Population Pharmacokinetics of Upadacitinib Using the Immediate-Release and Extended-Release Formulations in Healthy Subjects and Subjects with Rheumatoid Arthritis: Analyses of Phase I-III Clinical Trials

Pharmacokinetics, Efficacy, and Safety of Upadacitinib in Pediatric Patients With Polyarticular-Course Juvenile Idiopathic Arthritis: An Interim Analysis of an Open-Label, Phase 1 Trial

OBJECTIVE

This work aimed to evaluate the pharmacokinetics, efficacy, and safety of upadacitinib, an oral selective JAK inhibitor, in pediatric patients with polyarticular-course juvenile idiopathic arthritis (pcJIA).

METHODS

In an open-label, phase 1 study (SELECT-YOUTH), enrolled patients, aged 2 to <18 years with pcJIA, received body weight-based upadacitinib doses using a twice-daily oral solution or once-daily extended-release tablet based on their body weight and ability to swallow tablets. The study included a 7-day pharmacokinetic assessment, followed by a long-term efficacy and safety evaluation for up to 156 weeks, including an additional long-term safety cohort. This interim analysis included available pharmacokinetic and safety data and efficacy data collected through week 48.

RESULTS

A total of 57 patients received upadacitinib. The median time to maximum upadacitinib concentration was approximately three hours and one hour for the tablet and oral solution regimens, respectively; the harmonic mean functional half-life was approximately five hours and two hours, respectively. Juvenile idiopathic arthritis American College of Rheumatology 30, 50, 70, 90, and 100 responses at week 12 were 91.8%, 89.8%, 69.4%, 49.0%, and 32.7%, respectively. Efficacy was generally maintained through week 48, and improvement in additional efficacy end points was also observed. At a median exposure duration of 412 days, 52 of 57 patients reported adverse events; of these, 6 experienced serious adverse events. Adverse events were predominately mild to moderate in severity and consistent with the known safety profile of upadacitinib.

CONCLUSION

This interim analysis demonstrates that the bodyweight-based dosing regimen of upadacitinib was well tolerated and efficacious in pediatric patients with pcJIA.

The Role of Pharmacometrics in Advancing the Therapies for Autoimmune Diseases

Autoimmune diseases (AIDs) are a group of disorders in which the immune system attacks the body's own tissues, leading to chronic inflammation and organ damage. These diseases are difficult to treat due to variability in drug PK among individuals, patient responses to treatment, and the side effects of long-term immunosuppressive therapies. In recent years, pharmacometrics has emerged as a critical tool in drug discovery and development (DDD) and precision medicine. The aim of this review is to explore the diverse roles that pharmacometrics has played in addressing the challenges associated with DDD and personalized therapies in the treatment of AIDs. Methods: This review synthesizes research from the past two decades on pharmacometric methodologies, including Physiologically Based Pharmacokinetic (PBPK) modeling, Pharmacokinetic/Pharmacodynamic (PK/PD) modeling, disease progression (DisP) modeling, population modeling, model-based meta-analysis (MBMA), and Quantitative Systems Pharmacology (QSP). The incorporation of artificial intelligence (AI) and machine learning (ML) into pharmacometrics is also discussed. Results: Pharmacometrics has demonstrated significant potential in optimizing dosing regimens, improving drug safety, and predicting patient-specific responses in AIDs. PBPK and PK/PD models have been instrumental in personalizing treatments, while DisP and QSP models provide insights into disease evolution and pathophysiological mechanisms in AIDs. AI/ML implementation has further enhanced the precision of these models. Conclusions: Pharmacometrics plays a crucial role in bridging pre-clinical findings and clinical applications, driving more personalized and effective treatments for AIDs. Its integration into DDD and translational science, in combination with AI and ML algorithms, holds promise for advancing therapeutic strategies and improving autoimmune patients' outcomes.

Extrapolation of Upadacitinib Efficacy in Juvenile Idiopathic Arthritis Leveraging Pharmacokinetics, Exposure-Response Models, and Real-World Patient Data

Juvenile idiopathic arthritis (JIA) is the most prevalent pediatric rheumatic disease. While disease-modifying antirheumatic drugs (DMARDs), especially biologics, have greatly transformed the management of JIA, there remain some unmet medical needs that require new treatment options. The objective of this work was to describe and apply a modeling and simulation approach to extrapolate upadacitinib efficacy from the adult diseases, rheumatoid arthritis (RA) and psoriatic arthritis (PsA), to their respective pediatric diseases, polyarticular course JIA (pcJIA), and juvenile PsA (JPsA). A population pharmacokinetic model characterized upadacitinib pharmacokinetics in pediatric patients using data from two phase I studies in pediatric patients with pcJIA (N = 51) or atopic dermatitis (N = 33). Efficacy simulations were conducted using previously developed exposure-response models in adults with RA and PsA. Real-world pcJIA and JPsA patient databases were leveraged to construct representative patient profiles for the targeted population. Following administration of the proposed weight-based dosing regimen, the model-predicted median upadacitinib plasma exposures in pediatric patients were within 20% of those in adult RA and PsA patients receiving the approved adult regimen. Simulations demonstrate that upadacitinib efficacy in pcJIA and JPsA is predicted to be non-inferior to that in adults with RA or PsA, respectively. The results of this work enabled recent approvals of upadacitinib for the treatment of polyarticular JIA and JPsA in the United States. Upadacitinib safety in pediatrics is being further evaluated in ongoing clinical trials.

Pharmacokinetics and Exposure-Response Analyses to Support Dose Selection of Upadacitinib in Crohn's Disease

Upadacitinib, a selective Janus kinase inhibitor, is the first orally administered therapy approved for the treatment of Crohn's disease (CD). This work characterized the pharmacokinetics of upadacitinib in CD patients and evaluated the relationships between upadacitinib steady-state plasma exposures and efficacy as well as safety parameters during the 12-week induction and the 52-week maintenance periods, to provide dosing recommendations for the treatment of CD. Upadacitinib pharmacokinetics in CD patients administered the extended-release formulation were consistent with patient populations in other approved indications. None of the evaluated CD-specific patient characteristics (e.g., disease location and prior gastrointestinal surgeries) had a meaningful impact on upadacitinib pharmacokinetics. Exposure-response analyses during 12-week induction treatment showed that response across all evaluated efficacy end points were approaching a plateau at median plasma exposures associated with 45 mg QD. Analyses for the maintenance period demonstrated that 30 mg QD is predicted to provide an additional 8% to 10% benefit for endoscopic response and endoscopic remission compared with 15 mg QD in patients who failed biologics. The analyses for safety showed a statistically significant relationship between increasing upadacitinib plasma exposures and the percentage of patients experiencing >2 g/dL decrease in hemoglobin from Baseline during induction and showed shallow relationships for serious infections and herpes zoster during the maintenance period. These results demonstrated adequate absorption of the extended-release formulation of upadacitinib in CD patients. The exposure-response analyses confirmed that 45 mg QD dose maximized efficacy as induction treatment and supported the selection of 15 mg QD or 30 mg QD as the maintenance doses.

An interactive dose optimizer based on population pharmacokinetic study to guide dosing of methotrexate in Chinese patients with osteosarcoma

PURPOSE

Osteosarcoma is a rare tumor with an incidence of 4.4 cases per million per year in adolescent. High-dose methotrexate (HD-MTX) is the standard first-line chemotherapeutic agent for osteosarcoma. However, its efficacy can vary significantly among individuals due to wide pharmacokinetic variability. Despite this, only a few population pharmacokinetics (popPK) models based on Chinese patients with osteosarcoma have been reported. Thus, this study aimed to develop a HD-MTX popPK model and an individual model-based dose optimizer for osteosarcoma therapy.

METHOD

A total of 680 MTX serum concentrations from 57 patients with osteosarcoma were measured at the end of MTX infusion and 10 h, 24 h, 48 h, and 72 h after the start of infusion. Using the first-order conditional estimation method with NONMEM, a popPK model was estimated. Goodness-of-fit plots, visual predictive checks, and bootstrap analysis were generated to evaluate the final model. A dose optimizer tool was developed based on the validated models using R Shiny. Additionally, clinical data from 12 patients with newly diagnosed osteosarcoma were collected and used as the validation set to preliminarily verify the predictive ability of the popPK model and the dose optimizer tool.

RESULTS

Body surface area (BSA) was the most significant covariate for compartment distribution. Creatinine clearance (CrCL) and co-administration of NSAIDs were introduced as predictors for central compartmental and peripheral compartmental clearance, respectively. Co-administration of NSAIDs was associated with significantly higher MTX concentrations at 72 h (p = 0.019). The dose optimizer tool exhibited a high consistency in predicting MTX AUC compared to the actual AUC (r = 0.821, p < 0.001) in the validation set.

CONCLUSION

The dose optimizer tool could be used to estimate individual PK parameters, and optimize personalized MTX therapy in particular patients.

Pharmacokinetics, Safety, Tolerability, and Exploratory Efficacy of Upadacitinib in Children with Severe Atopic Dermatitis

PURPOSE

This study aims to characterize the pharmacokinetics, safety, tolerability, and exploratory efficacy of upadacitinib, an oral Janus kinase inhibitor approved for treating moderate to severe atopic dermatitis (AD) in adults and adolescents, in children with severe AD.

METHODS

In an open-label, multiple-dose, Phase 1 study, pediatric patients with severe AD from two age groups (2 to <6 years and 6 to <12 years) received bodyweight-based dosing regimens of upadacitinib using either twice-daily immediate-release (IR) oral solution or once-daily extended-release (ER) tablets. A pharmacokinetic assessment was conducted on Day 7 of the study, which was followed by a long-term safety and exploratory efficacy evaluation for up to 108 weeks. The results reported here are based on an interim analysis when the study had completed enrollment and pharmacokinetic assessment.

FINDINGS

A total of 35 patients were enrolled and received upadacitinib. The maximum upadacitinib plasma concentration was attained within a median time of 0.5 to 2 hours and 2 to 2.5 hours for the IR oral solution and ER tablet formulations, respectively. Upadacitinib functional half-life was generally shorter with IR oral solution relative to ER tablets. Upadacitinib apparent oral clearance decreased with decreasing body weight in the pediatric patients enrolled in this study. Upadacitinib was generally safe and well tolerated. The most common (≥3 patients) adverse events were upper respiratory tract infection, COVID-19 infection, headache, abdominal discomfort, vomiting, asthma, and cough. No new safety risks were identified compared to the known safety profile for upadacitinib in adults and adolescents. In the 30 patients with available exploratory efficacy data at Week 12, 36.7% achieved validated Investigator's Global Assessment scale for AD score of 0 or 1 (Validated Investigator Global Assessment for AD 0/1), and 70.0% had Eczema Area and Severity Index (EASI) improvement of at least 75% (EASI 75).

IMPLICATIONS

The characterized pharmacokinetic profiles in this study, together with the observed safety and exploratory efficacy results, support further investigation of the current upadacitinib dosing regimen in future confirmatory Phase 3 clinical trials in children with AD.

CLINICAL TRIAL NUMBER

NCT03646604, registered 2018-08-23.

Efficacy and Safety of Upadacitinib or Elsubrutinib Alone or in Combination for Patients With Systemic Lupus Erythematosus: A Phase 2 Randomized Controlled Trial

OBJECTIVE

The 48-week, phase 2 SLEek study (NCT03978520) evaluated the efficacy and safety of upadacitinib (JAK inhibitor) and elsubrutinib (BTK inhibitor) alone or in combination (ABBV-599) in adults with moderately to severely active systemic lupus erythematosus (SLE).

METHODS

Patients were randomized 1:1:1:1:1 to elsubrutinib 60 mg and upadacitinib 30 mg once daily (ABBV-599 high dose), elsubrutinib 60 mg and upadacitinib 15 mg once daily (ABBV-599 low dose), elsubrutinib 60 mg once daily (QD), upadacitinib 30 mg QD, or placebo QD. The primary endpoint was the proportion of patients achieving both Systemic Lupus Erythematosus Responder Index 4 (SRI-4) and glucocorticoid dose ≤10 mg QD at week 24. Additional assessments through week 48 included British Isles Lupus Assessment Group-Based Composite Lupus Assessment (BICLA) and Lupus Low Disease Activity State (LLDAS) responses, number of flares, time to first flare, and adverse events.

RESULTS

The study enrolled 341 patients. The ABBV-599 low dose and elsubrutinib arms were discontinued after a planned interim analysis showed lack of efficacy (no safety concerns). More patients achieved the primary endpoint with upadacitinib (54.8%; P = 0.028) and ABBV-599 high dose (48.5%; P = 0.081) versus placebo (37.3%). SRI-4, BICLA, and LLDAS response rates were higher for both upadacitinib and ABBV-599 high dose versus placebo at weeks 24 and 48. Flares were reduced, and time to first flare through week 48 was substantially delayed with both upadacitinib and ABBV-599 high dose versus placebo. No new safety signals were observed beyond those previously reported for upadacitinib or elsubrutinib.

CONCLUSION

Upadacitinib 30 mg alone or in combination with elsubrutinib (ABBV-599 high dose) demonstrated significant improvements in SLE disease activity and reduced flares and were well tolerated through 48 weeks.

Upadacitinib for the treatment of adult patients with active psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) is a rheumatic disorder that may be responsible for relevant articular impairment. The recently licensed Janus Kinase (JaK) inhibitors represent a new opportunity to improve PsA treatment. This review deals with the clinical usefulness of the selective JaK-1 inhibitor upadacitinib (UPA) in patients with PsA.

COVERED AREAS

Two phase-III studies are available: SELECT-PsA 1, performed in patients with an inadequate response to non-biological therapies, and SELECT-PsA 2, conducted in biologic-experienced patients. Long-term extension results and post-hoc analysis data of these two trials are also available.

EXPERT OPINION

The results provided by the trials indicate that UPA may be used to treat all of the clinical manifestations of PsA. Venous thromboembolism, cardiovascular events, and malignancy, the most feared adverse events associated with JaK inhibitor use, were not increased in the trial populations, yet long-term observational studies are needed to make sure that UPA is safe in this respect.

Population pharmacokinetics and exposure-response analyses for efficacy and safety of upadacitinib in patients with axial spondyloarthritis

Upadacitinib is an orally administered, selective, Janus kinase inhibitor that is approved for several auto-immune conditions, such as axial spondyloarthritis, an inflammatory rheumatic disease that includes ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). The approvals of upadacitinib for the treatment of AS and nr-axSpA were based on the safety and efficacy data for upadacitinib 15 mg once-daily compared to placebo from the SELECT-AXIS 1 and SELECT-AXIS 2 studies. Population pharmacokinetic analyses based on data from 244 patients with axSpA showed that the pharmacokinetics of upadacitinib were comparable in subjects with AS and nr-axSpA. Exposure-response relationships were characterized for key efficacy and safety end points using data from 482 patients with axSpA. The exposure-response analyses for efficacy based on Assessment of SpondyloArthritis International Society (ASAS)20 and ASAS40 responses at week 14, showed a clear differentiation from placebo with no evidence of increased responses with increasing upadacitinib plasma exposures. There were no clear exposure-response trends observed for safety end points that included serious infections, herpes zoster, pneumonia, lymphopenia (grade ≥3), neutropenia (grade ≥3), or a greater than 2 g/dL decrease in hemoglobin from baseline through week 14. The exposure-response analyses for efficacy and safety presented here supported the favorable benefit-risk profile with the use of upadacitinib 15 mg once-daily for the treatment of axSpA.

Development and validation of a multiplex HPLC-MS/MS assay for the monitoring of JAK inhibitors in patient plasma

Janus kinase inhibitors (JAKi) are oral small molecules used in the treatment of a broad spectrum of autoimmune and myeloproliferative diseases. JAKi exhibit significant intra- and inter-individual pharmacokinetic variabilities, due to fluctuations in compliance with oral treatments and their metabolism essentially driven by cytochrome P450 enzymes. Intrinsically, JAKi have dose-response relationship and narrow therapeutic index: therapeutic drug monitoring (TDM) is expected to optimize and adapt their dosage regimen in order to resolve problems of efficacy and tolerance linked to dose and safety. A sensitive analytical method using multiplex high-performance liquid-chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) was developed and validated for the simultaneous quantification in plasma of the 6 major currently used JAKi, namely abrocitinib, baricitinib, fedratinib, ruxolitinib, tofacitinib, and upadacitinib. Plasma samples are subjected to protein precipitation with MeOH, using stable isotopically labelled internal standards. The separation of JAKi in supernatants diluted 1:1 with ultrapure H2O was performed using a C18 column Xselect HSS T3 2.5 µm, 2.1x150 mm using a mobile phase composed of formic acid (FA) 0.2% and acetonitrile (+FA 0.1%) in gradient mode. The analytical run time for the multiplex assay was 7 min. JAKi drugs were monitored by electrospray ionization in the positive mode followed by triple-stage quadrupole MS/MS analysis. The method was validated according to SFSTP and ICH guidelines over the clinically relevant concentration ranges (0.5-200 ng/mL for abrocitinib, baricitinib and upadacitinib; 1-400 ng/mL for tofacitinib; 0.5-400 ng/mL for ruxolitinib, and 10-800 ng/mL for fedratinib). This multiplex HPLC-MS/MS assay achieved good performances in term of trueness (91.1-113.5%), repeatability (3.0-9.9%), and intermediate precision (4.5-11.3%). We developed and validated a highly sensitive method for the multiplex quantification of the JAKi abrocitinib, baricitinib, fedratinib, ruxolitinib, tofacitinib, and upadacitinib in human plasma. The method will be applied for prospective clinical pharmacokinetic studies to determine whether TDM programs for JAKi based on residual drug concentrations can be recommended using disease-specific therapeutic ranges.

Upadacitinib for the Treatment of Rheumatoid Arthritis: An Extensive Review

OBJECTIVES

To review the characteristics, efficacy, safety, pharmacoeconomics, and place in therapy of upadacitinib, a Janus kinase (JAK) inhibitor, in the treatment of rheumatoid arthritis (RA).

DATA SOURCES

PubMed (January 2003-May 2022) was searched using upadacitinib and ABT-494.

STUDY SELECTION AND DATA EXTRACTION

Human studies published in peer-reviewed publications in English were the primary sources for efficacy and safety data.

DATA SYNTHESIS

In randomized, double-blind, controlled clinical studies, upadacitinib demonstrated statistically significant improvement in RA symptoms as monotherapy and in combination with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) when compared with csDMARD monotherapy or to adalimumab or abatacept in combination with csDMARD therapy in patients with RA. American College of Rheumatology 20% response rates were 68% to 79% for upadacitinib monotherapy and 64% to 84% for upadacitinib plus csDMARD therapy, compared with 28% to 59% for csDMARD-only therapy and 63% to 74% for biologic DMARD (bDMARD) plus csDMARD therapy. Long-term extension studies demonstrated similar findings. Upadacitinib had similar rates of serious infections, herpes zoster, major cardiovascular events, and venous thromboembolic events as other JAK inhibitors. Upadacitinib was similar in cost to tofacitinib and twice as high as baricitinib based on current estimated costs to patients, but actual costs may vary.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Upadacitinib is an alternative therapy to other JAK inhibitors and bDMARDs in patients with moderate to severe RA who have had an inadequate response to a tumor necrosis factor inhibitor alone or in combination with a csDMARD.

CONCLUSIONS

Upadacitinib is an effective JAK inhibitor for use in RA.

Efficacy and Safety of Upadacitinib for Management of Moderate-to-Severe Atopic Dermatitis: An Evidence-Based Review

Atopic dermatitis (AD) is a common skin condition characterized by inflammation that presents with erythematous and pruritic skin. Its chronic relapse-remitting nature has a significant impact on the quality of life, and often requires ongoing management. Given the limited treatments available for AD, there remains a large need for effective and safe alternative therapies for long-term use. Janus kinase (JAK) inhibitors are a new class of agents that target the JAK-STAT pathway, which plays an important role in the production of proinflammatory cytokines involved in AD pathogenesis. Phase II and III clinical trials revealed that JAK inhibitors, such as upadacitinib, are effective and well-tolerated agents for the treatment of moderate-to-severe AD. As a result, upadacitinib was approved for use in patients with moderate-to-severe AD by the European Medicines Agency (2021), Health Canada (2021) and the FDA (2022) in the last year. It is important for dermatologists to be aware of the clinical evidence to continue incorporating the use of upadacitinib into the treatment algorithm for AD, which will ultimately lead to improved patient outcomes. Therefore, this review is an up-to-date summary of the clinical data available on the efficacy and safety of upadacitinib treatment for AD.

JAK inhibitors in lichen planus: A review of pathogenesis and treatments

Lichen planus (LP) is an auto-inflammatory skin disorder identified by a presence of T-cell lymphocytes at the dermal-epidermal junction. It is hypothesized that the INF-γ/CXCL10 axis fulfills a major role in the onset and persistence of chronic inflammation in LP. Since Janus kinases (JAKs) are involved in the transduction of INF-γ signals, they may be good targets for LP treatment. Several case reports and case series described the safety and efficacy of upadacitinib (2 articles), tofacitinib (6 articles), baricitinib (4 articles), and Ruxolitinib (1 Article) in the treatment of LP variants. The predominant variants that JAK inhibitors improved were lichen planopilaris, nail LP, and erosive LP. Considering the role of the JAK pathway in LP pathogenesis and the evidence provided by these reports, it seems JAK inhibitors would be effective therapeutic agents for LP treatment. Hence, these agents should be trialed and evaluated further.

Utility of Modeling and Simulation Approach to Support the Clinical Relevance of Dissolution Specifications: a Case Study from Upadacitinib Development

Dissolution specifications are often essential in assuring the quality and consistency of therapeutic benefits of drug lots released to the market as in vitro dissolution is often considered to be a surrogate for bioavailability. Despite the importance of demonstrating the clinical relevance of the dissolution specifications, it is often challenging to achieve this goal. In this case study, a modeling and simulation approach was utilized to support the clinical relevance of the dissolution specifications for upadacitinib extended-release tablets. A level A in vitro in vivo correlation was developed and utilized in predicting upadacitinib plasma exposures for formulations which correspond to the upper and lower dissolution limits. Exposure-response models for upadacitinib efficacy and safety in patients with moderate to severe rheumatoid arthritis (RA) were utilized to conduct clinical trial simulations to evaluate the efficacy and safety of formulations at the upper and lower dissolution boundaries. Each simulated clinical trial consisted of three treatment arms: (1) upadacitinib 15 mg QD using the target formulation, (2) upadacitinib 15 mg QD using a formulation at the lower dissolution boundary, and (3) upadacitinib 15 mg QD using a formulation at the upper dissolution boundary. Each simulated trial included 300 patients per arm and simulations were replicated 200 times. Results demonstrated that formulations at the lower and upper dissolution boundaries are predicted to have noninferior efficacy and comparable safety to the target 15 mg extended-release formulation. This approach was successfully utilized in demonstrating the clinical relevance of upadacitinib extended-release tablet dissolution specifications. Graphical Abstract.

Evaluating upadacitinib for the treatment of psoriatic arthritis

INTRODUCTION

Psoriatic arthritis is an extra-cutaneous manifestation affecting up to 40% of psoriasis patients with multiple therapies recommended by international guidelines including conventional and targeted synthetic disease-modifying anti-rheumatic drugs (DMARDs) as well as biologics. Janus kinase inhibitors (JAKis) have emerged as a unique therapeutic target with tofacitinib the first to gain FDA approval in 2017. The non-selectivity of older JAKis increases the risk of off-target effects such as suppression of hemopoiesis hence the rationale for more selective alternatives.

AREAS COVERED

This paper explores the use of upadacitinib (a selective JAK1 inhibitor) for the treatment of psoriatic arthritis. It covers its chemical properties, pharmacokinetics, pharmacodynamics, efficacy, safety and regulation.

EXPERT OPINION

In our opinion, upadacitinib is set to play an important role in the treatment of psoriatic arthritis as demonstrated by the SELECT-PsA trials especially in patients with poor or non-response to current first-line therapies. It's JAK1 receptor selectivity promises a lower side effect profile compared to the older nonselective JAKis but this will require confirmation with long-term clinical trial data.

Upadacitinib in patients from China, Brazil, and South Korea with rheumatoid arthritis and an inadequate response to conventional therapy

Aim

This study assessed the efficacy and safety of upadacitinib (UPA), in combination with conventional synthetic disease‐modifying antirheumatic drugs (csDMARDs), in Chinese, Brazilian, and South Korean patients with active rheumatoid arthritis (RA) and an inadequate response (IR) to csDMARDs.

Methods

Patients on stable csDMARDs were randomized (1:1) to once‐daily UPA 15 mg or matching placebo (PBO) for a 12‐week, double‐blind period. The primary endpoint was the proportion of patients achieving ≥20% improvement in American College of Rheumatology criteria (ACR20) at week 12.

Results

In total, 338 patients were randomized and treated, of whom 310 (91.7%) completed the double‐blind phase. The study met the primary endpoint of ACR20 at week 12 for UPA 15 mg vs PBO (71.6% vs 31.4%, P < .001), with a treatment difference observed as early as week 1. All ranked and other key secondary endpoints, including more stringent responses such as ACR50, ACR70 (≥50%/70% improvement in ACR criteria), and Disease Activity Score in 28 joints using C‐reactive protein <2.6, were met for UPA 15 mg vs PBO. The incidence of serious infections (2.4% vs 0.6%) and herpes zoster (HZ: 1.8% vs 0.6%) was higher with UPA 15 mg vs PBO. There was one case of venous thromboembolism reported in the UPA group.

Conclusion

UPA 15 mg in combination with csDMARDs demonstrated clinical and functional improvement and an acceptable safety profile over 12 weeks among patients from China, Brazil, and South Korea who had moderately to severely active RA and an IR to csDMARDs.

Selectivity Profile of the Tyrosine Kinase 2 Inhibitor Deucravacitinib Compared with Janus Kinase 1/2/3 Inhibitors

INTRODUCTION

Deucravacitinib, a novel, oral, selective inhibitor of tyrosine kinase 2 (TYK2) signaling, acts via an allosteric mechanism by binding to the enzyme's regulatory domain instead of the catalytic domain. This unique binding provides high functional selectivity for TYK2 versus the closely related Janus kinases (JAKs) 1/2/3. Deucravacitinib was efficacious in phase 2 and 3 psoriasis trials, without clinical or laboratory parameters indicative of JAK 1/2/3 inhibition being observed. This analysis compared the kinase specificities of deucravacitinib versus JAK 1/2/3 inhibitors at therapeutic exposures.

METHODS

Signaling via JAK 1/3, JAK 2/2, and TYK2/JAK 2 dimers was measured in in vitro whole blood assays. Concentrations providing half-maximal inhibition (IC₅₀) in these assays were determined for deucravacitinib and the JAK 1/2/3 inhibitors tofacitinib, upadacitinib, and baricitinib. Newly derived whole blood IC₅₀ values were plotted against available pharmacokinetic profiles using doses evaluated in phase 2/3 trials. Simulated average daily inhibition and durations over which concentrations exceeded IC₅₀ were evaluated.

RESULTS

At clinically relevant exposures, projected steady-state deucravacitinib plasma concentrations were higher than TYK2 IC₅₀ for approximately 9-18 h. Maximal plasma concentrations (C_max) of deucravacitinib were 8- to 17-fold lower than JAK 1/3 IC₅₀ and > 48- to > 102-fold lower than JAK 2/2 IC₅₀. Simulated daily average TYK2 inhibition by deucravacitinib ranged from 50% to 69%. Simulations indicated that tofacitinib, upadacitinib, and baricitinib at steady state exhibited varying degrees of JAK 1/3 (daily average inhibition, 70-94%) and JAK 2/2 (23%-67%) inhibition at therapeutic concentrations, with C_max values 17- to 33-fold lower than their TYK2 IC₅₀ levels.

CONCLUSION

At clinically relevant doses and exposures, deucravacitinib demonstrates highly selective inhibition of TYK2 and not JAK 1/2/3. Tofacitinib, upadacitinib, and baricitinib variably inhibit JAK 1/2/3 but not TYK2. These results indicate that deucravacitinib is a distinct class of kinase inhibitor compared with JAK 1/2/3 inhibitors.

Upadacitinib pharmacokinetics and exposure-response analyses of efficacy and safety in psoriatic arthritis patients - Analyses of phase III clinical trials

Upadacitinib is an oral Janus kinase inhibitor approved for the treatment of rheumatoid arthritis (RA) and recently approved by the European Medicines Agency for the treatment of psoriatic arthritis (PsA). The efficacy and safety profile of upadacitinib in PsA have been established in the SELECT‐PsA program in two global phase III studies, which evaluated upadacitinib 15 and 30 mg q.d. The analyses described here characterized upadacitinib pharmacokinetics and exposure‐response relationships for efficacy and safety endpoints using data from the SELECT‐PsA studies. Upadacitinib pharmacokinetics in patients with PsA were characterized through a Bayesian population analysis approach and were comparable to pharmacokinetics in patients with RA. Exposure‐response relationships for key efficacy and safety endpoints were characterized using data from 1916 patients with PsA. The percentage of patients achieving efficacy endpoints at week 12 (American College of Rheumatology [ACR]50 and ACR70), 16 and 24 (sIGA0/1) increased with increasing upadacitinib average plasma concentration over a dosing interval, whereas no clear exposure‐response trend was observed for ACR20 at week 12 or ACR20/50/70 at week 24 within the range of plasma exposures evaluated in the phase III PsA studies. No clear trends for exposure‐response relationships were identified for experiencing pneumonia, herpes zoster infection, hemoglobin less than 8 g/dl, lymphopenia (grade ≥ 3), or neutropenia (grade ≥ 3) after 24 weeks of treatment. Shallow relationships with plasma exposures were observed for serious infections and hemoglobin decrease greater than 2 g/dl from baseline at week 24. Based on exposure‐response analyses, the upadacitinib 15 mg q.d. regimen is predicted to achieve robust efficacy in patients with PsA and to be associated with limited incidences of reductions in hemoglobin or occurrence of serious infections.

JAK selectivity and the implications for clinical inhibition of pharmacodynamic cytokine signalling by filgotinib, upadacitinib, tofacitinib and baricitinib

OBJECTIVE

Janus kinase inhibitors (JAKinibs) are efficacious in rheumatoid arthritis (RA) with variable reported rates of adverse events, potentially related to differential JAK family member selectivity. Filgotinib was compared with baricitinib, tofacitinib and upadacitinib to elucidate the pharmacological basis underlying its clinical efficacy and safety.

METHODS

In vitro JAKinib inhibition of signal transducer and activator of transcription phosphorylation (pSTAT) was measured by flow cytometry in peripheral blood mononuclear cells and whole blood from healthy donors and patients with RA following cytokine stimulation of distinct JAK/STAT pathways. The average daily pSTAT and time above 50% inhibition were calculated at clinical plasma drug exposures in immune cells. The translation of these measures was evaluated in ex vivo-stimulated assays in phase 1 healthy volunteers.

RESULTS

JAKinib potencies depended on cytokine stimulus, pSTAT readout and cell type. JAK1-dependent pathways (interferon (IFN)α/pSTAT5, interleukin (IL)-6/pSTAT1) were among the most potently inhibited by all JAKinibs in healthy and RA blood, with filgotinib exhibiting the greatest selectivity for JAK1 pathways. Filgotinib (200 mg once daily) had calculated average daily target inhibition for IFNα/pSTAT5 and IL-6/pSTAT1 that was equivalent to tofacitinib (5 mg two times per day), upadacitinib (15 mg once daily) and baricitinib (4 mg once daily), with the least average daily inhibition for the JAK2-dependent and JAK3-dependent pathways including IL-2, IL-15, IL-4 (JAK1/JAK3), IFNγ (JAK1/JAK2), granulocyte colony stimulating factor, IL-12, IL-23 (JAK2/tyrosine kinase 2) and granulocyte-macrophage colony-stimulating factor (JAK2/JAK2). Ex vivo pharmacodynamic data from phase 1 healthy volunteers clinically confirmed JAK1 selectivity of filgotinib.

CONCLUSION

Filgotinib inhibited JAK1-mediated signalling similarly to other JAKinibs, but with less inhibition of JAK2-dependent and JAK3-dependent pathways, providing a mechanistic rationale for its apparently differentiated efficacy:safety profile.

Effect of Upadacitinib on the Pharmacokinetics of Rosuvastatin or Atorvastatin in Healthy Subjects

This phase 1, 2‐part, 2‐period, open‐label, drug‐drug interaction study evaluated the potential for pharmacokinetic interactions between upadacitinib and rosuvastatin, an organic anion transporting polypeptide (OATP) 1B1 and breast cancer resistance protein substrate, or atorvastatin, a cytochrome P450 3A, OATP1B1, and OATP1B3 substrate, in 36 healthy volunteers. During period 1, a single dose of rosuvastatin (5 mg; part 1) or atorvastatin (10 mg; part 2) was administered on day 1, followed by a washout period of 5 days. During period 2, once‐daily doses of upadacitinib extended‐release (30 mg) were administered on days 1 to 10, and a single dose of rosuvastatin (5 mg; part 1) or atorvastatin (10 mg; part 2) was administered 1 hour after the upadacitinib dose on day 7. Serial blood samples were collected for assays of drug concentrations. In Part 1, rosuvastatin maximum observed plasma concentration (C_max) and area under the plasma concentration–time curve from time 0 to infinity (AUC_inf) were 23% and 33% lower, respectively, when administered with upadacitinib relative to when administered alone. In part 2, atorvastatin C_max and AUC_inf was 11% and 23% lower, respectively, when administered with upadacitinib relative to when administered alone. The C_max and AUC_inf of the active metabolite ortho‐hydroxyatorvastatin remained unchanged. Administration of a single 5‐mg dose of rosuvastatin or a single 10‐mg dose of atorvastatin had no relevant effect on upadacitinib C_max or area under the plasma concentration–time curve. These results demonstrated that upadacitinib has no clinically relevant effect on the pharmacokinetics of rosuvastatin and atorvastatin or on substrates transported by OATP1B or breast cancer resistance protein.

Upadacitinib in Rheumatoid Arthritis: A Benefit-Risk Assessment Across a Phase III Program

Treating to a target of clinical remission or low disease activity is an important principle for managing rheumatoid arthritis (RA). Despite the availability of biologic disease-modifying antirheumatic drugs (bDMARDs), a substantial proportion of patients with RA do not achieve these treatment targets. Upadacitinib is a once-daily, oral Janus kinase (JAK) inhibitor with increased selectivity for JAK1 over JAK2, JAK3, and tyrosine kinase 2. The SELECT phase III upadacitinib clinical program comprised five pivotal trials of approximately 4400 patients with RA, including inadequate responders (IR) to conventional synthetic (cs)DMARDs or bDMARDs. This review aims to provide insights into the benefit-risk profile of upadacitinib in patients with RA. Upadacitinib 15 mg once daily, in combination with csDMARDs or as monotherapy, achieved all primary and ranked secondary endpoints in the five pivotal trials across csDMARD-naïve, csDMARD-IR, and bDMARD-IR populations. Upadacitinib 15 mg also demonstrated significantly higher rates of remission and low disease activity in all five pivotal trials, compared with placebo, methotrexate, or adalimumab. Labeled warnings of JAK inhibitors include serious infections, herpes zoster, malignancies, major cardiovascular events, and venous thromboembolic events. Short- and long-term integrated analyses showed that upadacitinib 15 mg was associated with increased risk of herpes zoster and creatine phosphokinase elevations compared with methotrexate and adalimumab but otherwise had comparable safety with these active comparators. This review suggests that upadacitinib 15 mg had a favorable benefit-risk profile. The safety of upadacitinib will continue to be monitored in long-term extensions and post-marketing studies.

Exposure-Response Analyses for Upadacitinib Efficacy in Subjects With Atopic Dermatitis-Analyses of Phase 2b Study to Support Selection of Phase 3 Doses

Upadacitinib is a selective Janus kinase 1 inhibitor that was recently approved for treatment of rheumatoid arthritis and is currently being evaluated for treatment of several other autoimmune diseases, including atopic dermatitis (AD). The relationships between upadacitinib plasma exposure and efficacy (assessed as Eczema Area Severity Index [EASI]-75, EASI-90, and Investigator Global Assessment [IGA] 0/1) in subjects with moderate to severe atopic dermatitis were characterized using the data from 167 subjects who were enrolled in a phase 2b dose-ranging study. Subjects were randomized to receive once daily doses of monotherapy treatment with upadacitinib extended-release 7.5, 15, or 30 mg or placebo for 16 weeks. Logistic regression models were developed and utilized to simulate efficacy for upadacitinib with an approximate phase 3 sample size. Based on exposure-response models, 15 mg once daily is predicted to achieve EASI-75, EASI-90, and IGA 0/1 responses in 48%, 26%, and 29% of subjects, respectively, compared with placebo responses of 9%, 2%, and 2%, respectively, whereas 30 mg once daily is predicted to provide an additional approximately 20% greater efficacy for these end points relative to 15 mg once daily. These analyses supported the selection of upadacitinib doses that are being evaluated in ongoing global phase 3 studies in atopic dermatitis.

Characterization of the Effect of Upadacitinib on the Pharmacokinetics of Bupropion, a Sensitive Cytochrome P450 2B6 Probe Substrate

This phase 1 study characterized the effect of multiple doses of upadacitinib, an oral Janus kinase 1 selective inhibitor, on the pharmacokinetics of the cytochrome P450 (CYP) 2B6 substrate bupropion. Healthy subjects (n = 22) received a single oral dose of bupropion 150 mg alone (study period 1) and on day 12 of a 16-day regimen of upadacitinib 30 mg once daily (study period 2). Serial blood samples for measurement of bupropion and hydroxybupropion plasma concentrations were collected in each study period. The central values (90% confidence intervals) for the ratios of change were 0.87 (0.79-0.96) for bupropion maximum plasma concentration (Cmax ), 0.92 (0.87-0.98) for bupropion area under the plasma-concentration time curve from time 0 to infinity (AUCinf ), 0.78 (0.72-0.85) for hydroxybupropion Cmax , and 0.72 (0.67-0.78) for hydroxybupropion AUCinf when administered with, relative to when administered without, upadacitinib. After multiple-dose administration of upadacitinib 30 mg once daily, upadacitinib mean ± SD AUC0-24 was 641 ± 177 ng·h/mL, and Cmax was 83.3 ± 30.7 ng/mL. These results confirm that upadacitinib has no relevant effect on pharmacokinetics of substrates metabolized by CYP2B6.

Selective JAK1 Inhibitors for the Treatment of Atopic Dermatitis: Focus on Upadacitinib and Abrocitinib

Atopic dermatitis is a common, chronic, immune-mediated disease associated with several comorbidities. Elevated levels of T helper (Th)2, Th22, and also some Th1 and Th17 cytokines are found in atopic dermatitis skin lesions. Similar to psoriasis, there is a tendency towards increased use of more targeted therapies. However, there are still several unmet needs in the treatment of atopic dermatitis concerning long-term efficacy, tolerability, safety, route of administration, and cost. The increased knowledge of atopic dermatitis pathogenesis and the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways has allowed the development of new compounds to inhibit this intracellular signaling pathway implicated in atopic dermatitis-related immune responses. Currently, JAK inhibitors are an important focus of therapeutic research for atopic dermatitis. Upadacitinib and abrocitinib are oral small molecules that inhibit the JAK/STAT pathway by selectively blocking JAK1. Data from phase II and III trials are encouraging, revealing that JAK1 inhibitors are effective and well-tolerated agents for moderate-to-severe atopic dermatitis. Selective JAK1 inhibitors may represent an important therapeutic option to be included in the treatment algorithm of atopic dermatitis, owing to oral administration and a favorable safety and tolerability profile. In this article, we review the current evidence on the efficacy and safety of oral selective JAK1 inhibitors for the treatment of atopic dermatitis.

Population pharmacokinetic analysis of peficitinib in patients with rheumatoid arthritis

Aims

To analyse the population pharmacokinetics (PK) of peficitinib in patients with rheumatoid arthritis (RA) and assess the potential PK covariates to identify the requirement for dose adjustment in RA patients.

Methods

The analysis incorporated 2464 observations from 98 healthy volunteers and 4919 observations from 989 RA patients. A population PK model for peficitinib in RA patients was constructed by a nonlinear mixed effect model using NONMEM with prior information from a healthy volunteer model.

Results

A 2‐compartment model with sequential zero‐ and first‐order absorption and lag time was constructed for RA patients. Covariate exploration in the RA patient model revealed that estimated glomerular filtration rate (eGFR) and lymphocyte count had a significant effect on apparent total systemic clearance (CL), which was 91.7 L/h (2.3% relative standard error). Compared with the mean population CL, the model predicted mean changes in CL of 12.3 and −10.7% in patients with observed minimum and maximum lymphocyte count of 500 and 4600 10⁶/L, respectively, and mean changes in CL of −17.8 and 16.7% in patients with minimum and maximum eGFR of 36.4 and 188 mL/min/1.73m², respectively. The simulated population mean area under plasma concentration–time curve for 24 hours after dosing showed a 1.35‐fold increase in patients with severe renal impairment (eGFR 22.5 mL/min/1.73m²) compared with patients with reference eGFR (91.5 mL/min/1.73m²).

Conclusion

The population PK model identified eGFR and lymphocyte count as covariates for CL. The magnitude of changes was not considered clinically relevant, indicating no requirement for dose adjustment.

PK, PD, and interactions: the new scenario with JAK inhibitors and S1P receptor modulators, two classes of small molecule drugs, in IBD

INTRODUCTION

Inflammatory bowel diseases (IBDs) are immune-mediated chronic inflammatory disorders of the gastrointestinal tract whose pathogenesis is not yet fully understood. Despite the advent of biological agents, there are still unmet needs for IBD patients, due to suboptimal rate of sustained remission achieved. Small molecule drugs (SMDs), the next generation of selective drugs in IBD, show promising results in ongoing trials.

AREAS COVERED

We describe the pharmacodynamics and pharmacokinetic features of novel SMDs and their main differences with biologic agents.

EXPERT OPINION

Small molecule drugs are a promising class of drugs for the treatment of ulcerative colitis and Crohn's disease with good results in inducing and maintaining remission. Hence, over the next few years physicians will have numerous options of small molecule drugs for the treatment of patients with IBD. This group of drugs are potentially easier to use over biological agents due to pharmacokinetic features such as oral administration, short half-life, high volume of distribution, and lack of immunogenicity. On the other hand, drug-drug interactions can happen with small-molecule drugs, principally due to competitive metabolic and clearance mechanisms.

Safety of Janus Kinase Inhibitors in Older Patients: A Focus on the Thromboembolic Risk

The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway is a membrane-to-nucleus signaling cascade that effects activation of gene transcription. JAK inhibitors have demonstrated effectiveness in autoimmune diseases such as rheumatoid arthritis. An increased risk of infection, mainly varicella-zoster reactivation, with these new agents is of concern. Comorbid conditions, along with pharmacokinetic variations in drug metabolism in the older population, further increase the risk of adverse outcomes. Newly raised concerns for potential adverse effects such as deep vein thrombosis and pulmonary embolism are essential considerations for clinicians. Older patients are at increased risk because of multiple comorbid conditions and pharmacokinetic changes related to drug metabolism and excretion. Both the US FDA and the European Medicines Agency have issued warnings regarding this risk. These warnings highlight individuals aged > 50 years with concomitant cardiovascular risk factors. Furthermore, the FDA released a black box warning for increased thromboembolic risk associated with JAK inhibitors. As the use of these drugs increases, a solid understanding of adverse effects and risks is critical to those treating older adults.

Evaluating upadacitinib for the treatment of rheumatoid arthritis

INTRODUCTION

The introduction of JAKs inhibitors for the treatment of rheumatoid arthritis represents a promising new era in the management of the disease. New compounds under investigation, like upadacitinib, with greater selectivity for JAK1 inhibition have recently been approved for the treatment of adults with moderately to severely active rheumatoid arthritis who have had an inadequate response or intolerance to conventional synthetic disease-modifying antirheumatic drugs.

AREAS COVERED

Herein, the authors review the pharmacological data, the therapeutic efficacy, and safety data of upadacitinib before providing the reader with their critical evaluation and future perspectives.

EXPERT OPINION

Upadacitinib was able to accomplish all the primary and secondary end points in most of the trials, with a safety profile that is similar to the other JAK inhibitors. It has also demonstrated superiority over a tumor necrosis factor inhibitor and data on new indications is also favorable. Upadacitinib is a promising new drug for the treatment of rheumatoid arthritis.

GLOSSARY

Adalimumab: ADA; American College of Rheumatology: ACR; Assessment of Spondylarthritis International Society 40: ASAS40; Ankylosis Spondylitis: AS; Area under the Curve: AUC; Biological Disease-modifying arthritis drugs: bDMARDs; Clinical disease activity index: CDAI; C Reactive Protein: CRP; Conventional Synthetic Disease-modifying arthritis drugs: csDMARDs; Deep Venous Thrombosis: DVT; Disease arthritis score: DAS.

Efficacy and Safety of Upadacitinib in a Randomized Trial of Patients With Crohn's Disease

BACKGROUND & AIMS

We evaluated the efficacy and safety of upadacitinib, an oral selective Janus kinase 1 inhibitor, in a randomized trial of patients with Crohn's disease (CD).

METHODS

We performed a double-blind, phase 2 trial in adults with moderate to severe CD and inadequate response or intolerance to immunosuppressants or tumor necrosis factor antagonists. Patients were randomly assigned (1:1:1:1:1:1) to groups given placebo; or 3 mg, 6 mg, 12 mg, or 24 mg upadacitinib twice daily; or 24 mg upadacitinib once daily and were evaluated by ileocolonoscopy at weeks 12 or 16 of the induction period. Patients who completed week 16 were re-randomized to a 36-week period of maintenance therapy with upadacitinib. The primary endpoints were clinical remission at week 16 and endoscopic remission at week 12 or 16 using the multiple comparison procedure and modeling and the Cochran-Mantel-Haenszel test, with a 2-sided level of 10%.

RESULTS

Among the 220 patients in the study, clinical remission was achieved by 13% of patients receiving 3 mg upadacitinib, 27% of patients receiving 6 mg upadacitinib (P < .1 vs placebo), 11% of patients receiving 12 mg upadacitinib, and 22% of patients receiving 24 mg upadacitinib twice daily, and by 14% of patients receiving 24 mg upadacitinib once daily, vs 11% of patients receiving placebo. Endoscopic remission was achieved by 10% (P < .1 vs placebo), 8%, 8% (P < .1 vs placebo), 22% (P < .01 vs placebo), and 14% (P < .05 vs placebo) of patients receiving upadacitinib, respectively, vs none of the patients receiving placebo. Endoscopic but not clinical remission increased with dose during the induction period. Efficacy was maintained for most endpoints through week 52. During the induction period, patients in the upadacitinib groups had higher incidences of infections and serious infections vs placebo. Patients in the twice-daily 12 mg and 24 mg upadacitinib groups had significant increases in total, high-density lipoprotein, and low-density lipoprotein cholesterol levels compared with patients in the placebo group.

CONCLUSIONS

In a phase 2 trial of patients with CD, upadacitinib induced endoscopic remission in a significant proportion of patients compared with placebo. Upadacitinib's benefit/risk profile supports further development for treatment of CD. (Clinicaltrials.gov, Number: NCT02365649).

Efficacy of Upadacitinib in a Randomized Trial of Patients With Active Ulcerative Colitis

BACKGROUND & AIMS

We evaluated the efficacy and safety of upadacitinib, an oral selective inhibitor of Janus kinase 1, as induction therapy for ulcerative colitis (UC).

METHODS

We performed a multicenter, double-blind, phase 2b study of 250 adults with moderately to severely active UC and an inadequate response, loss of response, or intolerance to corticosteroids, immunosuppressive agents, and/or biologic therapies. Patients were randomly assigned to groups that received placebo or induction therapy with upadacitinib (7.5 mg, 15 mg, 30 mg, or 45 mg, extended release), once daily for 8 weeks. The primary endpoint was the proportion of participants who achieve clinical remission according to the adapted Mayo score at week 8. No multiplicity adjustments were applied.

RESULTS

At week 8, 8.5%, 14.3%, 13.5%, and 19.6% of patients receiving 7.5 mg, 15 mg, 30 mg, or 45 mg upadacitinib, respectively, achieved clinical remission compared with none of the patients receiving placebo (P = .052, P = .013, P = .011, and P = .002 compared with placebo, respectively). Endoscopic improvement at week 8, defined as endoscopic subscore of ≤ 1, was achieved in 14.9%, 30.6%, 26.9%, and 35.7% of patients receiving upadacitinib 7.5 mg, 15 mg, 30 mg, or 45 mg, respectively, compared with 2.2% receiving placebo (P = .033, P < .001, P < .001, and P < .001 compared with placebo, respectively). One event of herpes zoster and 1 participant with pulmonary embolism and deep venous thrombosis (diagnosed 26 days after treatment discontinuation) were reported in the group that received upadacitinib 45 mg once daily. Increases in serum lipid levels and creatine phosphokinase with upadacitinib were observed.

CONCLUSION

In a phase 2b trial, 8 weeks of treatment with upadacitinib was more effective than placebo for inducing remission in patients with moderately to severely active UC. (ClinicalTrials.gov, Number: NCT02819635).

Clinical Pharmacokinetics of Upadacitinib: Review of Data Relevant to the Rheumatoid Arthritis Indication

Upadacitinib is a Janus kinase 1 inhibitor developed for treatment of moderate to severe rheumatoid arthritis (RA) and was recently approved by the US Food and Drug Administration for this indication in adults who have had an inadequate response or intolerance to methotrexate. Upadacitinib is currently under regulatory review by other agencies around the world. Ongoing trials are investigating the use of upadacitinib in other inflammatory autoimmune diseases. In this article, we review the clinical pharmacokinetic data available to date for upadacitinib that supported the clinical development program in RA and ultimately regulatory applications for upadacitinib in treatment of patients with moderate to severe RA.

Upadacitinib: First Approval

Upadacitinib (Rinvoq™), an orally-administered Janus kinase 1 (JAK-1) inhibitor, is being developed by AbbVie for the treatment of rheumatoid arthritis. In August 2019, based on positive results from multinational phase III trials conducted in patients with rheumatoid arthritis, upadacitinib received marketing approval in the USA for the treatment of moderately to severely active rheumatoid arthritis and an inadequate response or intolerance to methotrexate. This article summarizes the milestones in the development of upadacitinib leading to this first approval for the treatment of rheumatoid arthritis.

Design, synthesis, and pharmacological evaluation of 4- or 6-phenyl-pyrimidine derivatives as novel and selective Janus kinase 3 inhibitors

As non-receptor tyrosine kinases, Janus kinases (JAKs) have become an attractive target for the treatment of autoimmune diseases and cancers. JAKs play a pivotal role in innate immunity, inflammation, and hematopoiesis by mediating the signaling of numerous cytokines, growth factors, and interferons (IFNs). Selective inhibitors of a variety of JAK members are expected to inhibit pro-inflammatory cytokine-mediated inflammation and immune responses, while preventing targeting other subtypes of JAKs. In this work, poorly selective compounds based on 4- or 6-phenyl-pyrimidine derivatives have been improved to highly potent and selective compounds by designing a covalent binding tether, which attaches to the unique cysteine (Cys909) residue in JAK3. Compound 12 exhibited potent JAK3 inhibitory activity (IC₅₀ = 1.7 nM) with an excellent selectivity profile when compared to the other JAK isoforms (>588-fold). In a cellular assay, compound 12 strongly inhibited JAK3-dependent signaling and T cell proliferation. Moreover, in vivo data revealed that compound 12 significantly suppressed oxazolone (OXZ)-induced delayed hypersensitivity responses in Balb/c mice. Compound 12 also displayed decent pharmacokinetic properties and was suitable for in vivo use. Taken together, these results indicated that compound 12 may be a promising tool compound as a selective JAK3 inhibitor for treating autoimmune diseases.

Preferential Inhibition of JAK1 Relative to JAK3 by Upadacitinib: Exposure-Response Analyses of Ex Vivo Data From 2 Phase 1 Clinical Trials and Comparison to Tofacitinib

Upadacitinib is a selective Janus kinase (JAK) 1 inhibitor being developed for treatment of rheumatoid arthritis. This study characterizes the relationships between upadacitinib exposure and interleukin (IL)-6-induced signal transducer and activator of transcription proteins 3 (STAT3) phosphorylation (pSTAT3) and IL-7-induced STAT5 phosphorylation (pSTAT5) in the ex vivo setting as measures for JAK1 and JAK1/JAK3 inhibition, respectively, with comparison to tofacitinib. Drug plasma concentrations and ex vivo IL-6-induced pSTAT3 and IL-7-induced pSTAT5 in blood from subjects evaluated in 2 phase 1 studies who received immediate-release 1 mg to 48 mg upadacitinib, 5 mg twice daily (BID) tofacitinib, or placebo were determined. Exposure-response models were developed, and the effects of different upadacitinib doses on ex vivo biomarker responses were simulated and compared to tofacitinib. Upadacitinib (and tofacitinib) reversibly inhibited IL-6-induced pSTAT3 and IL-7-induced pSTAT5 in a concentration-dependent manner. Model-estimated values of 50% of the maximum effect were 60.7 nM for upadacitinib and 119 nM for tofacitinib for IL-6-induced pSTAT3 inhibition, and 125 nM for upadacitinib and 79.1 nM for tofacitinib for IL-7-induced pSTAT5 inhibition. Tofacitinib 5 mg BID is estimated to have a similar magnitude of effect on IL-6-induced pSTAT3 to ∼3 mg BID of upadacitinib (immediate-release formulation), whereas a 4-fold higher dose of upadacitinib (∼12 mg BID), is estimated to show a similar magnitude of inhibition on IL-7-induced pSTAT5 as tofacitinb 5 mg BID. This study confirms that in humans, upadacitinib has greater selectivity for JAK1 vs JAK3 relative to the rheumatoid arthritis approved dose of tofacitinib, and results from these analyses informed the selection of upadacitinib IR doses evaluated in phase 2.

Effects of Upadacitinib Coadministration on the Pharmacokinetics of Sensitive Cytochrome P450 Probe Substrates: A Study With the Modified Cooperstown 5+1 Cocktail

The aim of this study was to characterize the effects of upadacitinib, a Janus kinase 1 inhibitor, on in vivo activity of different cytochrome P450 (CYP) enzymes using a cocktail approach. Healthy subjects (n = 20) received single oral doses of the modified Cooperstown 5+1 cocktail drugs (midazolam [CYP3A], caffeine [CYP1A2], warfarin + vitamin K [CYP2C9], omeprazole [CYP2C19], and dextromethorphan [CYP2D6]) without upadacitinib and on day 11 (midazolam) or 12 (all other probes) of a 15-day regimen of upadacitinib 30 mg once daily (extended-release formulation). Serial blood samples and 12-hour urine samples were collected for assays of the probe substrates and select metabolites. The ratio (90%CI) of area under the plasma concentration-time curve from time 0 to infinity (AUCinf ) central values when the cocktail drugs were administered with upadacitinib relative to when administered alone were 0.74 (0.68-0.80) for midazolam, 1.22 (1.15-1.29) for caffeine, 1.11 (1.07-1.15) for S-warfarin, 1.07 (0.95-1.22) for dextromethorphan, and 0.82 (0.72-0.94) for omeprazole. The ratio (90%CI) was 1.09 (1.00-1.19) for 5-hydroxy-omeprazole to omeprazole AUCinf ratio and 1.17 (0.97-1.41) for dextromethorphan to dextrorphan 12-hour molar urinary ratio. Upadacitinib 30 mg once daily (a dose that is twice the optimal dose in rheumatoid arthritis based on phase 3 results) has a limited effect on CYP3A activity (26% decrease in exposure of midazolam, a sensitive CYP3A substrate) and no relevant effects on CYP1A2, CYP2C9, CYP2C19, or CYP2D6 activity in vivo. No clinically relevant changes in plasma exposures are expected for drugs that are substrates for the evaluated CYP enzymes when coadministered with upadacitinib.

Exposure-Response Analyses of Upadacitinib Efficacy and Safety in Phase II and III Studies to Support Benefit-Risk Assessment in Rheumatoid Arthritis

Exposure–response analyses of upadacitinib (UPA) key efficacy and safety end points (3,685 and 4,577 subjects for efficacy and safety, respectively) using data from phase II and phase III rheumatoid arthritis (RA) studies were conducted to support benefit–risk assessment. Percentage of subjects achieving American College of Rheumatology (ACR)20/50/70, disease activity score 28 (C‐reactive protein) (DAS28‐CRP) ≤ 3.2, and DAS28‐CRP < 2.6 increased with increasing UPA plasma exposures. With the small number of observed safety events, no clear trends for exposure–response relationships were identified for pneumonia, herpes zoster infection, changes in platelet count, lymphopenia (Grade ≥ 4), or neutropenia (Grade ≥ 3) up to Week 26. Shallow exposure–response relationships were observed for > 2 g/dL decrease in hemoglobin, lymphopenia Grade ≥ 3 at Week 12/14, and serious infections at Week 24/26. Exposure–efficacy analyses demonstrate that UPA 15 mg q.d. (once daily) dose provided the optimal benefit–risk in RA through maximizing efficacy with only small incremental benefit with 30 mg q.d.; and with consistency across RA subpopulations and with UPA monotherapy or combination with conventional synthetic disease‐modifying antirheumatic drugs.

Exposure-Response Analyses for Upadacitinib Efficacy and Safety in the Crohn's Disease CELEST Study and Bridging to the Extended-Release Formulation

Upadacitinib plasma concentrations, efficacy, and safety data from 216 subjects with moderate‐to‐severe active Crohn's disease (CD) from the 16‐week induction period of the CELEST study were analyzed to characterize upadacitinib exposure–response relationships in CD. Subjects in CELEST received either placebo or upadacitinib (3, 6, 12, 24 mg b.i.d. or 24 mg q.d.). Exposure–response models were developed and utilized to simulate efficacy of induction doses of the immediate‐release (IR) and extended‐release (ER) formulations. Upadacitinib exposures associated with 18–24 mg b.i.d. (IR formulation) or 45–60 mg q.d. (ER formulation) are estimated to have greater efficacy during 12‐week induction in patients with CD compared with lower doses. No exposure–response relations were observed with decreases in hemoglobin or lymphocytes at week 16 or with herpes zoster infections, pneumonia, or serious infections during 16 weeks of treatment in this study. These analyses informed the selection of upadacitinib induction dose for phase III studies in CD.

Development of In Vitro-In Vivo Correlation for Upadacitinib Extended-Release Tablet Formulation

Upadacitinib is a selective Janus Kinase 1 inhibitor which is being developed for the treatment of several inflammatory diseases including rheumatoid arthritis. Upadacitinib was evaluated in Phase 3 studies as an oral extended-release (ER) formulation administered once daily. The purpose of this study was to develop a level A in vitro-in vivo correlation (IVIVC) for upadacitinib ER formulation. The pharmacokinetics of four upadacitinib extended-release formulations with different in vitro release characteristics and an immediate-release capsule formulation of upadacitinib were evaluated in 20 healthy subjects in a single-dose, randomized, crossover study. In vivo pharmacokinetic data and in vitro dissolution data (USP Dissolution Apparatus 1; pH 6.8; 100 rpm) were used to establish a level A IVIVC. Three formulations were used to establish the IVIVC, and the fourth formulation was used for external validation. A non-linear IVIVC best described the relationship between upadacitinib in vitro dissolution and in vivo absorption profiles. The absolute percent prediction errors (%PE) for upadacitinib Cmax and AUC were less than 10% for all three formulations used to establish the IVIVC, as well as for the %PE for the external validation formulation and the overall mean internal validation. Model was cross-validated using the leave-one-out approach; all evaluated cross-validation runs met the regulatory acceptance criteria. A level A IVIVC was successfully developed and validated for upadacitinib ER formulation, which meets the FDA and EMA regulatory validation criteria and can be used as surrogate for in vivo bioequivalence.

Characterization of the Effect of Hepatic Impairment on Upadacitinib Pharmacokinetics

Upadacitinib is a selective Janus kinase 1 inhibitor being developed for the treatment of several inflammatory autoimmune diseases, including rheumatoid arthritis. Upadacitinib is a nonsensitive substrate for metabolism by cytochrome P450 3A enzymes. This open-label, single-dose, multicenter study assessed the pharmacokinetics of upadacitinib following oral administration of a single 15-mg dose of the upadacitinib extended-release formulation in subjects with mild (n = 6) and moderate (n = 6) hepatic impairment relative to demographically matched healthy subjects (n = 6). Subjects were assigned to 1 of the 3 groups according to the Child-Pugh classification. Relative to subjects with normal hepatic function, the ratios (90% confidence intervals) of upadacitinib area under the plasma concentration-versus-time profile from time 0 to infinity (AUCinf ) for subjects with mild and moderate hepatic impairment were 1.28 (0.91-1.79) and 1.24 (0.87-1.76), respectively. The central ratios of upadacitinib maximum observed concentration (Cmax ) were 1.04 (0.77-1.39) and 1.43 (1.05-1.95) in subjects with mild and moderate hepatic impairment, respectively, compared with subjects with normal hepatic function. No clinically significant changes in vital signs or hematology measurements were observed, and no new safety events were identified in this study. These results indicate that mild and moderate hepatic impairment has no clinically relevant effect on upadacitinib pharmacokinetics.