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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IntroductionCryopyrin-associated periodic syndrome (CAPS) represents a spectrum of three auto-inflammatory syndromes, familial cold auto-inflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal-onset multisystem inflammatory disease/chronic infantile neurological cutaneous and articular syndrome (NOMID/CINCA) with etiology linked to mutations in the NLRP3 gene resulting in elevated interleukin-1β (IL-1β) release. CAPS is a rare hereditary auto-inflammatory disease, which may start early in childhood and requires a life-long treatment. Canakinumab, a fully human anti-IL-1β antibody, produces sustained selective inhibition of IL-1β. This study was conducted to assess the efficacy, safety, and pharmacokinetics of canakinumab in the treatment of pediatric CAPS patients.MethodsSeven pediatric patients (five children and two adolescents) with CAPS were enrolled in a phase II, open-label study of canakinumab in patients with CAPS. Canakinumab was administered at a dose of 2 mg/kg subcutaneously (s.c.) (for patients with body weight ≤ 40 kg) or 150 mg s.c. (for patients with body weight > 40 kg) with re-dosing upon each relapse. The primary efficacy variable was time to relapse following achievement of a complete response (defined as a global assessment of no or minimal disease activity and no or minimal rash and values for serum C-reactive protein (CRP) and/or serum amyloid A (SAA) within the normal range, < 10 mg/L).ResultsAll patients achieved a complete response within seven days after the first dose of canakinumab and responses were reinduced on retreatment following relapse. Improvements in symptoms were evident within 24 hours after the first dose, according to physician assessments. The estimated median time to relapse was 49 days (95% CI 29 to 68) in children who received a dose of 2 mg/kg. Canakinumab was well tolerated. One serious adverse event, vertigo, was reported, but resolved during treatment.ConclusionsCanakinumab, 2 mg/kg or 150 mg s.c., induced rapid and sustained clinical and biochemical responses in pediatric patients with CAPS.Trial registration numberClinicalTrials.gov: NCT00487708