The in vitro pharmacology of baricitinib, upadacitinib, and tofacitinib was evaluated to understand differences among these JAK inhibitors (JAKis) at the cellular level.
Peripheral blood mononuclear ...cells from healthy donors were incubated with different JAKis, levels of phosphorylated signal transducer and activator of transcription (pSTAT) were measured following cytokine stimulation, and half maximum inhibitory concentration (IC
) values were calculated in phenotypically gated leukocyte subpopulations. Therapeutic dose relevance of the in vitro analysis was assessed using calculated mean concentration-time profiles over 24 h obtained from JAKi-treated subjects. Time above IC
and average daily percent inhibition of pSTAT formation were calculated for each JAKi, cytokine, and cell type.
Distinct JAKis displayed different in vitro pharmacologic profiles. For example, tofacitinib and upadacitinib were the most potent inhibitors of the JAK1/3-dependent cytokines tested (interleukin IL-2, IL-4, IL-15, and IL-21) with lower IC
values and increased time above IC
translating to a greater overall inhibition of STAT signaling during the dosing interval. All JAKis tested inhibited JAK1/2-dependent cytokines (e.g., IL-6 and interferon IFN-γ), the JAK1/tyrosine kinase 2 (TYK2)-dependent cytokines IL-10 and IFN-α, the JAK2/2-dependent cytokines IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF), and the JAK2/TYK2-dependent cytokine granulocyte colony-stimulating factor (G-CSF), but often to significantly differing degrees.
Different JAKis modulated distinct cytokine pathways to varying degrees, and no agent potently or continuously inhibited an individual cytokine signaling pathway throughout the dosing interval. Notably, baricitinib inhibited JAK1/3 signaling to a lesser extent than upadacitinib and tofacitinib, while upadacitinib, baricitinib, and tofacitinib inhibited the signaling of JAK2/2-dependent cytokines, including GM-CSF and IL-3, as well as the signaling of the JAK2/TYK2-dependent cytokine G-CSF.
In a phase 3 randomized trial of 1307 patients with rheumatoid arthritis receiving background methotrexate, the oral JAK1 and JAK2 inhibitor baricitinib showed superior efficacy to placebo and to the ...anti–tumor necrosis factor α monoclonal antibody adalimumab.
Rheumatoid arthritis is a systemic autoimmune disease characterized by inflammatory synovitis and progressive joint destruction, which are associated with severe disability and increased mortality. Progress in treatment with the use of conventional synthetic disease-modifying antirheumatic drugs (DMARDs), such as methotrexate, and biologic DMARDs that target tumor necrosis factor (TNF) has made clinical remission a realistic target.
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Activated Janus kinases (JAKs) play pivotal roles in intracellular signaling from cell-surface receptors for multiple cytokines implicated in the pathologic processes of rheumatoid arthritis.
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Baricitinib, an orally available small molecule, provides reversible inhibition of JAK1 and JAK2 and has shown clinical efficacy in studies . . .
Inflammation signaled by Janus kinases (JAKs) promotes progression of diabetic kidney disease (DKD). Baricitinib is an oral, reversible, selective inhibitor of JAK1 and JAK2. This study tested the ...efficacy of baricitinib versus placebo on albuminuria in adults with Type 2 diabetes at high risk for progressive DKD.
In this Phase 2, double-blind, dose-ranging study, participants were randomized 1:1:1:1:1 to receive placebo or baricitinib (0.75 mg daily; 0.75 mg twice daily; 1.5 mg daily; or 4 mg daily), for 24 weeks followed by 4-8 weeks of washout.
Participants (N = 129) were 63±9.1 (mean±standard deviation) years of age, 27.1% (35/129) women and 11.6% (15/129) African-American race. Baseline hemoglobin A1c (HbA1c) was 7.3±1% and estimated glomerular filtration rate was 45.0±12.1 mL/min/1.73 m2 with first morning urine albumin-creatinine ratio (UACR) of 820 (407-1632) (median; interquartile range) mg/g. Baricitinib, 4 mg daily, decreased morning UACR by 41% at Week 24 compared with placebo (ratio to baseline 0.59, 95% confidence interval 0.38-0.93, P = 0.022). UACR was decreased at Weeks 12 and 24 and after 4-8 weeks of washout. Baricitinib 4 mg decreased inflammatory biomarkers over 24 weeks (urine C-X-C motif chemokine 10 and urine C-C motif ligand 2, plasma soluble tumor necrosis factor receptors 1 and 2, intercellular adhesion molecule 1 and serum amyloid A). The only adverse event rate that differed between groups was anemia at 32.0% (8/25) for baricitinib 4 mg daily versus 3.7% (1/27) for placebo.
Baricitinib decreased albuminuria in participants with Type 2 diabetes and DKD. Further research is required to determine if baricitinib reduces DKD progression.
Population pharmacokinetic (popPK) modeling was used to characterize the PK profile of the oral Janus kinase (JAK)1/JAK2 inhibitor, baricitinib, in 18 patients with Mendelian interferonopathies who ...are enrolled in a compassionate use program. Patients received doses between 0.1 to 17 mg per day. Covariates of weight and renal function significantly influenced volume‐of‐distribution and clearance, respectively. The half‐life of baricitinib in patients less than 40 kg was substantially shorter than in adult populations, requiring the need for dosing up to 4 times daily. On therapeutic doses, the mean area‐under‐the‐concentration‐vs.‐time curve was 2,388 nM*hr, which is 1.83‐fold higher than mean baricitinib exposures in adult patients with rheumatoid arthritis receiving doses of 4 mg once‐daily. Dose‐dependent decreases in interferon (IFN) biomarkers confirmed an in vivo effect of baricitinib on type‐1 IFN signaling. PopPK and pharmacodynamic data support a proposal for a weight‐ and estimated glomerular filtration rate‐based dosing regimen in guiding baricitinib dosing in patients with rare interferonopathies.
In this phase 3 study involving patients with an inadequate response to biologic disease-modifying antirheumatic drugs, baricitinib, an oral JAK1 and JAK2 inhibitor, led to clinical improvement at 12 ...weeks. Infections were more frequent with baricitinib than with placebo.
The discomfort, disability, and joint damage that characterize rheumatoid arthritis result from an autoimmune inflammatory response elicited by numerous cell populations and cytokines. Biologic therapies targeting T or B cells and cytokines, such as tumor necrosis factor α (TNF-α) or interleukin-6, have improved outcomes for patients who do not have responses to treatment with conventional, synthetic disease-modifying antirheumatic drugs (DMARDs) such as methotrexate.
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However, since many patients do not have a sufficient response to these biologic DMARDs or have unacceptable side effects, new therapies are needed.
Circulating cytokines, on binding to cell-surface receptors, signal through activation of intracellular tyrosine kinases, . . .
The efficacy of drotrecogin alpha (activated) (DrotAA) for sepsis has been controversial. In this trial, there was no significant difference in all-cause mortality at 28 or 90 days between adults ...with sepsis who were treated with DrotAA and those treated with placebo.
Recombinant human activated protein C, or drotrecogin alfa (activated) (DrotAA), was approved for the treatment of severe sepsis in 2001 on the basis of the Prospective Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study,
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a phase 3 international, randomized, controlled trial that was stopped early for efficacy after the enrollment of 1690 patients with severe sepsis. Absolute mortality in the intention-to-treat population was reduced by 6.1 percentage points, a relative risk reduction of 19.4%. Subsequent subgroup analysis suggested that the mortality benefit was limited to patients with increased illness severity (i.e., those with more than one . . .
Monogenic IFN-mediated autoinflammatory diseases present in infancy with systemic inflammation, an IFN response gene signature, inflammatory organ damage, and high mortality. We used the JAK ...inhibitor baricitinib, with IFN-blocking activity in vitro, to ameliorate disease.
Between October 2011 and February 2017, 10 patients with CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures), 4 patients with SAVI (stimulator of IFN genes-associated STING-associated vasculopathy with onset in infancy), and 4 patients with other interferonopathies were enrolled in an expanded access program. The patients underwent dose escalation, and the benefit was assessed by reductions in daily disease symptoms and corticosteroid requirement. Quality of life, organ inflammation, changes in IFN-induced biomarkers, and safety were longitudinally assessed.
Eighteen patients were treated for a mean duration of 3.0 years (1.5-4.9 years). The median daily symptom score decreased from 1.3 (interquartile range IQR, 0.93-1.78) to 0.25 (IQR, 0.1-0.63) (P < 0.0001). In 14 patients receiving corticosteroids at baseline, daily prednisone doses decreased from 0.44 mg/kg/day (IQR, 0.31-1.09) to 0.11 mg/kg/day (IQR, 0.02-0.24) (P < 0.01), and 5 of 10 patients with CANDLE achieved lasting clinical remission. The patients' quality of life and height and bone mineral density Z-scores significantly improved, and their IFN biomarkers decreased. Three patients, two of whom had genetically undefined conditions, discontinued treatment because of lack of efficacy, and one CANDLE patient discontinued treatment because of BK viremia and azotemia. The most common adverse events were upper respiratory infections, gastroenteritis, and BK viruria and viremia.
Upon baricitinib treatment, clinical manifestations and inflammatory and IFN biomarkers improved in patients with the monogenic interferonopathies CANDLE, SAVI, and other interferonopathies. Monitoring safety and efficacy is important in benefit-risk assessment.
ClinicalTrials.gov NCT01724580 and NCT02974595.
This research was supported by the Intramural Research Program of the NIH, NIAID, and NIAMS. Baricitinib was provided by Eli Lilly and Company, which is the sponsor of the expanded access program for this drug.
Both clopidogrel and prasugrel require biotransformation to active metabolites by cytochrome P450 (CYP) enzymes. Among persons treated with clopidogrel, carriers of reduced-function CYP2C19 alleles ...have significantly lower levels of active metabolite, diminished platelet inhibition, and higher rates of adverse cardiovascular events. The effect of CYP polymorphisms on the clinical outcomes in patients treated with prasugrel remains unknown.
The associations between functional variants in CYP genes, plasma concentrations of active drug metabolite, and platelet inhibition in response to prasugrel were tested in 238 healthy subjects. We then examined the association of these genetic variants with cardiovascular outcomes in a cohort of 1466 patients with acute coronary syndromes allocated to treatment with prasugrel in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38 trial. Among the healthy subjects, no significant attenuation of the pharmacokinetic or the pharmacodynamic response to prasugrel was observed in carriers versus noncarriers of at least 1 reduced-function allele for any of the CYP genes tested (CYP2C19, CYP2C9, CYP2B6, CYP3A5, and CYP1A2). Consistent with these findings, in subjects with acute coronary syndromes treated with prasugrel, no significant associations were found between any of the tested CYP genotypes and risk of cardiovascular death, myocardial infarction, or stroke.
Common functional CYP genetic variants do not affect active drug metabolite levels, inhibition of platelet aggregation, or clinical cardiovascular event rates in persons treated with prasugrel. These pharmacogenetic findings are in contrast to observations with clopidogrel, which may explain, in part, the different pharmacological and clinical responses to the 2 medications.
To investigate baricitinib (LY3009104, formerly INCB028050), a novel, oral inhibitor of JAK1/JAK2 in patients with moderate to severe rheumatoid arthritis (RA) despite treatment with methotrexate.
In ...this phase IIb study, 301 patients were randomised 2:1:1:1:1 to receive once daily doses of placebo or 1, 2, 4 or 8 mg baricitinib for 12 weeks. Patients assigned to 2, 4 and 8 mg baricitinib continued blinded treatment for an additional 12 weeks. Patients assigned to placebo or 1 mg baricitinib were reassigned to 2 mg twice daily or 4 mg once daily baricitinib between weeks 12-24. The primary endpoint was the proportion of patients in the combined 4 and 8 mg groups achieving an American College of Rheumatology 20% (ACR20) response versus placebo at week 12.
Significantly more patients in the combined baricitinib 4 and 8 mg groups compared with placebo achieved an ACR20 response at week 12 (76% vs 41%, p<0.001). At week 12, significant differences versus placebo were also observed in patients achieving ACR50, ACR70 and remission as measured by Disease Activity Score for 28-joint counts, Clinical Disease Activity Index and Simplified Disease Activity Index. Patients receiving 2, 4, or 8 mg baricitinib maintained or improved in all measures through 24 weeks. Similar proportions of patients experienced at least one adverse event in the placebo and baricitinib groups. Serious infections developed in three patients receiving baricitinib. No cases of tuberculosis, herpes zoster, opportunistic infections or deaths were reported. Dose-dependent decreases in haemoglobin were observed with baricitinib.
Baricitinib improved the signs and symptoms of RA in methotrexate inadequate responders with active disease. Baricitinib was well tolerated with no unexpected safety findings through week 24.
NCT01185353.
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