Oral Therapy in Psoriatic Arthritis: JAK, TYK2, and the End of Methotrexate Monotherapy?

Alvin F. Wells, MD, PhD, addressed persistent gaps in psoriatic arthritis (PsA) care, particularly delayed diagnosis and undertreatment, and reviewed the expanding role of oral targeted therapies during his Masterclasses in Dermatology session, “Addressing Unmet Needs in Psoriatic Arthritis: Diagnosis, Pathogenesis, and Newer/Emerging Oral Therapies.”

Psoriasis affects approximately 7.5 million adults in the United States, and up to 30% develop PsA. “We know there’s some synchrony between the gut, the skin, and the joint.” Most patients develop psoriasis before joint symptoms, and the peak onset occurs between ages 30 and 50 years. PsA is a “heterogeneous disease that manifests in multiple ways across different domains,” including peripheral arthritis, axial disease, enthesitis, dactylitis, nail disease, and skin manifestations. Limited screening tools, absence of definitive biomarkers, and variable presentations contribute to diagnostic delay.

Pathogenetically, JAK/STAT signaling mediates the inflammatory and metabolic interplay within psoriatic synovium. In vitro data demonstrate that JAK inhibition suppresses pathogenic synovial fibroblast activity, including MCP-1 and IL-6 secretion, migration, matrix metalloproteinase expression, and glycolytic metabolism. “This inhibition shows effective suppression of inflammatory mechanisms that drive pathogenic functions of PsA synovial fibroblasts, further supporting the role of JAK inhibition as a therapeutic target for the treatment of PsA.​” These mechanistic insights underpin the clinical efficacy of JAK and TYK2 inhibitors in PsA.

Dr Wells addressed that methotrexate, once considered foundational, carries significant toxicity risks, including organ system toxicity, bone marrow suppression, pulmonary injury, teratogenicity, and malignancy concerns.

Apremilast (PDE4 inhibitor) demonstrated American College of Rheumatology 20 responses in PALACE 1–3, including in patients with prior biologic exposure. However, joint and skin responses remain modest compared with newer agents.

The oral TYK2 inhibitor deucravacitinib represents a more targeted advance. In POETYK PsA-1 and PsA-2, deucravacitinib demonstrated superior efficacy vs placebo at week 16 across musculoskeletal and dermatologic endpoints, overall disease activity measures, and quality-of-life metrics. Radiographic inhibition and durable responses were observed through week 52.

Next, Dr Wells did a comparative analyses of drugs in PsA and suggested that small molecules and biologics vary in joint and skin efficacy profiles. Selection should account for domain predominance, prior biologic exposure, comorbid inflammatory bowel disease, and patient preference.

 “JAK/STAT signaling mediates the complex interplay between inflammation and cellular metabolism in PsA pathogenesis,” concluded Dr Wells. “Newer treatment options have allowed better clinical responses in most patients, including new oral therapies.”

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Reference

Wells AF. Addressing unmet needs in psoriatic arthritis: diagnosis, pathogenesis, and newer/emerging oral therapies. Presented at: Masterclasses in Dermatology; February 19–22, 2026; Sarasota, FL.