JAK inhibitors and COVID-19.

During SARS-CoV-2 infection, the innate immune response can be inhibited or delayed, and the subsequent persistent viral replication can induce emergency signals that may culminate in a cytokine storm contributing to the severe evolution of COVID-19. Cytokines are key regulators of the immune response and virus clearance, and, as such, are linked to the-possibly altered-response to the SARS-CoV-2. They act via a family of more than 40 transmembrane receptors that are coupled to one or several of the 4 Janus kinases (JAKs) coded by the human genome, namely JAK1, JAK2, JAK3, and TYK2. Once activated, JAKs act on pathways for either survival, proliferation, differentiation, immune regulation or, in the case of type I interferons, antiviral and antiproliferative effects. Studies of graft-versus-host and systemic rheumatic diseases indicated that JAK inhibitors (JAKi) exert immunosuppressive effects that are non-redundant with those of corticotherapy. Therefore, they hold the potential to cut-off pathological reactions in COVID-19. Significant clinical experience already exists with several JAKi in COVID-19, such as baricitinib, ruxolitinib, tofacitinib, and nezulcitinib, which were suggested by a meta-analysis (Patoulias et al.) to exert a benefit in terms of risk reduction concerning major outcomes when added to standard of care in patients with COVID-19. Yet, only baricitinib is recommended in first line for severe COVID-19 treatment by the WHO, as it is the only JAKi that has proven efficient to reduce mortality in individual randomized clinical trials (RCT), especially the Adaptive COVID-19 Treatment Trial (ACTT-2) and COV-BARRIER phase 3 trials. As for secondary effects of JAKi treatment, the main caution with baricitinib consists in the induced immunosuppression as long-term side effects should not be an issue in patients treated for COVID-19.We discuss whether a class effect of JAKi may be emerging in COVID-19 treatment, although at the moment the convincing data are for baricitinib only. Given the key role of JAK1 in both type I IFN action and signaling by cytokines involved in pathogenic effects, establishing the precise timing of treatment will be very important in future trials, along with the control of viral replication by associating antiviral molecules.

Positioning of tofacitinib in treatment of ulcerative colitis: a global perspective.

INTRODUCTION: Tofacitinib has emerged as a useful drug for the treatment of ulcerative colitis (UC). AREAS COVERED: There is an unmet need for cost-effective, non-immunogenic drugs with a safe adverse effect profile to treat patients with ulcerative colitis. In the present review, we evaluate the available literature to inform the appropriate positioning of tofacitinib in the current drug landscape and identify subsets where its use should be done with caution. EXPERT OPINION: Tofacitinib is helpful in the treatment of patients where the standard conventional or biological therapies have failed or were not tolerated. With lower costs of the generic drug than the biologicals (or biosimilars), it could be an important therapy in low- to middle-income countries. The risk of infections, especially Herpes Zoster and tuberculosis, needs to be addressed before initiation. Tofacitinib should be avoided in patients with venous thromboembolism and cardiovascular disease risk factors. Due to limited evidence, the use is not recommended in pregnancy, while it should be used with caution in elderly citizens. Future trials should look into the head-to-head comparison of tofacitinib with biologicals. The role of tofacitinib in acute severe colitis needs evaluation with comparative trials with current standards of care.

Efficacy and safety of tofacitinib in Chinese patients with active psoriatic arthritis: a phase 3, randomised, double-blind, placebo-controlled study.

OBJECTIVES: Efficacy and safety of tofacitinib, an oral Janus kinase inhibitor, were evaluated in a 6-month, double-blind, phase 3 study in Chinese patients with active (polyarthritic) psoriatic arthritis (PsA) and inadequate response to ≥1 conventional synthetic disease-modifying antirheumatic drug. METHODS: Patients were randomised (2:1) to tofacitinib 5 mg twice daily (N=136) or placebo (N=68); switched to tofacitinib 5 mg twice daily after month (M)3 (blinded). PRIMARY ENDPOINT: American College of Rheumatology (ACR50) response at M3. Secondary endpoints (through M6) included: ACR20/50/70 response; change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI); ≥75% improvement in Psoriasis Area and Severity Index (PASI75) response, and enthesitis and dactylitis resolution. Safety was assessed throughout. RESULTS: The primary endpoint was met (tofacitinib 5 mg twice daily, 38.2%; placebo, 5.9%; p<0.0001). M3 ACR20/ACR70/PASI75 responses, and enthesitis and dactylitis resolution rates, were higher and HAQ-DI reduction was greater for tofacitinib 5 mg twice daily versus placebo. Incidence of adverse events (AEs)/serious AEs (M0-3): 68.4%/0%, tofacitinib 5 mg twice daily; 75.0%/4.4%, placebo. One death was reported with placebo→tofacitinib 5 mg twice daily (due to accident). One serious infection, non-serious herpes zoster, and lung cancer case each were reported with tofacitinib 5 mg twice daily; four serious infections and one non-serious herpes zoster case were reported with placebo→tofacitinib 5 mg twice daily (M0-6). No non-melanoma skin cancer, major adverse cardiovascular or thromboembolism events were reported. CONCLUSION: In Chinese patients with PsA, tofacitinib efficacy was greater than placebo (primary and secondary endpoints). Tofacitinib was well tolerated; safety outcomes were consistent with the established safety profile in PsA and other indications. TRIAL REGISTRATION NUMBER: NCT03486457.

Cytochromes P450 2C8 and 3A Catalyze the Metabolic Activation of the Tyrosine Kinase Inhibitor Masitinib.

Masitinib is a small molecule tyrosine kinase inhibitor under investigation for the treatment of amyotrophic lateral sclerosis, mastocytosis, and COVID-19. Hepatotoxicity has been reported in some patients while taking masitinib. The liver injury is thought to involve hepatic metabolism of masitinib by cytochrome P450 (P450) enzymes to form chemically reactive, potentially toxic metabolites. The goal of the current investigation was to determine the P450 enzymes involved in the metabolic activation of masitinib in vitro. In initial studies, masitinib (30 µM) was incubated with pooled human liver microsomes in the presence of NADPH and potassium cyanide to trap reactive iminium ion metabolites as cyano adducts. Masitinib metabolites and cyano adducts were analyzed using reversed-phase liquid chromatography-tandem mass spectrometry. The primary active metabolite, N-desmethyl masitinib (M485), and several oxygenated metabolites were detected along with four reactive metabolite cyano adducts (MCN510, MCN524, MCN526, and MCN538). To determine which P450 enzymes were involved in metabolite formation, reaction phenotyping experiments were conducted by incubation of masitinib (2 µM) with a panel of recombinant human P450 enzymes and by incubation of masitinib with human liver microsomes in the presence of P450-selective chemical inhibitors. In addition, enzyme kinetic assays were conducted to determine the relative kinetic parameters (apparent Km and Vmax) of masitinib metabolism and cyano adduct formation. Integrated analysis of the results from these experiments indicates that masitinib metabolic activation is catalyzed primarily by P450 3A4 and 2C8, with minor contributions from P450 3A5 and 2D6. These findings provide further insight into the pathways involved in the generation of reactive, potentially toxic metabolites of masitinib. Future studies are needed to evaluate the impact of masitinib metabolism on the toxicity of the drug in vivo.

Activity of ertapenem/zidebactam (WCK 6777) against problem Enterobacterales.

BACKGROUND: Secondary healthcare will remain pressured for some years, both because SARS-CoV-2 will circulate as a nosocomial pathogen, and owing to backlogs of patients awaiting delayed elective procedures. These stresses will drive the use of Outpatient Parenteral Antibiotic Therapy (OPAT), which will need to cover increasingly resistant Gram-negative opportunists. We evaluated the activity of ertapenem/zidebactam, proposed for 2 + 2 g q24h administration. MATERIALS AND METHODS: MICs were determined, by BSAC agar dilution, for 1632 Enterobacterales submitted to the UK national reference laboratory for investigation of antimicrobial resistance. RESULTS: Over 90% of Escherichia coli with AmpC, ESBLs, KPC, metallo- or OXA-48 carbapenemases were inhibited by ertapenem/zidebactam 1:1 at ertapenem's current 0.5 mg/L breakpoint. For other major Enterobacterales, the proportions inhibited by ertapenem/zidebactam 1:1 at 0.5 mg/L were mostly 65% to 90% but were lower for Klebsiella pneumoniae/oxytoca with metallo- or OXA-48 ß-lactamases. However, animal studies support an 8 mg/L breakpoint for ertapenem/zidebactam, based on a shortened T>MIC being needed compared with ertapenem alone. On this basis ertapenem/zidebactam would count as active against 90%-100% of isolates in all groups except K. pneumoniae/oxytoca with MBLs (±OXA-48), where MICs and percent susceptibility vary substantially even with inocula within the BSAC acceptable range. CONCLUSIONS: Ertapenem/zidebactam has a proposed once-daily regimen well suited to OPAT. Even on highly conservative breakpoint projections, it has potential against MDR E. coli, including metallo-carbapenemase producers. If trial data sustain the 8 mg/L breakpoint indicated by animal experiments, its potential will extend widely across infections due to ESBL-, AmpC- and carbapenemase-producing Enterobacterales.

Ibrutinib plus Bendamustine and Rituximab in Untreated Mantle-Cell Lymphoma.

BACKGROUND: Ibrutinib, a Bruton's tyrosine kinase inhibitor, may have clinical benefit when administered in combination with bendamustine and rituximab and followed by rituximab maintenance therapy in older patients with untreated mantle-cell lymphoma. METHODS: We randomly assigned patients 65 years of age or older to receive ibrutinib (560 mg, administered orally once daily until disease progression or unacceptable toxic effects) or placebo, plus six cycles of bendamustine (90 mg per square meter of body-surface area) and rituximab (375 mg per square meter). Patients with an objective response (complete or partial response) received rituximab maintenance therapy, administered every 8 weeks for up to 12 additional doses. The primary end point was progression-free survival as assessed by the investigators. Overall survival and safety were also assessed. RESULTS: Among 523 patients, 261 were randomly assigned to receive ibrutinib and 262 to receive placebo. At a median follow-up of 84.7 months, the median progression-free survival was 80.6 months in the ibrutinib group and 52.9 months in the placebo group (hazard ratio for disease progression or death, 0.75; 95% confidence interval, 0.59 to 0.96; P = 0.01). The percentage of patients with a complete response was 65.5% in the ibrutinib group and 57.6% in the placebo group (P = 0.06). Overall survival was similar in the two groups. The incidence of grade 3 or 4 adverse events during treatment was 81.5% in the ibrutinib group and 77.3% in the placebo group. CONCLUSIONS: Ibrutinib treatment in combination with standard chemoimmunotherapy significantly prolonged progression-free survival. The safety profile of the combined therapy was consistent with the known profiles of the individual drugs. (Funded by Janssen Research and Development and Pharmacyclics; SHINE ClinicalTrials.gov number, NCT01776840.).

Tofacitinib in paediatric dermatoses: a narrative review.

Tofacitinib has revolutionized the treatment of numerous dermatological conditions in different age groups. However, evidence for its effectiveness, safety and tolerability in the paediatric population is limited. We performed a literature search, which showed that oral tofacitinib is a reliable option in refractory juvenile dermatomyositis, severe alopecia areata, atopic dermatitis and psoriasis. Topical tofacitinib is an effective option in vitiligo and halo naevus. The risk-benefit ratio should be assessed prior to consideration of this molecule. In this narrative review, we have attempted to present a summary of the evidence of using tofacitinib (oral and topical) in paediatric dermatoses.

A Computational-Experimental Investigation of the Molecular Mechanism of Interleukin-6-Piperine Interaction.

Herein, we elucidate the biophysical aspects of the interaction of an important protein, Interleukin-6 (IL6), which is involved in cytokine storm syndrome, with a natural product with anti-inflammatory activity, piperine. Despite the role of piperine in the inhibition of the transcriptional protein NF-κB pathway responsible for activation of IL6 gene expression, there are no studies to the best of our knowledge regarding the characterisation of the molecular interaction of the IL6-piperine complex. In this context, the characterisation was performed with spectroscopic experiments aided by molecular modelling. Fluorescence spectroscopy alongside van't Hoff analyses showed that the complexation event is a spontaneous process driven by non-specific interactions. Circular dichroism aided by molecular dynamics revealed that piperine caused local α-helix reduction. Molecular docking and molecular dynamics disclosed the microenvironment of interaction as non-polar amino acid residues. Although piperine has three available hydrogen bond acceptors, only one hydrogen-bond was formed during our simulation experiments, reinforcing the major role of non-specific interactions that we observed experimentally. Root mean square deviation (RMSD) and hydrodynamic radii revealed that the IL6-piperine complex was stable during 800 ns of simulation. Taken together, these results can support ongoing IL6 drug discovery efforts.

Real-world evidence of the effectiveness and safety of generic tofacitinib in rheumatoid arthritis patients: a retrospective, single-centre analysis from Western India.

Generic tofacitinib has been available in India for more than a year and is widely used in rheumatoid arthritis (RA) therapy. There is scarce real-world data on its effectiveness and safety from India, especially given infection endemicity. We retrospectively analysed records (demographic and clinical information, haematology and biochemistry, adverse events) of patients prescribed generic tofacitinib from a single centre in Mumbai, India. Disease activity was calculated using the disease activity score-28 and erythrocyte sedimentation rate (DAS28-ESR) and other tools, and we used paired T-tests for significant response. We defined clinical tofacitinib failure as a composite outcome, including clinician's decision to change to an alternative disease-modifying anti-rheumatic drug (DMARD) or flare after self-withdrawal. We performed logistic regression and survival analysis for determinants of clinical failure. We reviewed records of 102 patients (92 female; median age: 53 years) with mean RA duration of 146 months. Thirteen had prior treatment with innovator tofacitinib. There was significant improvement in disease activity parameters at a mean duration of 186 days. No serious adverse events were reported; 4 patients had tuberculosis and 19 patients had mild COVID-19 while on treatment. Clinical failure was seen in 25 patients, and mean time to failure on survival analysis was 357 days. No baseline characteristic predicted clinical failure. Generic tofacitinib showed good effectiveness and a tolerable adverse effect profile, despite tuberculosis endemicity and COVID-19. Setting up registries would be valuable in gaining more data on generic tofacitinib. Key Points • There is scarce data from India regarding the use of tofacitinib in rheumatoid arthritis, despite widespread use. • In this retrospective analysis of 102 patients at a single centre, we found tofacitinib monotherapy was efficacious and tolerable. • Tuberculosis was detected in four and nineteen patients had mild covid.

Zanubrutinib versus bendamustine and rituximab in untreated chronic lymphocytic leukaemia and small lymphocytic lymphoma (SEQUOIA): a randomised, controlled, phase 3 trial.

BACKGROUND: Zanubrutinib is a next-generation, selective Bruton tyrosine kinase inhibitor with efficacy in relapsed chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). We compared zanubrutinib with bendamustine-rituximab to determine its effectiveness as frontline therapy in patients with CLL or SLL. METHODS: We conducted an open-label, multicentre, phase 3 study at 153 academic or community hospitals in 14 countries and regions. Eligible patients had untreated CLL or SLL requiring treatment as per International Workshop on CLL criteria; were aged 65 years or older, or 18 years or older and had comorbidities; and had an Eastern Cooperative Oncology Group performance status score of 0-2. A central interactive web response system randomly assigned patients without del(17)(p13·1) to zanubrutinib (group A) or bendamustine-rituximab (group B) by sequential block method (permutated blocks with a random block size of four). Patients with del(17)(p13·1) were enrolled in group C and received zanubrutinib. Zanubrutinib was administered orally at 160 mg twice per day (28-day cycles); bendamustine at 90 mg/m2 of body surface area on days 1 and 2 for six cycles plus rituximab at 375 mg/m2 of body surface area the day before or on day 1 of cycle 1, and 500 mg/m2 of body surface area on day 1 of cycles 2-6, were administered intravenously. The primary endpoint was progression-free survival per independent review committee in the intention-to-treat population in groups A and B, with minimum two-sided α of 0·05 for superiority. Safety was analysed in all patients who received at least one dose of study treatment. The study is registered with ClinicalTrials.gov, NCT03336333, and is closed to recruitment. FINDINGS: Between Oct 31, 2017, and July 22, 2019, 590 patients were enrolled; patients without del(17)(p13·1) were randomly assigned to zanubrutinib (group A; n=241) or bendamustine-rituximab (group B; n=238). At median follow-up of 26·2 months (IQR 23·7-29·6), median progression-free survival per independent review committee was not reached in either group (group A 95% CI not estimable [NE] to NE; group B 28·1 months to NE). Progression-free survival was significantly improved in group A versus group B (HR 0·42 [95% CI 0·28 to 0·63]; two-sided p<0·0001). The most common grade 3 or worse adverse event was neutropenia (27 [11%] of 240 patients in group A, 116 [51%] of 227 in group B, and 17 [15%] of 111 patients in group C). Serious adverse events occurred in 88 (37%) of 240 patients in group A, 113 (50%) of 227 patients in group B, and 45 (41%) of 111 patients in group C. Adverse events leading to death occurred in 11 (5%) of 240 patients in group A, 12 (5%) of 227 patients in group B, and three (3%) of 111 patients in group C, most commonly due to COVID-19 (four [2%] of 240 patients in group A), diarrhoea, and aspiration pneumonia (two each [1%] of 227 patients in group B). INTERPRETATION: Zanubrutinib significantly improved progression-free survival versus bendamustine-rituximab, with an acceptable safety profile consistent with previous studies. These data support zanubrutinib as a potential new treatment option for untreated CLL and SLL. FUNDING: BeiGene.

The efficacy of curcumin-piperine co-supplementation on clinical symptoms, duration, severity, and inflammatory factors in COVID-19 outpatients: a randomized double-blind, placebo-controlled trial.

BACKGROUND: COVID-19 pandemic has made the disease a major global problem by creating a significant burden on health, economic, and social status. To date, there are no effective and approved medications for this disease. Curcumin as an anti-inflammatory agent can have a positive effect on the control of COVID-19 complications. This study aimed to assess the efficacy of curcumin-piperine supplementation on clinical symptoms, duration, severity, and inflammatory factors in patients with COVID-19. METHODS: Forty-six outpatients with COVID-19 disease were randomly allocated to receive two capsules of curcumin-piperine; each capsule contained 500 mg curcumin plus 5 mg piperine or placebo for 14 days. RESULTS: Mean changes in complete blood count, liver enzymes, blood glucose levels, lipid parameters, kidney function, and c-reactive protein (CRP) were not significantly different between the two groups. There was a significant improvement in health status, including dry cough, sputum cough, ague, sore throat, weakness, muscular pain, headache, and dyspnea at week 2 in both curcumin-piperine and placebo groups (P value < 0.05); however, the improvement in weakness was more in the curcumin-piperine group than with placebo group (P value 025). CONCLUSION: The present study results showed that curcumin-piperine co-supplementation in outpatients with COVID-19 could significantly reduce weakness. However, in this study, curcumin-piperine co-supplementation could not significantly affect the other indices, including biochemical and clinical indices. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20121216011763N46 . 2020-10-31.

Treatment of MDA5-positive dermatomyositis complicated by gangrenous cholecystitis with tofacitinib.

BACKGROUND: Dermatomyositis is a rare idiopathic inflammatory disease with diverse presentations that can have varying degrees of cutaneous and systemic involvement. This phenotypic heterogeneity makes DM a therapeutic challenge. Some therapeutic drugs, such as hormones and immunosuppressants, have poor therapeutic effects. In recent years, tofacitinib has been reported to be effective in the treatment of dermatomyositis. CASE PRESENTATION: We report a case of anti-MDA5 antibody-positive dermatomyositis that was relieved after treatment with tofacitinib, during which gallbladder gangrene and suppurative cholecystitis occurred. After cholecystectomy, we continued to use tofacitinib and achieved a good therapeutic effect. CONCLUSIONS: Tofacitinib is effective in the treatment of anti-MDA5 antibody-positive dermatomyositis, but the risk of infection is increased. It can still be used after infection control. Close follow-up should be performed during the use of tofacitinib.

Semi-Synthesis of N-Aryl Amide Analogs of Piperine from Piper nigrum and Evaluation of Their Antitrypanosomal, Antimalarial, and Anti-SARS-CoV-2 Main Protease Activities.

Piper nigrum, or black pepper, produces piperine, an alkaloid that has diverse pharmacological activities. In this study, N-aryl amide piperine analogs were prepared by semi-synthesis involving the saponification of piperine (1) to yield piperic acid (2) followed by esterification to obtain compounds 3, 4, and 5. The compounds were examined for their antitrypanosomal, antimalarial, and anti-SARS-CoV-2 main protease activities. The new 2,5-dimethoxy-substituted phenyl piperamide 5 exhibited the most robust biological activities with no cytotoxicity against mammalian cell lines, Vero and Vero E6, as compared to the other compounds in this series. Its half-maximal inhibitory concentration (IC50) for antitrypanosomal activity against Trypanosoma brucei rhodesiense was 15.46 ± 3.09 µM, and its antimalarial activity against the 3D7 strain of Plasmodium falciparum was 24.55 ± 1.91 µM, which were fourfold and fivefold more potent, respectively, than the activities of piperine. Interestingly, compound 5 inhibited the activity of 3C-like main protease (3CLPro) toward anti-SARS-CoV-2 activity at the IC50 of 106.9 ± 1.2 µM, which was threefold more potent than the activity of rutin. Docking and molecular dynamic simulation indicated that the potential binding of 5 in the 3CLpro active site had the improved binding interaction and stability. Therefore, new aryl amide analogs of piperine 5 should be investigated further as a promising anti-infective agent against human African trypanosomiasis, malaria, and COVID-19.

sEH-derived metabolites of linoleic acid drive pathologic inflammation while impairing key innate immune cell function in burn injury.

Fatty acid composition in the Western diet has shifted from saturated to polyunsaturated fatty acids (PUFAs), and specifically to linoleic acid (LA, 18:2), which has gradually increased in the diet over the past 50 y to become the most abundant dietary fatty acid in human adipose tissue. PUFA-derived oxylipins regulate a variety of biological functions. The cytochrome P450 (CYP450)­formed epoxy fatty acid metabolites of LA (EpOMEs) are hydrolyzed by the soluble epoxide hydrolase enzyme (sEH) to dihydroxyoctadecenoic acids (DiHOMEs). DiHOMEs are considered cardioprotective at low concentrations but at higher levels have been implicated as vascular permeability and cytotoxic agents and are associated with acute respiratory distress syndrome in severe COVID-19 patients. High EpOME levels have also correlated with sepsis-related fatalities; however, those studies failed to monitor DiHOME levels. Considering the overlap of burn pathophysiology with these pathologies, the role of DiHOMEs in the immune response to burn injury was investigated. 12,13-DiHOME was found to facilitate the maturation and activation of stimulated neutrophils, while impeding monocyte and macrophage functionality and cytokine generation. In addition, DiHOME serum concentrations were significantly elevated in burn-injured mice and these increases were ablated by administration of 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), a sEH inhibitor. TPPU also reduced necrosis of innate and adaptive immune cells in burned mice, in a dose-dependent manner. The findings suggest DiHOMEs are a key driver of immune cell dysfunction in severe burn injury through hyperinflammatory neutrophilic and impaired monocytic actions, and inhibition of sEH might be a promising therapeutic strategy to mitigate deleterious outcomes in burn patients.

Physiologically-Based Pharmacokinetic Modelling to Investigate Baricitinib and Tofacitinib Dosing Recommendations for COVID-19 in Geriatrics.

Janus kinase (JAK) inhibitors baricitinib and tofacitinib are recommended by the US National Institutes of Health as immunomodulatory drugs for coronavirus disease 2019 (COVID-19) treatment. In addition, baricitinib has recently received Emergency Use Authorization from the US Food and Drug Administration, although the instruction provided dosing information only for adults. Geriatrics with organ dysfunction are one of the most vulnerable cohorts when combating the pandemic. The aim of the present work was to evaluate current dosing strategies of baricitinib and tofacitinib for potential COVID-19 treatment for White and Chinese geriatric patients with chronic renal impairment. An established physiologically-based pharmacokinetic (PBPK) modeling framework for age-dependent simulations was utilized. PBPK drug models adopted from literature were first verified. Several population models representing different age groups, ethnicities, and stages of renal impairment were used for prospective simulations. Notwithstanding the increase in systemic exposure of both drugs resulting from renal dysfunction was more pronounced for geriatrics than general White populations, our simulations confirmed their current dosage adjustments based on renal functions are broadly adequate. The exception being White older subjects with mild renal impairment where current recommendation of 4 mg baricitinib yielded a 2.31-fold increase in systemic exposure, and reduction to 2 mg could mitigate the potential risk to an acceptable 1.15-fold. Comparable relationships between systemic exposure and renal dysfunction were observed for both drugs in the Chinese population. In summary, PBPK modeling of both JAK inhibitors supports the rational and prudent dose adjustments of these COVID-19 therapeutics among adult patients of different age groups and renal functions.