London, UK – May 15, 2026 – As the global rheumatology community converges on London for the European Alliance of Associations for Rheumatology (EULAR) 2026 congress, attention is sharply focused on the evolving landscape of psoriatic arthritis (PsA) treatment. While recent years have seen significant advancements with the introduction of targeted biologics such as AbbVie’s Skyrizi (risankizumab) and Johnson & Johnson’s Tremfya (guselkumab), a considerable unmet need persists. Patients continue to grapple with issues of treatment durability and the significant impact of comorbidities like obesity on treatment efficacy and overall disease management. This persistent challenge fuels intense pharmaceutical interest, with companies actively pursuing innovative therapies to address these gaps.
The immunology sector, particularly in rheumatology, has experienced a dramatic upswing, buoyed by the blockbuster success of established drugs like Sanofi’s Dupixent (dupilumab) and the aforementioned Skyrizi, which collectively generate billions in revenue. This robust market performance incentivizes further investment and research into novel treatments for inflammatory conditions like PsA. Clinical Trials Arena has delved into the most promising late-stage drug candidates poised to potentially reshape the PsA treatment paradigm, engaging with leading experts to gauge their potential uptake and impact.
Icotyde: A New Oral Frontier in Psoriatic Arthritis?
Johnson & Johnson (J&J), in partnership with Protagonist Therapeutics, is at the forefront of this evolving treatment landscape with its oral interleukin-23 (IL-23) inhibitor, Icotyde (icotrokinra). Fresh off its US regulatory approval for plaque psoriasis, the drug is now undergoing rigorous evaluation in three late-stage clinical trials for psoriatic arthritis. These include the ICONIC-PsA 1 and ICONIC-PsA 2 trials, which are assessing Icotyde in both biologic-naïve and experienced patient populations, respectively. A crucial third trial, ICONIC-ASCEND, is directly comparing Icotyde against AbbVie’s established IL-23 blocker, Stelara (ustekinumab), a pivotal move that will provide direct comparative efficacy data. Collectively, these trials involve over 2,000 patients across numerous global sites, underscoring the significant investment and expectation surrounding Icotyde’s potential in PsA.
Dr. Arthur Kavanaugh, Professor of Medicine and Rheumatologist at UC San Diego Health, acknowledges the potential appeal of Icotyde, drawing parallels to its anticipated success in psoriasis. However, he notes a critical divergence in clinical practice: "Dermatologists are increasingly adopting IL-23 blockers earlier in the treatment pathway for psoriasis, whereas rheumatologists treating PsA tend to be more cautious, often reserving these agents for later lines of therapy." This difference in prescribing patterns could influence the speed of Icotyde’s adoption within the PsA community.
Alexis Ogdie, Professor of Medicine at the University of Pennsylvania Perelman School of Medicine, offers a nuanced perspective on Icotyde’s profile. While the drug exhibits a favorable safety profile, she points to its potentially slower onset of action: "The drug appears to be slow-acting, which might make it less appealing for patients with highly active disease who are seeking rapid symptomatic relief." This characteristic could position Icotyde as a more suitable option for patients with moderate disease activity or those who prioritize long-term disease control over immediate symptom management.
Furthermore, Ogdie suggests that Icotyde may not be a revolutionary game-changer for PsA, citing the modest efficacy observed with the broader IL-23 class in this indication. Laura Coates, Honorary Consultant Rheumatologist at Oxford University Hospitals, echoes these sentiments. She highlights that Icotyde’s efficacy does not appear to surpass that of existing biologics. Additionally, the requirement for patients to fast each morning could be a deterrent, especially as longer-acting injectable therapies continue to enter the market. Despite these reservations, Coates remains cautiously optimistic: "I believe Icotyde will eventually see broad uptake in PsA, likely as a valuable oral option for a specific patient segment." The convenience of an oral formulation, if proven effective and well-tolerated, could indeed offer a significant advantage for patients who prefer to avoid injections.
MoonLake’s Sonelokimab: Challenging the IL-17 Dominance
Swiss biotech firm MoonLake Therapeutics is also vying for a significant share of the PsA market with its novel IL-17A and IL-17F inhibitor, sonelokimab. This therapy is positioned as a potential competitor to UCB’s Bimzelx (bimekizumab), another potent IL-17A/F inhibitor. Sonelokimab is currently undergoing Phase III evaluation in the IZAR-1 trial, focusing on patients who have not previously received disease-modifying therapies (DMTs). The trial, expected to complete its primary endpoint assessment in February 2027, has enrolled approximately 960 patients across 168 global sites, indicating a substantial commitment to establishing sonelokimab’s efficacy and safety in this patient population.
A key differentiator for sonelokimab is its nanobody-based delivery system, which MoonLake claims offers superior tissue penetration compared to traditional antibody-based approaches. However, Dr. Christopher Ritchlin, Professor of Medicine and Chief of Allergy, Immunology, and Rheumatology at the University of Rochester Medical Center, emphasizes the need for empirical evidence: "Sonelokimab will likely face a significant challenge competing with Bimzelx in PsA unless it can demonstrate clear differentiation in terms of efficacy or cost." The current market is already populated with effective IL-17 inhibitors, meaning any new entrant must offer a compelling advantage.
Coates shares a similar perspective, noting that while sonelokimab’s Phase II results met her expectations for the IL-17 class, it may be perceived as a "me too" option if approved. This sentiment is further amplified by sonelokimab’s prior performance in hidradenitis suppurativa (HS), where it failed to outperform Bimzelx. Adeleke Badejo, Managing Immunology Analyst at GlobalData, suggests that this outcome could limit sonelokimab’s ability to capture substantial market share across all indications, including PsA.
Despite these hurdles, Ogdie acknowledges sonelokimab’s "very strong" performance in Phase II trials, emphasizing that late-stage studies will be crucial in elucidating its comparative benefits. The nanobody technology, if it translates into superior clinical outcomes, could indeed offer a unique selling proposition. The potential for improved tissue penetration could lead to more consistent and profound therapeutic effects in the skin and joints affected by PsA.
Sprye Therapeutics: Exploring a Novel Mechanism of Action with SPY072
Amidst the growing dominance of interleukin blockers, Sprye Therapeutics is charting a different course with its extended half-life antibody targeting tumor necrosis factor-like cytokine 1A (TL1A), SPY072. This novel approach is being investigated in the Phase II SKYWAY-RD trial, which is assessing SPY072’s potential across a spectrum of rheumatological conditions, including PsA, axial spondyloarthritis (axSpA), and rheumatoid arthritis (RA).
The PsA sub-study within SKYWAY-RD is a placebo-controlled trial designed to evaluate SPY072 in patients with moderate-to-severe PsA who have failed to respond adequately to standard of care treatments, including NSAIDs, small molecule DMARDs, or existing biologic therapies. The broader trial has enrolled approximately 285 patients across 57 sites, with a predicted primary completion date of October 31, 2026.
The anti-TL1A class offers a potentially dual mechanism of action, aiming to suppress the immune response driving PsA and, crucially, prevent fibrotic tissue formation. Badejo elaborates on this potential: "While the dual effect of these drugs might be more critical in other inflammatory diseases like Crohn’s, it could still offer significant benefits in PsA, where fibrosis remains a concern." The potential to mitigate joint damage and structural changes could represent a significant advancement in long-term disease management.
Badejo further suggests that if anti-TL1A therapies demonstrate efficacy comparable to anti-IL-23 agents, they are likely to gain widespread adoption. Pharmaceutical companies are expected to leverage the anti-fibrotic benefits in their marketing campaigns, highlighting a unique advantage.
Coates views SPY072 and other TL1A inhibitors as offering a "truly novel mechanism in rheumatology." This could position them as valuable future options for patients who have exhausted treatment with established therapies like TNF, IL-17, or IL-23 inhibitors. She adds, "The extended half-life and potential for infrequent dosing could also give it an edge, but this depends critically on proven effectiveness and safety. There are potential safety or immune-related uncertainties with the class, as it influences such a different target, so we need further data to understand more." The precise impact of modulating TL1A on the broader immune system requires thorough investigation to ensure a favorable risk-benefit profile.
Sprye is not alone in its pursuit of the anti-TL1A market. MSD (Merck & Co.) is also actively investigating this pathway with its Phase II study, MK-7240-015, evaluating tulisokibart in adults with PsA. The presence of multiple companies exploring this novel mechanism underscores its perceived therapeutic potential.
Implications for the Future of PsA Treatment
The upcoming EULAR 2026 congress serves as a critical juncture for assessing the progress and future direction of psoriatic arthritis management. The late-stage development of Icotyde, sonelokimab, and SPY072 signifies a dynamic period of innovation. While established players continue to refine existing treatment paradigms, these emerging therapies offer the prospect of improved patient outcomes through novel mechanisms, enhanced convenience, and potentially greater durability.
Physicians are eager for new therapeutic options, particularly those that address the limitations of current treatments. Drugs that offer long-term disease control, mitigate comorbidities, and possess a favorable safety profile will undoubtedly have the most profound impact on the PsA treatment landscape. The clinical data emerging from the late-stage trials of these candidates will be closely scrutinized, guiding future treatment decisions and shaping the therapeutic strategies for psoriatic arthritis for years to come. The promise of oral formulations, differentiated mechanisms of action, and potentially improved efficacy underscores a hopeful outlook for patients living with this chronic and often debilitating condition.
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