Deucravacitinib (Sotyktu) 3-Year POETYK Extension Data: 69% Maintain PASI 75 with No Increased Infection or Malignancy Risk

What Is Deucravacitinib and Why Is Its Selectivity Important?

Deucravacitinib (brand name Sotyktu, developed by Bristol-Myers Squibb) represents a fundamentally different approach to Janus kinase pathway modulation. While earlier JAK inhibitors such as tofacitinib (Xeljanz), baricitinib (Olumiant), and upadacitinib (Rinvoq) block JAK1, JAK2, and/or JAK3, deucravacitinib exclusively inhibits tyrosine kinase 2 (TYK2) through an allosteric mechanism that binds the TYK2 pseudokinase (JH2) domain rather than the catalytic (JH1) domain. This unique binding mode provides over 100-fold selectivity for TYK2 versus JAK1, JAK2, and JAK3, which is critical because JAK1/2 inhibition is responsible for the immunosuppression, cytopenias, lipid elevations, and thromboembolic events that led the FDA to impose boxed warnings on tofacitinib, baricitinib, and upadacitinib.

TYK2 specifically mediates signaling downstream of the IL-23, IL-12, and type I interferon receptors — three cytokine pathways centrally implicated in psoriasis pathogenesis. IL-23 drives the differentiation and expansion of pathogenic Th17 cells that produce IL-17A and IL-17F, the effector cytokines responsible for keratinocyte hyperproliferation and epidermal inflammation. IL-12 promotes Th1 cell differentiation and IFN-gamma production, contributing to the chronic inflammatory infiltrate. By selectively suppressing these pathways without broadly compromising host defense (which depends on JAK1/2-mediated IFN-gamma, IL-6, and hematopoietic cytokine signaling), deucravacitinib achieves targeted immunomodulation with a more favorable safety profile than pan-JAK inhibitors.

What Do the 3-Year POETYK Extension Results Show?

The POETYK long-term extension (LTE) enrolled patients who completed the 52-week POETYK PSO-1 or PSO-2 parent trials and continued open-label deucravacitinib 6 mg once daily for an additional two years (total approximately 156 weeks). Based on long-term extension data, PASI 75 was maintained by approximately 69% of patients, PASI 90 by roughly 41%, and complete clearance (PASI 100) by approximately 18% at the three-year mark. The static Physician's Global Assessment (sPGA) score of 0 or 1 (clear or almost clear) was achieved by a majority of patients continuing treatment.

Importantly, response rates appeared to plateau by approximately week 24 and remained stable through year 3, with no evidence of secondary loss of efficacy — a phenomenon sometimes observed with biologic therapies due to immunogenicity. Dermatology Life Quality Index (DLQI) improvements were also maintained, with a substantial proportion of patients reporting no impact on quality of life at three years. Among patients who had been randomized to placebo in the parent trials and switched to deucravacitinib at week 16 or 24, response rates at three years were comparable to those who received deucravacitinib from the outset, indicating full efficacy can be achieved regardless of delayed initiation.

How Does the Safety Profile Compare to TNF Inhibitors and IL-17/IL-23 Biologics?

Cumulative safety analysis across the POETYK long-term extension demonstrated a reassuring profile. The rate of serious infections remained consistent with the rate observed during the placebo-controlled period and comparable to background rates in the psoriasis population. Notably, no significant signal for opportunistic infections, including herpes zoster requiring hospitalization or disseminated disease, was observed — a notable distinction from JAK1/2/3 inhibitors, where herpes zoster rates of 3–4 per 100 patient-years have been consistently documented in clinical trials. There were no reported cases of active tuberculosis.

Malignancy rates (excluding non-melanoma skin cancer) remained consistent with age- and sex-matched population background rates and did not increase with longer exposure duration. MACE events and venous thromboembolism (DVT or PE) occurred at rates within background population expectations. These data stand in contrast to the ORAL Surveillance study of tofacitinib, which demonstrated increased rates of MACE and malignancy versus TNF inhibitors in rheumatoid arthritis patients aged 50 and older with cardiovascular risk factors, leading to the FDA boxed warning now applied to all JAK inhibitors.

Compared to injectable biologics commonly used in psoriasis, deucravacitinib's safety profile appears favorable. TNF inhibitors carry well-documented risks of serious infections (approximately 1.8–2.5 per 100 patient-years in registry data), demyelinating disease, and heart failure exacerbation. IL-17 inhibitors (secukinumab, ixekizumab) are associated with candidiasis and a theoretical concern regarding inflammatory bowel disease. IL-23 inhibitors (guselkumab, risankizumab, tildrakizumab) have excellent safety profiles but require injection and are generally more expensive. Deucravacitinib's oral route, once-daily dosing, and favorable safety data position it as an attractive first-line systemic option for patients preferring oral therapy over injection.

Who Is a Good Candidate for Deucravacitinib Treatment?

The long-term data strengthen the evidence supporting deucravacitinib as a first-line oral systemic therapy for moderate-to-severe plaque psoriasis. The ideal candidate profile includes patients who prefer oral medication over injectable biologics, those with cardiovascular risk factors or a history of venous thromboembolism where JAK1/2/3 inhibitors would be contraindicated or high-risk, patients who have failed or cannot tolerate methotrexate or other conventional systemics (acitretin, cyclosporine, apremilast), and those seeking the convenience of once-daily dosing without the need for extensive laboratory monitoring.

The POETYK PSO-1 trial demonstrated deucravacitinib's superiority over apremilast (Otezla), the other oral systemic commonly used in psoriasis, with PASI 75 rates of approximately 53% versus 32% at week 16. For patients who require higher levels of skin clearance (PASI 90+), IL-23 inhibitors such as risankizumab (Skyrizi) and guselkumab (Tremfya) remain the most effective options, achieving PASI 90 rates in the range of 72–75% at one year in clinical trials. However, deucravacitinib's approximately 41% PASI 90 rate at three years is clinically meaningful and sufficient for a large proportion of patients. Contraindications include severe hepatic impairment, active serious infection, and concomitant use of strong immunosuppressants. Pregnancy is a contraindication based on preclinical data.