Population Pharmacokinetics of Losmapimod in Healthy Subjects and Patients with Rheumatoid Arthritis and Chronic Obstructive Pulmonary Diseases

An open-label pilot study of losmapimod to evaluate the safety, tolerability, and changes in biomarker and clinical outcome assessments in participants with facioscapulohumeral muscular dystrophy type 1

INTRODUCTION

Facioscapulohumeral muscular dystrophy (FSHD) is a genetic disease caused by aberrant DUX4 expression, leading to progressive muscle weakness. No effective pharmaceutical treatment is available. Losmapimod, a small molecule selective inhibitor of p38 α/β MAPK, showed promising results in a phase 1 trial for the treatment of FSHD, prompting additional studies. We report the findings of an open-label phase 2 trial (NCT04004000) investigating the safety, tolerability, pharmacokinetics, pharmacodynamics, and exploratory efficacy of losmapimod in participants with FSHD1.

METHODS

This study was conducted at a single site in the Netherlands from August 2019 to March 2021, with an optional, ongoing open-label extension. Participants aged 18 to 65 years with FSHD1 took 15 mg of losmapimod twice daily for 52 weeks. Primary endpoints were measures of losmapimod safety and tolerability. Secondary endpoints were assessments of losmapimod pharmacokinetics and pharmacodynamics.

RESULTS

Fourteen participants were enrolled. No deaths, serious treatment-emergent adverse events (TEAEs), or discontinuations due to TEAEs were reported. Losmapimod achieved blood concentrations and target engagements that were previously associated with decreased DUX4 expression in vitro. Clinical outcome measures showed a trend toward stabilization or improvement.

CONCLUSIONS

Losmapimod was well tolerated and may be a promising new treatment for FSHD; a larger phase 3 study is ongoing.

Losmapimod Protected Epileptic Rats From Hippocampal Neuron Damage Through Inhibition of the MAPK Pathway

Objective: This research aimed to validate the therapeutic effect of losmapimod and explore the underlying mechanism in its treatment of epilepsy.

Methods: A rat model of epilepsy was constructed with an injection of pilocarpine. Microarray analysis was performed to screen aberrantly expressed mRNAs and activated signaling pathways between epileptic rats and normal controls. A TdT-mediated dUTP nick-end labeling (TUNEL) assay was used to identify cell apoptosis. Hippocampal cytoarchitecture was visualized with Nissl staining. The secretion of inflammatory factors as well as the marker proteins in the mitogen-activated protein kinase (MAPK) pathway were detected by Western blot. A Morris water maze navigation test evaluated the rats’ cognitive functions.

Results: Activation of the MAPK signaling pathway was observed in epilepsy rats. A decrease in the MAPK phosphorylation level by application of losmapimod protected against epilepsy by reducing neuron loss. Losmapimod effectively improved memory, reduced the frequency of seizures, protected the neuron from damage, and limited the apoptosis of neurons in epilepsy rats.

Conclusion: The application of losmapimod could partly reverse the development of epilepsy.

(5R)-5-hydroxytriptolide (LLDT-8) prevents collagen-induced arthritis through OPG/RANK/RANKL signaling in a rat model of rheumatoid arthritis

(5R)-5-hydroxytriptolide (LLDT-8) extracts from Tripterygium have anti-inflammatory, antineoplastic and immunity adjustment functions. The present study used a collagen-induced arthritis (CIA) model to evaluate whether LLDT-8 prevents collagen-induced arthritis, and investigated the signaling underlying this. Male Sprague-Dawley rats were induced to generate CIA, mimicking rheumatoid arthritis (RA). The presence of arthritis was determined using RA progression scores. The inflammatory cytokines interleukin (IL)-1β, IL-6 and nuclear factor-κB were detected using enzyme-linked immunosorbent assay kits. Induced nitric oxide synthase (iNOS) and matrix metalloprotease (MMP)-13 protein expression were measured using western blot analysis. Lastly, reverse transcription-quantitative polymerase chain reaction was used to evaluate osteoprotegerin (OPG) and receptor activator of nuclear factor κB (RANK) gene expression. LLDT-8 improved RA progression scores and reduced the incidence and severity of CIA. Furthermore, LLDT-8 administration inhibited collagen-induced inflammation and iNOS protein expression in arthritic rats. The current data indicated that MMP-13 production was suppressed and OPG/RANKL expression was increased by LLDT-8 treatment in the arthritic rat. The present results suggest that LLDT-8 attenuates CIA through OPG/RANK/RANK ligand signaling in a rat model of RA.

Inherent low Erk and p38 activity reduce Fas Ligand expression and degranulation in T helper 17 cells leading to activation induced cell death resistance

Activation Induced Cell Death of T helper cells is central to maintaining immune homeostasis and a perturbation often manifests in aberrant T helper cells that is associated with immunopathologies. Significant presence of T cells positive for IL-17A (Th17) and dual positive for IFN-γ/IL-17A (Th1/Th17) in both effector (CD45RA+RO+) and memory (CD45RA-RO+) compartments with differential FasL protein in RA peripheral blood suggested their differential TCR AICD sensitivity. Lowered active caspase-3 in Th17 and Th1/Th17 over Th1 cells confirmed their capability to resist AICD and pointed to early upstream events. Differential MAPK activities, FasL protein and downstream caspase-3 activities in murine Th1 and Th17 cells established distinct TCR mediated signaling pathways and suggested low Erk and p38 activity as pivotal for AICD sensitivity. We extrapolated our mouse and human data and report that Fas-FasL is the preferred death pathway for both Th1 and Th17 and that inherently low Erk2 activity protected Th17 cells from TCR AICD. The presence of significantly higher numbers of aberrant T helper cells in RA also suggest an inflammatory cytokine milieu and AICD insensitive T cell link to sustained inflammation. Re sensitization to apoptosis by targeting MAPK activity especially Erk2 in RA might be of therapeutic value.

Serum Trace Element Concentrations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a condition that is associated with oxidative stress. Serum trace elements and their related transport proteins, e.g., albumin and ceruloplasmin, play an important role in the antioxidant defense. Trace element status may therefore be involved in the pathogenesis of RA or be affected by the disease activity of this chronic inflammatory condition. The study participants were 110 patients with RA and 100 sex- and age-matched healthy volunteers. Serum concentrations of albumin, ceruloplasmin, selenium, zinc, copper, and zinc/copper ratio were measured in all subjects. The relationship between these parameters and disease activity score was also assessed. Lower concentrations of serum Alb, Zn, and Se were independently related to disease activity index. High concentrations of serum copper were associated with the presence of RA. Serum Cu concentrations were positively related to disease activity as assessed by the disease activity score. Low serum concentrations of Zn and Se, and high serum Cu concentrations may be associated with the presence of RA or be a consequence of this condition. Of the trace elements that were investigated in the present study, only serum Cu was positively correlated with disease activity.

Emerging treatment options to improve cardiovascular outcomes in patients with acute coronary syndrome: focus on losmapimod

Each year, despite optimal use of recommended acute and secondary prevention therapies, 4%–5% of patients with acute coronary syndrome (ACS) experience relapse of ACS or other cardiovascular events including stroke, heart failure, or sudden cardiac death after the index ACS. The sudden atherosclerotic plaque rupture leading to an ACS event is often accompanied by inflammation, which is thought to be a key pathogenic pathway to these excess cardiovascular events. Losmapimod is a novel, oral p38 mitogen-activated protein kinase (MAPK) inhibitor that targets MAPKs activated in macrophages, myocardium, and endothelial cells that occur as a part of global coronary vascular inflammation following plaque rupture. This review aims to 1) discuss the pathophysiological pathways through which p38 MAPKs may play key roles in initiation and progression of inflammatory disease and how losmapimod is thought to counteract these p38 MAPKs, and 2) to describe the efficacy and safety data for losmapimod obtained from preclinical studies and randomized controlled trials that support the hypothesis that it has promise as a treatment for patients with ACS.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of losmapimod in healthy Japanese volunteers

This phase 1 study characterized the safety, tolerability, pharmacokinetics, and pharmacodynamics of losmapimod and its metabolite GSK198602 following single and repeat doses of oral losmapimod in healthy Japanese volunteers. Subjects (n = 41) received single oral doses of losmapimod (2.5, 7.5, 20 mg) or matching placebo on 3 separate days (n = 20) or losmapimod 7.5 mg or matching placebo twice daily for 14 days (n = 21). Assessments included maximum observed plasma concentration (Cmax ), time to Cmax (Tmax ), apparent terminal-phase half-life (t1/ )2 , area under the curve (AUC), and change in C-reactive protein and phosphorylated heat shock protein 27 levels. No serious adverse events occurred during the study, and there were no safety concerns regarding clinical laboratory parameters, 12-lead electrocardiogram, or vital signs. The losmapimod Tmax was 3-4 hours, and the mean t1/2 was approximately 7.9-9.0 hours, with no appreciable difference in Tmax and apparent clearance following oral dosing between dosing regimens. Single and repeat oral doses of losmapimod were well tolerated in healthy Japanese volunteers. The Tmax of GSK198602 was similar to and t1/2 was slightly longer than those of losmapimod. Approximate dose-proportional increases in exposure to losmapimod and GSK198602 were observed in AUC with single-dose administration. Repeat-dose trough concentrations reached steady state within 2 days, with an observed accumulation ratio of 1.56 and 1.91 for losmapimod and GSK198602, respectively.

Therapeutic potential of p38 MAP kinase inhibition in the management of cardiovascular disease

p38 mitogen-activated protein kinases (p38 MAPKs) are key signalling molecules that regulate cellular behavior in response to environmental stresses. They regulate pro-inflammatory cytokines and therefore p38 MAPKs are implicated in the pathogenesis of many inflammatory-driven conditions, including atherosclerosis. Therapeutic inhibition of p38 MAPKs to attenuate inflammation has been the focus of comprehensive research in the last 2 decades, following the discovery of p38α as the molecular target of pyrindinyl imidazole compounds, which suppress the cytokines tumor necrosis factor-α and interleukin-1. The potential of p38 MAPK inhibitors was initially explored within archetypal inflammatory conditions such as rheumatoid arthritis and Crohn's disease, but early studies demonstrated poor clinical efficacy and unacceptable side effects. Subsequent clinical trials evaluating different p38 MAPK inhibitor compounds in disease models such as chronic obstructive pulmonary disease (COPD) and atherosclerosis have shown potential clinical efficacy. This review aims to provide succinct background information regarding the p38 MAPK signaling pathway, a focus of p38 MAPKs in disease, and a brief summary of relevant pre-clinical studies. An update of human clinical trial experience encompassing a clinically orientated approach, dedicated to cardiovascular disease follows. It provides a current perspective of the therapeutic potential of p38 MAPK inhibitors in the cardiovascular domain, including safety, tolerability, and pharmacokinetics.