Efficacy and safety of tofacitinib monotherapy, tofacitinib with methotrexate, and adalimumab with methotrexate in patients with rheumatoid arthritis (ORAL Strategy): a phase 3b/4, double-blind, head-to-head, randomised controlled trial.

BACKGROUND: Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis. The Oral Rheumatoid Arthritis triaL (ORAL) Strategy aimed to assess the comparative efficacy of tofacitinib monotherapy, tofacitinib plus methotrexate, and adalimumab plus methotrexate for the treatment of rheumatoid arthritis in patients with a previous inadequate response to methotrexate. METHODS: ORAL Strategy was a 1 year, double-blind, phase 3b/4, head-to-head, non-inferiority, randomised controlled trial in patients aged 18 years or older with active rheumatoid arthritis despite methotrexate therapy. Patients were randomly assigned (1:1:1) to receive oral tofacitinib (5 mg twice daily) monotherapy, oral tofacitinib (5 mg twice daily) plus methotrexate, or subcutaneous adalimumab (40 mg every other week) plus methotrexate at 194 centres in 25 countries. Eligible patients received live zoster vaccine at investigators' discretion. The primary endpoint was the proportion of patients who attained an American College of Rheumatology response of at least 50% (ACR50) at month 6 in the full analysis set (patients who were randomly assigned to a group and received at least one dose of the study treatment). Non-inferiority between groups was shown if the lower bound of the 98·34% CI of the difference between comparators was larger than -13·0%. This trial is registered with ClinicalTrials.gov, number NCT02187055. FINDINGS: 1146 patients received treatment (384 had tofacitinib monotherapy; 376 had tofacitinib and methotrexate; and 386 had adalimumab and methotrexate). At 6 months, ACR50 response was attained in 147 (38%) of 384 patients with tofacitinib monotherapy, 173 (46%) of 376 patients with tofacitinib and methotrexate, and 169 (44%) of 386 patients with adalimumab and methotrexate. Non-inferiority was declared for tofacitinib and methotrexate versus adalimumab and methotrexate (difference 2% [98·34% CI -6 to 11]) but not for tofacitinib monotherapy versus either adalimumab and methotrexate (-6 [-14 to 3]) or tofacitinib and methotrexate (-8 [-16 to 1]). In total, 23 (6%) of 384 patients receiving tofacitinib monotherapy, 26 (7%) of 376 patients receiving tofacitinib plus methotrexate, and 36 (9%) of 386 patients receiving adalimumab plus methotrexate discontinued due to adverse events. Two (1%) of the 384 patients receiving tofacitinib monotherapy died. No new or unexpected safety issues were reported for either treatment in this study for up to 1 year. INTERPRETATION: Tofacitinib and methotrexate combination therapy was non-inferior to adalimumab and methotrexate combination therapy in the treatment of rheumatoid arthritis in patients with an inadequate response to methotrexate in this trial. Tofacitinib monotherapy was not shown to be non-inferior to either combination. FUNDING: Pfizer Inc.

Tofacitinib versus methotrexate in rheumatoid arthritis.

BACKGROUND: Methotrexate is the most frequently used first-line antirheumatic drug. We report the findings of a phase 3 study of monotherapy with tofacitinib, an oral Janus kinase inhibitor, as compared with methotrexate monotherapy in patients with rheumatoid arthritis who had not previously received methotrexate or therapeutic doses of methotrexate. METHODS: We randomly assigned 958 patients to receive 5 mg or 10 mg of tofacitinib twice daily or methotrexate at a dose that was incrementally increased to 20 mg per week over 8 weeks; 956 patients received a study drug. The coprimary end points at month 6 were the mean change from baseline in the van der Heijde modified total Sharp score (which ranges from 0 to 448, with higher scores indicating greater structural joint damage) and the proportion of patients with an American College of Rheumatology (ACR) 70 response (≥70% reduction in the number of both tender and swollen joints and ≥70% improvement in three of five other criteria: the patient's assessment of pain, level of disability, C-reactive protein level or erythrocyte sedimentation rate, global assessment of disease by the patient, and global assessment of disease by the physician). RESULTS: Mean changes in the modified total Sharp score from baseline to month 6 were significantly smaller in the tofacitinib groups than in the methotrexate group, but changes were modest in all three groups (0.2 points in the 5-mg tofacitinib group and <0.1 point in the 10-mg tofacitinib group, as compared with 0.8 points in the methotrexate group [P<0.001 for both comparisons]). Among the patients receiving tofacitinib, 25.5% in the 5-mg group and 37.7% in the 10-mg group had an ACR 70 response at month 6, as compared with 12.0% of patients in the methotrexate group (P<0.001 for both comparisons). Herpes zoster developed in 31 of 770 patients who received tofacitinib (4.0%) and in 2 of 186 patients who received methotrexate (1.1%). Confirmed cases of cancer (including three cases of lymphoma) developed in 5 patients who received tofacitinib and in 1 patient who received methotrexate. Tofacitinib was associated with increases in creatinine levels and in low-density and high-density lipoprotein cholesterol levels. CONCLUSIONS: In patients who had not previously received methotrexate or therapeutic doses of methotrexate, tofacitinib monotherapy was superior to methotrexate in reducing signs and symptoms of rheumatoid arthritis and inhibiting the progression of structural joint damage. The benefits of tofacitinib need to be considered in the context of the risks of adverse events. (Funded by Pfizer; ORAL Start ClinicalTrials.gov number, NCT01039688.).

The mechanism of action of tofacitinib - an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterised by infiltration of immune cells into the affected synovium, release of inflammatory cytokines and degradative mediators, and subsequent joint damage. Both innate and adaptive arms of the immune response play a role, with activation of immune cells leading to dysregulated expression of inflammatory cytokines. Cytokines work within a complex regulatory network in RA, signalling through different intracellular kinase pathways to modulate recruitment, activation and function of immune cells and other leukocytes. As our understanding of RA has advanced, intracellular signalling pathways such as Janus kinase (JAK) pathways have emerged as key hubs in the cytokine network and, therefore, important as therapeutic targets. Tofacitinib is an oral JAK inhibitor for the treatment of RA. Tofacitinib is a targeted small molecule, and an innovative advance in RA therapy, which modulates cytokines critical to the progression of immune and inflammatory responses. Herein we describe the mechanism of action of tofacitinib and the impact of JAK inhibition on the immune and inflammatory responses in RA.

Effects of the oral Janus kinase inhibitor tofacitinib on patient-reported outcomes in patients with active rheumatoid arthritis: results of two Phase 2 randomised controlled trials.

OBJECTIVES: Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). Here we investigated the effects of tofacitinib on patient-reported outcomes (PRO) in patients with active RA. METHODS: Two, 6-month, double-blind, placebo-controlled Phase 2b studies were performed. The combination study evaluated patients with inadequate response to methotrexate who received tofacitinib 1-15 mg twice daily (BID), 20 mg once daily or placebo, on background methotrexate. In the monotherapy study, patients with inadequate response to disease-modifying anti-rheumatic drugs received tofacitinib 1-15 mg BID, adalimumab 40 mg once every other week or placebo. PROs measured were: Patient's Assessment of Arthritis Pain (PAAP), Patient's Assessment of Disease Activity, HAQ-DI, FACIT-F and SF-36. RESULTS: In the combination study (n=507), significant improvements (p<0.05) versus placebo were observed at Week 12 in PAAP (visual analogue scale) and HAQ-DI for all tofacitinib groups. In the monotherapy study (n=384), significant improvements in PAAP were observed at Week 12 for tofacitinib 5, 10 and 15 mg BID, and in HAQ-DI for tofacitinib 3, 5, 10 and 15 mg BID. Significant improvements versus placebo were seen at Week 2 in PAAP (both studies) and HAQ­DI (monotherapy study) with tofacitinib, and were maintained throughout each study. In both studies, improvements in several domains of the SF-36 in the tofacitinib groups were observed at Weeks 12 and 24. CONCLUSIONS: In patients with active RA, tofacitinib, either in combination with methotrexate or as monotherapy, demonstrated rapid and sustained improvement in pain, physical functioning and health-related quality of life.

Predicting the probability of successful efficacy of a dissociated agonist of the glucocorticoid receptor from dose-response analysis.

PF-04171327 is a dissociated agonist of the glucocorticoid receptor (DAGR) being developed to retain anti-inflammatory efficacy while reducing unwanted effects. Our aim was to conduct a longitudinal dose-response analysis to identify the DAGR doses with efficacy similar to or greater than prednisone 10 mg once daily (QD). The data included were from a Phase 2, randomized, double-blind, parallel-group study in 323 subjects with active rheumatoid arthritis on a background of methotrexate. Subjects received DAGR 1, 5, 10 or 15 mg, prednisone 5 or 10 mg, or placebo QD for 8 weeks. The Disease Activity Score 28-4 calculated using C-Reactive Protein (DAS28-4 CRP) was the efficacy endpoint utilized in this dose-response model. For DAGR, the maximum effect (Emax) on DAS28-4 CRP was estimated to be -1.2 points (95 % CI -1.7, -0.84), and the evaluated dose range provided 31-87 % of the Emax; for prednisone 5 and 10 mg, the estimated effects were -0.27 (95 % CI -0.55, 0.006) and -0.94 point (95 % CI -1.3, -0.59), respectively. Stochastic simulations indicated that the DAGR 1, 5, 10 and 15 mg have probabilities of 0.9, 29, 54 and 62 %, respectively, to achieve efficacy greater than prednisone 10 mg at week 8. DAGR 9 mg estimated probability was 50 % suggesting that DAGR ≥9 mg QD has an effect on DAS28-4 CRP comparable to or greater than prednisone 10 mg QD. This work informs dose selection for late-stage confirmatory trials.

Tofacitinib or adalimumab versus placebo in rheumatoid arthritis.

BACKGROUND: Tofacitinib (CP-690,550) is a novel oral Janus kinase inhibitor that is being investigated for the treatment of rheumatoid arthritis. METHODS: In this 12-month, phase 3 trial, 717 patients who were receiving stable doses of methotrexate were randomly assigned to 5 mg of tofacitinib twice daily, 10 mg of tofacitinib twice daily, 40 mg of adalimumab once every 2 weeks, or placebo. At month 3, patients in the placebo group who did not have a 20% reduction from baseline in the number of swollen and tender joints were switched in a blinded fashion to either 5 mg or 10 mg of tofacitinib twice daily; at month 6, all patients still receiving placebo were switched to tofacitinib in a blinded fashion. The three primary outcome measures were a 20% improvement at month 6 in the American College of Rheumatology scale (ACR 20); the change from baseline to month 3 in the score on the Health Assessment Questionnaire-Disability Index (HAQ-DI) (which ranges from 0 to 3, with higher scores indicating greater disability); and the percentage of patients at month 6 who had a Disease Activity Score for 28-joint counts based on the erythrocyte sedimentation rate (DAS28-4[ESR]) of less than 2.6 (with scores ranging from 0 to 9.4 and higher scores indicating greater disease activity). RESULTS: At month 6, ACR 20 response rates were higher among patients receiving 5 mg or 10 mg of tofacitinib (51.5% and 52.6%, respectively) and among those receiving adalimumab (47.2%) than among those receiving placebo (28.3%) (P<0.001 for all comparisons). There were also greater reductions in the HAQ-DI score at month 3 and higher percentages of patients with a DAS28-4(ESR) below 2.6 at month 6 in the active-treatment groups than in the placebo group. Adverse events occurred more frequently with tofacitinib than with placebo, and pulmonary tuberculosis developed in two patients in the 10-mg tofacitinib group. Tofacitinib was associated with an increase in both low-density and high-density lipoprotein cholesterol levels and with reductions in neutrophil counts. CONCLUSIONS: In patients with rheumatoid arthritis receiving background methotrexate, tofacitinib was significantly superior to placebo and was numerically similar to adalimumab in efficacy. (Funded by Pfizer; ORAL Standard ClinicalTrials.gov number, NCT00853385.).

Tofacitinib (CP-690,550) in combination with methotrexate in patients with active rheumatoid arthritis with an inadequate response to tumour necrosis factor inhibitors: a randomised phase 3 trial.

BACKGROUND: Rheumatoid arthritis is a heterogeneous chronic disease, and no therapeutic agent has been identified which is universally and persistently effective in all patients. We investigated the effectiveness of tofacitinib (CP-690,550), a novel oral Janus kinase inhibitor, as a targeted immunomodulator and disease-modifying therapy for rheumatoid arthritis. METHODS: We did a 6-month, double-blind, parallel-group phase 3 study at 82 centres in 13 countries, including North America, Europe, and Latin America. 399 patients aged 18 years or older with moderate-to-severe rheumatoid arthritis and inadequate response to tumour necrosis factor inhibitors (TNFi) were randomly assigned in a 2:2:1:1 ratio with an automated internet or telephone system to receive twice a day treatment with: tofacitinib 5 mg (n=133); tofacitinib 10 mg (n=134); or placebo (n=132), all with methotrexate. At month 3, patients given placebo advanced to either tofacitinib 5 mg twice a day (n=66) or 10 mg twice a day (n=66). Primary endpoints included American College of Rheumatology (ACR)20 response rate, mean change from baseline in Health Assessment Questionnaire-Disability Index (HAQ-DI), and rates of disease activity score (DAS)28-4(ESR) less than 2·6 (referred to as DAS28<2·6), all at month 3. The full analysis set for the primary analysis included all randomised patients who received at least one dose of study medication and had at least one post-baseline assessment. This trial is registered with www.ClinicalTrials.gov, number NCT00960440. FINDINGS: At month 3, ACR20 response rates were 41·7% (55 of 132 [95% CI vs placebo 6·06-28·41]; p=0·0024) for tofacitinib 5 mg twice a day and 48·1% (64 of 133; [12·45-34·92]; p<0·0001) for tofacitinib 10 mg twice a day versus 24·4% (32 of 131) for placebo. Improvements from baseline in HAQ-DI were -0·43 ([-0·36 to -0·15]; p<0·0001) for 5 mg twice a day and -0·46 ([-0·38 to -0·17]; p<0·0001) for 10 mg twice a day tofacitinib versus -0·18 for placebo; DAS28<2·6 rates were 6·7% (eight of 119; [0-10·10]; p=0·0496) for 5 mg twice a day tofacitinib and 8·8% (11 of 125 [1·66-12·60]; p=0·0105) for 10 mg twice a day tofacitinib versus 1·7% (two of 120) for placebo. Safety was consistent with phase 2 and 3 studies. The most common adverse events in months 0-3 were diarrhoea (13 of 267; 4·9%), nasopharyngitis (11 of 267; 4·1%), headache (11 of 267; 4·1%), and urinary tract infection (eight of 267; 3·0%) across tofacitinib groups, and nausea (nine of 132; 6·8%) in the placebo group. INTERPRETATION: In this treatment-refractory population, tofacitinib with methotrexate had rapid and clinically meaningful improvements in signs and symptoms of rheumatoid arthritis and physical function over 6 months with manageable safety. Tofacitinib could provide an effective treatment option in patients with an inadequate response to TNFi. FUNDING: Pfizer.

Preclinical to clinical translation of tofacitinib, a Janus kinase inhibitor, in rheumatoid arthritis.

A critical piece in the translation of preclinical studies to clinical trials is the determination of dosing regimens that allow maximum therapeutic benefit with minimum toxicity. The preclinical pharmacokinetic (PK)/pharmacodynamic (PD) profile of tofacitinib, an oral Janus kinase (JAK) inhibitor, in a mouse collagen-induced arthritis (mCIA) model was compared with clinical PK/PD data from patients with rheumatoid arthritis (RA). Preclinical evaluations included target modulation and PK/PD modeling based on continuous subcutaneous infusion or oral once- or twice-daily (BID) dosing paradigms in mice. The human PK/PD profile was obtained from pooled data from four phase 2 studies in patients with RA, and maximal effect models were used to evaluate efficacy after 12 weeks of tofacitinib treatment (1-15 mg BID). In mCIA, the main driver of efficacy was inhibition of cytokine receptor signaling mediated by JAK1 heterodimers, but not JAK2 homodimers, and continuous daily inhibition was not required to maintain efficacy. Projected efficacy could be predicted from total daily exposure irrespective of the oral dosing paradigm, with a total steady-state plasma concentration achieving 50% of the maximal response (Cave50) of ~100 nM. Tofacitinib potency (ED50) in clinical studies was ~3.5 mg BID (90% confidence interval: 2.3, 5.5) or total Cave50 of ~40 nM, derived using Disease Activity Scores from patients with RA. The collective clinical and preclinical data indicated the importance of Cave as a driver of efficacy, rather than maximum or minimum plasma concentration (Cmax or Cmin), where Cave50 values were within ~2-fold of each other.

The pharmacokinetics, metabolism, and clearance mechanisms of tofacitinib, a janus kinase inhibitor, in humans.

Tofacitinib is a novel, oral Janus kinase inhibitor. The objectives of this study were to summarize the pharmacokinetics and metabolism of tofacitinib in humans, including clearance mechanisms. Following administration of a single 50-mg (14)C-labeled tofacitinib dose to healthy male subjects, the mean (standard deviation) total percentage of administered radioactive dose recovered was 93.9% (±3.6), with 80.1% (±3.6) in the urine (28.8% parent), and 13.8% (±1.9) in feces (0.9% parent). Tofacitinib was rapidly absorbed, with plasma concentrations and total radioactivity peaking at around 1 hour after oral administration. The mean terminal phase half-life was approximately 3.2 hours for both parent drug and total radioactivity. Most (69.4%) circulating radioactivity in plasma was parent drug, with all metabolites representing less than 10% each of total circulating radioactivity. Hepatic clearance made up around 70% of total clearance, while renal clearance made up the remaining 30%. The predominant metabolic pathways of tofacitinib included oxidation of the pyrrolopyrimidine and piperidine rings, oxidation of the piperidine ring side-chain, N-demethylation and glucuronidation. Cytochrome P450 (P450) profiling indicated that tofacitinib was mainly metabolized by CYP3A4, with a smaller contribution from CYP2C19. This pharmacokinetic characterization of tofacitinib has been consistent with its clinical experience in drug-drug interaction studies.

Tofacitinib (CP-690,550) in patients with rheumatoid arthritis receiving methotrexate: twelve-month data from a twenty-four-month phase III randomized radiographic study.

OBJECTIVE: The purpose of this 24-month phase III study was to examine structural preservation with tofacitinib in patients with rheumatoid arthritis (RA) with an inadequate response to methotrexate (MTX). Data from a planned 12-month interim analysis are reported. METHODS: In this double-blind, parallel-group, placebo-controlled study, patients receiving background MTX were randomized 4:4:1:1 to tofacitinib at 5 mg twice daily, tofacitinib at 10 mg twice daily, placebo to tofacitinib at 5 mg twice daily, and placebo to tofacitinib at 10 mg twice daily. At month 3, nonresponder placebo-treated patients were advanced in a blinded manner to receive tofacitinib as indicated above; remaining placebo-treated patients were advanced at 6 months. Four primary efficacy end points were all analyzed in a step-down procedure. RESULTS: At month 6, response rates according to the American College of Rheumatology 20% improvement criteria for tofacitinib at 5 mg and 10 mg twice daily were higher than those for placebo (51.5% and 61.8%, respectively, versus 25.3%; both P < 0.0001). At month 6, least squares mean (LSM) changes in total modified Sharp/van der Heijde score for tofacitinib at 5 mg and 10 mg twice daily were 0.12 and 0.06, respectively, versus 0.47 for placebo (P = 0.0792 and P ≤ 0.05, respectively). At month 3, LSM changes in the Health Assessment Questionnaire disability index score for tofacitinib at 5 mg and 10 mg twice daily were -0.40 (significance not declared due to step-down procedure) and -0.54 (P < 0.0001), respectively, versus -0.15 for placebo. At month 6, rates of remission (defined as a value <2.6 for the 4-variable Disease Activity Score in 28 joints using the erythrocyte sedimentation rate) for tofacitinib at 5 mg and 10 mg twice daily were 7.2% (significance not declared due to step-down procedure) and 16.0% (P < 0.0001), respectively, versus 1.6% for placebo. The safety profile was consistent with findings in previous studies. CONCLUSION: Data from this 12-month interim analysis demonstrate that tofacitinib inhibits progression of structural damage and improves disease activity in patients with RA who are receiving MTX.

Tofacitinib in combination with nonbiologic disease-modifying antirheumatic drugs in patients with active rheumatoid arthritis: a randomized trial.

BACKGROUND: Many patients with rheumatoid arthritis (RA) do not achieve adequate and safe responses with disease-modifying antirheumatic drugs (DMARDs). Tofacitinib is a novel, oral, Janus kinase inhibitor that treats RA. OBJECTIVE: To evaluate the efficacy and safety of tofacitinib in combination with nonbiologic DMARDs. DESIGN: 1-year, double-blind, randomized trial (ClinicalTrials.gov: NCT00856544). SETTING: 114 centers in 19 countries. PATIENTS: 792 patients with active RA despite nonbiologic DMARD therapy. INTERVENTION: Patients were randomly assigned 4:4:1:1 to oral tofacitinib, 5 mg or 10 mg twice daily, or placebo advanced to tofacitinib, 5 mg or 10 mg twice daily. MEASUREMENTS: Primary end points were 20% improvement in American College of Rheumatology (ACR20) criteria; Disease Activity Score for 28-joint counts based on the erythrocyte sedimentation rate (DAS28-4[ESR]) of less than 2.6; DAS28-4(ESR)-defined remission, change in Health Assessment Questionnaire Disability Index (HAQ-DI) score, and safety assessments. RESULTS: Mean treatment differences for ACR20 response rates (month 6) for the 5-mg and 10-mg tofacitinib groups compared with the combined placebo groups were 21.2% (95% CI, 12.2% to 30.3%; P < 0.001) and 25.8% (CI, 16.8% to 34.8%; P < 0.001), respectively. The HAQ-DI scores (month 3) and DAS28-4(ESR) less than 2.6 response rates (month 6) were also superior in the tofacitinib groups versus placebo. The incidence rates of serious adverse events for patients receiving 5-mg tofacitinib, 10-mg tofacitinib, or placebo were 6.9, 7.3, or 10.9 events per 100 patient-years of exposure, respectively. In the tofacitinib groups, 2 cases of tuberculosis, 2 cases of other opportunistic infections, 3 cardiovascular events, and 4 deaths occurred. Neutrophil counts decreased, hemoglobin and low- and high-density lipoprotein cholesterol levels increased, and serum creatinine levels had small increases in the tofacitinib groups. LIMITATIONS: Placebo groups were smaller and of shorter duration. Patients received primarily methotrexate. The ability to assess drug combinations other than tofacitinib plus methotrexate was limited. CONCLUSION: Tofacitinib improved disease control in patients with active RA despite treatment with nonbiologic DMARDs, primarily methotrexate. PRIMARY FUNDING SOURCE: Pfizer.

A phase IIb dose-ranging study of the oral JAK inhibitor tofacitinib (CP-690,550) versus placebo in combination with background methotrexate in patients with active rheumatoid arthritis and an inadequate response to methotrexate alone.

OBJECTIVE: To compare the efficacy, safety, and tolerability of 6 dosages of oral tofacitinib (CP-690,550) with placebo for the treatment of active rheumatoid arthritis (RA) in patients receiving a stable background regimen of methotrexate (MTX) who have an inadequate response to MTX monotherapy. METHODS: In this 24-week, double-blind, phase IIb study, patients with active RA (n = 507) were randomized to receive placebo or tofacitinib (20 mg/day, 1 mg twice daily, 3 mg twice daily, 5 mg twice daily, 10 mg twice daily, or 15 mg twice daily). All patients continued to receive a stable dosage of MTX. The primary end point was the American College of Rheumatology 20% improvement criteria (ACR20) response rate at week 12. RESULTS: At week 12, ACR20 response rates for patients receiving all tofacitinib dosages ≥3 mg twice daily (52.9% for 3 mg twice daily, 50.7% for 5 mg twice daily, 58.1% for 10 mg twice daily, 56.0% for 15 mg twice daily, and 53.8% for 20 mg/day) were significantly (P ≤ 0.05) greater than those for placebo (33.3%). Improvements were sustained at week 24 for the ACR20, ACR50, and ACR70 responses, scores for the Health Assessment Questionnaire disability index, the 3-variable Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP), and a 3-variable DAS28-CRP of <2.6. The most common treatment-emergent adverse events occurring in >10% of patients in any tofacitinib group were diarrhea, upper respiratory tract infection, and headache; 21 patients (4.1%) experienced serious adverse events. Sporadic increases in transaminase levels, increases in cholesterol and serum creatinine levels, and decreases in neutrophil and hemoglobin levels were observed. CONCLUSION: In patients with active RA in whom the response to MTX has been inadequate, the addition of tofacitinib at a dosage ≥3 mg twice daily showed sustained efficacy and a manageable safety profile over 24 weeks.

Phase IIb dose-ranging study of the oral JAK inhibitor tofacitinib (CP-690,550) or adalimumab monotherapy versus placebo in patients with active rheumatoid arthritis with an inadequate response to disease-modifying antirheumatic drugs.

OBJECTIVE: To compare the efficacy, safety, and tolerability of 5 doses of oral tofacitinib (CP-690,550) or adalimumab monotherapy with placebo for the treatment of active rheumatoid arthritis (RA) in patients with an inadequate response to disease-modifying antirheumatic drugs. METHODS: In this 24-week, double-blind, phase IIb study, patients with RA (n = 384) were randomized to receive placebo, tofacitinib at 1, 3, 5, 10, or 15 mg administered orally twice a day, or adalimumab at 40 mg injected subcutaneously every 2 weeks (total of 6 injections) followed by oral tofacitinib at 5 mg twice a day for 12 weeks. The primary end point was the responder rate according to the American College of Rheumatology 20% improvement criteria (ACR20) at week 12. RESULTS: Treatment with tofacitinib at a dose of ≥3 mg twice a day resulted in a rapid response with significant efficacy when compared to placebo, as indicated by the primary end point (ACR20 response at week 12), achieved in 39.2% (3 mg; P ≤ 0.05), 59.2% (5 mg; P < 0.0001), 70.5% (10 mg; P < 0.0001), and 71.9% (15 mg; P < 0.0001) in the tofacitinib group and 35.9% of patients in the adalimumab group (P = 0.105), compared with 22.0% of patients receiving placebo. Improvements were sustained at week 24, according to the ACR20, ACR50, and ACR70 response rates as well as classifications of remission according to the 3-variable Disease Activity Score in 28 joints (DAS28) using C-reactive protein and the 4-variable DAS28 using the erythrocyte sedimentation rate. The most common treatment-emergent adverse events (AEs) in patients across all tofacitinib treatment arms (n = 272) were urinary tract infection (7.7%), diarrhea (4.8%), headache (4.8%), and bronchitis (4.8%). CONCLUSION: Tofacitinib monotherapy at ≥3 mg twice a day was efficacious in the treatment of patients with active RA over 24 weeks and demonstrated a manageable safety profile.

Lack of effect of tofacitinib (CP-690,550) on the pharmacokinetics of the CYP3A4 substrate midazolam in healthy volunteers: confirmation of in vitro data.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Tofacitinib (CP-690,550) is a novel, oral Janus kinase inhibitor being investigated as a targeted immunomodulator and disease-modifying therapy in rheumatoid arthritis. • Non-renal elimination accounts for 70% of the total clearance of tofacitinib and the metabolism is primarily mediated by cytochrome P450 (CYP) 3A4. • This study was required to determine the effect of tofacitinib on the in vivo pharmacokinetics of a sensitive CYP3A4 substrate. WHAT THIS STUDY ADDS: • The pharmacokinetics of midazolam, a sensitive CYP3A4 substrate, are not altered when co-administered with tofacitinib in healthy subjects. • Tofacitinib is unlikely to affect the clearance of drugs metabolized by CYP enzymes. • There is no need for dose adjustments of CYP substrates when co-administered with tofacitinib. AIMS: To investigate inhibitive and inductive effects of tofacitinib (CP-690,550), a Janus kinase inhibitor, on CYP3A4 function via in vitro and in vivo studies. METHODS: In vitro experiments were conducted to assess the inhibition and induction potential of tofacitinib for major drug metabolizing enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4). A phase 1, randomized, open-label, two-way crossover study (NCT00902460) was conducted to confirm the lack of inhibitive/inductive effect on a sensitive CYP3A4 substrate, midazolam, in healthy subjects. Midazolam pharmacokinetics were assessed over 24 h following single dose 2 mg administration prior to administering tofacitinib and after twice daily dosing of tofacitinib 30 mg for 6 days. The primary endpoint was midazolam area under the concentration-time profile, from time 0 to infinity (AUC(0,∞)). RESULTS: In vitro studies demonstrated low potential for CYP inhibition (IC(50) estimates tofacitinib > 30 µm), CYP3A4 mRNA induction (observed at tofacitinib concentrations ≥ 25 µm) and no effect on enzymatic activity of CYP substrates. In the human study, AUC(0,∞) adjusted geometric mean ratio for midazolam plus tofacitinib to midazolam alone was 103.97% [90% confidence interval (CI) 95.57, 113.12], wholly within the pre-specified acceptance region (80, 125). The 90% CI for the ratio of adjusted geometric means of maximum plasma concentration (C(max) ) (95.98, 108.87) was also wholly within this acceptance region. CONCLUSIONS: These data confirm a lack of an inhibitive or inductive effect of tofacitinib on CYP3A activity in humans and, in conjunction with in vitro data, support the conclusion that tofacitinib is unlikely to influence the CYP enzyme system as a whole.

Estimating transformations for repeated measures modeling of continuous bounded outcome data.

Continuous bounded outcome data are unlikely to meet the usual assumptions for mixed-effects models of normally distributed and independent subject-specific and residual random effects. Additionally, overly complicated model structures might be necessary to account adequately for non-drug (time-dependent) and drug treatment effects. A transformation strategy with a likelihood component for censoring is developed to promote the simplicity of model structures and to improve the plausibility of assumptions on the random effects. The approach is motivated by Health Assessment Questionnaire Disability Index (HAQ-DI) data from a study in subjects with rheumatoid arthritis and is evaluated using a simulation study.

Population pharmacokinetic analysis of mycophenolic acid coadministered with either tasocitinib (CP-690,550) or tacrolimus in adult renal allograft recipients.

Tasocitinib (CP-690,550) is an orally active Janus kinase inhibitor that is in development for prophylaxis of acute rejection after kidney transplantation and for the treatment of select autoimmune diseases. The current study was conducted to evaluate the systemic exposure of mycophenolic acid (MPA) in de novo kidney transplant patients when coadministered with tasocitinib compared with exposure in patients receiving tacrolimus, which has no effect on MPA pharmacokinetics. Plasma MPA concentrations were obtained from 17 adult patients who received either 15 mg or 30 mg tasocitinib twice daily (eight patients) or tacrolimus (nine patients) after kidney transplantation. All patients also received concomitant mycophenolate mofetil, prednisone, and basiliximab induction. The median mycophenolate mofetil dose was 1000 mg twice daily. A two-compartment population pharmacokinetic model estimating oral clearance, between-patient variability in oral clearance, central volume of distribution, and residual variability in combination with historical estimates of first-order absorption rate constant, intercompartmental clearance, and peripheral volume of distribution adequately described the sparse MPA data. Based on individual estimates oral clearance from the population pharmacokinetic model, mean steady-state area under the concentration-time curve values for a mycophenolate mofetil dose of 1000 mg twice daily were 63 mg·hr/L (22%) and 59 mg·hr/L (36%) for the tasocitinib and tacrolimus groups, respectively. These results indicate that tasocitinib does not influence systemic MPA exposure.

Model-Based Comparison of Dose-Response Profiles of Tofacitinib in Japanese Versus Western Rheumatoid Arthritis Patients.

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). The aim of this analysis was to characterize the relationship between tofacitinib dose and efficacy, as measured by American College of Rheumatology (ACR) response rates, and to compare this between Japanese and Western patients with RA. Efficacy data were pooled from 2 double-blind, dose-ranging phase 2 studies of tofacitinib monotherapy 1-15 mg twice daily in patients with RA with an inadequate response to disease-modifying antirheumatic drugs (DMARDs). NCT00550446 was carried out in mostly Western patients and NCT00687193 in Japanese patients. ACR20, ACR50, and ACR70 response rates in week 12 were analyzed using maximum drug effect (Emax ) models on the logit domain. Both studies showed a dose-response for each end point, supporting the efficacy of tofacitinib in patients with inadequate response to DMARDs. Study-specific differences in Emax were noted, whereas potency (dose providing half the maximum effect [ED50 ]) was similar across studies. After adjustment for study differences in Emax by calculating the fractions of the maximum placebo-adjusted proportion of ACR responses, the estimated locations for the 5- and 10-mg twice-daily doses on the dose-response curves were similar for the 2 patient populations: ACR20, ACR50, andACR70 mean fractional responses for 5 and 10 mg twice daily were 0.78, 0.43, 0.32 and 0.90, 0.69, and 0.56, respectively, for the Japanese study and 0.54, 0.41, and 0.22 and 0.73, 0.61, and 0.40, respectively, for the Western study. This analysis therefore supports the rationale for the same dosing regimen in Japanese patients as in Western patients from an efficacy perspective.

Application of Physiologically Based Pharmacokinetic Modeling to Predict Drug Exposure and Support Dosing Recommendations for Potential Drug-Drug Interactions or in Special Populations: An Example Using Tofacitinib.

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. It is eliminated via multiple pathways including oxidative metabolism (∼70%) and renal excretion (29%). This study aimed to predict the impact of drug-drug interactions and renal or hepatic impairment on tofacitinib pharmacokinetics using a physiologically based pharmacokinetic (PBPK) model. The model was developed using Simcyp based on the physicochemical properties and in vitro and in vivo pharmacokinetics data for tofacitinib. The model was verified by comparing the predicted pharmacokinetic profiles with those observed in available clinical studies after single or multiple doses of tofacitinib, as well as with tofacitinib as a victim of drug-drug interactions (because of inhibition of cytochrome P450 [CYP450] 3A4, CYP450 2C19, or CYP450 induction). In general, good agreement was observed between Simcyp predictions and clinical data. The results from this study provide confidence in using the PBPK modeling and simulation approach to predict the pharmacokinetics of tofacitinib under intrinsic (eg, renal or hepatic impairment) or extrinsic (eg, inhibition of CYP450 enzymes and/or renal transporters) conditions. This approach may also be useful in predicting pharmacokinetics under untested or complex situations (eg, when a combination of intrinsic and extrinsic factors may impact pharmacokinetics) when conducting clinical studies may be difficult, in response to health authority questions regarding dosing in special populations, or for labeling discussions.

Phase 1 Dose-Escalation Study to Evaluate the Pharmacokinetics, Safety, and Tolerability of Tofacitinib in Japanese Healthy Volunteers.

The aim of the study was to characterize the pharmacokinetics, safety, and tolerability of tofacitinib, an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis in healthy Japanese volunteers, and to compare these outcomes with those of healthy Western volunteers. Twenty-five volunteers (Japanese, n = 16; Western [white], n = 9) were randomized to receive either 3 escalating single doses of tofacitinib (1, 5, and 30 mg), single-dose tofacitinib (15 mg) followed by multiple doses (15 mg twice daily for 5 days), or placebo. No significant differences in systemic exposure to tofacitinib were detected between the 2 ethnicities. Following single tofacitinib 1, 5, and 30 mg doses, mean area under the plasma concentration-time curve from time zero to infinity ratio (Japanese/Western) values were 96.6%, 93.5%, and 95.6%, respectively. Similarly, mean maximum observed plasma concentration ratio values were 99.5%, 118%, and 119%, respectively. Mean renal clearance was also similar, ranging across doses from 134 mL/min (5 mg) to 162 mL/min (1 mg) in Japanese volunteers, and 124 mL/min (30 mg) to 160 mL/min (1 mg) in Western volunteers. In both ethnicities, most adverse events were mild. No serious adverse events or deaths were reported. The pharmacokinetics of tofacitinib were well characterized in healthy Japanese volunteers and were similar to those in Western volunteers.