Selective JAK1 Inhibitor Research Articles

Disseminated Histoplasmosis in a Patient with Myelofibrosis on Ruxolitinib: A Case Report and Review of the Literature on Ruxolitinib-Associated Invasive Fungal Infections.

Ruxolitinib, a selective inhibitor of Janus kinases, is a standard treatment for intermediate/high-risk myelofibrosis (MF) but is associated with a predisposition to opportunistic infections, especially herpes zoster. However, the incidence and characteristics of invasive fungal infections (IFIs) in these patients remain uncertain. In this report, we present the case of a 59-year-old woman with MF who developed disseminated histoplasmosis after seven months of ruxolitinib use. The patient clinically improved after ten weeks of combined amphotericin B and azole therapy, and ruxolitinib was discontinued. Later, the patient received fedratinib, a relatively JAK2-selective inhibitor, without relapse of histoplasmosis. We also reviewed the literature on published cases of proven IFIs in patients with MF who received ruxolitinib. Including ours, we identified 28 such cases, most commonly due to Cryptococcus species (46%). IFIs were most commonly disseminated (39%), followed by localized lung (21%) infections. Although uncommon, a high index of suspicion for opportunistic IFIs is needed in patients receiving JAK inhibitors. Furthermore, the paucity of data regarding the optimal management of IFIs in patients treated with JAK inhibitors underscore the need for well-designed studies to evaluate the epidemiology, pathobiology, early diagnosis, and multimodal therapy of IFIs in patients with hematological malignancies receiving targeted therapies.

Baricitinib Demonstrates Rapid Action Within Just 2 Months of Treatment in Severe and Unresponsive Alopecia Areata: A Case Report

Alopecia areata (AA) is a form of nonscarring alopecia, and is the most common immune-mediated cause of hair loss worldwide. Numerous therapeutic schedules available as off-label options have demonstrated only limited results. However, in 2022, baricitinib, a selective JAK1 and JAK2 inhibitor, was approved as an oral administered systemic therapy for severe AA. Based on this, the authors used it in a 21-year-old White female, who presented with a 15-year history of severe AA (Severity of Alopecia Tool score [SALT]: score 88) and immense psychological burden. After laboratory examinations within normal limits, baricitinib was administered as monotherapy with a 4 mg daily dosage. The severe AA improved rapidly after the first month, and resulted in total hair restoration just after the second month under baricitinib treatment. Besides clinical improvement, SALT score impressively reduced to 30 and 10, respectively, in 2 and 6 months. Six months later, the patient is keeping up the same treatment with no sign of relapse, and is on a 2-month follow-up schedule. In the authors’ patient, almost total hair restoration was achieved in less than 3 months of treatment, which strongly advocates for the addition of baricitinib in the dermatologic armament as a safe, adequate, and fast AA remedy.

Abstract 4998: Pralsetinib induces opportunistic infection in RET fusion-positive NSCLC patients via inhibition of IL-2 production by blocking Jak3-Stat5 activation

Abstract Background: Oncogenic alteration in RET, representing 1-2% of non-small cell lung cancer (NSCLC), is one of the important targets. Pralsetinib is a selective RET inhibitor that targets RET fusions. We present a case series on opportunistic infections and the mechanism of immunosuppression. Methods: From October 2021 to March 2022, we administered pralsetinib to a total of 15 patients with NSCLC harboring RET fusion. We retrospectively analyzed the clinical efficacy and adverse event related to pralsetinib. To investigate the potential impact of pralsetinib on T-cells, we examined cytokine release from Jurkat T (JT) cells after pralsetinib treatment. To test if Stat5 bind to IL-2 promotor, we conducted Chromatin Immunoprecipitation (ChIP). Results: Out of a total of 18 patients with measurable disease, 14 patients (93%) achieved a partial response. With the median follow-up duration of 8.7 months, four cases of opportunistic infections were occurred. Notably, three patients (16.6%) experienced invasive pulmonary aspergillosis, and one patient (5.5%) experienced cytomegalovirus pneumonia. To mimic conditions akin to activated T cells, we treated JT cells with PMA and ionomycin, inducing IL-2 release through the binding of NFAT, AP-1, and NF-κB to the IL-2 promoter. Following approximately two weeks of pralsetinib treatment, a decrease of IL-2 releases, the inhibition of Jak3 and the reduced-expression of JunB and c-Jun was observed. Additionally, to investigate the direct correlation between Jak3 and IL-2 release, JT cells were treated with ritlecitinib, the Jak3-selective inhibitor, for approximately two weeks. Like pralsetinib, a reduction in IL-2 release was observed. Furthermore, based on the evidence that Stat5 inhibition leads to reduced IL-2 release, we also showed that the transcription factor Stat5, a direct downstream signaling component of Jak3, binds to the IL-2 promoter during the activation of Jurkat T cells. Conclusion: Pralsetinib inhibits additional IL-2 production by blocking Jak3/Stat5 activation triggered by IL-2 released during early T cell activation. As a result, the Jak3 inhibition induced by pralsetinib leads to a decrease in JunB/c-Jun expression and blocking Stat5 activation by reducing IL-2 release. Consequently, Pralsetinib-related opportunistic infections may be caused by inhibition of the JAK3 pathway and IL-2 release. Citation Format: Shinkyo Yoon, Hyun-Min Ryu, Sang-We Kim, Kang-Seo Park, Dae Ho Lee. Pralsetinib induces opportunistic infection in RET fusion-positive NSCLC patients via inhibition of IL-2 production by blocking Jak3-Stat5 activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4998.

JAK-inhibitors in the therapy of comorbid diseases – atopic dermatitis and alopecia areata: literature review and experience of clinical practice

Atopic dermatitis (AtD) is currently considered as a systemic disease due to the fact, that disorders of innate and adaptive immune response, especially pronounced in severe course, are manifested not only in skin inflammation, but also can be realized in the development of other chronic diseases, including autoimmune profile. One of the autoimmune comorbid diseases in AtD is alopecia areata (AA), which is confirmed by epidemiologic data, clinical features and identification of common immune links of pathogenesis in the case of association of these diseases. Janus-kinase inhibitors, which represent a new class of targeted synthetic basic anti-inflammatory drugs, are currently the main pathogenetic treatments for severe forms of AtD and AA. Acting on several immune axes, these drugs selectively and reversibly modulate the signaling activity of key inflammatory cytokines, which makes them the most promising strategy for systemic therapy of these dermatoses, including in cases of their combination. The article covers the review of pathophysiology and application of first and second generation JAK-inhibitors in AtD and AA, including the analysis of their efficacy in the simultaneous presence of these pathological conditions. We present own observations of two patients with severe comorbid conditions AtD and AA, treated with the JAK-inhibitors abrocitinib and upadacitinib. These examples confirm the efficacy of Janus-kinase inhibitors in AtD and AA in real clinical practice and describe the experience of switching from one JAK-inhibitor of the first generation to another, selective JAK-inhibitor, as well as the effect of of these drugs on the course of both pathologies. Taking into account the necessity of long-term use of JAK-inhibitors, further study of their long-term efficacy and safety remains relevant.

Selective JAK-Inhibitors in Spondyloarthritis.

As our research interest and knowledge increases in the field of Spondyloarthritis, new aspects also emerge as regards to their therapeutic approach. JAK inhibitors (JAKi) are a relatively new treatment option, aiming molecules in the JAK-STAT pathway, which has a leading role in the pathophysiology of both Psoriatic Arthritis and Axial Spondyloarthritis. JAKi exhibit different selectivity towards the four different members of the JAK family (namely JAK1, JAK2, JAK3, and TYK2), possibly reflecting different efficacy and safety profile. Although knowledge is more consolidated for rheumatoid arthritis in which JAKi are being used for more than 10 years, data are still accumulating for PsA/SpA. In this review we aim to present and assess current knowledge about the efficacy of JAKi (with a focus on selective JAKi) in the treatment of patients with SpA and evaluate their safety profile as some concerns may arise around this therapeutic option.

Upadacitinib for the treatment of moderate-to-severe Crohn's disease.

Despite an increasing number of therapies for Crohn's disease (CD), half of patients do not respond to initial treatment or lose response over time, highlighting the need for novel therapies. Inhibition of Janus kinases (JAKs) hasemerged as an important therapeutic target for CD. Upadacitinib is an orally administered selective JAK1 inhibitor, which is effective for the induction and maintenance of remission in moderately-to-severely active CD, including in patients with prior failure of biological therapy. Nonselective JAK inhibition has been associated with thromboembolic disease, cardiovascular eventsand malignancy in patients older than 50years with rheumatoid arthritis and pre-existing cardiovascular risk factors, which should be considered upon prescription. Upadacitinib is the first and currently only oral advanced therapy for CD.

DISEASE MODELING IN INFLAMMATORY BOWEL DISEASE (IBD) USING PATIENT-DERIVED EXPLANTS (PDE) REVEALS CHEMOKINES AS A RELEVANT TARGET OF JAK INHIBITION

Abstract Despite a recent explosion of approved drugs for IBD that primarily target cytokines and T-cell trafficking, therapeutic response rates remain low (30-50 %), underscoring the need for more efficacious treatments with fewer side effects. From a drug development perspective, it takes over 10 years for a new drug to reach the market with >90% attrition rates. The realization that drug testing in animal models does not always translate to humans, particularly for complex diseases of high heterogeneity like IBD, leaving a significant gap in pre-clinical drug evaluation. Technologies such as organoids or “gut on a chip” attempted to fulfill this gap, but among their limitations are lack of tissue complexity and an externally induced, and often biased, “disease state” that fails to capture patient heterogeneity and underlying disease mechanisms. We developed a Therapeutic Response Predictor Assay for IBD (TheRPA _ibd) which is based on establishing short term explant cultures from the patient’s diseased tissue (PDE). PDEs can be treated with various candidate drugs or their combinations and inform whether an individual patient is a responder or non-responder to the particular treatment. TheRPA_ibd has been clinically validated for anti-TNF with a predictive accuracy of 0.87 (p<0.0001). TheRPA_ibd was used to comparatively evaluate 6 JAK inhibitors (JAKi) with different JAK isoform selectivity (tofacitinib, baricitinib, upadacitinib, ritlecitinib, filgotinib, and peficitinib). PDEs were derived from mucosal inflamed biopsies obtained during colonoscopy or surgical resection (26 CD/11 UC). JAKi responses were evaluated using targeted and bulk gene expression, antibody arrays and multiplex ELISA. Our analysis, in addition to previously described cytokines, identified several chemokines as downstream targets of JAK inhibition: CXCL1; CXCL2; CXCL3; CXCL5; CXCL8; CXCL9; CXCL10; CXCL11; CXCL16; CCL10; CCL20. Of clinical importance, interrogation of publicly available gene expression IBD datasets confirmed a robust dysregulation of those targets in both UC and CD. Such findings open new avenues for exploring chemokine-driven pathways as potential therapeutic targets in IBD and potentially additional inflammatory conditions. From a mechanistic perspective, JAK1 or JAK3 selective inhibitors appeared to lack broader cytokine and chemokine inhibition compared to pan-JAKi. Notably, as a target, TYK2 was found to be critical for maximizing the anti-inflammatory effects of JAKi. The PDE-based assay (TheRPA) not only enables selection of patient-tailored treatments but also as a “clinical trial in a dish” platform can efficiently contribute to candidate drug de-risking and prioritization. As a proof of concept, using this technology we have been able to demonstrate efficacy in CD of certain JAK inhibitors prior to their FDA approval for this indication.

P716 Efficacy and safety of upadacitinib during induction in Crohn’s disease: Real-world experience

Abstract Background Upadacitinib is a selective JAK1 inhibitor that has recently been approved for treatment of moderate-severe Crohn’s disease, with Phase III clinical trials showing positive efficacy and safety profiles. Our aim was to evaluate the real-world experience of upadacitinib in a refractory cohort of Canadian patients with Crohn’s disease. Methods This was a two-centre retrospective study looking at 12-week induction data for patients with active Crohn’s disease from McGill University Health Centre and Hamilton Health Sciences. The primary outcome was clinical remission at 12 weeks, with secondary outcomes including clinical response, biochemical remission, and biochemical response. Clinical remission was defined as a Harvey-Bradshaw index (HBI) < 5. Clinical response was defined as an HBI reduction of ≥ 3. Biochemical remission was defined as a c-reactive protein (CRP) < 5 mg/L and/or fecal calprotectin (FCP) < 250 μg/g. Biochemical response was defined as a reduction of CRP or fecal calprotectin by 50% from baseline. These parameters were all evaluated at 8 and 12 weeks. Adverse events were summarized for patients who had follow up data available and included in the efficacy analysis. Results There were 28 patients who were treated in total, all of which had multiple biologic treatment failures. Baseline median age was 37, median HBI was 9, median CRP was 9.41 mg/L, and median FCP was 580 μg/g. The median disease duration was 13.5 years. Four patients discontinued upadacitinib due to no response or side effects. For all available data including patients who discontinued upadacitinib, clinical remission was achieved at 12 weeks in eight patients (8/11, 72.7%). Clinical response was achieved in eight patients (8/11, 72.7%), biochemical remission was achieved in four patients (4/11, 36.4%), and biochemical response was achieved in six patients (6/11, 54.6%). Of those that were initially on steroids (n=5), four patients (4/5, 80.0%) were able to wean off steroids and achieved a steroid-free clinical or biochemical response at 12 weeks. Of those who had previously been on off-label tofacitinib (n=5), clinical follow-up data was available for three patients at the end of the 12-week induction period. Two patients achieved clinical remission (2/3, 66.7%) and three patients had a clinical response (3/3, 100%). Among 13 patients with follow-up data, adverse events were observed in three patients (3/13, 23.1%), with two having non-serious infections (2/13, 15.4%) and one having fevers of unknown origin (1/13, 7.69%). Conclusion This real-world multicentre Canadian induction study shows favourable efficacy and tolerability of upadacitinib in refractory active Crohn’s disease.

P590 Use of upadacitinib in Refractory Paediatric Inflammatory Bowel Diseasein: A Single-Center Cohort Study

Abstract Background Upadacitinib (UPA) is a novel selective JAK-1 inhibitor that has demonstrated efficacy in the treatment of ulcerative colitis (UC) and Crohn's disease (CD) and has received regulatory approval in adults only. Current data on the efficacy of this drug in children are limited. We report our experience in the treatment of pediatric patients with UC and CD with failure of immunosuppressive and biologic therapies. The aim of this study was to evaluate short-term effectiveness and safety UPA therapy in children with IBD. Methods Disease activity was monitored using clinical PUCAI/PCDAI scores, faecal calprotectin (FC), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), platelet. Hemoglobin (Hb), leukocyte, total cholesterol, prothrombin time, INR - international normalized ratio, fibrinogen, activated partial thromboplastin time, thrombin time were evaluated to assess side effects. At baseline biochemical and previous therapies were recorded. Results We performed a prospective analysis of clinical outcomes from January to October 2023 during UPA therapy 11 children aged 12 to 16 years (4 boys, 7 girls) 3 with UС and 8 with CD. All 11 children had received immunosuppressive and biological therapies prior to UPA prescription without success. UPA induction was administered in UC for 8 weeks and CD for 12 weeks at a dose of 45 mg once a day, then 15 mg once a day as maintenance. At the beginning 2 (18%) of 11 children had high PUCAI/PCDAI disease activity and remain 9 (82%) had mild disease activity. Elevated white blood cells was determined in 3 (27%) out of 11 children, platelet increase in 9 (82%) children, and Hb less than 110 g/L in 6 (54%) children, elevation of ESR and CRP was observed in 7 (63%) subjects. FC was elevated in 5 (62.5%) out of 8 children. Total cholesterol was normal in all patients, coagulation tests showed increased fibrinogen in 3 out of 11 children. After induction 3 (27%) of 11 children achieved remission and 8 (73%) had clinical response according to the PUCAI/PCDAI score. Elevated white blood cells was detected in 2 (18%) and decrease Hb persisted in 3 (27%) out of 11 children, elevation of ESR persisted in 5 (45%) and CRP in 6 (54%) of 11 children. FC was elevated in 6 (75%) out 8 patients. Total cholesterol and the coagulation tests remained within normal range. Side effects were not observed and UPA maintenance treatment was continued in all children. Conclusion In this real-world experience in drug-resistant pediatric patients with UC and CD we verified the efficacy and safety of UPA, but longer follow-up is needed.

P087 IFN-γ-Induced Intestinal Epithelial Cell Type-Specific Cytotoxic Responses of Human Enteroids: PANoptosis and The Protective Role of Selective JAK1 Inhibitors

Abstract Background Interferon-gamma (IFN-γ) plays an important role in the development of intestinal injury and inflammatory bowel disease (IBD). Using human intestinal organoid (enteorid) models, this study was investigated 1) what is the major response of intestinal epithelial cells (IECs) induced by IFN-γ to elucidate; 2) which programmed cell death (PCD) pathways cause IFN-γ-induced cell death on IECs in the absence of intestinal microbiota and immune cells; 3) how the expression of cell-cell adhesion molecules in epithelial cells is altered by IFN-γ; 4) how epithelial cell differentiation is altered by IFN-γ; 5) whether there is a difference in IFN-γ-induced PCD between different epithelial cell types; and 6) which molecules can block IFN-γ-induced PCD in IECs. Methods Using human enteroids, the major response of IECs induced by IFN-γ was evaluated, focusing on the IFN-γ-induced PCD pathway. The intestinal epithelial cell type-specific response to IFN-γ was assessed by bulk and single-cell RNA sequencing (RNA-seq). Furthermore, the molecules to block IFN-γ-induced PCD in IECs were evaluated. Results As the concentration of IFN-γ in the culture media increased, disruption of organoid structure, growth arrest, and cell death were observed in IFN-γ-treated enteroids on organoid reconstitution, MTT, and EdU assay. Bulk RNA-seq and western blot were identified the activation of pyroptosis, apoptosis, and necroptosis to form the collective inflammatory cell death pathway of PANoptosis. Single-cell RNA-seq indicated that IFN-γ altered epithelial cell differentiation in human enteroids, including expansion of the intstinal stem cell (ISC) population and depletion of the enterocyte population. PCD-associated gene expression was upregulated in enterocytes and goblet cells, but not in ISCs and paneth cells. Individual PCD inhibitors may be insufficient to prevent IFN-γ-induced cytotoxicity, whereas upadacitinib interferes with the downstream signaling of IFN-γ by inhibiting the activity of JAK1 kinase, resulting in effective blocking of PANoptosis. Conclusion PANoptosis is the major mechanism of IFN-γ-induced IEC damage, which was blocked by a selective JAK1 inhibitor. ECs were particularly susceptible to IFN-γ-induced PANoptosis. * This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (2022R1A2B5B02002092 and 2021R1C1C2095192) and Future Medicine 2030 Project of the Samsung Medical Center (SMO1230011).

P535 Effectiveness of upadacitinib in patients with Ulcerative Colitis: a real-life, multicenter, Italian report

Abstract Background Upadacitinib (UPA) is an oral, selective JAK inhibitor, that has recently received approval in Italy for the treatment of Ulcerative colitis (UC). To our knowledge, only few data of real-life studies are available. The aim of our observational data collection is to report the first real-life experiences with UPA in UC in terms of effectiveness and safety. Methods These data come from four Italian IBD centers. Adult patients with a diagnosis of UC, who have been prescribed UPA for active disease, after failure of at least one anti-TNF therapy, were enrolled. After an induction period of 8 weeks with a 45 mg daily dosage, treatment efficacy were assessed using the partial Mayo score (pMS) and the fecal calprotectin levels (CP). Treatment-related adverse events were also recorded. Results Among 20 patients who started UPA, 12 have completed the induction and were therefore enrolled and evaluated before starting UPA and at the end of the 8 weeks induction period. 83% (10 patients) had previously failed two or more biological therapies, including tofacitinib (3 patients, 25%). 3 patients (25%) were tapering systemic corticosteroids and 3 patients (25%) were receiving topical steroids when they started UPA. In the pre-treatment evaluation, the mean pMs was 5,25 (SD 2,26) and the median CP was 1270 ug/g (411- 3152). At the end of induction (week 8), 10 patients (83%) achieved clinical remission and one patient showed clinical response with a decrease of 6 points of pMS. One patient underwent colectomy after 4 weeks of ineffective therapy. The mean pMS at week 8 was 0 (SD 0,92) (Fig. 1), with a median CP of 88 ug/g (5-4639). Reported adverse events, that however did not cause drug discontinuation, were one case of leukopenia and one case of acne. To the date of the last evaluation, all patients maintained the achieved results, with a mean follow-up period of 92 days. A further analysis excluding the physician global assessment from pMS has been performed, to obtain a sort of patient-reported outcome 2 (PRO-2): the results, in terms of percentage reduction of the scores, were in line with the presented data. Despite the limited number of patients who completed the induction (11), we observed statistical significance in the difference between pretreatment and post-induction values of all the measured variables (Tab. 1, Fig. 1). Conclusion With this first Italian report in a real-life setting, UPA showed promising effects in rapidly inducing clinical remission and in normalizing a sensitive marker of intestinal inflammation. Moreover, it seems to be well tolerated. Long-term real-life studies, including endoscopic and histologic evaluations, are needed to confirm efficacy and safety of UPA in maintaining stable remission in UC patients.

Structure-guided design of potent JAK1-selective inhibitors based on 4-amino-7H-pyrrolo[2,3-d]pyrimidine with anti-inflammatory efficacy.

In a continuous effort to develop Janus kinase 1 (JAK1)-selective inhibitors, a novel series of 4-amino-7H-pyrrolo[2,3-d]pyrimidine derivatives bearing the piperidinyl fragment were designed and synthesized according to a combination strategy. Through enzymatic assessments, the superior compound 12a with an IC50 value of 12.6 nM against JAK1 was identified and a 10.7-fold selectivity index over JAK2 was achieved. It was indicated that 12a displayed considerable effect in inhibiting the pro-inflammatory NO generated from lipopolysaccharide (LPS)-induced RAW264.7 macrophages, while on normal RAW264.7 cells, 12a exerted a weak cytotoxicity effect (IC50 = 143.3 μM). Furthermore, H&E stain assay demonstrated the conspicuous capacity of 12a to suppress CCl4-induced hepatic fibrosis levels in a dose-dependent manner in vivo. The binding model of 12a ideally reflects the excellent activity of JAK1 over the homologous kinase JAK2. Overall, 12a, a JAK1-selective inhibitor, exhibited potential for liver fibrosis and inflammatory diseases.

The effects of suppressing inflammation by tofacitinib may simultaneously improve glycaemic parameters and inflammatory markers in rheumatoid arthritis patients with comorbid type 2 diabetes: a proof-of-concept, open, prospective, clinical study

BackgroundA consistent connection has been increasingly reported between rheumatoid arthritis (RA), insulin resistance (IR), and type 2 diabetes (T2D). The β-cell apoptosis induced by pro-inflammatory cytokines, which could be exaggerated in the context of RA, is associated with increased expression pro-apoptotic proteins, which is dependent on JAnus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) activation. On these bases, we aimed to evaluate if the administration of tofacitinib, a potent and selective JAK inhibitor, could simultaneously improve glycaemic parameters and inflammatory markers in patients with RA and comorbid T2D.MethodsThe primary endpoint was the change in the 1998-updated homeostatic model assessment of IR (HOMA2-IR) after 6 months of treatment with tofacitinib in RA patients with T2D. Consecutive RA patients with T2D diagnosis were included in this proof-of-concept, open, prospective, clinical study, which was planned before the recent emergence of safety signals about tofacitinib. Additional endpoints were also assessed regarding RA disease activity and metabolic parameters.ResultsForty consecutive RA patients with T2D were included (female sex 68.9%, mean age of 63.4 ± 9.9 years). During 6-month follow-up, a progressive reduction of HOMA2-IR was observed in RA patients with T2D treated with tofacitinib. Specifically, a significant effect of tofacitinib was shown on the overall reduction of HOMA2-IR (β = − 1.1, p = 0.019, 95%CI − 1.5 to − 0.76). Also, HOMA2-β enhanced in these patients highlighting an improvement of insulin sensitivity. Furthermore, although a longer follow-up is required, a trend in glycated haemoglobin reduction was also recorded. The administration of tofacitinib induced an improvement in RA disease activity, and a significant reduction of DAS28-CRP and SDAI was observed; 76.8% of patients achieved a good clinical response. In this study, no major adverse events (AEs) were retrieved without the identification of new safety signals. Specifically, no life-threatening AEs and cardiovascular and/or thromboembolic events were recorded.ConclusionsThe administration of tofacitinib in RA with T2D led to a simultaneous improvement of IR and inflammatory disease activity, inducing a “bidirectional” benefit in these patients. However, further specific designed and powered studies are warranted to entirely evaluate the metabolic effects of tofacitinib in RA patients with T2D.

Tofacitinib: The selected selective JAK inhibitor in paediatric dermatology

Tofacitinib: The selected selective JAK inhibitor in paediatric dermatology

Upadacitinib Efficacy for the Treatment of Concomitant Psoriasis and Alopecia Areata

Upadacitinib is a selective JAK-1 inhibitor initially approved for the treatment of rheumatoid arthritis and recently psoriatic arthritis (PsA). We present a patient with Atopic Dermatitis (AD), Psoriasis (PsO), PsA and Alopecia Areata (AA) refractory to multiple agents however, successfully treated with upadacitinib. Our patient initially presented with refractory PsO and PsA, leading to treatment with ixekizumab. However, subsequent development of pruritic, erythematous scaly lesions, along with AA, prompted a shift to dupilumab. When distressing PsA and suboptimal outcomes with previous treatments persisted, prior biologics were discontinued and upadacitinib was initiated. Over a three-month period, the patient achieved complete clearance of PsO, significant improvement in AA and resolution of her PsA and AD. This report highlights the therapeutic benefits of upadacitinib in treating inflammatory cutaneous conditions like AA and PsO and further suggests a need for clinical trials to explore its broad therapeutic spectrum.

Single-center Experience With Upadacitinib for Adolescents With Refractory Inflammatory Bowel Disease.

Upadacitinib (UPA) is a novel selective JAK inhibitor approved for adults with ulcerative colitis (UC) and with positive phase 3 data for Crohn's disease (CD). Pediatric off-label use is common due to delays in pediatric approvals; real-world data on UPA are needed to understand the safety and effectiveness in pediatric IBD. This is a single-center retrospective case series study of adolescents (12-17 years) with inflammatory bowel disease IBD on UPA. The primary outcome was postinduction steroid-free clinical remission (SF-CR) defined as Pediatric UC Activity Index (PUCAI) or Pediatric CD Activity Index (PCDAI) ≤10. Secondary outcomes include postinduction clinical response (decrease ≥12.5 in PUCAI/PCDAI), postinduction C-reactive protein (CRP) normalization, 6-month SF-CR, and intestinal ultrasound response and remission. Adverse events were recorded through last follow-up. Twenty patients (9 CD, 10 UC, 1 IBD-U; 55% female; median age 15 years, 90% ≥2 biologics) were treated with UPA for ≥12 weeks (median 51 [43-63] weeks). Upadacitinib was used as monotherapy in 55% and as combination with ustekinumab and vedolizumab in 35% and 10%, respectively. Week 12 SF-CR was achieved in 75% (15/20) and 80% (16/20) with CRP normalization. About 3/4 (14/19) achieved SF-CR at 6 months. Adverse event occurred in 2 patients (10%): Cytomegaloviruscolitis requiring hospitalization and hyperlipidemia requiring no treatment. In the 75% with ultrasound monitoring, response and remission were achieved in 77% and 60%, respectively. While awaiting pediatric registration trials, our data suggest that UPA is effective in inducing and maintaining SF-CR in adolescents with highly-refractory IBD with an acceptable safety profile.

Efficacy of oral JAK1 or JAK1/2 inhibitor for treating refractory pruritus in dystrophic epidermolysis bullosa: A retrospective case series.

Refractory pruritus is the most distressing, disease-related symptom in patients with dystrophic epidermolysis bullosa (DEB), inducing an itch-scratch-blister cycle. Chronic inflammation is a hallmark of DEB, thus upregulation of inflammatory cytokines and Janus kinase (JAK) signaling may play a role in DEB-related pruritus. We retrospectively reviewed the medical records of DEB patients with refractory pruritus who were treated with either baricitinib, a JAK1/2 inhibitor, or upadacitinib, a selective JAK1 inhibitor. Patients received baricitinib (4 mg) or upadacitinib (15 mg) once a day for 2-32 weeks. A total of 12 DEB patients (six recessive DEB and six dominant DEB) were included in this study. The mean±SD baseline pruritus visual analog scale (VAS) score was 7.5 ± 1.7. Upadacitinib or baricitinib treatment resulted in a rapid and sustained decrease in itch. Four out of 12 patients (33.3%) and seven out of 10 patients (70%) showed a decrease of at least 3 points in the pruritus VAS score from baseline at weeks 2 and 4, respectively. The mean percentage changes from baseline in pruritus VAS scores at weeks 2 and 4 were -42.9% and -52.7%, respectively. Subgroup analysis showed greater reductions in the pruritus VAS score in the baricitinib group (n = 5) compared to the upadacitinib group (n = 7), and in patients with epidermolysis bullosa pruriginosa (n = 3) compared to other subtypes of DEB (n = 9); however, these differences did not reach statistical significance. Three out of 10 (33.3%) patients showed at least a 2-point reduction in pain intensity from baseline at week 4. Eight out of 12 patients (66.7%) also showed a reduction in the number of new blisters, which correlated with a reduction in the pruritus score. No patient discontinued treatment because of serious adverse events. Our results suggest that JAK1 or JAK1/2 inhibitors could be a promising treatment option for DEB-related pruritus. Long-term safety should be assessed in future studies.

Comparison of the Enzymatic and Cellular Profiles of Clinical JAK2 Inhibitors for the Treatment of Myelofibrosis

Introduction: Three Janus kinase 2 (JAK2) inhibitors (JAKinibs) have been approved by the FDA for the treatment of myelofibrosis (MF): ruxolitinib, fedratinib, and pacritinib; a fourth one, momelotinib, is currently under FDA review. In addition to JAK2, these drugs also inhibit other kinases with distinct profiles with potential implications in their observed pharmacology. Published data on kinase inhibitory profiles of the four JAKinibs are limited and were determined under differing assay conditions (Wernig G et al. Cancer Cell 2008; Pardanani A et al. Leukemia 2009; Quintás-Cardama A et al. Blood 2010; Singer J et al. J Exp Pharm 2016), which limits head-to-head comparisons and understanding of their JAK2 inhibition unrelated effects. Here, we present full kinome profiling data for these four JAKinibs. Additionally, we have compared their effects on signaling and proliferation in myeloid cells and other human cells. Methods and Results: Enzymatic assays performed in the presence of 1 mM ATP showed that ruxolitinib is the most potent JAK2 inhibitor (IC 50 4 nM) followed by fedratinib (14 nM), momelotinib (51 nM), and pacritinib (53 nM). Inhibition of other JAK family proteins such as JAK1 and TYK2 were also observed to varying degrees with each drug, and these enzymatic activities were consistent with inhibition of STAT signaling in response to different cytokines in secreted embryonic alkaline phosphatase (SEAP) cellular reporter assays (HEK-Blue Detection, InvivoGen, San Diego, CA). Full kinome analyses (372 activity assays of 356 unique wild-type protein kinases) were conducted (Reaction Biology, Malvern, PA) with determination of percentage inhibition at 100 nM of each drug with 10 μM ATP. Kinases exhibiting >50% inhibition with any of the drugs were then evaluated for dose-response to each drug with 100 μM ATP. The results shown in the Figure demonstrate that fedratinib, momelotinib, and pacritinib inhibited additional kinases outside of the JAK family with similar potency to JAK2 inhibition, whereas ruxolitinib was relatively selective for JAK2 inhibition. In contrast to published reports on the inhibitory activities of pacritinib and momelotinib against ALK2 ( ACVR1), the inhibition of ALK2 observed here was 5-10 times weaker than JAK2 inhibition. Furthermore, pacritinib and momelotinib were both weaker inhibitors of ALK2 activity when compared with their potency towards more than 30 other kinases screened. Fedratinib, pacritinib, and momelotinib, but not ruxolitinib, exhibited high inhibitory potencies against FLT3 and/or KIT kinases, both of which are critical for the self-renewal and differentiation of normal hematopoietic stem cells. In cellular assays monitoring JAK2 signaling (pSTAT5 level in SET2 cells), ruxolitinib was the most potent agent (IC 50 14 nM), followed by momelotinib (205 nM), pacritinib (429 nM), and fedratinib (672 nM). Similar trends were observed in other cellular assays assessing antiproliferative effects in JAK2-dependent myeloid cell lines. In cells not dependent on JAK pathway signaling for growth in culture, such as primary human fibroblasts and endothelial cells, ruxolitinib showed weak or no inhibition at 5 μM, while fedratinib, pacritinib and momelotinib showed anti-proliferative effects with low micromolar IC 50s. Similar trends were observed in human HEK293 and HepG2 cell lines, which are commonly used to assess drug effects on general cell health. We analyzed the effects of the JAKinibs on the differentiation of CD34 + hematopoietic stem and progenitor cells (HSPCs) derived from healthy donors at concentrations observed in the plasma of MF patients enrolled in clinical trials. Consistent with their activity on multiple kinases, including FLT3 and KIT, fedratinib and pacritinib elicited the most pronounced decrease in overall viability, affecting HSPCs and megakaryocytes. In contrast, ruxolitinib as a more selective JAK2 inhibitor, showed the least effect on the differentiation of normal CD34 + HSPCs. Conclusion: JAKinibs clinically evaluated for treatment of MF exhibit distinct kinase inhibition profiles and cellular activities. Amongst the agents tested in this study, ruxolitinib was the most potent and selective JAK2 inhibitor. At concentrations several fold above clinically relevant concentrations, ruxolitinib had no observable effects on the health of cells not reliant on JAK/STAT mediated signaling.

Patient Characteristics, Treatment Patterns, and Health Outcomes in a Real-World Population of Patients with Myelofibrosis Treated with Fedratinib

Introduction: Myelofibrosis (MF) is a type of myeloproliferative neoplasm characterized by bone marrow fibrosis, splenomegaly, progressive anemia, and debilitating constitutional symptoms. Fedratinib (FEDR) is a selective Janus kinase-2 inhibitor (JAK2i) approved for the treatment of adult patients with intermediate (int)-2 or high-risk primary or secondary MF. Patients with MF have a median overall survival of 5-7 years; however, prior to FEDR approval, ruxolitinib (RUX) was the only approved JAK2i for MF treatment, with the majority of patients discontinuing RUX within 3 years of treatment initiation (Harrison C, et al. Ann Hematol 2020;99:1177-1191). Given the current availability and use of FEDR, the primary study objective was to describe demographics, clinical characteristics, and treatment patterns of patients with MF receiving FEDR in real-world practice settings after prior RUX treatment. A secondary objective was to assess changes in MF-related symptoms and spleen size during FEDR treatment. Methods: We report interim data from a medical records review of adult patients with MF who received FEDR treatment after RUX discontinuation (due to treatment refractoriness, relapse, or intolerance) in Canada (CAN), Germany (GER), and the United Kingdom (UK). Data collection is ongoing, and we present data abstracted from March through May 2023. Patients were required to have an int-2 or high-risk MF diagnosis at FEDR initiation and to have initiated FEDR after date of first availability in each country (CAN: Sep 21, 2020, GER: Feb 9, 2021, UK: Nov 1, 2021) up to 6 months prior to data abstraction. Patients who received allogenic, hematopoietic cell transplantation after initial MF diagnosis or participated in a JAK2i trial were excluded. Spleen size evaluation through palpation at FEDR initiation and at least once within the first 6 months of FEDR use was required. Study outcomes measured were patient characteristics, treatment patterns, MF-related symptoms, and spleen size evaluations. Descriptive statistics are reported. Results: A total of 58 patients (CAN: 13, GER: 32, UK: 13) were included in the analysis. Median age at MF diagnosis and FEDR initiation was 67.9 and 71.8 years, respectively. 65.5% of patients were male, and 91.4% were White. Most patients were diagnosed with primary MF (60.3%) and had JAK2 V617F mutation (84.5%). Among patients who had a bone marrow biopsy (n = 51), 58.8% had grade 2 bone marrow fibrosis. Mean baseline Charlson Comorbidity Index score was 2.5. Median time from MF diagnosis and RUX treatment discontinuation to FEDR initiation was 34.0 months and 0.7 months, respectively. Most common reasons for FEDR initiation were splenomegaly (75.9%), RUX failure (67.2%), and to achieve symptom control (63.8%) (Table). Over a median follow-up of 12.1 months after FEDR initiation, 19 patients (32.7%) discontinued FEDR treatment with a median treatment duration of 7.7 months. Among the 39 patients taking FEDR at data abstraction, median treatment duration was 12.5 months. At FEDR initiation, 48.3% and 51.7% had int-2 risk and high-risk MF, respectively. The most common MF-related symptoms presented were fatigue (74.1%), abdominal discomfort (63.8%), and night sweats (46.6%) (Table). 62.1% of patients initiated FEDR treatment at the recommended therapeutic dose of 400 mg, and 74.1% were receiving 400 mg at end of follow-up/treatment discontinuation. Among patients with ≥ 1 FEDR dose change, titration to therapeutic dose (68.4%) was the most common reason for their first dose change. MF-related symptoms decreased in the first 6 months of FEDR treatment, including fatigue (74.1% [at FEDR initiation] reduced to 52.8% [at 6 months after FEDR initiation]), abdominal discomfort (63.8% reduced to 11.3%), and night sweats (46.6% reduced to 3.8%). The proportion of patients with severe (palpable spleen:> 20 cm) and moderate splenomegaly (palpable spleen: 11-20 cm) decreased from FEDR initiation to 6 months after initiation (severe splenomegaly: 32.8% to 7.5%, moderate splenomegaly: 55.2% to 15.1%) (Figure). Conclusion: Thepatients included in this study exhibited a significant level of illness . In this interim analysis, patients treated with FEDR following RUX treatment failure showed resolution of MF-related symptoms and a marked decrease in splenomegaly in the initial 6-month period, demonstrating the real-world effectiveness of FEDR treatment in patients with MF.

Janus Kinase (JAK) 1 Inhibition Results in Significant Changes in Serum Proteins and Peripheral T-Cell Populations That Correlated with Clinical Scores in Chronic Graft Versus Host Disease (GVHD) Patients (an Analysis from GRAVITAS-309)

Background: Chronic GVHD (cGVHD) occurs in 30-70% of allogeneic hematopoietic cell transplantation patients, and the rate has increased over the past 2 decades. Based on the degree of organ involvement, cGVHD is classified as mild, moderate, or severe. Standard treatment includes systemic corticosteroids (CS), together with immunosuppressive agents. GRAVITAS-309 (NCT03584516) was designed as a 2-part, multicenter, randomized trial to assess efficacy and safety of itacitinib, an orally bioavailable, selective JAK1 inhibitor, in combination with CS as first-line treatment for moderate to severe cGVHD. The dose-finding, open-label, randomized portion of the study initially investigated itacitinib at 200 mg once daily (qd) and 300 mg qd in combination with CS (methylprednisolone or prednisone); both doses were well tolerated. The trial was expanded to test itacitinib 400 mg qd and 300 mg twice daily (bid); the initial 300 mg qd cohort was expanded and a CS monotherapy cohort was added. Results from the expanded portion of the study (n=139 patients) showed improved overall response rate (ORR) at 6 months in patients treated with itacitinib + CS vs CS alone (Im, et al. Blood 2022;140[Suppl 1]:1870). Here, we analyzed samples collected from patients in 4 cohorts (cohort A [300 mg qd], cohort B [400 mg qd], cohort C [300 mg bid], and cohort D [CS alone]) for systemic proteins and immune cell populations, to support investigation into the itacitinib mechanism of action and to correlate with clinical outcomes. Methods: Peripheral blood mononuclear cells (PBMCs) and serum were collected before treatment (baseline, day 1), and day 7, day 14 (PBMCs only), and day 28 following treatment initiation. Serum proteins were analyzed using the OLINK Target 96 platform, and circulating T-cell subsets were measured using flow cytometry of PBMCs and presented as a percentage of parent population. Samples were assessed irrespective of patients' response. Most of the patients (70-100% per cohort) with samples available for analysis were responders (achieved complete or partial responses). Results: Serum levels of proteins, including several proposed as potential prognostic cGVHD biomarkers, changed significantly at day 28 relative to baseline following treatment with itacitinib (Table 1). Levels of elafin, a marker of acute GVHD of the skin, were significantly reduced and levels of dickkopf-3 (DKK3), a marker of sclerotic and nonsclerotic cGVHD, were significantly increased in itacitinib cohorts only. Based on a repeated measures correlation analysis, both markers significantly correlated with overall clinical skin scores (elafin: r=+0.43; DKK3: r=-0.53; both P<0.001). Serum levels of other reported markers of cGVHD, including osteopontin, C-X-C motif chemokine ligand (CXCL) 9 and CXCL10, were significantly decreased exclusively in itacitinib-treated cohorts, and not in the CS only cohort. Some proteins, including matrix metalloproteinase (MMP) 3, increased in all cohorts, suggesting that changes in these proteins cannot be attributed to itacitinib alone, but may reflect response to CS; other proteins, such as suppression of tumorigenicity (ST2), remained unchanged in response to treatment in all cohorts. CS treatment alone resulted in an increase in naive CD4 T cells (CD4 +CD8 ->CD45RA +CCR7 -) and a corresponding reduction of CD4 effector memory T cells (CD4 +CD8 ->CD45RA -CCR7 +) within 28 days (Figure 1, cohort D). Changes in naive CD4 T cells following CS monotherapy were significantly attenuated by itacitinib ( P<0.05 vs CS at day 28), particularly at the 400 mg qd dose (Figure 1, cohort B), which demonstrated the best ORR at 6 months (53% with 400 mg qd vs 36% with CS). Conclusions: Analysis of patient samples from GRAVITAS-309 revealed that serum elafin and DKK3 levels significantly correlated with skin GVHD scores, possibly reflecting the systemic origin of observed skin manifestations. Serum levels of osteopontin, CXCL9, and CXCL10 were specifically reduced by itacitinib in patients with cGVHD and may represent potential pharmacodynamic markers. Observed changes in different peripheral T-cell populations in patients' samples following itacitinib treatment were consistent with those reported in murine GVHD models, suggesting a potential role of naive CD4 + T cells in driving this disease. Planned future analyses will include identification of novel biomarkers that correlate with organ involvement.