Reflections from the OARSI 2022 clinical trials symposium: The pain of OA-Deconstruction of pain and patient-reported outcome measures for the benefit of patients and clinical trial design.

OBJECTIVE: Osteoarthritis (OA) drug development is hampered by a number of challenges. One of the main challenges is the apparent discordance between pain and structure, which has had a significant impact on drug development programs and has led to hesitance among stakeholders. Since 2017, the Clinical Trials Symposium (CTS) has been hosted under the Osteoarthritis Research Society International (OARSI) leadership. OARSI and the CTS steering committee yearly invite and encourage discussions on selected special subject matter between regulators, drug developers, clinicians, clinical researchers, biomarker specialists, and basic scientists to progress drug development in the OA field. METHOD: The main topic for the 2022 OARSI CTS was to elucidate the many facets of pain in OA and to enable a discussion between regulators (Food and Drug Administration (FDA) and the European Medicines Agency (EMA)) and drug developers to clarify outcomes and study designs for OA drug development. RESULTS: Signs or symptoms indicative of nociceptive pain occur in 50-70% of OA patients, neuropathic-like pain in 15-30% of patients, and nociplastic pain in 15-50% of patients. Weight-bearing knee pain is associated with bone marrow lesions and effusions. There are currently no simple objective functional tests whose improvements correlate with patient perceptions. CONCLUSIONS: The CTS participants, in collaboration with the FDA and EMA, raised several suggestions that they consider key to future clinical trials in OA including the need for more precise differentiation of pain symptoms and mechanisms, and methods to reduce placebo responses in OA trials.

Reflections from the 2021 OARSI clinical trial symposium: Considerations for understanding biomarker assessments in osteoarthritis drug development - Should future studies focus on disease activity, rather than status?

Objective: Osteoarthritis (OA) is heterogeneous disease, for which drug development has proven to be challenging, both facilitated and hampered by changing guidelines. This is evident by the current lack of approved treatments, which improve joint function and delay joint failure. There is a need to bring together key stakeholders to discuss, align and enhance the processes for OA drug development to benefit patients. Design: To facilitate drug development, the Osteoarthritis Research Society International (OARSI) initiated a series of annual clinical trials symposia (CTS). The aim of these symposia was to bring together academics, translational and clinical scientists, regulators, drug developers, and patient advocacy groups to share, refine and enhance the drug development process for the benefit of patients. Results: OARSI is now considered the leading organization to facilitate open dialogue between all these stakeholders, in the intersection of understanding of the pathologies and drug development. Clearly, such a pivotal task needs an annual forum to allow stakeholders to share and discuss information, as possible solutions are joint efforts rather than a single stakeholder contribution. Conclusions: The main topic of the 2021 CTS was how to improve clinical studies to help patients through overcoming barriers to development of new disease modifying treatments for OA. One key aspect was the focus on definitions of disease activity, status and the definitions of "illness vs disease". There is a clear medical need to couple a given disease activity with the optimal intervention for the right patient.

A Phase 2b randomized trial of lorecivivint, a novel intra-articular CLK2/DYRK1A inhibitor and Wnt pathway modulator for knee osteoarthritis.

OBJECTIVE: Lorecivivint (LOR; SM04690), an investigational Wnt pathway modulator, previously demonstrated patient-reported and radiographic outcome improvements vs placebo in clinically relevant subjects with moderate to severe knee osteoarthritis (OA). This study's objective was to identify effective LOR doses. DESIGN: Subjects in this 24-week, Phase 2b, multicenter, randomized, double-blind, placebo (PBO)-controlled trial received an intra-articular injection of 2 mL LOR (0.03, 0.07, 0.15, or 0.23 mg), PBO, or dry-needle sham. The primary efficacy endpoints were changes in Pain NRS [0-10], WOMAC Pain [0-100], WOMAC Function [0-100], and radiographic mJSW outcomes, which were measured using baseline-adjusted analysis of covariance at Week 24. Multiple Comparison Procedure-Modeling (MCP-Mod) was performed for dose modeling. RESULTS: In total, 695/700 subjects were treated. Pain NRS showed significant improvements vs PBO after treatment with 0.07 mg and 0.23 mg LOR at Weeks 12 (-0.96, 95% CI [-1.54, -0.37], P = 0.001; -0.78 [-1.39, -0.17], P = 0.012) and 24 (-0.70 [-1.34, -0.06], P = 0.031; -0.82 [-1.51, -0.12], P = 0.022). Additionally, 0.07 mg LOR significantly improved WOMAC Pain and Function subscores vs PBO at Week 12 (P = 0.04, P = 0.021), and 0.23 mg LOR significantly improved both WOMAC subscores at Week 24 (P = 0.031, P = 0.017). No significant differences from PBO were observed for other doses. No radiographic progression was observed in any group at Week 24. MCP-Mod identified 0.07 mg LOR as the lowest effective dose. CONCLUSION: This 24-week Phase 2b trial demonstrated the efficacy of LOR on PROs in knee OA subjects. The optimal dose for future studies was identified as 0.07 mg LOR.

Modulation of the Wnt pathway through inhibition of CLK2 and DYRK1A by lorecivivint as a novel, potentially disease-modifying approach for knee osteoarthritis treatment.

OBJECTIVES: Wnt pathway upregulation contributes to knee osteoarthritis (OA) through osteoblast differentiation, increased catabolic enzymes, and inflammation. The small-molecule Wnt pathway inhibitor, lorecivivint (SM04690), which previously demonstrated chondrogenesis and cartilage protection in an animal OA model, was evaluated to elucidate its mechanism of action. DESIGN: Biochemical assays measured kinase activity. Western blots measured protein phosphorylation in human mesenchymal stem cells (hMSCs), chondrocytes, and synovial fibroblasts. siRNA knockdown effects in hMSCs and BEAS-2B cells on Wnt pathway, chondrogenic genes, and LPS-induced inflammatory cytokines was measured by qPCR. In vivo anti-inflammation, pain, and function were evaluated following single intra-articular (IA) lorecivivint or vehicle injection in the monosodium iodoacetate (MIA)-induced rat OA model. RESULTS: Lorecivivint inhibited intranuclear kinases CDC-like kinase 2 (CLK2) and dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A). Lorecivivint inhibited CLK2-mediated phosphorylation of serine/arginine-rich (SR) splicing factors and DYRK1A-mediated phosphorylation of SIRT1 and FOXO1. siRNA knockdowns identified a role for CLK2 and DYRK1A in Wnt pathway modulation without affecting ß-catenin with CLK2 inhibition inducing early chondrogenesis and DYRK1A inhibition enhancing mature chondrocyte function. NF-κB and STAT3 inhibition by lorecivivint reduced inflammation. DYRK1A knockdown was sufficient for anti-inflammatory effects, while combined DYRK1A/CLK2 knockdown enhanced this effect. In the MIA model, lorecivivint inhibited production of inflammatory cytokines and cartilage degradative enzymes, resulting in increased joint cartilage, decreased pain, and improved weight-bearing function. CONCLUSIONS: Lorecivivint inhibition of CLK2 and DYRK1A suggested a novel mechanism for Wnt pathway inhibition, enhancing chondrogenesis, chondrocyte function, and anti-inflammation. Lorecivivint shows potential to modify structure and improve symptoms of knee OA.

A small-molecule inhibitor of the Wnt pathway (SM04690) as a potential disease modifying agent for the treatment of osteoarthritis of the knee.

OBJECTIVES: Osteoarthritis (OA) is a degenerative disease characterized by loss of cartilage and increased subchondral bone within synovial joints. Wnt signaling affects the pathogenesis of OA as this pathway modulates both the differentiation of osteoblasts and chondrocytes, and production of catabolic proteases. A novel small-molecule Wnt pathway inhibitor, SM04690, was evaluated in a series of in vitro and in vivo animal studies to determine its effects on chondrogenesis, cartilage protection and synovial-lined joint pathology. DESIGN: A high-throughput screen was performed using a cell-based reporter assay for Wnt pathway activity to develop a small molecule designated SM04690. Its properties were evaluated in bone-marrow-derived human mesenchymal stem cells (hMSCs) to assess chondrocyte differentiation and effects on cartilage catabolism by immunocytochemistry and gene expression, and glycosaminoglycan breakdown. In vivo effects of SM04690 on Wnt signaling, cartilage regeneration and protection were measured using biochemical and histopathological techniques in a rodent acute cruciate ligament tear and partial medial meniscectomy (ACLT + pMMx) OA model. RESULTS: SM04690 induced hMSC differentiation into mature, functional chondrocytes and decreased cartilage catabolic marker levels compared to vehicle. A single SM04690 intra-articular (IA) injection was efficacious in a rodent OA model, with increased cartilage thickness, evidence for cartilage regeneration, and protection from cartilage catabolism observed, resulting in significantly improved Osteoarthritis Research Society International (OARSI) histology scores and biomarkers, compared to vehicle. CONCLUSIONS: SM04690 induced chondrogenesis and appeared to inhibit joint destruction in a rat OA model, and is a candidate for a potential disease modifying therapy for OA.

A novel Wnt pathway inhibitor, SM04690, for the treatment of moderate to severe osteoarthritis of the knee: results of a 24-week, randomized, controlled, phase 1 study.

OBJECTIVE: To assess the safety, pharmacokinetics, and exploratory efficacy of SM04690, a novel Wnt pathway inhibitor, as a potential disease modifying treatment for knee osteoarthritis (OA). DESIGN: Subjects with Kellgren-Lawrence grade 2-3 knee OA were randomized in successive dose-escalation cohorts to receive a knee intra-articular (IA) injection with 0.03, 0.07, or 0.23 mg SM04690, or placebo (PBO) (4:1 ratio). Safety, pharmacokinetics, efficacy (WOMAC Total/Function/Pain, Pain VAS, Physician Global Assessment [MDGA], and OMERACT-OARSI Response), OA-related biomarker (P1NP, ß-CTX, and cartilage oligomeric matrix protein [COMP]), and radiographic/imaging data were collected at baseline and during 24-week follow-up. RESULTS: 61 subjects (SM04690 n = 50; PBO n = 11) enrolled. Two dose limiting toxicities (DLTs), increased pain following injection and paroxysmal tachycardia (also the single serious AE), were reported in the 0.07 mg cohort. A total of 72 AEs were reported; Sixteen (occurring in eight subjects) were considered related to study medication. There were three discontinuations; one due to an AE (0.03 mg cohort). Bone marrow edema (BME) remained constant for most subjects. No doses were excluded from further study due to DLT criteria. Plasma levels of SM04690 were below the limit of detection at all time points. At Week 24, improvements from baseline were seen in all cohorts for the exploratory measures WOMAC Total, WOMAC Function, WOMAC Pain, MDGA, Pain VAS, and OMERACT-OARSI response. Joint space width (JSW) improvement was observed in the 0.07 mg cohort (P = 0.02 vs PBO). CONCLUSION: SM04690 appeared safe and well tolerated, with no evidence of systemic exposure. Exploratory efficacy analyses suggested positive trends for measurements of OA pain, function and disease-modifying osteoarthritis drug (DMOAD) properties. CLINICALTRIALS. GOV REGISTRATION: NCT02095548.

Provocation of experimental aortic inflammation and dilatation by inflammatory mediators and Chlamydia pneumoniae.

BACKGROUND: The macrophage appears to have a key role in the inflammation and proteolysis associated with the growth and development of abdominal aortic aneurysms. The role of inflammatory mediators and Chlamydia pneumoniae in stimulating the influx of macrophages and dilatation of the abdominal aorta was investigated in an experimental model. METHODS: Periaortic application of calcium chloride solution (and monocyte chemoattractant protein (MCP) 1, a cocktail of cytokines or C. pneumoniae) to the abdominal aorta of New Zealand White rabbits was performed at laparotomy. Some animals were fed a cholesterol-rich diet. The diameter of the aorta was measured by ultrasonography and after perfusion fixation, 3 weeks after laparotomy. Aortic sections were stained with RAM-11 to identify macrophages for counting. The presence of C. pneumoniae DNA was confirmed using the polymerase chain reaction. RESULTS: Aortic macrophage influx in response to MCP-1, thioglycollate or C. pneumoniae was more than doubled in the cholesterol-fed animals. In response to human recombinant MCP-1 (1 microg) the mean(s.d.) macrophage count increased from 79(19) to 340(215) per unit area (P < 0.02). Even in cholesterol-fed animals, application of MCP-1 (recombinant human or rabbit form) was not associated with aortic dilatation. Application of thioglycollate 0.1 mol/l, or live or formalin-inactivated C. pneumoniae (0.5 x 108 organisms), was associated with a similar increase in macrophages to that caused by MCP-1 and a significant (approximately twofold) increase in aortic diameter after 3 weeks. CONCLUSION: Macrophage influx into rabbit abdominal aorta, without macrophage activation, is insufficient to cause experimental aortic dilatation. C. pneumoniae antigens appeared to stimulate aortic dilatation, probably by specific activation of macrophages.