Retrospective population pharmacokinetics of levocetirizine in atopic children receiving cetirizine: the ETAC study

Rupatadine Oral Solution Titration by Body Weight in Paediatric Patients Suffering from Allergic Rhinitis: A Population Pharmacokinetic Study

Background

Allergic rhinitis (AR) and chronic urticaria, both are treated in children with doses of second generation of antihistamines that have been mostly based on extrapolation of data obtained in adults. The objectives of this work were to develop a model to explain the pharmacokinetics (PK) of rupatadine, a second generation antihistamine, administered to children 2−11 years old and to calculate the non-compartmental PK parameters for two groups of age (2–5 and 6–11 years old) based on the individual Bayesian estimates from the selected model.

Methods

Data from two PK studies with rupatadine oral solution (1 mg/mL) were pooled: Study A, an extensive blood sampling study performed in 11 children (6–11 years old) who received a single oral dose of rupatadine; and Study B, a sparse blood sampling study in 40 children (2–5 years old) receiving multiple oral doses. A simultaneous population PK model was developed using data available for all children. Using individual Bayesian estimates from the selected model, steady-state plasma concentrations for both studies were simulated and the non-parametric PK parameters were calculated for two age groups: 2–5 years (subgroup I) and 6–11 years (subgroup II).

Results

A two-compartment model with first-order absorption and elimination with clearance depending on body weight, better described the PK of rupatadine for 2–11 year old children. The plasma clearance dependence on weight was linear. The mean (SD) non-compartment PK parameters calculated using simulated plasma profiles at steady state were: C_max, 2.54 (1.26) vs 1.96 (0.52) ng/mL; AUC_0-24h, 10.74 (3.09) vs 10.38 (4.31) ng/mL/h; and t_1/2, 12.28 (3.09) vs 15.94 (4.09) h, for children 6–11 and 2–5 years old, respectively.

Conclusions

The PK of rupatadine depends on the weight of paediatric patients but not on their age. The dosage strategy adjusted by body weight in children 2–11 years old (2.5 mL if weight 10–25 kg, and 5 mL if ≥ 25 kg) provides similar exposure between the two groups of age, and to that obtained in adults with the 10 mg dose tablet formulation.

Levocetirizine: a modern H1-antihistamine for the treatment of allergic rhinitis

Levocetirizine is the latest of the H(1)-antihistamines indicated for adults and children (as young as 2 years old) suffering from allergic rhinitis and chronic idiopathic urticaria. Currently, it is the only therapy registered for treatment of persistent allergic rhinitis, as defined by the Allergic Rhinitis & its Impact on Asthma guidelines. Pharmacologic studies have shown levocetirizine to have a more favorable pharmacokinetic/pharmacodynamic profile than other commonly employed H(1)-antihistamines. This reflects its superiority in controlling the symptoms of seasonal, perennial and persistent allergic rhinitis in well-controlled trials. Clinical trials and postmarketing surveillance have indicated that levocetirizine is safe and well tolerated, and leads to clinically significant improvements in the quality of life of patients. It is also reported to reduce comorbidities as well as overall treatment costs when administered continuously over the longterm.

Levocetirizine for the treatment of allergic rhinitis and chronic idiopathic urticaria in adults and children

BACKGROUND

Levocetirizine (LCZ) is a second-generation antihistamine that was approved in January 2008 for the relief of symptoms of seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR), and chronic idiopathic urticaria (CIU) in adults and children aged > or = 6 years.

OBJECTIVES

This article reviews the available literature on the pharmacokinetics and pharmacodynamics, clinical efficacy and tolerability, and effect on quality of life (QoL) of LCZ.

METHODS

A search of the English-language literature was performed using the following databases: MEDLINE (1966-February 2009), International Pharmaceutical Abstracts (19 70-February 2009), Database of Abstracts of Reviews of Effectiveness, Cochrane Database of Systematic Reviews, EMBASE Drugs & Pharmacology (1991-February 2009), Blackwell Synergy, CINAHL Plus with Full Text, EBSCOhost, ScienceDirect, and Wiley Interscience. The search terms were levocetirizine, allergic rhinitis, chronic idiopathic urticaria, antihistamine, pharmacokinetics, quality of life, drug interactions, case reports, and cost. Publications describing studies of > or = 2 weeks' duration that concerned the efficacy, tolerability, pharmacoeconomics, and/or QoL effects of LCZ were included in the review.

RESULTS

In 4 studies in adult patients with moderate to severe PAR, LCZ 5 mg/d was associated with significant improvements in symptom scores for sneezing, rhinorrhea, and ocular/nasal pruritus at 4 to 6 weeks compared with placebo (P < or = 0.05). In 3 studies, nasal congestion scores were significantly improved within 4 to 6 weeks compared with placebo (P < 0.001). LCZ 5 mg/d was associated with improvements compared with placebo in scores for the ability to do housework, complete work activities, and engage in outdoor activities at 6 months (P < or = 0.011). In a 6-week study in children with moderate to severe SAR, LCZ 5 mg/d was associated with significant improvements compared with placebo in sneezing, rhin-orrhea, and itchy nose (P < 0.004); significant improvements in symptoms from baseline were also seen in a 4-week study in adults with SAR (P < 0.001). One study in patients with SAR reported no significant difference between LCZ and fluticasone compared with fluticasone monotherapy in terms of improvement in QoL, nasal airflow obstruction, sneezing, or pruritus. In a 6-week study in patients with moderate to severe CIU, LCZ 5 mg/d was significantly more effective than placebo in reducing overall CIU symptoms (P < 0.05). In two 4-week studies, one comparing LCZ 5 mg/d with placebo and the other comparing it with desloratadine (DSL), LCZ was significantly more effective than either comparator in terms of improvement in scores for pruritus severity (P < or = 0.001 vs placebo; P < 0.004 vs DSL) and duration (P < or = 0.001 vs placebo; P = 0.009 vs DSL). LCZ was significantly more effective than placebo (but not DSL) in reducing the number and size of wheals (both, P = 0.001). In a 12-week, open-label, crossover study, patients reported significantly longer symptom relief with cetirizine than LCZ (P < 0.005). The most commonly reported adverse events in two 6-month studies in adults with PAR treated with LCZ 5 mg/d included headache (23.8%), pharyngitis (19.4%), influenza (14.6%), fatigue (8.3%), and somnolence (8.3%). There is serious concern about the possibility of febrile seizures in infants treated with LCZ. Three pharmacoeconomic studies of LCZ 5 mg/d were identified, one comparing it with placebo in patients with PAR, one comparing it with placebo in patients with CIU, and another comparing it with second-generation antihistamines and montelukast in patients with PAR. Because of design limitations and differences in comparators in these studies, it was not possible to determine the cost-effectiveness of LCZ in the treatment of PAR or CIU.

CONCLUSIONS

In the studies reviewed, LCZ 5 mg/d was effective in reducing symptoms of PAR, SAR, and CIU and improving QoL, with an acceptable tolerabili-ty profile. There is a need for studies of longer durations, head-to-head comparisons against other anti-histamines, drug-interaction studies, safety studies in infants, and cost-effectiveness analyses.

Population pharmacokinetic and pharmacodynamic analysis in allergic diseases

In this chapter, we introduce the concepts and methodologies of population analysis as applied to analyzing pharmacokinetic and pharmacodynamic data. One of the key determining characteristics of the population approach is that through it, one seeks not only to characterize deterministic trends in the data, but also to identify and estimate the magnitudes of the important sources of variability within the data. The first section of this chapter provides an introduction to the primary concepts of, and motivation for, population modeling by way of a hypothetical case study. Then, the various methodologies that have been employed throughout the history of population analysis are described in further detail. Of these, the most commonly employed today is nonlinear mixed-effects (NLME) modeling. Finally, notable examples of the application of population PK and PK/PD modeling to treatments for allergies and asthma are discussed. Population PK models have frequently been used to extrapolate exposures to special populations, such as pediatrics, as well as to optimize treatment regimens and trial designs for these populations. Population PK/PD models have most frequently been applied to analyzing and interpreting data from wheal and flare trials, but are also becoming increasingly important in the analysis of PD data from monoclonal antibodies.

H1-antihistamine treatment in young atopic children: effect on urticaria

BACKGROUND

There are few published, randomized, double-masked, placebo-controlled, clinical trials of interventions for urticaria in the pediatric population.

OBJECTIVE

To study the effect of long-term treatment with the H1-antihistamine levocetirizine on urticaria in young atopic children.

METHODS

In the randomized, double-masked, parallel-group Early Prevention of Asthma in Atopic Children Study, children with atopic dermatitis aged 12 to 24 months at enrollment received levocetirizine, 0.125 mg/kg, or matching placebo twice daily for 18 months. On a diary card, the child's caregiver recorded the days on which urticaria was observed. This was validated by the study investigator and entered into the electronic case report form, along with any additional relevant information.

RESULTS

A total of 510 atopic children (mean +/- SEM age, 19.4 +/- 0.2 months) composed the intention-to-treat population. During the subsequent 18 months, 27.5% (70/255) of the children taking levocetirizine and 41.6% (106/255) of the children taking placebo experienced urticaria (P < .001). The mean +/- SEM number of urticaria episodes was 0.71 +/- 0.11 in those receiving levocetirizine and 1.71 +/- 0.25 in those receiving placebo (P < .001). The mean +/- SEM duration of urticaria episodes was 4.43 +/- 1.57 days in those receiving levocetirizine and 5.36 +/- 1.27 days in those receiving placebo (P < .001).

CONCLUSIONS

Urticaria is common in atopic toddlers and deserves recognition as an important disorder that occurs early in the atopic marathon. Regular long-term treatment with levocetirizine effectively prevents and treats urticaria in young children. The results of this study strengthen the evidence base for the use of relatively nonsedating, second-generation H1-antihistamines in the pediatric population.

Levocetirizine does not prolong the QT/QTc interval in healthy subjects: results from a thorough QT study

OBJECTIVE

To conduct a thorough QT study of levocetirizine, a non-sedating antihistamine, in accordance with International Conference on Harmonisation (ICH) E14 guidance.

METHODS

The study was designed as a single-dose, placebo and positive-controlled, four-way crossover, randomised trial in which 52 healthy male and female subjects participated. Levocetirizine (5 and 30 mg) and placebo were administered double-blind, and the positive control, moxifloxacin (400 mg), was open-label. Electrocardiograms (ECGs) were obtained by continuous Holter monitoring at various time points (three per time point) during a 24-h period at baseline and after each treatment. The ECGs were read centrally in a blinded manner. QT intervals were corrected for heart rate using a gender- and study-specific correction (QTcSS) and Fridericia's correction (QTcF). The largest QTc time-matched and baseline-subtracted difference between each active drug and the placebo (largest delta delta QTcSS) was derived from a mixed-effect analysis of variance.

RESULTS

The one-sided 95% upper limits of the largest delta delta QTcSS for levocetirizine were 5.7 ms (5 mg) and 3.9 ms (30 mg), with mean estimates of 2.9 and 1.1 ms, respectively. Similar results were obtained for the delta delta QTcF data. Statistically, moxifloxacin significantly lengthened the QTcSS, with a one-sided 95% lower limit of the largest delta delta QTcSS of 10.5 ms and a mean estimate of 13.4 ms. There was no relationship between the measured delta QTcSS and the plasma concentration of levocetirizine, whereas a statistically significant linear relationship was observed with the plasma concentration of moxifloxacin [slope estimate 0.004 ms/(ng/mL); 95% confidence interval: 0.003-0.005].

CONCLUSIONS

Overall, the results of this thorough QT study indicate that the methodology of the trial was valid and sensitive enough to demonstrate the absence of effect of levocetirizine at both therapeutic (5 mg) and supra-therapeutic (30 mg) doses on cardiac repolarisation.

Safety of levocetirizine treatment in young atopic children: An 18-month study

There are more than 40 H(1)-antihistamines available worldwide. Most of these medications have never been optimally studied in prospective, randomized, double-masked, placebo-controlled trials in children. The aim was to perform a long-term study of levocetirizine safety in young atopic children. In the randomized, double-masked Early Prevention of Asthma in Atopic Children Study, 510 atopic children who were age 12-24 months at entry received either levocetirizine 0.125 mg/kg or placebo twice daily for 18 months. Safety was assessed by: reporting of adverse events, numbers of children discontinuing the study because of adverse events, height and body mass measurements, assessment of developmental milestones, and hematology and biochemistry tests. The population evaluated for safety consisted of 255 children given levocetirizine and 255 children given placebo. The treatment groups were similar demographically, and with regard to number of children with: one or more adverse events (levocetirizine, 96.9%; placebo, 95.7%); serious adverse events (levocetirizine, 12.2%; placebo, 14.5%); medication-attributed adverse events (levocetirizine, 5.1%; placebo, 6.3%); and adverse events that led to permanent discontinuation of study medication (levocetirizine, 2.0%; placebo, 1.2%). The most frequent adverse events related to: upper respiratory tract infections, transient gastroenteritis symptoms, or exacerbations of allergic diseases. There were no significant differences between the treatment groups in height, mass, attainment of developmental milestones, and hematology and biochemistry tests. The long-term safety of levocetirizine has been confirmed in young atopic children.

Population pharmacokinetics of levocetirizine in very young children: the pediatricians' perspective

Developmental changes during infancy and childhood can affect drug pharmacokinetics (PK), i.e., absorption, distribution, metabolism, and renal excretion. This, in turn, influences optimal dosing, efficacy, and safety. To date, of the 40 H1-antihistamines available worldwide, only 11 have been studied in children using a PK approach. Here, we provide the pediatricians' perspective on the population PK of levocetirizine, the pharmacologically active enantiomer of cetirizine, in very young children who received oral cetirizine, and describe the factors that influence levocetirizine PK in this population. In a prospective, randomized, double-blind, parallel-group, placebo-controlled study, very young children received oral cetirizine 0.25 mg/kg twice daily for 18 months. Plasma levocetirizine concentrations were measured in timed, sparse blood samples collected at steady-state (3, 12 and 18 months after commencement of treatment) for the purpose of monitoring safety, and levocetirizine population, PK parameters were derived by using non-linear mixed effects modeling. In 343 children (age 14-46 months, body weight 8.2-20.5 kg), a total of 943 blood samples were obtained. Compliance with cetirizine dosing was documented. The population PK model used predicted that with increasing body weight, levocetirizine oral clearance would increase by 0.044 l/h/kg, and levocetirizine volume of distribution would increase by 0.639 l/kg. Levocetirizine PK were not influenced by eosinophilia, sensitization to allergens, allergic disease, gastroenteritis/diarrhea, or concomitant ingestion of other medications. This population PK model predicts that in very young children, the oral clearance of levocetirizine will be rapid and will increase as body weight and age increase, therefore, levocetirizine dosing should be based on body weight and age in this population. Compared with older patients, on a mg/kg basis, relatively higher doses may be needed, and twice-daily dosing may be necessary, as previously reported for the related racemic H1-antihistamine cetirizine.