Base and Covariate Population Pharmacokinetic Analyses of Dupilumab Using Phase 3 Data

Dupilumab in patients with chronic spontaneous urticaria (LIBERTY-CSU CUPID): Two randomized, double-blind, placebo-controlled, phase 3 trials

BACKGROUND

Chronic spontaneous urticaria (CSU) is a chronic inflammatory disease characterized by recurrent pruritic wheals (hives) and/or angioedema. Patients with CSU could remain symptomatic despite standard-of-care H1 antihistamines (H1-AH) or anti-IgE (omalizumab) treatment. Dupilumab blocks IL-4/IL-13 signaling and is approved for multiple type 2/atopic indications.

OBJECTIVE

We conducted two phase 3, randomized, placebo-controlled, double-blind trials comparing dupilumab with placebo in patients with symptomatic CSU despite H1-AH.

METHODS

In LIBERTY-CSU CUPID Study A, patients were omalizumab-naive (n = 138, aged ≥6 years). In Study B, patients were omalizumab-intolerant/incomplete responders (n = 108, aged ≥12 years). The primary end point was either change from baseline over 7 days in the Urticaria Activity Score (UAS7) or Itch Severity Score (ISS7) at week 24, with the other as a key secondary end point, depending on regional regulatory requirements. Studies were pooled for safety assessment.

RESULTS

In Study A, UAS7 and ISS7 improved with dupilumab versus placebo (difference -8.5 [95% CI, -13.2 to -3.9; P = .0003] and -4.2 [95% CI, -6.6 to -1.8; P = .0005]). In Study B, tested at α = 0.043 after interim analysis, UAS7 improved (difference -5.8 [95% CI, -11.4 to -0.3; P = .0390]), with a numerical trend in ISS7 (difference -2.9 [95% CI, -5.7 to -0.07; nominal P = .0449, not significant]). Pooled safety data were consistent between dupilumab and placebo and with the known dupilumab safety profile.

CONCLUSIONS

Dupilumab reduced urticaria activity by reducing itch and hives severity in omalizumab-naive patients with CSU uncontrolled with H1-AH. Although the primary end point for Study B was not met, dupilumab effects were small in patients who were omalizumab-intolerant/incomplete responders.

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 Concentration-Response of Dupilumab in Patients with Seasonal Allergic Rhinitis

Patients with moderate to severe allergic rhinitis may benefit from subcutaneous immunotherapy (SCIT), despite the risk of systemic allergic reaction. Dupilumab is a fully human monoclonal antibody that blocks the shared receptor component for interleukin (IL)-4 and IL-13, key drivers of the type 2 inflammation seen in allergic rhinitis, thereby inhibiting their signaling. In the LIBERTY Grass AID trial (NCT03558997), 16 weeks of treatment with 300 mg dupilumab every 2 weeks plus Timothy grass (TG) SCIT did not reduce TG allergen challenge nasal symptom scores compared with SCIT only but did improve tolerability of SCIT up-titration in patients with a history of grass pollen-induced seasonal allergic rhinitis. Here we present the pharmacokinetics of functional serum dupilumab and concentration-response relationships in 52 patients enrolled in this trial. Functional dupilumab concentrations and concentrations of TG-specific immunoglobulin E (IgE) and IgG4 were assessed in blood samples collected from dupilumab-only and SCIT+dupilumab-treated groups. Mean functional dupilumab concentrations were similar in both groups and reached a steady state of approximately 70-80 mg/L at week 5. One week after the end of treatment, TG-specific IgG4 concentrations were increased in the SCIT+dupilumab group, but not in the dupilumab-only group, over the range of dupilumab concentrations evaluated, whereas no changes were seen for TG-specific IgE concentrations. This study demonstrates that SCIT does not alter functional concentrations of serum dupilumab, and the impact of SCIT on TG-specific immunoglobulins is not affected by functional dupilumab concentrations over the range studied, indicating that maximum response was achieved in all patients. This article is protected by copyright. All rights reserved.

The Posology of Dupilumab in Pediatric Patients With Atopic Dermatitis

Dupilumab demonstrated efficacy with an acceptable safety profile in two randomized, double-blind, placebo-controlled, parallel-group, phase III trials in adolescents (12-17 years; LIBERTY AD ADOL) and children (6-11 years; LIBERTY AD PEDS) with atopic dermatitis (AD) treated for 16 weeks. Here, we present the pharmacokinetic profiles and exposure-response (E-R) relationships of dupilumab that guided the posology in these populations. A total of 251 adolescent patients with moderate-to-severe AD were randomized to subcutaneous dupilumab monotherapy every 2 weeks (q2w; 200 mg q2w, baseline weight < 60 kg; 300 mg q2w, ≥ 60 kg), dupilumab 300 mg every 4 weeks (q4w; non-weight tiered), or placebo; 367 children with severe AD were randomized to dupilumab q2w (100 mg q2w, baseline weight < 30 kg; 200 mg q2w, ≥ 30 kg), dupilumab 300 mg q4w, or placebo. Children received concomitant topical corticosteroids in addition to dupilumab, and loading doses were administered at the start of therapy. Mean dupilumab trough concentrations at week 16 for weight subcategories in each dosing regimen were compared with adult exposures for the approved dupilumab 300 mg q2w regimen. Positive E-R relationships were demonstrated between dupilumab trough concentrations and AD outcome measures across patient populations and regimens; no relationship was observed with treatment-emergent conjunctivitis. Based on these analyses, a weight-tiered posology was proposed for adolescents (200/300 mg q2w in patients 30-< 60 kg/≥ 60 kg) and children (300 mg q4w in patients 15-< 30 kg, 200 mg q2w in patients 30-< 60 kg) with moderate-to-severe AD.

Population pharmacokinetic analysis of dupilumab in adult and adolescent patients with asthma

A population pharmacokinetic model was developed using data from healthy subjects and patients with moderate‐to‐severe asthma receiving intravenous or subcutaneous dupilumab doses. A total of nine phase I to phase III studies were pooled (202 healthy subjects and 1912 patients with asthma including 68 adolescents) in the model development. The best model was a two‐compartment model with parallel linear and nonlinear Michaelis–Menten elimination with first order absorption. The PK parameter estimates were distribution volume of central compartment 2.76 L, linear elimination rate 0.0418 1/day, and subcutaneous bioavailability 60.9%. Pharmacokinetics (PK) properties of dupilumab in patients with asthma were determined to be comparable to those of healthy subjects and patients with atopic dermatitis. Only body weight exerts a notable effect explaining between‐subject variability in dupilumab PK, but dose adjustment for weight is not warranted based on results from clinical studies. There is no PK difference between adolescent and adult patients with asthma after correction for body weight.

Base and Covariate Population Pharmacokinetic Analyses of Dupilumab in Adolescents and Children ≥6 to <12 Years of Age Using Phase 3 Data

Population pharmacokinetic (PK) base and covariate analyses were conducted using data from adolescents with moderate‐to‐severe atopic dermatitis (AD) and children ≥6 to <12 years of age with severe AD. Two phase 3 studies were analyzed (165 adolescents and 241 children on active treatment). A 2‐compartment model with linear and Michaelis‐Menten elimination and 3 transit compartments describing lag time in absorption was utilized. Weight, albumin, body mass index, and Eczema Area and Severity Index score were statistically significant covariates in at least 1 of the age populations. Only body weight had a consequential effect on central volume. Although an absorption rate and target‐mediated clearance somewhat decreased with age, no dose adjustment was needed in addition to the adjustment for weight already implemented in the phase 3 studies. Otherwise, population PK parameters and covariates were similar across the 2 pediatric subpopulations and in adults. No allometric changes in elimination rate and beta half‐life were observed with weight. Parameterization of models in terms of rates was a useful alternative to parameterization in terms of clearances, allowing for an absence of repeated covariates and preventing overparameterization. The model adequately described dupilumab pharmacokinetics in the pediatric populations.

A phase 2, open-label study of single-dose dupilumab in children aged 6 months to <6 years with severe uncontrolled atopic dermatitis: pharmacokinetics, safety and efficacy

BACKGROUND

Dupilumab has demonstrated efficacy and acceptable safety in adults and children (aged 6-17 years) with moderate-to-severe atopic dermatitis (AD), but effective systemic therapy with a favorable risk-benefit profile in younger children remains a significant unmet need.

OBJECTIVES

To determine the pharmacokinetics, safety and efficacy of single-dose dupilumab in children with severe AD aged ≥6 months to <6 years.

METHODS

This open-label, multicenter, phase 2, sequential, two-age cohort, two-dose level study (LIBERTY AD PRE-SCHOOL; NCT03346434) included an initial cohort of older children aged ≥2 to <6 years, followed by a younger cohort aged ≥6 months to <2 years. Pharmacokinetic sampling, safety monitoring and efficacy assessments were performed during the 4-week period after a single subcutaneous injection of dupilumab, in two sequential dosing groups (3 mg/kg, then 6 mg/kg). The use of standardized, low-to-medium potency topical corticosteroids was allowed.

RESULTS

Forty patients were enrolled (20/age cohort, 10/dose level within a cohort) between December 20, 2017 and July 22, 2019. Within each age cohort, pharmacokinetic exposures after a single injection of dupilumab increased in a greater than dose-proportional manner. At week 3, treatment with 3 and 6 mg/kg dupilumab reduced scores of mean Eczema Area and Severity Index by -44.6% and -49.7% (older cohort) and -42.7% and -38.8% (younger cohort), and mean Peak Pruritus NRS scores by -22.9% and -44.7% (older cohort) and -11.1% and -18.2% (younger cohort), respectively. At week 4, improvements in most efficacy outcomes diminished in both age groups, particularly with the lower dose. The safety profile was comparable to that seen in adults, adolescents and children.

CONCLUSIONS

Single-dose dupilumab was generally well tolerated and substantially reduced clinical signs/symptoms of AD. Slightly better responses were seen in older than younger children. The pharmacokinetics of dupilumab were non-linear, consistent with previous studies in adults and adolescents.