The investigation of interleukin 1β (IL-1β) in human inflammatory diseases is hampered by the fact that it is virtually undetectable in human plasma. We demonstrate that by administering the anti–human IL-1β antibody canakinumab (ACZ885) to humans, the resulting formation of IL-1β–antibody complexes allowed the detection of in vivo–produced IL-1β. A two-compartment mathematical model was generated that predicted a constitutive production rate of 6 ng/d IL-1β in healthy subjects. In contrast, patients with cryopyrin-associated periodic syndromes (CAPS), a rare monogenetic disease driven by uncontrolled caspase-1 activity and IL-1 production, produced a mean of 31 ng/d. Treatment with canakinumab not only induced long-lasting complete clinical response but also reduced the production rate of IL-1β to normal levels within 8 wk of treatment, suggesting that IL-1β production in these patients was mainly IL-1β driven. The model further indicated that IL-1β is the only cytokine driving disease severity and duration of response to canakinumab. A correction for natural IL-1 antagonists was not required to fit the data. Together, the study allowed new insights into the production and regulation of IL-1β in man. It also indicated that CAPS is entirely mediated by IL-1β and that canakinumab treatment restores physiological IL-1β production.

AimOmalizumab, a humanized IgG monoclonal antibody that binds to human immunoglobulin E (IgE), interrupts the allergic cascade in asthmatic patients. The aim was to compare simultaneously drug exposure and IgE biomarker responses in Japanese and White patient populations. MethodsAn instantaneous equilibrium drug-ligand binding and turnover population model was built from 202 Japanese patients. A posterior predictive evaluation for the steady-state distributions of omalizumab and IgE was then carried out against 531 White patients. ResultsThe mean parameters estimated from the Japanese patients were as follows: omalizumab clearance 7.32 Ϯ 0.153 ml h -1 , IgE clearance 71.0 Ϯ 4.68 ml h -1 and the difference between that for omalizumab and the complex 5.86 Ϯ 0.920 ml h -1 , the volume of distribution for omalizumab and IgE 5900 Ϯ 107 ml, and that for the complex 3630 Ϯ 223 ml, the rate of IgE production 30.3 Ϯ 2.04 mg h -1 . Half-lives of IgG (23 days) and IgE (2.4 days) were close to previous reports. The dissociation constant for binding, 1.07 nM, was similar to in vitro values. Clearance and volume of distribution for omalizumab varied with bodyweight, whereas the clearance and rate of production of IgE were predicted accurately by baseline IgE. Overall, these covariates explained much of the interindividual variability. ConclusionsThe predictiveness of the Japanese model was confirmed by Monte-Carlo simulations for a White population, also providing evidence that the pharmacokinetics of omalizumab and IgE were similar in these two populations. Furthermore, the model enabled the estimation of not only omalizumab disposition parameters, but also the binding with and the rate of production, distribution and elimination of its target, IgE. IntroductionOmalizumab is a recombinant DNA-derived humanized monoclonal antibody that selectively binds human immunoglobulin E (IgE). The antibody is an immunoglobulin (Ig) G 1 k with a human framework and complementarity determining regions (CDRs) from a humanized anti-IgE murine antibody [1]. The causal role of IgE in allergic disease is well established [1-3]. The British Journal of Clinical Pharmacology DOI:10.1111DOI:10. /j.1365DOI:10. -2125DOI:10. .2006 Administration of omalizumab significantly decreases serum free IgE concentrations, resulting in improved control of atopic asthma and, most probably, other atopic conditions. As a result of omalizumab binding to IgE, lowering its free concentration, total serum IgE concentrations rise. Such an increase could occur by two mechanisms: (i) omalizumab-IgE complexes could be eliminated more slowly than free IgE due to the ability of the IgG portion of complexes to access the Brambell receptor, sparing them from lysosomal degradation [13], and (ii) the complexes, being of higher molecular mass (at least 340 kDa for the dimer but up to 1000 kDa for the hexamer [14]), filter less effectively through the vascular endothelium and are therefore retained within the smaller plasma volume of distribution [15][16][17][18].However, these ...

BackgroundUsing a monoclonal antibody with greater affinity for IgE than omalizumab, we examined whether more complete suppression of IgE provided greater pharmacodynamic effects, including suppression of skin prick responses to allergen.ObjectiveTo explore the pharmacokinetics, pharmacodynamics and safety of QGE031 (ligelizumab), a novel high-affinity humanized monoclonal IgG1κ anti-IgE.MethodsPreclinical assessments and two randomized, placebo-controlled, double-blind clinical trials were conducted in atopic subjects. The first trial administered single doses of QGE031 (0.1–10 mg/kg) or placebo intravenously, while the second trial administered two to four doses of QGE031 (0.2– 4 mg/kg) or placebo subcutaneously at 2-week intervals. Both trials included an open-label omalizumab arm.ResultsSixty of 73 (82%) and 96 of 110 (87%) subjects completed the intravenous and subcutaneous studies, respectively. Exposure to QGE031 and its half-life depended on the QGE031 dose and serum IgE level. QGE031 had a biexponential pharmacokinetic profile after intravenous administration and a terminal half-life of approximately 20 days. QGE031 demonstrated dose- and time-dependent suppression of free IgE, basophil FcεRI and basophil surface IgE superior in extent (free IgE and surface IgE) and duration to omalizumab. At Day 85, 6 weeks after the last dose, skin prick wheal responses to allergen were suppressed by > 95% and 41% in subjects treated subcutaneously with QGE031 (2 mg/kg) or omalizumab, respectively (P < 0.001). Urticaria was observed in QGE031- and placebo-treated subjects and was accompanied by systemic symptoms in one subject treated with 10 mg/kg intravenous QGE031. There were no serious adverse events.Conclusion and Clinical RelevanceThese first clinical data for QGE031, a high-affinity IgG1κ anti-IgE, demonstrate that increased suppression of free IgE compared with omalizumab translated to superior pharmacodynamic effects in atopic subjects, including those with high IgE levels. QGE031 may therefore benefit patients unable to receive, or suboptimally treated with, omalizumab.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• It had been hypothesized that there must be a relationship between free IgE concentrations and the signs and symptoms of asthma -after all, this is what drove the development of omalizumab. • However, although many statistical analyses of free IgE and spirometry data for patients equilibrated on omalizumab had shown a difference between placebo and treatment, no consistent time-and IgE-dependent relationship had been shown due to the narrow range of free IgE being studied and the sparse nature of the sampling and clinical measurements in Phase III trials. WHAT THIS STUDY ADDS• The above problem was solved using a pharmacokinetic-pharmacodynamic (PK-PD) model to estimate free IgE concentrations for all time points throughout and after treatment with omalizumab, together with patient daily diary data.• This allowed for the first time the direct correlation between free IgE and signs and symptoms of asthma to be observed. • Doses and regimens for omalizumab could then be derived, through PK-PD model simulation, for suppressing free IgE to a point correlated with an improvement in clinical symptoms. AIMSOmalizumab, a subcutaneously administered anti-IgE antibody, is effective for moderate-to-severe persistent allergic asthma. The aims were to (i) describe the population pharmacodynamics of free IgE with a mechanism-based, nonlinear, omalizumab-IgE binding model; (ii) deduce a target-free IgE suppression level by correlation with clinical outcomes; and (iii) check the adequacy of current approved dosing tables and explore potential doses and regimens beyond. METHODSConcentration data (omalizumab, free and total IgE) were obtained from 1781 patients aged 12-79 years, in four sparsely sampled randomized, placebo-controlled studies and 152 subjects in a richly sampled single-dose study. NONMEM predictive performance across the range of bodyweights (39-150 kg) and baseline IgE (19-1055 IU ml -1 ) was checked by simulation. Predicted free IgE levels were correlated with time-averaged patient diary clinical outcomes. RESULTSThe model accurately predicted observed omalizumab, free and total IgE concentrations. Free IgE concentrations correlated well with clinical signs and symptoms, allowing a target concentration of 14 ng ml -1 , at the midpoint of 4-week clinical observation periods, to be set for determining the dose and regimen for omalizumab. CONCLUSIONSThe omalizumab-IgE binding model is predictive for free IgE and demonstrates a nonlinear time-dependent relationship between free IgE suppression and clinical outcomes in asthma. Although currently approved dosing tables are close to optimal, it should be possible to treat patients with higher levels of baseline IgE if higher doses can be administered.

Canakinumab is a high-affinity human monoclonal anti-interleukin-1β (IL-1β) antibody of the IgG1/κ isotype designed to bind and neutralize the activity of human IL-1β, a pro-inflammatory cytokine. Canakinumab is currently being investigated on the premise that it would exert anti-inflammatory effects on a broad spectrum of diseases, driven by IL-1β. This paper focuses on the analysis of the pharmacokinetic and pharmacodynamic data from the canakinumab clinical development programme, describing results from the recently approved indication for the treatment of cryopyrin-associated periodic syndromes (CAPS) under the trade name ILARIS®, as well as diseases such as rheumatoid arthritis, asthma and psoriasis.Canakinumab displays pharmacokinetic properties typical of an IgG1 antibody. In a CAPS patient weighing 70 kg, slow serum clearance (0.174 L/day) was observed with a low total volume of distribution at steady state (6.0 L), resulting in a long elimination half-life of 26 days. The subcutaneous absolute bioavailability was high (70%). Canakinumab displays linear pharmacokinetics, with a dose-proportional increase in exposure and no evidence of accelerated clearance or time-dependent changes in pharmacokinetics following repeated administration was observed. The pharmacokinetics of canakinumab in various diseases (e.g. CAPS, rheumatoid arthritis, psoriasis or asthma) are comparable to those in healthy individuals. No sex- or age-related pharmacokinetic differences were observed after correction for body weight.An increase in total IL-1β was observed in both healthy subjects and all patient populations following canakinumab dosing, reflecting the ability of canakinumab to bind circulating IL-1β. The kinetics of total IL-1β along with the pharmacokinetics of canakinumab were characterized by a population-based pharmacokinetic-binding model, where the apparent in vivo dissociation constant, signifying binding affinity of canakinumab to circulating IL-1β, was estimated at 1.07 ± 0.173 nmol/L in CAPS patients.During development of canakinumab a cell line change was introduced. Pharmacokinetic characterization was performed in both animals and humans to assure that this manufacturing change did not affect the pharmacokinetic/pharmacodynamic properties of canakinumab.

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Although it is routine to predict the blood or plasma pharmacokinetics of compounds for man based upon preclinical studies, the real value of such predictions only comes when linked to drug effects. In the first example, the immunomodulator, FTY720, the first sphingosine-1-phosphate receptor agonist, stimulates the sequestration of lympho-cytes into lymph nodes thus removing cells from blood circulation. A prior physiology-based pharmacokinetic model fitted the concentration-time course of FTY720 in rats. This was connected to an indirect response model of the lympho-cyte system to characterise the cell trafficking effects. The IC 50 of FTY720 was different in the rat compared with the monkey; man was assumed to be similar to the monkey. The systemic lymphocyte half-lives were also different between species. To make predictions of the pharmacodynamic behaviour for man, two elements are required, i) systemic exposure, in this case from an upscaled physiology based model, and ii) an estimate of lymphocyte turnover in man, gained from the literature from other drug treatments. Predictions compared well with clinical results. The second example is the monoclonal antibody Xolair, designed to bind immunoglobulin E for atopic diseases. A mechanism based two-site binding model described the kinetics of both Xolair and endogenous IgE. This model has been reused for other monoclonal antibodies designed to bind fluid-phase ligands. Sensitivity analysis shows that if differences across species in the kinetics of the endogenous system are not accounted for, then pharmacokinetic/pharmacodynamic models may give misleading predictions of the time course and extent of the response.