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Objective: Behçet's disease (BD) is a systemic vasculitis with inflammatory lesions mediated by cytotoxic T cells and neutrophils. Apremilast, an orally available small‐molecule drug that selectively inhibits phosphodiesterase 4 (PDE4), has been recently approved for the treatment of BD. We aimed to investigate the effect of PDE4 inhibition on neutrophil activation in BD. Methods: We studied surface markers and reactive oxygen species (ROS) production by flow cytometry, and neutrophil extracellular traps (NETs) production and molecular signature of neutrophils by transcriptome analysis before and after PDE4 inhibition. Results: Activation surface markers (CD64, CD66b, CD11b, and CD11c), ROS production, and NETosis were up‐regulated in BD patient neutrophils compared to healthy donor neutrophils. Transcriptome analysis revealed 1,021 significantly dysregulated neutrophil genes between BD patients and healthy donors. Among dysregulated genes, we found a substantial enrichment for pathways linked to innate immunity, intracellular signaling, and chemotaxis in BD. Skin lesions of BD patients showed increased infiltration of neutrophils that colocalized with PDE4. Inhibition of PDE4 by apremilast strongly inhibited neutrophil surface activation markers as well as ROS production, NETosis, and genes and pathways related to innate immunity, intracellular signaling, and chemotaxis. Conclusion: We highlight key biologic effects of apremilast on neutrophils in BD. [ABSTRACT FROM AUTHOR]

Objective: To preclinically characterize a mutant form of growth and differentiation factor 5, R399E, with reduced osteogenic properties as a potential disease‐modifying osteoarthritis (OA) drug. Methods: Cartilage, synovium, and meniscus samples from patients with OA were used to evaluate anabolic and antiinflammatory properties of R399E. In the rabbit joint instability model, 65 rabbits underwent transection of the anterior cruciate ligament plus partial meniscectomy. Three intraarticular (IA) R399E doses were administered biweekly 6 times, and static incapacitance was determined to assess joint pain. OA was evaluated 13 weeks after surgery. In sheep, medial meniscus transection was performed to induce OA, dynamic weight bearing was measured in‐life, and OA was assessed after 13 weeks. Results: Intermittent exposure to R399E (1 week per month) was sufficient to induce cell proliferation and release of anabolic markers in 3‐dimensional chondrocyte cultures. R399E also inhibited the release of interleukin‐1β (IL‐1β), IL‐6, and prostaglandin E2 from cartilage with synovium, meniscal cell, and synoviocyte cultures. In rabbits, the mean difference (95% confidence interval [95% CI]) in weight bearing for R399E compared to vehicle was −5.8 (95% confidence interval [95% CI] −9.54, −2.15), −7.2 (95% CI −10.93, −3.54), and −7.7 (95% CI −11.49, −3.84) for the 0.6, 6, and 60 μg doses, respectively, 6 hours after the first IA injection, and was statistically significant through the entire study for all doses. Cartilage surface structure improved with the 6‐μg dose. Structural and symptomatic improvement with the same dose was confirmed in the sheep model of OA. Conclusion: R399E influences several pathologic processes contributing to OA, highlighting its potential as a disease‐modifying therapy. [ABSTRACT FROM AUTHOR]

The article provides information on the challenges in managing systemic sclerosis (SSc) and the recent developments in SSc treatment, including the first FDA approvals for medications. It discusses the paradigm shift in trial design and outcome measurements, introducing the American College of Rheumatology Combined Response Index in Systemic Sclerosis (CRISS) score and cohort enrichment strategies.

An editorial is presented on the treatment met expected pharmacodynamic targets, decreasing phosphorylated Bruton's tyrosine kinase levels, dampening plasmablast signals, and lowering anti–double-stranded DNA and IgG levels. Topics include the treatment did not demonstrate efficacy as defined by the primary end point of SLE Disease Activity Index and the many clinical trials in SLE have failed to differentiate investigational agents from placebo in prespecified primary and secondary end points.