Effects of Renal Impairment on the Pharmacokinetics of Abrocitinib and Its Metabolites

Practical Management of the JAK1 Inhibitor Abrocitinib for Atopic Dermatitis in Clinical Practice: Special Safety Considerations

Abrocitinib, an oral, once-daily, Janus kinase (JAK) 1-selective inhibitor, is approved for the treatment of adults and adolescents with moderate-to-severe atopic dermatitis (AD). Abrocitinib has shown rapid and sustained efficacy in phase 3 trials and a consistent, manageable safety profile in long-term studies. Rapid itch relief and skin clearance are more likely to be achieved with a 200-mg daily dose of abrocitinib than with dupilumab. All oral JAK inhibitors are associated with adverse events of special interest and laboratory changes, and initial risk assessment and follow-up monitoring are important. Appropriate selection of patients and adequate monitoring are key for the safe use of JAK inhibitors. Here, we review the practical use of abrocitinib and discuss characteristics of patients who are candidates for abrocitinib therapy. In general, abrocitinib may be used in all appropriate patients with moderate-to-severe AD in need of systemic therapy, provided there are no contraindications, e.g., in patients with active serious systemic infections and those with severe hepatic impairment, as well as pregnant or breastfeeding women. For patients aged ≥ 65 years, current long-time or past long-time smokers, and those with risk factors for venous thromboembolism, major adverse cardiovascular events, or malignancies, a meticulous benefit-risk assessment is recommended, and it is advised to start with the 100-mg dose, when abrocitinib is the selected treatment option.

Targeted Systemic Therapies for Adults with Atopic Dermatitis: Selecting from Biologics and JAK Inhibitors

Therapeutic options for people with moderate or severe atopic dermatitis refractory to topical therapy have rapidly expanded in recent years. These new targeted immunomodulatory agents-biologics and Janus kinase (JAK) inhibitors-have each demonstrated high levels of efficacy and acceptable safety in mostly placebo-controlled clinical trials for atopic dermatitis, but there is no universally applicable algorithm to help choose between them for a given patient. Hence, patients and physicians should utilize shared decision making, discussing efficacy, safety, mode of delivery, monitoring, costs, speed of onset, and other factors to reach individualized treatment decisions. In this review, we try to aid shared decision making by summarizing the efficacy, safety, and monitoring of biologics and oral JAK inhibitors for adults with atopic dermatitis. Network meta-analyses suggest that higher doses of abrocitinib and upadacitinib are more effective than biologics. They also show that, among biologics, dupilumab is likely more effective than tralokinumab and lebrikizumab. Biologics are generally considered safer than JAK inhibitors, although concerns about JAK inhibitors are mainly extrapolated from older generation JAK inhibitors used in higher-risk populations. We also outline evidence and considerations for choosing and using systemic immunomodulatory treatments for special populations including pregnant individuals, those with human immunodeficiency virus (HIV), hepatitis B and C, end stage kidney disease, and older adults.

Navigating the atopic dermatitis toolbox: Challenging scenarios and shared decision-making

Atopic dermatitis (AD) is a chronic inflammatory disease with a complex pathogenesis and heterogeneous clinical presentation. Recently, multiple advanced therapies were approved for the treatment of moderate-severe AD, including the biologics dupilumab, tralokinumab, and lebrikizumab and oral Janus kinase inhibitors abrocitinib, upadacitinib, and baricitinib. These treatments have different efficacy, safety, and tolerability profiles and monitoring requirements. The availability of multiple recently approved therapies poses a clinical challenge for health care providers and patients on how to select the best treatment for patients. This article aims to highlight clinical considerations and patient perspectives to guide shared decision-making for biologic and oral systemic therapy, particularly Janus kinase inhibitors, in AD. Important aspects to consider include treatment goals, medical history, symptom severity, physician assessments, safety profile of drugs, and the risk predispositions in patients.

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.

Low-dose apatinib in subjects with renal impairment: A pharmacokinetics study

OBJECTIVE

In patients with renal impairment, we studied apatinib and its major metabolites (M1-1, M1-2, M1-6, and M9-2) for pharmacokinetics.

METHODS

Subjects with different renal functions were given a single oral dose of apatinib mesylate tablets of 250 mg. Pharmacokinetic samples were collected at 1 hour before dosing,0.25, 0.5, 1, 2, 3, 4, 6, 8, 24, 48, 72, and 96 h after dosing. The pharmacokinetic parameters of apatinib and its major metabolites were calculated by noncompartmental analysis.

RESULTS

Comparing PK parameters of the mild or moderate renal impairment group with the healthy group: the geometric mean ratios of maximum observed drug concentration (Cmax), the area under the plasma drug concentration-time curve from time 0 to the final quantifiable time (AUC0-t), and the area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC0-inf) were all about one. No significant effect of mild and moderate renal impairment on apatinib pharmacokinetics was observed. Mild and moderate renal impairment was also not observed to have a significant effect on the pharmacokinetics of metabolites M1-1, M1-2, and M1-6. However, mild and moderate renal impairment had a certain increase in exposure to the metabolite M9-2. Considering that M9-2 has no inhibitory effect on protein tyrosine kinase, it has no clinical significance. In addition, the proportion of cumulative excretion of apatinib and its major metabolites was small and almost negligible in all three groups of subjects.

CONCLUSION

Patients with mild and moderate renal impairment do not need to adjust the dose of apatinib when using low dose (250 mg) apatinib.

JAK-STAT pathway inhibitors in dermatology

The JAK-STAT signaling pathway mediates important cellular processes such as immune response, carcinogenesis, cell differentiation, division and death. Therefore, drugs that interfere with different JAK-STAT signaling patterns have potential indications for various medical conditions. The main dermatological targets of JAK-STAT pathway inhibitors are inflammatory or autoimmune diseases such as psoriasis, vitiligo, atopic dermatitis and alopecia areata; however, several dermatoses are under investigation to expand this list of indications. As JAK-STAT pathway inhibitors should gradually occupy a relevant space in dermatological prescriptions, this review presents the main available drugs, their immunological effects, and their pharmacological characteristics, related to clinical efficacy and safety, aiming to validate the best dermatological practice.

A Review on the Safety of Using JAK Inhibitors in Dermatology: Clinical and Laboratory Monitoring

Janus kinase (JAK) inhibitors are disease-modifying agents with efficacy in treating a spectrum of burdensome dermatologic conditions. The US Food and Drug Administration (FDA) recently placed a black box warning on this class of medications due to safety concerns based on data from studies investigating tofacitinib in patients with rheumatoid arthritis. Here we provide an overview of the timeline of FDA approval of JAK inhibitors in dermatology. We also discuss the available safety profiles of approved oral JAK1 inhibitors, namely abrocitinib and upadacitinib, oral baricitinib, a JAK1/2 inhibitor, deucravacitinib, a Tyk2 inhibitor, and the topical JAK1/2 inhibitor ruxolitinib in dermatology patients. Additionally, we offer suggestions for initial screening and laboratory monitoring for patients receiving JAK inhibitors. We found that the rates of venous thromboembolism reported in trials ranged from no events to 0.1-0.5% in dermatology-specific phase 3 clinical trials compared with no events in the placebo. The rates of cardiovascular events ranged from no events to 0.4-1.2% compared with no events to 0.5-1.2% in the placebo. The rates of serious infections were 0.4-4.8% compared with no events to 0.5-1.3% in the placebo. The rates of nonmelanoma skin cancer (NMSC) ranged from no event to 0.6-0.9% compared with no events in the placebo. The rates of non-NMSC ranged from no event to 0.2-0.7% compared with no event to 0.6% in the placebo. Most patients who developed these adverse events had risk factors for the specific event. The most common adverse events of oral JAK inhibitors included upper respiratory infections, nasopharyngitis, nausea, headache, and acne. Dermatologists should consider patients' baseline risk factors for developing serious complications when prescribing oral JAK inhibitors.

Efficacy and Safety of JAK1 Inhibitor Abrocitinib in Atopic Dermatitis

Abrocitinib is a JAK1 selective inhibitor recently approved for the treatment of moderate-to-severe atopic dermatitis in adults. It has demonstrated efficacy and safety in several clinical trials, both in children and adults, in monotherapy, and compared with dupilumab. The expected EASI-75 response rate estimates at week 12 are 62.9% (95% CrI 42.5-79.9%) for abrocitinib 200 mg and 43.0% (95% CrI 24.8-64.0%) for abrocitinib 100 mg. Abrocitinib has shown a faster effect than dupilumab as regards early alleviation of itch. Because of the incomplete target selectivity of JAK inhibitors, when abrocitinib treatment is considered, laboratory screening is necessary, latent tuberculosis must be screened for, active infections are a contraindication, and special caution must be exerted in treating elderly patients and those predisposed to thromboembolic events. Even though recent meta-analyses of clinical trials have not shown that atopic dermatitis, or its treatment with JAK inhibitors or dupilumab, modify the risk of deep venous thrombosis or pulmonary embolism, long-term follow-up studies will better define the safety profile of abrocitinib.

Population Pharmacokinetic/Pharmacodynamic Modeling of the Effect of Abrocitinib on QT Intervals in Healthy Volunteers

Abrocitinib is a selective Janus kinase 1 inhibitor for the treatment of moderate to severe atopic dermatitis (AD). To assess the relationship between abrocitinib plasma concentrations and heart rate (HR)-corrected QT (QTc) and HR and calculate the effect of abrocitinib on these parameters at supratherapeutic concentrations, 36 healthy volunteers received single doses of abrocitinib 600 mg, placebo, and moxifloxacin 400 mg in a 3-period crossover study. The relationship between change from baseline in Fridericia-corrected QTc (∆QTcF) values and abrocitinib plasma concentrations was modeled using a prespecified linear mixed-effects model. The 90%CIs for time-matched placebo-corrected ∆QTcF (∆∆QTcF) were calculated from model parameter estimates and assessed against the regulatory threshold (10 millisecond) at the predicted supratherapeutic concentration in patients with atopic dermatitis (2156 ng/mL). Mean (90%CI) time-matched placebo-corrected change from baseline in HR (∆∆HR) was calculated similarly. At the supratherapeutic concentration, mean (90%CI) estimates for ∆∆QTcF and ∆∆HR were 6.00 (4.52-7.49) milliseconds and 6.51 (5.23-7.80) bpm, respectively. Despite a concentration-dependent effect on ∆QTcF and ∆HR, with statistically significant slopes (90%CI) of 0.0026 (0.0018-0.0035) milliseconds/(ng/mL) and 0.0031 (0.0024-0.0038) bpm/(ng/mL), respectively, abrocitinib does not have a clinically significant effect on QTc interval or HR at supratherapeutic exposures.