Ethnic sensitivity assessment of pharmacokinetics and pharmacodynamics of omalizumab with dosing table expansion

Population-Based Pharmacodynamic Modeling of Omalizumab in Pediatric Patients with Moderate to Severe Persistent Inadequately Controlled Allergic Asthma

Omalizumab is the first approved anti-immunoglobulin E (IgE) agent for the treatment of moderate to severe persistent inadequately controlled allergic asthma in adults and adolescents (≥ 12 years old). In 2016, it was approved in pediatric patients (6-11 years old). The objective of this study was to quantitatively characterize the relationship between serum free IgE and pulmonary function (as measured by forced expiratory volume in 1 s [FEV1]) in pediatrics using a population-based pharmacodynamic model. Data collected during the steroid-stable period (first 24 weeks) of an omalizumab trial with pediatric asthma patients (Study IA05) were used to build the pediatric IgE-FEV1 model. The previously developed population IgE-FEV1 model in adults/adolescents was adapted to characterize the FEV1 and IgE relationship in pediatrics with different magnitude and onset of response. The pediatric IgE-FEV1 model adequately characterized the IgE-FEV1 relationship in pediatrics, particularly at the extremes of the observed body weights (i.e., ≤ 30 kg) and IgE values at screening (i.e., > 700 IU/mL). The estimated sigmoidal free IgE-FEV1 curves were similar in shape and maximum effect, but the estimated free IgE concentration leading to 50% maximum effect (IC50) in pediatric patients (39.4, 95% confidence interval [CI] 24.3-63.9 ng/mL) was higher than estimated in adults (19.8, 95% CI 15.1-24.5 ng/mL). The model further confirmed that the current omalizumab dosing rationale based on the mean target free IgE level of 25 ng/ml was appropriate. The pediatric model can be used to predict population FEV1 response for omalizumab when combined with an omalizumab pharmacokinetic-IgE model.

Physiologically-Based Pharmacokinetic Modeling of Omalizumab to Predict the Pharmacokinetics and Pharmacodynamics in Pediatric Patients

Omalizumab is widely used in clinical practice; however, knowledge gaps in the dosage of omalizumab for children aged 2-6 years with moderate-to-severe persistent allergic asthma have been identified. The aim of this study was to explore dosing regimens for moderately-to-severely allergic pediatric patients aged 2-6 years. The physiologically-based pharmacokinetic (PBPK) model of omalizumab was developed and verified in adult patients, extrapolated to pediatric patients, and simulated for omalizumab by adding two observation chambers (free IgE and total IgE). The simulation results showed that the fold errors of the predicted and observed values of the area under the curve (AUC) and peak plasma concentration (C_max ) were between 0.5 and 2.0, and the average folding error and the absolute average folding error values for all concentration-time data points were 1.09 and 1.48, respectively. The PBPK model combined with pharmacokinetic/pharmacodynamic analysis of omalizumab demonstrated that both the model-derived dose and the original dose could control the average free IgE of 2-6-year-old children with moderate-to-severe allergic asthma below 25 ng/mL, and some of the model-derived doses were lower. This conclusion provides a basis for the selection of dosage in clinical practice reference.

Pharmacokinetic equivalence of CT-P39 and reference omalizumab in healthy individuals: A randomised, double-blind, parallel-group, Phase 1 trial

BACKGROUND

CT-P39 is being developed as a biosimilar of reference omalizumab. This study aimed to assess the pharmacokinetic equivalence of CT-P39 to European Union-approved and United States-licensed reference omalizumab (EU- and US-omalizumab, respectively).

METHODS

This two-part, randomised, parallel-group, double-blind Phase 1 trial (NCT04018313) was conducted in healthy individuals with a total immunoglobulin E (IgE) level ≤100  international units (IU)/ml at screening. In part 2, described herein, participants were randomised (1:1:1) to receive a single 150 mg subcutaneous dose of CT-P39, EU-omalizumab, or US-omalizumab. The primary endpoint was pharmacokinetic equivalence in terms of area under the concentration-time curve (AUC) from time zero to the last quantifiable concentration (AUC_0-last ), AUC from time zero to infinity (AUC_0-inf ), and maximum serum concentration (C_max ). Equivalence was concluded if 90% confidence intervals (CIs) of the geometric least-squares means ratios were contained within the predefined 80%-125% equivalence margin. Additional pharmacokinetic parameters, pharmacodynamics, safety, and immunogenicity were also evaluated.

RESULTS

Overall, 146 participants were randomised (CT-P39, N = 47; EU-omalizumab, N = 49; US-omalizumab, N = 50). For all primary pharmacokinetic parameters, 90% CIs for pairwise treatment comparisons were within the 80%-125% equivalence margin, demonstrating pharmacokinetic equivalence. Decreases in free IgE and increases in total IgE serum concentrations were comparable across groups. CT-P39 was well tolerated. Safety endpoints were comparable across groups: there were no treatment-related serious adverse events, deaths, or discontinuations due to treatment-emergent adverse events.

CONCLUSIONS

CT-P39 was well tolerated and demonstrated pharmacokinetic equivalence with EU-omalizumab and US-omalizumab following administration of a single dose in healthy individuals.

Pharmacokinetics, pharmacodynamics, and exposure-efficacy of dupilumab in adults with atopic dermatitis

The pharmacokinetics (PKs) and exposure-efficacy of dupilumab have not been fully described for adults with atopic dermatitis (AD). Our objectives were to analyze the PKs and exposure-efficacy of dupilumab in adults with AD and compare the results of Japanese and overall populations. Adults with moderate-to-severe AD were randomly assigned to dupilumab (300 mg weekly [qw] or every 2 weeks [q2w], 200 mg q2w, 300 mg every 4 weeks [q4w], or 100 mg q4w) or placebo for 16 weeks in a randomized, double-blind, placebo-controlled, dose-ranging phase IIb trial (NCT01859988). This analysis included 379 patients (58 Japanese). Functional dupilumab concentrations increased in a dose-dependent manner; at lower concentrations, increases were greater than dose-proportional because of nonlinear, target-mediated clearance. Dupilumab pharmacokinetics were comparable in Japanese and non-Japanese patients with similar body weights. Week 16 efficacy parameters, including Investigator's Global Assessment score 0/1, greater than or equal to 75% reduction from baseline in the Eczema Area and Severity Index (EASI), and percentage change from baseline in EASI and pruritus Numerical Rating Scale, generally increased with week 16 trough concentration; the plateau of these exposure-efficacy relationships occurred for most patients at exposures associated with the 300 mg q2w and 300 mg qw regimens. Japanese ethnicity did not remain in the population PK model as covariate with or without accounting for body weight differences. In Japanese and non-Japanese patients, efficacy responses increased with week 16 dupilumab trough concentrations in a similar manner. Dupilumab 300 mg qw and q2w regimens were recommended for further evaluation in larger phase III studies.

Pharmacokinetics and exposure-efficacy relationships of omalizumab in patients with nasal polyps

The anti-immunoglobulin E (IgE) antibody, omalizumab (Xolair), is approved in the United States for the treatment of allergic asthma and chronic spontaneous urticaria, and has recently been studied for the treatment of nasal polyposis following completion of the two replicate phase 3 studies (POLYP 1 and POLYP 2). The dosing of omalizumab used in the phase 3 studies is based on a combination of patients' pre-treatment IgE level and body weight, similar to the approach used in allergic asthma. The objectives of the current analyses were to evaluate whether the pharmacokinetics (PK) of omalizumab and its pharmacodynamic (PD) effect on free and total IgE level in chronic rhinosinusitis with nasal polyps (CRSwNP) are consistent with those in allergic asthma via population PK/PD modeling and simulation, and to graphically explore exposure-response relationships and free IgE-response relationships in CRSwNP. Omalizumab PK and PD effect of total and free IgE in CRSwNP are generally consistent with those in asthma. Observed post-treatment free IgE suppressions were generally within the target range of the baseline IgE- and body weight-based omalizumab dosing table, with 74.2% and 93.0% of patients achieving a serum free IgE level below 25 ng/mL and 50 ng/mL, respectively at Week 24. Exposure-response analyses indicated that there was no clear correlation between omalizumab or free IgE concentration and key efficacy endpoints within the POLYP studies. Overall, these results indicate that the body weight and IgE-based dosing regimen of omalizumab was appropriate for use in CRSwNP patients.

Pediatric Dose Selection for Therapeutic Proteins

In selecting optimal dosing regimens in support of the clinical use of monoclonal antibodies and other therapeutic proteins in pediatric indications, the unique pharmacokinetic properties of this class of biologics, as well as the underlying physiologic and pathophysiologic processes and their modulation by childhood growth and development, needs to be appreciated. During drug development, first-in-pediatric dose selection is a capstone event in the pediatric investigation plan that relies heavily on extrapolation of pharmacokinetic and pharmacodynamic data from adult to pediatric populations. It is facilitated by combinations of pharmacometric approaches, including allometry, physiologically based pharmacokinetic modeling, and population pharmacokinetic analyses, although data on reliability and qualification of some of these tools in the context of therapeutic proteins are still limited but emerging. Presented data suggest nonlinear relationships between body weight and both clearance and volume of distribution for therapeutic proteins in pediatric populations, with allometric exponents of 0.75 and 0.8, respectively. For newborns and infants (<1 year), even higher nonlinearity seems to occur. Translation of the quantitative characterization of the pediatric pharmacokinetics of therapeutic proteins into dosing regimens for the drug label requires compromising between precision dosing and clinical practicability, with tiered dosing algorithms based on size or age strata being the currently most frequently applied methodology.

Ligelizumab treatment for severe asthma: learnings from the clinical development programme

Objective

Ligelizumab is a humanised IgG1 anti-IgE antibody that binds IgE with higher affinity than omalizumab. Ligelizumab had greater efficacy than omalizumab on inhaled and skin allergen provocation responses in mild allergic asthma. This multi-centre, randomised, double-blind study was designed to test ligelizumab in severe asthma patients not adequately controlled with high-dose inhaled corticoids plus long-acting β2-agonist.

Methods

Patients received 16 weeks ligelizumab (240 mg q2w), omalizumab or placebo subcutaneously, and ACQ-7 was measured as primary outcome at Week 16. In addition, the study generated dose-ranging data of ligelizumab and safety data.

Results

A total of 471 patients, age 47.4 ± 13.36 years, were included in the study. Treatment with ligelizumab did not significantly improve asthma control (ACQ-7) and exacerbation rates compared to omalizumab and placebo. Therefore, primary and secondary objectives of the study were not met. The compound was well tolerated, and the safety profile showed no new safety findings. Pharmacokinetic data demonstrated faster clearance and lower serum concentrations of ligelizumab than historical omalizumab data, and exploratory in vitro data showed differential IgE blocking properties relative to FcεRI and FcεRII/CD23 between the two compounds.

Conclusion

Ligelizumab failed to demonstrate superiority over placebo or omalizumab. Although ligelizumab is more potent than omalizumab at inhibiting IgE binding to the high-affinity FcεRI, there is differential IgE blocking properties relative to FcεRI and FcεRII/CD23 between the two compounds. Therefore, the data suggest that different anti-IgE antibodies might be selectively efficacious for different IgE-mediated diseases.

Determinants of omalizumab dose-related efficacy in oral immunotherapy: Evidence from a cohort of 181 patients

BACKGROUND

Omalizumab has been shown to improve the safety and feasibility of oral immunotherapy (OIT), but the optimal dosage strategy is unknown.

OBJECTIVE

Our aim was to identify determinants of omalizumab dose-related efficacy in the context of OIT.

METHODS

The study sample consisted of a clinical cohort of 181 patients treated with omalizumab-enabled oral immunotherapy at 3 centers. Patients received omalizumab for at least 2 months before an initial food escalation (IFE) with a mix of up to 6 allergens. Progression through IFE steps was assessed with survival analysis. Continued food dose tolerance with omalizumab weaning was also documented.

RESULTS

Omalizumab dosage per weight alone was strongly associated with progression through the IFE (χ² = 28.18; P < .0001), whereas the standard dosage per weight and total IgE level used for asthma was not (χ² = 0.001; P = .97). When the values at time of IFE were estimated through pharmacokinetics and pharmacodynamics simulation, IFE outcome was best predicted by a model that includes levels of free allergen-specific IgE and their interaction with blocking omalizumab-IgE complexes and free omalizumab levels in serum (χ² = 65.84; degrees of freedom [df] = 2; P < .0005). The occurrence of immediate-type reactions to food dosing subsequent to weaning of omalizumab was associated with a greater ratio of specific IgE level to total IgE level at baseline (geometric mean 0.39 vs 0.16 in those without symptom; P < .0001).

CONCLUSION

In the context of OIT and IgE-mediated disease, omalizumab dosages should be adjusted for body weight alone, independently of total IgE level. The fraction of allergen-specific/total IgE may be useful to predict patients at greater risk of food dosing reactions subsequent to weaning.

Influence of Antigen Mass on the Pharmacokinetics of Therapeutic Antibodies in Humans

Therapeutic antibodies are increasingly used to treat various diseases, including neoplasms and chronic inflammatory diseases. Antibodies exhibit complex pharmacokinetic properties, notably owing to the influence of antigen mass, i.e. the amount of antigenic targets to which the monoclonal antibody binds specifically. This review focuses on the influence of antigen mass on the pharmacokinetics of therapeutic antibodies quantified by pharmacokinetic modelling in humans. Out of 159 pharmacokinetic studies, 85 reported an influence of antigen mass. This influence led to non-linear elimination decay in 50 publications, which was described using target-mediated drug disposition or derived models, as quasi-steady-state, irreversible binding and Michaelis-Menten models. In 35 publications, the pharmacokinetics was apparently linear and the influence of antigen mass was described as a covariate of pharmacokinetic parameters. If some reported covariates, such as the circulating antigen level or tumour size, are likely to be correlated to antigen mass, others, such as disease activity or disease type, may contain little information on the amount of antigenic targets. In some cases, antigen targets exist in different forms, notably in the circulation and expressed at the cell surface. The influence of antigen mass should be soundly described during the early clinical phases of drug development. To maximise therapeutic efficacy, sufficient antibody doses should be administered to ensure the saturation of antigen targets by therapeutic antibodies in all patients. If necessary, antigen mass should be taken into account in routine clinical practice.

Understanding Inter-Individual Variability in Monoclonal Antibody Disposition

Monoclonal antibodies (mAbs) are currently the largest and most dominant class of therapeutic proteins. Inter-individual variability has been observed for several mAbs; however, an understanding of the underlying mechanisms and factors contributing to inter-subject differences in mAb disposition is still lacking. In this review, we analyze the mechanisms of antibody disposition and the putative mechanistic determinants of inter-individual variability. Results from in vitro, preclinical, and clinical studies were reviewed evaluate the role of the neonatal Fc receptor and Fc gamma receptors (expression and polymorphism), target properties (expression, shedding, turnover, internalization, heterogeneity, polymorphism), and the influence of anti-drug antibodies. Particular attention is given to the influence of co-administered drugs and disease, and to the physiological relevance of covariates identified by population pharmacokinetic modeling, as determinants of variability in mAb pharmacokinetics.