1-100 mg/kg) of BIIB033 or placebo were administered via IV infusion or subcutaneous injection to 72 healthy volunteers, and multiple ascending doses (MAD; 0.3-100 mg/kg; 2 doses separated by 14 days) of BIIB033 or placebo were administered via IV infusion to 47 participants with relapsing-remitting or secondary progressive MS. Safety assessments included adverse event (AE) monitoring, neurologic examinations, conventional and nonconventional MRI, EEG, optical coherence tomography, retinal examinations, and evoked potentials. Serum and CSF PK as well as the immunogenicity of BIIB033 were also evaluated. RESULTS: All 72 healthy volunteers and 47 participants with MS were included in the safety analyses. BIIB033 infusions were well tolerated. The frequency of AEs was similar between BIIB033 and placebo. There were no serious AEs or deaths. No clinically significant changes in any of the safety measures were observed. BIIB033 PK was similar between healthy volunteers and participants with MS. Doses of ≥10 mg/kg resulted in BIIB033 concentrations similar to or higher than the concentration associated with 90% of the maximum remyelination effect in rat remyelination studies. The incidence of anti-drug antibody production was low. CONCLUSIONS: The emerging safety, tolerability, and PK of BIIB033 support advancing BIIB033 into phase II clinical development as a potential treatment for CNS demyelination disorders. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that BIIB033 is well tolerated and safe (serious adverse event rate 0%, 95% confidence interval 0-7.6%).

Population pharmacokinetics of daclizumab high-yield process in healthy volunteers: integrated analysis of intravenous and subcutaneous, single- and multiple-dose administration.

BACKGROUND AND OBJECTIVE: Daclizumab is a humanized monoclonal antibody that blocks the α-subunit of the interleukin-2 receptor with demonstrated benefits in the treatment of multiple sclerosis. The present work aimed to characterize the pharmacokinetics of daclizumab high-yield process (HYP) in healthy volunteers. METHODS: Three double-blind, randomized, placebo-controlled, phase I studies evaluated the pharmacokinetics of daclizumab HYP in healthy volunteers following single subcutaneous administration (50, 150, or 300 mg), multiple subcutaneous administrations (100 or 200 mg biweekly with a 200 mg loading dose), or single intravenous administration (200 or 400 mg). Measurable serum concentrations (n = 925) from 70 subjects treated with daclizumab HYP in the three studies were analyzed using non-linear mixed-effects modeling. RESULTS: A two-compartment model with a first-order absorption and elimination adequately described daclizumab HYP pharmacokinetics. Daclizumab HYP clearance, inter-compartmental clearance, and central and peripheral volumes of distribution were 10 mL/h, 44 mL/h, 3.89 L, and 2.52 L, respectively, scaled by [bodyweight (kg)/70] with 0.54 and 0.64 exponents for clearance and volume parameters, respectively. Lag-time, mean absorption time, and absolute bioavailability (100-300 mg) for subcutaneous administration were 2 h, 4.6 days, and 84 %, respectively. Bodyweight explained only ~20 % of daclizumab HYP pharmacokinetic variability. With this limited dataset, sex, age, race, or presence of antibodies did not correlate with daclizumab HYP clearance. The estimated effective half-life was 21-25 days. The developed model was robust in bootstrap evaluation and predicted the data adequately in stochastic simulations. CONCLUSIONS: Daclizumab HYP is characterized by slow clearance, linear pharmacokinetics (at doses ≥100 mg), high subcutaneous bioavailability, and a half-life suitable for monthly administration.

Two-way interaction study between ritonavir boosted danoprevir, a potent HCV protease inhibitor, and ketoconazole in healthy subjects.

BACKGROUND: Danoprevir is a potent, highly selective, macrocyclic, orally bioavailable inhibitor of the hepatitis C virus protease, and a substrate of cytochrome P450 (CYP) 3A. It is co-administered with low-dose ritonavir, a potent CYP3A inhibitor, to enhance danoprevir pharmacokinetics. Ketoconazole is a substrate for and potent selective inhibitor of CYP3A. METHODS: In this open-label, 3-period study, the 2-way interaction potential between ritonavir-boosted danoprevir (danoprevir/r) and ketoconazole was investigated in 18 healthy subjects. Subjects initially received ketoconazole 200 mg q24h for 4 days (Period 1) followed by a 7-day washout period. Danoprevir/r 100/100 mg q12h was then given for 10 days (Period 2) followed by a further 4 days of danoprevir/r 100/100 mg q12h plus ketoconazole 200 mg q24h (Period 3). Serial blood samples were collected for the determination of danoprevir, ritonavir and/or ketoconazole plasma concentrations, and calculation of pharmacokinetic parameters. Safety and tolerability were monitored throughout the study. RESULTS: Co-administration of ketoconazole with danoprevir/r modestly increased the danoprevir AUCτ by 1.44-fold, with no effect on danoprevir Cmax. Co-administration of danoprevir/r with ketoconazole substantially increased ketoconazole AUCτ and Cmax by 3.71-fold and 1.73-fold, respectively. Danoprevir/r was well tolerated when administered alone or with ketoconazole. CONCLUSIONS: These results indicate that the effect of potent CYP3A inhibitors, such as ketoconazole, on danoprevir/r pharmacokinetics is not likely to be clinically relevant.

Efficacy and safety of danoprevir-ritonavir plus peginterferon alfa-2a-ribavirin in hepatitis C virus genotype 1 prior null responders.

Danoprevir (DNV) is a hepatitis C virus (HCV) protease inhibitor that achieves high sustained virologic response (SVR) rates in combination with peginterferon alfa-2a-ribavirin in treatment-naive HCV genotype 1 (G1)-infected patients. This study explored the efficacy and safety of ritonavir-boosted DNV (DNVr) plus peginterferon alfa-2a-ribavirin in G1-infected prior peginterferon-ribavirin null responders. Null responders (<2-log10 reduction in HCV RNA level at week 12) were given an open-label combination of 100 mg of ritonavir and 100 mg of DNV (100/100 mg DNVr) every 12 h (q12h) plus peginterferon alfa-2a-ribavirin for 12 weeks. All patients achieving an early virologic response (EVR; ≥2-log10 decrease in HCV RNA by week 12) continued treatment with peginterferon alfa-2a-ribavirin; those without an EVR discontinued all study drugs. Twenty-four prior null responders were enrolled; 16 patients (67%) were infected with HCV G1b, and 8 (33%) were infected with G1a. Ninety-six percent of patients had an IL28B non-CC genotype. A sustained virologic response at 24 weeks posttreatment (SVR24) was achieved in 67% of patients, with a higher rate in G1b-infected (88%) than G1a-infected (25%) patients. Resistance-related breakthrough occurred in 4/8 G1a and 1/16 G1b patients through the DNV resistance-associated variant (RAV) NS3 R155K. NS3 R155K was also detected in 2/2 G1a patients who relapsed. Treatment was well tolerated. Two patients withdrew prematurely from study medications due to adverse events. Two serious adverse events were reported; both occurred after completion of DNVr therapy and were considered unrelated to treatment. No grade 3 or 4 alanine aminotransferase (ALT) elevations were observed. DNVr plus peginterferon alfa-2a-ribavirin demonstrated high SVR24 rates in HCV G1b-infected prior null responders and was well tolerated. (This study has been registered at ClinicalTrials.gov under registration no. NCT01185860.).

A randomised study of the effect of danoprevir/ritonavir or ritonavir on substrates of cytochrome P450 (CYP) 3A and 2C9 in chronic hepatitis C patients using a drug cocktail.

PURPOSE: The aim of this study was to evaluate the effects of danoprevir in combination with low-dose ritonavir (danoprevir/r) and placebo plus low-dose ritonavir on the pharmacokinetics of probe drugs for cytochrome P450 (CYP) 3A and CYP2C9, in patients with chronic hepatitis C. METHODS: A total of 54 patients infected with hepatitis C virus genotype 1 received an oral drug cocktail (2 mg midazolam, 10 mg warfarin and 10 mg vitamin K) before and after 14 days of dosing with either danoprevir/r or placebo plus low-dose ritonavir (placebo/r). Serial pharmacokinetic samples were collected up to 24 (midazolam) and 72 (S-warfarin) h post-dose. Plasma concentrations of midazolam, α-hydroxymidazolam and S-warfarin were measured using validated assays. Pharmacokinetic parameters were estimated using non-compartmental analysis, and geometric mean ratios (GMRs) and 90 % confidence intervals (CIs) for the differences between baseline and post-dosing values were calculated. RESULTS: Danoprevir/r and placebo/r significantly increased midazolam area under the time-concentration curve (AUC0-∞) and reduced the midazolam metabolic ratio while S-warfarin AUC0-∞ was modestly decreased. When danoprevir data were pooled across doses, the midazolam GMR (90 % CI) AUC0-∞ was 9.41 (8.11, 10.9) and 11.14 (9.42, 13.2) following danoprevir/r and placebo/r dosing, respectively, and the S-warfarin GMR (90 % CI) AUC0-∞ was 0.72 (0.68, 0.76) and 0.76 (0.69, 0.85), respectively. The effects of danoprevir/r and placebo/r appeared to be qualitatively similar. CONCLUSIONS: Substantial inhibition of CYP3A- and modest induction of CYP2C9- activity were observed with danoprevir/r and low-dose ritonavir.

Impact of low-dose ritonavir on danoprevir pharmacokinetics: results of computer-based simulations and a clinical drug-drug interaction study.

BACKGROUND AND OBJECTIVE: Danoprevir, a potent, selective inhibitor of the hepatitis C virus (HCV) NS3/4A protease, is metabolized by cytochrome P450 (CYP) 3A. Clinical studies in HCV patients have shown a potential need for a high danoprevir daily dose and/or dosing frequency. Ritonavir, an HIV-1 protease inhibitor (PI) and potent CYP3A inhibitor, is used as a pharmacokinetic enhancer at subtherapeutic doses in combination with other HIV PIs. Coadministering danoprevir with ritonavir as a pharmacokinetic enhancer could allow reduced danoprevir doses and/or dosing frequency. Here we evaluate the impact of ritonavir on danoprevir pharmacokinetics. METHODS: The effects of low-dose ritonavir on danoprevir pharmacokinetics were simulated using Simcyp, a population-based simulator. Following results from this drug-drug interaction (DDI) model, a crossover study was performed in healthy volunteers to investigate the effects of acute and repeat dosing of low-dose ritonavir on danoprevir single-dose pharmacokinetics. Volunteers received a single oral dose of danoprevir 100 mg in a fixed sequence as follows: alone, and on the first day and the last day of 10-day dosing with ritonavir 100 mg every 12 hours. RESULTS: The initial DDI model predicted that following multiple dosing of ritonavir 100 mg every 12 hours for 10 days, the danoprevir area under the plasma concentration-time curve (AUC) from time zero to 24 hours and maximum plasma drug concentration (C(max)) would increase by about 3.9- and 3.2-fold, respectively. The clinical results at day 10 of ritonavir dosing showed that the plasma drug concentration at 12 hours postdose, AUC from time zero to infinity and C(max) of danoprevir increased by approximately 42-fold, 5.5-fold and 3.2-fold, respectively, compared with danoprevir alone. The DDI model was refined with the clinical data and sensitivity analyses were performed to better understand factors impacting the ritonavir-danoprevir interaction. CONCLUSION: DDI model simulations predicted that danoprevir exposures could be successfully enhanced with ritonavir coadministration, and that a clinical study confirming this result was warranted. The clinical results demonstrate that low-dose ritonavir enhances the pharmacokinetic profile of low-dose danoprevir such that overall danoprevir exposures can be reduced while sustaining danoprevir trough concentrations.