Exposure-Response Characterization of Tofacitinib Efficacy in Moderate to Severe Ulcerative Colitis: Results From Phase II and Phase III Induction and Maintenance Studies

A Phase I, Randomized, Multi-Dose Study to Evaluate the Enteric Selectivity and Safety of JAK Inhibitor, Lorpucitinib, in Healthy Participants

Janus kinase (JAK) signaling has been implicated in human inflammatory diseases, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. Lorpucitinib (JNJ-64251330) is an oral, small molecule, pan-JAK inhibitor. Unlike systemic JAK antagonists, lorpucitinib was found to have enteric (gut)-selective properties, providing possible applications in diseases of the human gastrointestinal tract. Here, lorpucitinib was evaluated in a phase I, two-part, dosing study (NCT04552197) to assess pharmacokinetics, pharmacodynamic biomarkers, and safety in healthy participants. In part 1, 24 participants were randomized to 1 of 4 treatment arms receiving either lorpucitinib (30 mg daily, 30 mg every 12 hours (q12h), or 75 mg q12h) or tofacitinib (5 mg q12h) for 5 days. Part 2 was a food-effect study in which 12 participants received a single 75-mg dose of lorpucitinib under either fasting or fed conditions. In part 1, plasma and gut tissue concentrations of lorpucitinib showed approximately dose-proportional increases. At all doses, lorpucitinib concentrations were significantly higher (392- to 1928-fold) in the gut mucosal biopsies vs. the corresponding plasma samples, demonstrating high enteric selectivity and significantly exceeding both the tissue concentrations (> 200-fold) and tissue/plasma ratios observed with tofacitinib. JAK inhibition in biopsies was confirmed via reduction in pSTAT-3 levels. In part 2, lorpucitinib plasma concentrations were detectable but at low levels, with no statistical differences in PK parameters between the fed and fasted groups. Lorpucitinib was safe and well-tolerated, and the data may be useful in designing studies to evaluate lorpucitinib in patients with JAK/STAT-driven gastrointestinal diseases.

Beyond Population-Level Targets for Drug Concentrations: Precision Dosing Needs Individual-Level Targets that Include Superior Biomarkers of Drug Responses

The purpose of precision dosing is to increase the chances of therapeutic success in individual patients. This is achieved in practice by adjusting doses to reach precision dosing targets determined previously in relevant populations, ideally with robust supportive evidence showing improved clinical outcomes compared with standard dosing. But is this implicit assumption of translatable population-level precision dosing targets correct and the best for all patients? In this review, the types of precision dosing targets and how they are determined are outlined, problems with the translatability of these targets to individual patients are identified, and ways forward to address these challengers are proposed. Achieving improved clinical outcomes to support precision dosing over standard dosing is currently hampered by applying population-level targets to all patients. Just as "one-dose-fits-all" may be an inappropriate philosophy for drug treatment overall, a "one-target-fits-all" philosophy may limit the broad clinical benefits of precision dosing. Defining individual-level precision dosing targets may be needed for greatest therapeutic success. Superior future precision dosing targets will integrate several biomarkers that together account for the multiple sources of drug response variability.

Therapeutic Drug Monitoring for Biologic and Small-Molecule Therapies for Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, necessitates long-term medical therapy to manage symptoms and prevent complications. Therapeutic drug monitoring (TDM) has emerged as a strategy to optimize treatment efficacy, particularly with anti-tumour necrosis factor (anti-TNF) alpha drugs. This review explores the role of TDM for non-anti-TNF advanced therapies in IBD, focusing on vedolizumab, ustekinumab, tofacitinib, upadacitinib, risankizumab and ozanimod. Methods: The literature search, conducted through OVID (Medline) and PubMed, delves into proactive versus reactive TDM, timing of monitoring and methods for measuring drug levels and anti-drug antibodies. Results: While ustekinumab and vedolizumab exhibit exposure-response relationships, consensus on target levels and the role of TDM adjustments remains elusive. Limited data on risankizumab suggest a dose-dependent response, while for small molecule therapies (janus kinase inhibitors and ozanimod), the absence of real-world data and commercially available TDM tools pose challenges. Conclusion: At present, with the available data, there is a limited role for TDM in non-anti-TNF biologic and small-molecule therapies. This review underscores the need for further research to delineate the utility of TDM in guiding treatment decisions for these agents.

JAK/STAT pathway: Extracellular signals, diseases, immunity, and therapeutic regimens

Janus kinase/signal transduction and transcription activation (JAK/STAT) pathways were originally thought to be intracellular signaling pathways that mediate cytokine signals in mammals. Existing studies show that the JAK/STAT pathway regulates the downstream signaling of numerous membrane proteins such as such as G-protein-associated receptors, integrins and so on. Mounting evidence shows that the JAK/STAT pathways play an important role in human disease pathology and pharmacological mechanism. The JAK/STAT pathways are related to aspects of all aspects of the immune system function, such as fighting infection, maintaining immune tolerance, strengthening barrier function, and cancer prevention, which are all important factors involved in immune response. In addition, the JAK/STAT pathways play an important role in extracellular mechanistic signaling and might be an important mediator of mechanistic signals that influence disease progression, immune environment. Therefore, it is important to understand the mechanism of the JAK/STAT pathways, which provides ideas for us to design more drugs targeting diseases based on the JAK/STAT pathway. In this review, we discuss the role of the JAK/STAT pathway in mechanistic signaling, disease progression, immune environment, and therapeutic targets.

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

INTRODUCTION

Tofacitinib has emerged as a useful drug for the treatment of ulcerative colitis (UC).

AREAS COVERED

There is an unmet need for cost-effective, non-immunogenic drugs with a safe adverse effect profile to treat patients with ulcerative colitis. In the present review, we evaluate the available literature to inform the appropriate positioning of tofacitinib in the current drug landscape and identify subsets where its use should be done with caution.

EXPERT OPINION

Tofacitinib is helpful in the treatment of patients where the standard conventional or biological therapies have failed or were not tolerated. With lower costs of the generic drug than the biologicals (or biosimilars), it could be an important therapy in low- to middle-income countries. The risk of infections, especially Herpes Zoster and tuberculosis, needs to be addressed before initiation. Tofacitinib should be avoided in patients with venous thromboembolism and cardiovascular disease risk factors. Due to limited evidence, the use is not recommended in pregnancy, while it should be used with caution in elderly citizens. Future trials should look into the head-to-head comparison of tofacitinib with biologicals. The role of tofacitinib in acute severe colitis needs evaluation with comparative trials with current standards of care.