Small Molecule JAK Inhibitor Research Articles

P034 Assessment of age as a risk factor for adverse events in patients from the tofacitinib ulcerative colitis clinical program

BACKGROUND: Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). Safety and efficacy of tofacitinib were demonstrated in Phase (P) 2/3 induction studies (NCT00787202; NCT01465763; NCT01458951), a 52-week, P3 maintenance study (NCT01458574), and are being further investigated in an ongoing, open-label, long-term extension (OLE) study (NCT01470612). This analysis assessed age as a risk factor for adverse events (AEs) in the tofacitinib UC clinical program. METHODS: Analyses of AEs were performed for 2 cohorts: the Maintenance Cohort (patients who received placebo or tofacitinib 5 or 10 mg twice daily in the maintenance study) and the Overall Cohort (all tofacitinib-treated patients in the P2/P3/OLE studies [as of December 2016]), stratified by age (≥65 years vs <65 years). AEs of special interest included serious infections (SIs), opportunistic infections (OIs), herpes zoster (HZ), malignancies (excluding non-melanoma skin cancer [NMSC]), NMSC, major adverse cardiovascular events (MACE), and gastrointestinal perforations. Risk factors (based on baseline characteristics) for SIs, OIs, HZ, and NMSC in the Overall Cohort were evaluated using multivariate Cox proportional regression models. RESULTS: AEs occurred in 75.3% (placebo) and 75.9% (tofacitinib) of patients in the Maintenance Cohort, and 82.1% in the Overall Cohort (in which 83.9% received predominantly tofacitinib 10 mg twice daily). Most patients (Maintenance Cohort: 180/198 [90.9%] and 364/394 [92.4%] receiving placebo and tofacitinib, respectively; Overall Cohort: 1,080/1,157 [93.3%]) were aged <65 years. In both the placebo and tofacitinib groups of the Maintenance Cohort, rates of AEs, serious AEs, severe AEs, and discontinuations due to AEs were numerically higher in patients aged ≥65 years (placebo: 83.3%, 11.1%, 11.1%, and 22.2%; tofacitinib: 80.0%, 16.7%, 10.0%, and 16.7%) vs <65 years (placebo: 74.4%, 6.1%, 9.4%, and 18.3%; tofacitinib: 75.5%, 4.4%, 7.1%, and 8.8%). AEs of special interest were generally infrequent in both the placebo and tofacitinib groups of the Maintenance Cohort. In the Overall Cohort, AE, serious AE, and severe AE rates were numerically higher in patients aged ≥65 years (88.3%, 19.5%, and 15.6%) vs <65 years (81.7%, 14.3%, and 12.2%). OI, HZ, malignancies (excluding NMSC), NMSC, and MACE rates were numerically higher in patients aged ≥65 years (3.9%, 14.3%, 2.6%, 5.3%, and 2.6%) vs <65 years (1.7%, 5.0%, 0.6%, 0.7%, and 0.2%); SI and gastrointestinal perforation rates were similar between age groups (≥65 years: 2.6% and 0.0%; <65 years: 2.9% and 0.4%). In multivariate modeling in the Overall Cohort, increasing age (every 10 years) was associated with increased risk of OIs (hazard ratio [95% confidence interval] 1.54 [1.15, 2.08]) and HZ (1.58 [1.34, 1.87]), but not SIs or NMSC (univariate modeling: 1.0 [0.78, 1.27] and 2.31 [1.46, 3.66]). CONCLUSION(S): In the tofacitinib UC program, AE rates were higher among patients aged ≥65 years vs those aged <65 years, regardless of whether they received tofacitinib or placebo. In multivariate analyses, older age was associated with increased OI and HZ risk. Although this is consistent with the general population, due to the small number of patients aged ≥65 years (<10% of the total), these findings should be interpreted with caution.

A systematic review and meta-analysis of infection risk with small molecule JAK inhibitors in rheumatoid arthritis.

To evaluate the risk of serious infection (SI) and herpes zoster (HZ) in rheumatoid arthritis patients receiving JAK inhibitors. We conducted a systematic literature review and meta-analysis of phase II and III randomized controlled trials of tofacitinib (5 mg bid), baricitinib (4 mg od) and upadacitinib (15 mg od). Patient-exposure years were calculated. A per-protocol analysis was applied, incorporating follow-up time from patients randomized to placebo who cross into the treatment arm. Pooled incidence rates per 100 person-years of SI and HZ were calculated. Incidence rate ratios (IRRs) of drug vs placebo were compared using a meta-synthesis approach. Twenty-one studies were included in the meta-analysis; 11 tofacitinib (5888 patients), six baricitinib (3520 patients) and four upadacitinib studies (1736 patients). For SI, the incidence rates were 1.97 (95% CI: 1.41, 2.68), 3.16 (95% CI: 2.07, 4.63) and 3.02 (95% CI: 0.98, 7.04), respectively. The IRRs comparing treatment arm to placebo were statistically non-significant: 1.22 (95% CI: 0.60, 2.45), 0.80 (95% CI: 0.46, 1.38) and 1.14 (95% CI: 0.24, 5.43), respectively. For HZ, the incidence rates were 2.51 (95% CI: 1.87, 3.30), 3.16 (95% CI: 2.07, 4.63) and 2.41 (95% CI: 0.66, 6.18), respectively. The IRR of HZ comparing baricitinib with placebo was 2.86 (95% CI: 1.26, 6.50). Non-significant IRRs were seen with tofacitinib and upadacitinib: 1.38 (95% CI: 0.66, 2.88) and 0.78 (95% CI: 0.19, 3.22), respectively. Indicator opportunistic infections excluding HZ were too rare to provide meaningful incidence rates. The absolute SI rates were low. However across the JAK inhibitors, the incidence of HZ is higher than expected for the population (3.23 per 100 patient-years). While the risk was numerically greatest with baricitinib, indirect comparisons between the drugs did not demonstrate any significant difference in risk. Prospero 2017 CRD4201707879.

STAT signaling as a marker of SLE disease severity and implications for clinical therapy.

The Janus kinase/signal transduction and activator of transcription (JAK-STAT) signaling pathway is implicated in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE). While small-molecule JAK inhibitors (Jakinibs) are currently under investigation for SLE, results of recent studies suggest, that the efficacy of drugs such as methotrexate (MTX) may also be due to their ability to suppress phosphorylation of STAT proteins. A previously identified STAT5 phosphorylation (pSTAT5) and STAT1 protein expression »signature« in circulating CD4+ T cells of patients with SLE was associated with perturbed homeostasis between conventional (Tcon) and activated regulatory (aTreg) subset and with time-adjusted cumulative disease activity during follow-up. Initial observations in SLE patient cohort were validated with additional markers of disease severity and patients were stratified according to medication status. Preliminary results show that lower CD4+ T-cell counts in patients with SLE are associated with higher pSTAT5 levels and Tcon homeostatic proliferation, which was previously found to drive lymphopenia associated autoimmunity. Relapsing disease was better predicted by pSTAT5 levels than CD4 counts. Further, significant correlation was found between mean pSTAT5 levels during follow- up and the markers of disease severity. As patients with SLE, also patients with rheumatoid arthritis (RA) not receiving methotrexate, had significantly higher increase in CD4+ T-cell pSTAT5 levels compared to patients not receiving this specific therapy. However, the difference in pSTAT5 between Tcon and aTreg was independent of treatment with MTX and significantly increased only in patients with SLE. CD4 depletion, driving homeostatic proliferation of Tcon subset, is therefore associated with higher pSTAT5 levels, which confer worse prognosis in patients with SLE. While treatment with MTX may decrease overall pSTAT5 levels in CD4+ T-cells also from patients with RA, increased pSTAT5 levels in Tcon relative to aTreg subset are specific for SLE.

Safety of Tofacitinib for Treatment of Ulcerative Colitis, Based on 4.4 Years of Data From Global Clinical Trials

Tofacitinib is an oral, small-molecule inhibitor of JAK approved in several countries for the treatment of ulcerative colitis (UC). We report integrated safety analyses of tofacitinib-treated patients with moderate to severe UC. Patients receiving placebo or tofacitinib (5 or 10 mg) twice daily were analyzed as 3 cohorts: induction (phase 2 and 3 induction studies, n= 1220), maintenance (phase 3 maintenance study, n= 592), and overall (patients receiving tofacitinib 5 or 10 mg twice daily in phase 2, phase 3, or open-label, long-term extension studies, n= 1157; 1613 patient-years' exposure). Incidence rates (IRs; patients with events per 100 patient-years of exposure) were evaluated for select adverse events. In the maintenance cohort, IRs for select adverse events were similar among treatment groups, except for a numerically higher IR of herpes zoster infection among patients who received tofacitinib 5 mg twice daily (2.1; 95% CI, 0.4-6.0) and statistically higher IR among patients who received tofacitinib 10 mg twice daily (IR, 6.6; 95% CI, 3.2-12.2) vs placebo (IR, 1.0, 95% CI, 0.0-5.4). For the overall cohort (84% received average dose of tofacitinib 10 mg twice daily), IRs were: death, 0.2 (95% CI, 0.1-0.6); serious infections, 2.0 (95% CI, 1.4-2.8); opportunistic infections, 1.3 (95% CI, 0.8-2.0); herpes zoster infection, 4.1 (95% CI, 3.1-5.2); malignancy (excluding non-melanoma skin cancer), 0.7 (95% CI, 0.3-1.2); non-melanoma skin cancer, 0.7 (95% CI, 0.3-1.2); major adverse cardiovascular events, 0.2 (95% CI, 0.1-0.6); and gastrointestinal perforations, 0.2 (95% CI, 0.0-0.5). In safety analyses of patients with moderate to severe UC treated with tofacitinib, we observed a dose relationship with herpes zoster infection. Although follow-up time was relatively short, the safety profile of tofacitinib for patients with UC appeared similar to that reported for patients with rheumatoid arthritis and for patients with UC treated with biologic agents, except for the higher IR of herpes zoster infection. ClinicalTrials.gov, no: NCT00787202, NCT01465763, NCT01458951, NCT01458574, and NCT01470612.

Improvement in Physicianʼs Global Assessment Within 2 Weeks in Patients With Ulcerative Colitis Treated With Tofacitinib

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). OCTAVE Induction 1 & 2 (NCT01465763 & NCT01458951) were identical, randomized, doubleblind, placebo-controlled Phase 3 trials in adult patients (pts) with moderately to severely active UC who had failed, or were intolerant to, steroids, immunomodulators, or tumor necrosis factor inhibitors [1]. Rapid onset of tofacitinib efficacy with significant improvements in pt-reported symptoms (Mayo stool frequency [SF] and rectal bleeding [RB] subscores) was observed within 3 days [2]. Here, we evaluate the time course of improvement in Physician's Global Assessment (PGA) in pts with UC following induction therapy with tofacitinib. Methods: The Mayo score includes the PGA, which comprises pts' levels of discomfort and overall wellbeing. PGA subscores of pts who received placebo or tofacitinib 10 mg twice daily (BID) for 8 weeks (wks) in OCTAVE Induction 1 & 2 were collected at baseline, and at Wks 2, 4, and 8 of the blinded treatment period. Comparisons between groups were made using stratified Cochran-Mantel-Haenszel chi-square test. Results: 905 pts received tofacitinib 10 mg BID (mean age 41.2 years; 59.2% male) and 234 pts received placebo (mean age 41.1 years; 56.4% male). At baseline, the mean total Mayo score in both the placebo group and the tofacitinib group was 9.0; the mean partial Mayo score (total Mayo score excluding endoscopic subscore) in both groups was 6.4. By Wk 2, 10.3% of pts treated with tofacitinib, compared with 3.4% of placebo-treated pts, achieved a PGA subscore of 0 (p<0.01). Similarly, by Wk 2, significantly more pts treated with tofacitinib vs placebo achieved a PGA subscore of 0 or 1 (41.3% vs 27.4%; p<0.0001). A greater proportion of tofacitinib-treated pts had a reduction of ≥1 PGA point from baseline, compared with placebo pts, at Wk 2 (52.0% vs 37.6%; p<0.0001). From Wk 2 to Wk 8, differences between tofacitinib-treated and placebo-treated pts increased for all three PGA subscores analyzed (p<0.01 for all comparisons). Conclusion: In these two randomized trials in pts with UC, treatment with tofacitinib was associated with a significant improvement in the PGA subscores within 2 wks - continuing through Wk 8 - coinciding with improvements in pt-reported symptoms (SF and RB).734 Figure 1 No Caption available.

Tofacitinib 15 Milligrams Twice Daily for Patients With Moderate to Severe Ulcerative Colitis: Results From 8-Week Induction Studies OCTAVE Induction 1 &amp; 2

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). Efficacy and safety of tofacitinib 10 mg twice daily (BID) induction therapy for UC was previously reported in two 8-week (wk), Phase 3 trials (OCTAVE Induction 1 & 2) [1]. Initially, patients (pts) were randomized (2:2:1) to tofacitinib 10 or 15 mg BID or placebo. Randomization to the 15 mg dose ceased after a protocol amendment. Methods: We report pooled efficacy and safety analyses from OCTAVE Induction 1 & 2 for tofacitinib 15 mg BID alongside placebo and 10 mg BID data previously reported [1]. Pts were ≥18 years of age and had failed, or were intolerant to, corticosteroids, immunomodulators, or tumor necrosis factor inhibitors. Remission (total Mayo score ≤2, no subscore >1, and rectal bleeding subscore of 0), mucosal healing (Mayo endoscopic subscore ≤1), and clinical response (decrease from baseline total Mayo score of ≥3 points and ≥30%, plus decrease in rectal bleeding subscore ≥1 or absolute subscore ≤1) were evaluated based on central reading of endoscopic subscore. Differences from placebo and 95% confidence intervals (CI) were calculated using an exact method. Results: Baseline demographics and disease characteristics of the 22 pts who received tofacitinib 15 mg BID during OCTAVE Induction 1 & 2 were generally consistent with the overall population (Table). At Wk 8 in the 15 mg BID group, remission (primary endpoint) was achieved by 9 (40.9%) pts, mucosal healing by 13 (59.1%) pts, and clinical response by 19 (86.4%) pts. Differences from placebo (95% CI) were 34.9% (15.6, 56.4) for remission, 45.4% (23.5, 65.3) for mucosal healing, and 55.6% (32.3, 67.8) for clinical response. There were numerically greater rates of adverse events (AEs) and infections with tofacitinib 15 mg BID compared with 10 mg BID and with placebo. There were no deaths, serious AEs, serious infections, herpes zoster, gastrointestinal perforations, opportunistic infections, malignancies, non-melanoma skin cancers, or major adverse cardiovascular events with tofacitinib 15 mg BID. Conclusion: Based on a small sample size of 22 pts who received tofacitinib 15 mg BID in OCTAVE Induction 1 & 2, observed treatment effect with 15 mg BID was greater than with placebo and numerically greater than with 10 mg BID. There were numerically greater rates of AEs and infections with 15 mg BID compared with 10 mg BID and placebo.720 Figure 1 No Caption available.

Tofacitinib, an Oral Janus Kinase Inhibitor, in the Treatment of Ulcerative Colitis: An Interim Analysis of an Open-Label, Long-Term Extension Study With up to 4.9 Years of Treatment

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). The efficacy and safety of tofacitinib was demonstrated as induction and maintenance therapy in patients (pts) with moderate to severe UC in 3 Phase 3, randomized, placebo-controlled studies [1]. Safety and efficacy of tofacitinib for UC are being evaluated in an ongoing, open-label, long-term extension (OLE) study [2]. Methods: We present an update (as of Nov 10 2017) of previous safety and efficacy data [2] of the OLE study (NCT01470612) in completers or treatment failures in OCTAVE Sustain (NCT01458574) and nonresponders in OCTAVE Induction 1/2. Eligibility was determined per Week (Wk) 8 data from OCTAVE Induction 1/2, or Wk 52 data (for completers) or early termination data from OCTAVE Sustain. Pts in remission (total Mayo score ≤2, no individual subscore >1, rectal bleeding subscore of 0) at Wk 52 of OCTAVE Sustain (per central read) were assigned to tofacitinib 5 mg twice daily (BID) in the OLE study; all others were assigned to 10 mg BID. At Month 2, all pts underwent endoscopy; induction nonresponders were mandated to withdraw if they did not show a clinical response. Binary efficacy endpoints were derived from Mayo score per local read. Results: Of 944 pts who received ≥1 dose of study drug (for up to 4.9 years), 326 (34.5%) discontinued due to insufficient clinical response, and 65 (6.9%) due to adverse events (AEs) excl. worsening UC. Serious and severe AEs occurred in 14.8% and 9.9% of pts, respectively. Serious infections were reported in 5 (2.9%) and 23 (3.0%) pts, herpes zoster in 10 (5.7%) and 47 (6.1%) pts, and major adverse cardiovascular events in 1 (0.6%) and 1 (0.1%) pts, in the 5 and 10 mg BID groups, respectively. Malignancies excl. nonmelanoma skin cancer (NMSC) were reported in 1 (0.6%) and 12 (1.6%) pts, and NMSC in 4 (2.3%) and 9 (1.2%) pts, in the 5 and 10 mg BID groups, respectively (no clustering of malignancy type). No new safety risks were identified. Available efficacy data up to Month 24 are shown (Table). Conclusion: In pts with moderate to severe UC in the OLE study, no new safety risks emerged compared with those observed with tofacitinib in rheumatoid arthritis. Efficacy data from the OLE study continue to support long-term efficacy with tofacitinib 5 or 10 mg BID up to 24 months beyond Wk 52 of OCTAVE Sustain.571 Figure 1 No Caption available.

Tofacitinib Induction Therapy Reduces Symptoms Within 3 Days for Patients With Ulcerative Colitis

Tofacitinib is an oral, small molecule inhibitor of JAK for the treatment of ulcerative colitis (UC). We evaluated the onset of symptom improvement in post-hoc analyses of data from 2 phase 3 trials of induction therapy with tofacitinib in patients with UC (OCTAVE Induction 1 and 2). The studies comprised patients with moderate to severe active UC who were intolerant to, orfailed by previous treatment with, corticosteroids, thiopurines, and/or tumor necrosis factor(TNF) antagonists. Patients received tofacitinib (10 mg twice daily, n = 905) or placebo (n = 234) for 8 weeks. Daily Mayo stool frequency and rectal bleeding subscores were calculated using diary data from the first 15 days of therapy. We analyzed data from subgroups including failure of prior anti-TNF therapy, baseline corticosteroid use, and baseline serum levels of C-reactive protein. Mean changes were significantly greater in patients given tofacitinib vs placebo in reductions from baseline stool frequency subscore (tofacitinib: -0.27 vs placebo: -0.11; P < .01), total number of daily bowel movements (-1.06 vs -0.27; P < .0001), and rectal bleeding subscore (-0.30 vs -0.14; P < .01) by day 3. Compared with placebo, more tofacitinib-treated patients had reductions from baseline in stool frequency subscore (by ≥1 point for tofacitinib, 241/837, 28.8% vs placebo, 39/218, 17.9%) (P < .01) and rectal bleeding subscore (by ≥1 point for tofacitinib, 266/830, 32.0% vs placebo, 43/214, 20.1%) (P < .01) by day 3. A consistent effect of tofacitinib was observed in all subgroups. In a post-hoc analysis of data from phase 3 trials of induction therapy with tofacitinib in patients with UC, we found significant improvements in symptoms among patients given tofacitinib compared with placebo within 3 days. These findings indicate the rapid onset of effect of this drug in patients with UC. ClinicalTrials.gov no: NCT01465763 and NCT01458951.

In vitro and in vivo characterization of the JAK1 selectivity of upadacitinib (ABT-494)

BackgroundAnti-cytokine therapies such as adalimumab, tocilizumab, and the small molecule JAK inhibitor tofacitinib have proven that cytokines and their subsequent downstream signaling processes are important in the pathogenesis of rheumatoid arthritis. Tofacitinib, a pan-JAK inhibitor, is the first approved JAK inhibitor for the treatment of RA and has been shown to be effective in managing disease. However, in phase 2 dose-ranging studies tofacitinib was associated with dose-limiting tolerability and safety issues such as anemia. Upadacitinib (ABT-494) is a selective JAK1 inhibitor that was engineered to address the hypothesis that greater JAK1 selectivity over other JAK family members will translate into a more favorable benefit:risk profile. Upadacitinib selectively targets JAK1 dependent disease drivers such as IL-6 and IFNγ, while reducing effects on reticulocytes and natural killer (NK) cells, which potentially contributed to the tolerability issues of tofacitinib.MethodsStructure-based hypotheses were used to design the JAK1 selective inhibitor upadacitinib. JAK family selectivity was defined with in vitro assays including biochemical assessments, engineered cell lines, and cytokine stimulation. In vivo selectivity was defined by the efficacy of upadacitinib and tofacitinib in a rat adjuvant induced arthritis model, activity on reticulocyte deployment, and effect on circulating NK cells. The translation of the preclinical JAK1 selectivity was assessed in healthy volunteers using ex vivo stimulation with JAK-dependent cytokines.ResultsHere, we show the structural basis for the JAK1 selectivity of upadacitinib, along with the in vitro JAK family selectivity profile and subsequent in vivo physiological consequences. Upadacitinib is ~ 60 fold selective for JAK1 over JAK2, and > 100 fold selective over JAK3 in cellular assays. While both upadacitinib and tofacitinib demonstrated efficacy in a rat model of arthritis, the increased selectivity of upadacitinib for JAK1 resulted in a reduced effect on reticulocyte deployment and NK cell depletion relative to efficacy. Ex vivo pharmacodynamic data obtained from Phase I healthy volunteers confirmed the JAK1 selectivity of upadactinib in a clinical setting.ConclusionsThe data presented here highlight the JAK1 selectivity of upadacinitinib and supports its use as an effective therapy for the treatment of RA with the potential for an improved benefit:risk profile.

Abstract 680: FLLL12 is a small molecule JAK2 inhibitor that inhibits JAK-STAT3 pathway in head and neck cancer

Abstract Purpose: We have recently reported that FLLL12, a synthetic curcumin analog, induces apoptosis of lung cancer cells through a death receptor (DR) 5-dependent pathway and in squamous cell carcinoma of head and neck (SCCHN) by modifying multiple Bcl-2 proteins. However, the direct molecular target (receptor) of FLLL12 is unknown. The purpose of the current study is to identify the receptor of FLLL12. Methods: Computer-aided molecular docking was used to predict molecular interaction. Isothermal titration calorimetry and thermal shift assays were used to confirm molecular interactions in a cell free system. SCCHN cell lines were used to study the effect of this interaction on JAK-STAT3 pathway. Protein expression levels were measured by Western blotting. Results: Computer-aided molecular docking modeling of FLLL12 and JAK2 (PDB code: 5CF5) predicted that FLLL12 fit well into the JAK2 catalytic pocket. Although curcumin also fit into the JAK2 catalytic pocket, the binding sites were different for FLLL12 and curcumin. Docking score for FLLL12, natural ligand and curcumin were -7.2, -12.1 and -6.9, respectively. FLLL12 also docked into the STAT3 catalytic pocket (PDB code: 5AX3). However, the docking score was worse than those for natural ligand and curcumin (-5.1, -7.3 and -7.4 respectively). We confirmed that FLLL12 interacted with JAK2 in a cell free system using recombinant JAK2. Isothermal titration calorimetry assay revealed one binding site for both FLLL12 and the FDA-approved JAK inhibitor ruxolitinib. The Ka values were 3.84E6±1.03E5 and 2.31E7±6.78E6 M-1, respectively. FLLL12 and JAK2 interactions were further confirmed by thermal shift assay. Kd values were 1.12±0.14 μM and 2.24 ±0.18 μM for ruxolitinib and FLLL12, respectively. Two hour pretreatment with FLLL12 also inhibited IL-6 induced phosphorylation of JAK2 and STAT3. Finally, FLLL12 strongly inhibited constitutively active STAT3 phosphorylation in SCCHN cell lines, a downstream effector of JAK. Conclusions: Our results strongly suggest that FLLL12 is a novel small molecule inhibitor for JAK2 and FLLL12-JAK2 interaction inhibits IL-6-induced as well as constitutively active STAT3 phosphorylation, thus has great promise for cancer prevention and therapy. Grant Support: Start-up fund from Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University and from Department of Pharmaceutical Sciences and Research, Marshall University. Citation Format: ARM Ruhul Amin, ASM Anisuzzaman, Abu B. Siddique, James R. Fuchs. FLLL12 is a small molecule JAK2 inhibitor that inhibits JAK-STAT3 pathway in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 680.

Stattic inhibits RANKL-mediated osteoclastogenesis by suppressing activation of STAT3 and NF-κB pathways

Tofacitinib, a small molecule JAK inhibitor, has been widely used to reduce inflammation and inhibit progression of bone destruction in rheumatoid arthritis. STAT3, a downstream signaling molecule of JAK, plays a key role in the activation of signaling in response to inflammatory cytokines. Thus, targeting STAT3 may be an inspiring strategy for treating osteoclast-related diseases such as rheumatoid arthritis. In this study, we first investigated the effects of Stattic, a STAT3 inhibitor, on receptor activator of NF-κB ligand (RANKL)-mediated osteoclastogenesis. Stattic inhibited osteoclast differentiation and bone resorption in RANKL-induced RAW264.7 cells in a dose-dependent manner. Stattic also suppressed RANKL-induced upregulation of osteoclast-related genes tartrate-resistant acid phosphatase, matrix metalloproteinase 9, cathepsin K, RANK, tumor necrosis factor receptor-associated factor 6, and osteoclast-associated receptor in RAW264.7 cells. Moreover, Stattic exhibited an inhibitory effect on cell proliferation and cell cycle progression at higher dosages. At the molecular level, Stattic inhibited RANKL-induced activation of STAT3 and NF-κB pathways, without significantly affecting MAPK signaling. In addition, Stattic inhibited RANKL-induced expression of osteoclast-related transcription factors c-Fos and NFATc1. Importantly, Stattic also prevented bone loss caused by ovariectomy. Together, our data confirm that Stattic restricts osteoclastogenesis and bone loss by disturbing RANKL-induced STAT3 and NF-κB signaling. Thus, Stattic represents a novel type of osteoclast inhibitor that could be useful for conditions such as osteoporosis and rheumatoid arthritis.

An Open-Label Pilot Study to Evaluate the Efficacy of Tofacitinib in Moderate to Severe Patch-Type Alopecia Areata, Totalis, and Universalis

Alopecia areata (AA) is a common autoimmune disease with a lifetime risk of ∼2%. In AA, the immune system targets the hair follicle, resulting in clinical hair loss. The prognosis of AA is unpredictable, and currently there is no definitive treatment. Our previous whole genome expression studies identified active immune circuits in AA lesions, including common γ-chain cytokine and IFN pathways. Because these pathways are mediated through JAK kinases, we prioritized clinical exploration of small molecule JAK inhibitors. In preclinical trials in mice, tofacitinib successfully prevented AA development and reversed established disease. In our tofacitinib trial in 12 patients with moderate to severe AA, 11 patients completed a full course of treatment with minimal adverse events. Following limited response to the initial dose (5 mg b.i.d.), the dose was escalated (10 mg b.i.d.) for nonresponding subjects. Eight of 12 patients demonstrated ≥50% hair regrowth, while three patients demonstrated <50% hair regrowth, as measured by Severity in Alopecia Tool scoring. One patient demonstrated no regrowth. Gene expression profiles and Alopecia Areata Disease Activity Index scores correlated with clinical response. Our open-label studies of ruxolitinib and tofacitinib have shown dramatic clinical responses in moderate to severe AA, providing strong rationale for larger clinical trials using JAK inhibitors in AA. ClinicalTrials.gov ID NCT02299297.

Symptomatic Improvement Within 3 Days With Tofacitinib Induction Therapy in Patients With Ulcerative Colitis: Results From OCTAVE Induction 1 and 2

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for ulcerative colitis (UC). Two Phase (P) 3 UC induction trials demonstrated the efficacy of tofacitinib 10 mg twice daily (BID) at Week 2 in partial Mayo score (PMS).1 We evaluated the onset of symptomatic improvement in a post-hoc analysis of diary data. Methods: OCTAVE Induction 1 (NCT01465763) & 2 (NCT01458951) were identical, randomized, placebo-controlled P3 trials in adult patients (pts) with moderately to severely active UC who had failed or were intolerant to steroids, immunomodulators, or tumor necrosis factor inhibitors. Pts received placebo (N=234) or tofacitinib 10 mg BID (N=905) for 8 weeks. Pooled data for OCTAVE Induction 1 & 2 are presented. At screening, pts electronically recorded their normal number of stools per day. During the study, pts continued a daily diary recording their number of bowel movements per day and the presence and description of any blood in the stools. Daily Mayo stool frequency (SF) and rectal bleeding (RB) subscores were calculated for each pt (subscore range of 0-3) based on that day's diary data for the first 15 days of therapy. Least squares mean (LSM) changes from baseline in SF and RB subscores were compared using a linear mixed-effects model. Binary endpoints were compared using stratified Cochran-Mantel-Haenszel chi-square test based on observed data. Results: At baseline for both the placebo and tofacitinib groups, mean SF Mayo subscore was 2.5 and mean RB Mayo subscore was 1.6. Significant improvements from baseline were observed with tofacitinib vs placebo at Day 3 for SF and RB subscores, and were maintained through to Day 15 (Figure). At Day 15, LSM changes from baseline for SF and RB subscores with tofacitinib were -0.74 and -0.76, respectively, vs -0.35 and -0.44, respectively, with placebo (P < 0.0001). At Day 15, 14.6% of tofacitinib-treated pts had an SF score of 0 vs 8.0% with placebo (P < 0.01), and 41.2% of tofacitinib-treated pts had an RB subscore of 0 vs 21.1% with placebo (P < 0.0001).FigureConclusion: In these two P3 induction studies of tofacitinib for pts with moderately to severely active UC, significant symptomatic improvements were observed with tofacitinib vs placebo as early as Day 3. These results support rapid onset of tofacitinib efficacy previously reported based on improvement in PMS.1 Funded by Pfizer Inc.

An Updated Analysis of In vitro Cytokine Inhibition Profiles of a Number of Janus Kinase Inhibitors at Clinically Meaningful Concentrations

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for ulcerative colitis. A number of JAK inhibitors are being investigated in the treatment of inflammatory diseases, eg tofacitinib, baricitinib and filgotinib (GLPG0634), but it is unclear how their JAK-dependent cytokine inhibition profiles differ. Methods: We used an integrated modeling approach (using knowledge of in vitro whole cell JAK inhibition potencies and plasma pharmacokinetics [PK]) to understand cytokine inhibition profiles for clinically meaningful doses of JAK inhibitors. IC50 values for interferon (IFN)α, IFNγ, interleukin (IL)-6, IL-15, IL-21, IL-10, IL-27, IL-12, IL-23 and erythropoietin (EPO) signaling of tofacitinib, baricitinib, and filgotinib and metabolite were measured in total lymphocytes, CD34+ cells (EPO) and CD3+ cells (IL-6) in human whole blood by a flow cytometry-based assay. Human daily average plasma concentrations (Cav) for tofacitinib (5 mg BID; 68 nM), baricitinib (4 mg QD; 27 nM), and filgotinib (200 mg QD; 474 nM) and metabolite (7438 nM) were converted to unbound values with measured plasma fraction unbound (fu) values of 0.61, 0.59, 0.49 and 0.42, respectively. Whole blood IC50 values were converted to unbound values with measured blood/plasma ratios of 1.2, 1.3, 1.2 and 1.1, respectively, and fu values. Percentage levels of cytokine inhibition were determined at clinically meaningful doses. Results: Tofacitinib and baricitinib were overall more potent inhibitors than filgotinib and metabolite (data not shown). Combining potency with clinical PK showed a similar cytokine inhibition profile (Table), with some exceptions. The greater level of IL-6 inhibition noted with filgotinib and metabolite did not translate into greater C-reactive protein reductions vs tofacitinib1 and baricitinib.2 The minor difference in IL-15 inhibition between tofacitinib1 and baricitinib3 did not translate into a clinically meaningful difference in natural killer cells.Table: Table. Overall % cytokine inhibition in the context of clinical concentrations for various JAK inhibitorsConclusion: Cytokine inhibition for a number of JAK inhibitors was generally similar when efficacious doses are considered, with only minor differences in percentage cytokine inhibition, suggesting limited differentiation of these JAK inhibitors based on JAK pharmacology. Funded by Pfizer Inc.

Efficacy of Tofacitinib in Patients With Ulcerative Colitis by Prior Tumor Necrosis Factor Inhibitor Treatment Status: Results From OCTAVE Induction and Maintenance Studies

Introduction: Many patients (pts) with ulcerative colitis (UC) treated with tumor necrosis factor inhibitors (TNFi) do not respond to initial therapy (primary non-response [NR]) or experience loss of response over time (secondary NR).1 Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for UC. Methods: Pts in OCTAVE Induction 1 & 2 with moderately to severely active UC who failed or were intolerant to steroids, immunomodulators or TNFi received placebo (PBO; N=234) or tofacitinib 10 mg twice daily (BID; N=905) for 8 weeks (wks). In OCTAVE Sustain, induction study clinical responders were rerandomized to PBO (N=198), tofacitinib 5 mg BID (N=198) or 10 mg BID (N=197) for 52 wks. Corticosteroids were allowed in OCTAVE Induction; corticosteroid taper was mandatory in OCTAVE Sustain. Subgroup analyses by prior TNFi failure status were conducted for remission, mucosal healing and clinical response at Wk 8 (OCTAVE Induction; pooled data) and Wk 52 (OCTAVE Sustain), and sustained steroid-free remission among remitters at baseline of OCTAVE Sustain. Between-group treatment differences and 95% confidence intervals using the normal approximation were calculated, as well as p values based on chi-square test. Results: At Induction baseline, 51.7% of pts had failed TNFi (of whom 55.7% had primary NR, 39.2% secondary NR and 32.6% ≥2 failed TNFi). At Wk 8 of OCTAVE Induction, consistent treatment effects were observed with tofacitinib 10 mg BID vs PBO for all endpoints and categories of prior TNFi treatment status (Table). Observed treatment effects for remission, mucosal healing and clinical response were similar for pts with and without prior TNFi failure, and for pts who failed 1 TNFi and who failed ≥2 TNFi. In OCTAVE Sustain, treatment effects were observed at Wk 52 for 5 mg and 10 mg vs PBO for all endpoints and TNFi treatment categories. Treatment effects in OCTAVE Sustain were generally greater for 10 mg BID vs 5 mg BID, especially in pts with prior TNFi failure.Table: Table. Efficacy in OCTAVE Induction and OCTAVE Sustain Stratified by Prior TNFi Treatment StatusConclusion: Tofacitinib was efficacious vs PBO as induction and maintenance therapy, regardless of prior TNFi failure. Benefits over PBO were apparent even in the most refractory populations, including induction of remission in pts with primary NR, and pts who had failed ≥2 TNFi. Funded by Pfizer Inc. 1. Roda G et al. Clin Trans Gastroenterol 2016:e135.

Tofacitinib, an Oral Janus Kinase Inhibitor, in the Treatment of Ulcerative Colitis: Open-Label, Long-term Extension Study

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for ulcerative colitis (UC). The efficacy and safety of tofacitinib was demonstrated as induction and maintenance therapy in 3 Phase 3, randomized, placebo-controlled studies (OCTAVE Induction 1, NCT01465763; OCTAVE Induction 2, NCT01458951; OCTAVE Sustain, NCT01458574) in patients (pts) with moderate to severe UC.1 Methods: We present interim safety and efficacy data up to 3 yrs of treatment (as of July 8, 2016) from an ongoing Phase 3, multicenter, open-label, long-term extension study (OLE; NCT01470612) in pts who had completed or demonstrated treatment failure in OCTAVE Sustain, or who were non-responders after completing OCTAVE Induction 1 or 2. Pts in remission at Week 52 of OCTAVE Sustain received tofacitinib 5 mg twice daily (BID); all others received 10 mg BID. At Month 2, all pts underwent endoscopy, and non-responders from induction were mandated to withdraw if no evidence of clinical response was shown. Remission was defined by a Mayo score ≤2 with no individual subscore >1, and rectal bleeding subscore of 0. Binary efficacy endpoints were derived from Mayo score, based on local-read endoscopic subscore. Results: 914 pts (5 mg BID, N=156 [17.1%]; 10 mg BID, N=758 [82.9%]) received ≥1 dose of study drug; 381 pts (41.7%) discontinued. The most frequent AE leading to discontinuation was worsening of UC. Serious and severe AEs occurred in 10.4% and 7.8% of pts, respectively (dose groups combined). The most frequent treatment-emergent AEs by system organ classes (both doses) were ‘infections/infestations' and ‘gastrointestinal disorders', and by preferred term were ‘nasopharyngitis' and ‘worsening of UC'. Serious infections AEs were reported in 4 (2.6%) and 14 (1.8%) pts with 5 and 10 mg BID, respectively. Malignancies excl. NMSC were reported in 9 (1.2%) pts in the 10 mg BID group (no clustering of malignancy type); none were reported in the 5 mg BID group. No new safety risks were identified. Data ‘as observed' for remission and mucosal healing at Months 2, 12, and 24 are shown.Table: Table. Summary of safety and efficacy in the OLE studyConclusion: In pts with moderate to severe UC who remained in the OLE study, no new safety concerns emerged compared with those observed with tofacitinib in rheumatoid arthritis. Efficacy results from this OLE study support sustained efficacy with tofacitinib 5 and 10 mg BID. Funded by Pfizer Inc.

Tofacitinib for Maintenance Therapy in Patients With Active Ulcerative Colitis in the Phase 3 OCTAVE Sustain Trial: Results by Local and Central Endoscopic Assessments

Introduction: Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for ulcerative colitis (UC). A Phase 3, randomized, double-blind, placebo-controlled maintenance study (OCTAVE Sustain, NCT01458574) demonstrated the efficacy of tofacitinib 5 and 10 mg twice daily (BID) vs placebo (PBO) in patients (pts) with moderate to severe UC.1 Methods: We describe clinical efficacy endpoints assessed by local endoscopy readings and previously reported results assessed by central readings, to compare local vs central readings in the assessment of tofacitinib efficacy. Pts who completed OCTAVE Induction 1 (NCT01465763) or OCTAVE Induction 2 (NCT01458951) studies and achieved clinical response (decrease of baseline Mayo score ≥3 points and ≥30%, with decrease in rectal bleeding subscore ≥1 or absolute rectal bleeding subscore ≤1) were eligible to participate in OCTAVE Sustain. 593 pts were randomized (1:1:1) to PBO, tofacitinib 5 or 10 mg BID for 53 weeks (wks). Pts' eligibility was assessed based on central endoscopic reading. Pts were permitted concomitant treatment with oral corticosteroids; tapering was mandatory from baseline. Concomitant treatment with immunosuppressants and biologics was prohibited. Efficacy endpoints at Wk 52 included remission (primary endpoint: Mayo score ≤2, no subscore >1 and rectal bleeding subscore of 0), mucosal healing (Mayo endoscopic subscore ≤1) and clinical response. Results: At Wk 52, remission was achieved by significantly more pts with both tofacitinib doses vs PBO, as demonstrated by both central and local endoscopic readings, and similar results were observed with mucosal healing, clinical response and sustained steroid-free remission among pts in remission at baseline. Efficacy assessed by local endoscopic readings was numerically greater than central readings, except for clinical response. There was good agreement between locally and centrally read endoscopic subscores (kappa=0.6 [95% CI 0.5, 0.6]). Conclusion: Efficacy assessed by local endoscopic readings was numerically greater than efficacy assessed by central readings for tofacitinib 5 and 10 mg BID vs PBO. Overall, local endoscopic readings were consistent with central readings. Both methods demonstrated that both tofacitinib doses were more effective than PBO for maintenance therapy in pts with moderately to severely active UC. Funded by Pfizer Inc.Table: Table. Summary of efficacy endpoints at Wk 52, determined by local and central reading

Pregnancy Outcomes in the Tofacitinib Ulcerative Colitis OCTAVE Studies

Introduction: Compared with controls, pregnant women with ulcerative colitis (UC) are at a higher risk of adverse outcomes incl. spontaneous abortion, preterm birth and low birth weight.1,2 Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for UC. Tofacitinib is feticidal and teratogenic in rats and rabbits at exposures 146 and 13 times, respectively, the human dose of 5 mg twice daily (BID). There are no adequate and well-controlled studies of tofacitinib in pregnant women. Methods: We report pregnancy outcomes from 3 randomized, placebo (PBO)-controlled studies (OCTAVE Induction 1, NCT01465763; OCTAVE Induction 2, NCT01458951; OCTAVE Sustain, NCT01458574) and 1 ongoing open-label extension study (OCTAVE long-term study, NCT01470612) of tofacitinib monotherapy in patients (pts) with moderate to severe UC.3 Pregnancy outcomes following maternal or paternal exposure to tofacitinib 5 or 10 mg BID were identified from Pfizer's internal safety database up to March 23, 2017. Trial protocols required use of highly effective contraception for women of childbearing potential, and for the study drug to be discontinued in any female pts that became pregnant. Results: 1139 unique pts (incl. PBO) enrolled in the OCTAVE trials; 296 were women of childbearing age. There were 25 pregnancies reported with exposure to tofacitinib. Of these, 11 were cases of maternal exposure, all during the 1st trimester, including: 2 (18.2%) spontaneous abortions (5 mg BID, n=1; 10 mg BID, n=1), 2 (18.2%) medical terminations (both 10 mg BID), 4 (36.4%) healthy newborns (all 10 mg BID) and 3 (27.3%) lost to follow up (all 10 mg BID). Of the 14 cases of paternal exposure, 11 (78.6%) were healthy newborns (5 mg BID, n=2; 10 mg BID, n=9) and 3 (21.4%) were pending/lost to follow up (5 mg BID, n=1; 10 mg BID, n=2). There were no cases of fetal death or congenital malformation. Conclusion: Based on limited data and follow up available, pregnancy and newborn outcomes among pts with UC with prenatal (maternal/paternal) exposure to tofacitinib appear to be similar to those reported for the UC population and those previously reported in pts with rheumatoid arthritis and psoriasis.4 Larger long-term follow-up studies are needed to examine safety of tofacitinib during pregnancy. Funded by Pfizer Inc.Table: Table. Summary of pregnancy outcomes in the OCTAVE program

MPN: Next Questions: Potential New Targets for MPN beside JAK2

The discovery of activating JAK2 mutations changed the landscape of MPN treatment dramatically, quickly prompting the development of small molecule inhibitors of JAK2. First-generation JAK inhibitors are ATP-competitive antagonists of the JAK kinase domain and each inhibits the activity of one or more JAK isoforms to different degrees. Ruxolitinib, a dual JAK1/2 inhibitor, was the first of its class to be approved for treatment of primary myelofibrosis (PMF) and post-PV/ET MF. Treatment with ruxolitinib has been shown to reduce spleen size and alleviate systemic symptoms of MF1, although the myelosuppressive effects of ruxolitinib, particularly anemia, are problematic for MF patients.

Non-cell-autonomous activation of IL-6/STAT3 signaling mediates FGF19-driven hepatocarcinogenesis

Hepatocellular carcinoma (HCC), a primary malignancy of the liver, is the second leading cause of cancer mortality worldwide. Fibroblast Growth Factor 19 (FGF19) is one of the most frequently amplified genes in HCC patients. Moreover, mice expressing an FGF19 transgene have been shown to develop HCC. However, the downstream signalling pathways that mediate FGF19-dependent tumorigenesis remain to be deciphered. Here we show that FGF19 triggers a previously unsuspected, non-cell-autonomous program to activate STAT3 signalling in hepatocytes through IL-6 produced in the liver microenvironment. We show that the hepatocyte-specific deletion of Stat3, genetic ablation of Il6, treatment with a neutralizing anti-IL-6 antibody or administration of a small-molecule JAK inhibitor, abolishes FGF19-induced tumorigenesis, while the regulatory functions of FGF19 in bile acid, glucose and energy metabolism remain intact. Collectively, these data reveal a key role for the IL-6/STAT3 axis in potentiating FGF19-driven HCC in mice, a finding which may have translational relevance in HCC pathogenesis.