Population pharmacokinetic and exposure-efficacy analysis of ixekizumab in paediatric patients with moderate-to-severe plaque psoriasis (IXORA-PEDS)

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Moderate-to-Severe Psoriasis

Psoriasis is a common inflammatory immune disorder due to chronic activation of the adaptive and innate immune responses. Therapies for psoriasis target reducing inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-17, and interleukin-22. Patients with inflammatory disorders have reduced metabolism by cytochrome P450 enzymes in the liver. The pharmacokinetic and pharmacodynamic changes due to psoriasis also have an impact on reaching therapeutic concentrations of the drug. Pharmacokinetic and pharmacodynamic data help determine the safety and clinical considerations necessary when utilizing drugs for plaque psoriasis. A literature search was performed on PubMed and Ovid MEDLINE for the pharmacokinetic and pharmacodynamic data of oral therapies and biologics utilized for moderate-to-severe plaque psoriasis. The findings from the literature search were organized into two sections: oral therapies and biologics. The pharmacokinetic and pharmacodynamic parameters in healthy patients, patients with psoriasis, and special populations are discussed in each section. The oral therapies described in this review include methotrexate, cyclosporine, apremilast, tofacitinib, and deucravacitinib. Biologics include tumor necrosis factor-alpha inhibitors, interleukin-17 inhibitors, ustekinumab, and interleukin-23 inhibitors. Clinical considerations for these therapies include drug toxicities, dosing frequency, and anti-drug antibodies. Methotrexate and cyclosporine have a risk for hepatoxicity and renal impairment, respectively. Moreover, drugs metabolized via cytochrome P450, including tofacitinib and apremilast have decreased clearance in patients with psoriasis, requiring dose adjustments. Patients treated with therapies such as adalimumab can develop anti-drug antibodies that reduce the long-term efficacy of the drug. Additionally, overweight patients benefit from more frequent dosing to achieve better psoriasis clearance.

Safety, tolerability, pharmacokinetics and efficacy of HB0017, a humanized monoclonal antibody that targets interleukin-17A, in healthy participants and patients with moderate-to-severe plaque psoriasis

BACKGROUND

Several interleukin (IL)-17 inhibitors have been approved for the treatment of moderate-to-severe plaque psoriasis (PsO). There is still scope for the development of affordable treatments for PsO.

OBJECTIVES

To assess, in a phase Ia study, the safety, tolerability and pharmacokinetics (PK) of HB0017, a humanized monoclonal antibody that targets IL-17A, in healthy participants and patients with moderate-to-severe plaque PsO; and, in a phase Ib study, to assess the efficacy of HB0017 in patients with moderate-to-severe plaque PsO.

METHODS

The phase Ia study (NCT04505033) was a randomized double-blind placebo-controlled dose-escalation study in healthy participants. Each cohort of 10 volunteers was randomly assigned to receive either a single dose of HB0017 (50 mg, 150 mg, 300 mg or 450 mg) or the matching placebo at a ratio of 4 : 1. The phase Ib study (NCT05442788) was a randomized double-blind placebo-controlled dose-escalation study in enrolled patients with moderate-to-severe plaque PsO. Each cohort of 10 patients was randomly assigned to receive either multiple doses of HB0017 (150 mg, 300 mg or 450 mg) or the matching placebo at a ratio of 4 : 1.

RESULTS

HB0017 demonstrated dose-proportional linear PK and was tolerated across the dose range assessed. In the phase Ia and Ib studies, participants in both the HB0017 and placebo groups experienced treatment-emergent adverse events (69% vs. 87%, 96% vs. 100%, respectively). HB0017 demonstrated clinically meaningful effects in patients with moderate-to-severe plaque PsO. PASI 75 [≥ 75% improvement in Psoriasis Area and Severity Index (PASI)], PASI 90 (≥ 90% improvement in PASI) and static Physician Global Assessment (sPGA) 0/1 (i.e. 'clear' or 'almost clear') responses were 100% for the HB0017 300-mg group, with maximal improvements (100% or near 100% reductions from baseline) in PASI score observed at week 12, while the duration of effect was evident up to week 20. There was no clinical response in any participant in the placebo group in the phase Ib study.

CONCLUSIONS

Overall, HB0017 showed acceptable safety and tolerability in both healthy participants and patients with moderate-to-severe plaque PsO. An encouraging signal of efficacy with a longer half-life provides HB0017 with the potential to be added to the currently available range of biologics targeting IL-17A.

Population pharmacokinetic/pharmacodynamic analysis of AK111, an IL-17A monoclonal antibody, in subjects with moderate-to-severe plaque psoriasis

AK111 is an innovative IL-17A antibody, presenting high affinity to IL-17A and showing similar pharmacokinetic (PK) characteristics to those of typical immunoglobulin (Ig) G1 antibodies. To optimize the dosage regimen for phase 2/3 clinical trials, PK and pharmacodynamics (PD) of AK111 were first characterized in Chinese moderate-to-severe plaque psoriasis patients in a phase 1b study. AK111 PK serum sample and Psoriasis Area and Severity Index (PASI) score data were collected from 48 moderate-to-severe psoriasis patients in this study. Non-linear mixed-effects modeling was used for the population PK/PD analysis. A one-compartment model with a first-order absorption and a first-order elimination best described the PK behavior of AK111. The apparent systemic clearance was 0.182 L/day, and the central volume was 6.65 L. The exposure–response relationship was characterized using an indirect response model. The pharmacological effect of AK111 was described in the form of inhibiting the formation of psoriatic plaque, whereas placebo was quantified in the form of promoting the degradation of psoriatic skin lesions. The maximum effect of drug effect (I_max) and placebo effect (PLB_max) was 1 and 0.429, respectively. The rate constant for psoriatic plaque production (K_in) was 0.474 PASI/day and psoriatic plaque loss (K_out) was 0.024 day⁻¹. The body surface area (BSA) affected by psoriasis was identified as a significant covariate on Kout. The simulation results confirmed that all of the predicted PASI90 response rates at week 12 were higher than 60% at 150 and 300 mg dose levels with different regimens and could reach higher than 80% at week 24. We hope this first PK/PD study of AK111 in Chinese moderate-to-severe plaque psoriasis patients will be of help in the further clinical development of AK111 and provide a reference to the dosage optimization for similar antibodies with a long half-life.

Minimal Physiologically-Based Pharmacokinetic (mPBPK) Metamodeling of Target Engagement in Skin Informs Anti-IL17A Drug Development in Psoriasis

The pharmacologic effect(s) of biotherapeutics directed against soluble targets are driven by the magnitude and duration of free target suppression at the tissue site(s) of action. Interleukin (IL)-17A is an inflammatory cytokine that plays a key role in the pathogenesis of psoriasis. In this work, clinical trial data from two monoclonal antibodies (mAbs) targeting IL-17A for treatment of psoriasis (secukinumab and ixekizumab) were analyzed simultaneously to quantitatively predict their target engagement (TE) profiles in psoriatic skin. First, a model-based meta-analysis (MBMA) for clinical responses was conducted separately for each drug based on dose. Next, a minimal physiologically-based pharmacokinetic (mPBPK) model was built to assess skin site IL-17A target engagement for ixekizumab and secukinumab simultaneously. The mPBPK model captured the observed drug PK, serum total IL-17A, and skin drug concentration-time profiles reasonably well across the different dosage regimens investigated. The developed mPBPK model was then used to predict the average TE (i.e., free IL-17A suppression) in skin achieved over a 12-weeks treatment period for each drug following their respective regimens and subsequently assess the TE-efficacy response relationship. It was predicted that secukinumab achieved 98.6% average TE in the skin at 300 mg q4w SC while ixekizumab achieved 99.9% average TE under 160 mg (loading) followed by 80 mg q2w SC. While direct quantification of free IL-17A levels at the site of action is technically challenging, integrated mPBPK-MBMA approaches offer quantitative predictions of free IL-17A levels at the site of action to facilitate future drug development via IL-17A suppression in psoriasis.