AbbVie’s new immunology standard-bearer Skyrizi kneels to UCB’s Bimzelx in psoriatic arthritis

Bimzelx Shows Superior Joint Relief Over Skyrizi in Head-to-Head Phase 3

UCB's Bimzelx demonstrated superior efficacy over AbbVie's Skyrizi in a Phase 3 head-to-head study for psoriatic arthritis. At 16 weeks, 49.1% of patients on Bimzelx achieved ACR50, a measure of at least 50% improvement in joint symptoms, compared to 38.4% on Skyrizi, a statistically significant difference. While Bimzelx also showed numerically better outcomes for minimal disease activity (43% vs 39.9%), this difference did not reach statistical significance, impacting further hierarchical analysis of secondary endpoints. Both drugs are already approved for psoriatic arthritis and plaque psoriasis.

• Superior Joint Symptom Improvement: UCB's Bimzelx achieved a statistically significant superior response in joint symptoms compared to AbbVie's Skyrizi in a Phase 3 head-to-head trial for psoriatic arthritis. At 16 weeks, 49.1% of patients treated with Bimzelx reached ACR50, indicating at least a 50% improvement in joint symptoms, quality of life, and functional performance, significantly outperforming Skyrizi's 38.4% response rate.
• Mixed Secondary Endpoint Results: While Bimzelx demonstrated a numerically better outcome for minimal disease activity at 16 weeks, with 43% of patients achieving this compared to 39.9% on Skyrizi, this difference was not statistically significant. Consequently, further statistical analysis of other secondary endpoints was precluded due to the study's hierarchical design, despite UCB reporting better outcomes across several other measures, including early joint relief and complete psoriasis clearance.
• Implications for Psoriatic Arthritis Treatment: This head-to-head trial provides critical comparative data for the psoriatic arthritis treatment landscape, where both Bimzelx and Skyrizi are already approved therapies. The results underscore Bimzelx's strong efficacy in joint relief, offering clinicians and patients additional evidence to inform treatment decisions in a competitive market. The study reinforces the value of rigorous comparative research in immunology.

Bimzelx's Head-to-Head Victory Over Skyrizi in Psoriatic Arthritis

Recent clinical trials and real-world studies have provided valuable insights into emerging therapies for psoriatic arthritis, particularly highlighting the efficacy of IL-17 and IL-23 inhibitors. These studies demonstrate both promising efficacy outcomes and generally favorable safety profiles across diverse patient populations.

• TOGETHER-PsA Trial (2026) evaluated ixekizumab plus tirzepatide versus ixekizumab alone in 271 overweight/obese PsA patients, achieving the primary endpoint of simultaneous ACR50 and ≥10% weight reduction in 31.7% versus 0.8% of patients (P<0.001), with safety profiles consistent with previous studies and no new safety concerns

• TOFA-PREDICT Trial (2026) examined tofacitinib compared with methotrexate or etanercept in 80 PsA patients using a four-arm randomized design, with 50% achieving minimal disease activity at 16 weeks and an integrated multi-omics model achieving AUC=0.70±0.19 for predicting treatment response

• PARWCH Database Study (2025) compared adalimumab, secukinumab, and upadacitinib in 187 PsA patients over 24 weeks, showing comparable peripheral joint efficacy but superior skin outcomes for secukinumab and upadacitinib (PASI90: SEC vs. ADA, Coef=1.84, p=0.006), with 85 adverse events in 48 patients and no serious adverse events

• Real-world guselkumab study (2025) followed 70 PsA patients for 12 months, demonstrating significant reductions in DAS28, DAPSA, MASES, and ASDAS scores with a 79% retention rate and no significant adverse events reported

• Bimekizumab case series (2026) reported complete remission of joint and skin manifestations in three challenging PsA cases treated with the dual IL-17A/F inhibitor, including patients with isolated axial disease, severe psoriasis with morbid obesity, and refractory disease with multiple prior biologic failures

• Reuma.pt Registry Study (2025) tracked health-related quality of life in 342 PsA patients over three years, showing significant improvements in EQ-5D scores, with poorer outcomes associated with prior exposure to three or more biologics (β=-0.182; p=0.04) and biologic switching during follow-up (β=-0.150; p=0.002)

The Rigorous Design of the Bimzelx vs. Skyrizi PsA Trial

Key psoriatic arthritis trials have employed diverse study designs with standardized efficacy endpoints to establish treatment benefit across different therapeutic classes. The trials range from phase 2 proof-of-concept studies to large-scale head-to-head comparisons, with durations spanning 12 to 52 weeks and patient populations including both biologic-naïve and biologic-experienced cohorts.

Bimzelx's Impact on the Evolving Psoriatic Arthritis Treatment Landscape

The psoriatic arthritis treatment landscape has undergone significant transformation over the past five years, driven by the introduction of novel therapeutic mechanisms and accumulating real-world evidence. Janus kinase inhibitors have emerged as a unique therapeutic class, with upadacitinib, a selective JAK1 inhibitor, demonstrating high efficacy in phase III clinical trials (SELECT-PsA 1 and SELECT-PsA 2). The drug proved non-inferior to adalimumab across multiple disease domains including dactylitis, enthesitis, spondylitis, physical function, pain, fatigue, and quality of life. JAK1 receptor selectivity offers promise for improved safety profiles compared to nonselective JAK inhibitors, which carry increased risk of off-target effects such as hematopoietic suppression. Additionally, novel mechanisms including TYK2/JAK1 inhibitors like brepocitinib and selective allosteric TYK2 inhibitors such as deucravacitinib have shown significant efficacy in phase II trials, expanding the therapeutic armamentarium beyond traditional biologics.

Real-world evidence has provided crucial insights into treatment persistence and comparative effectiveness across biologic classes. A comprehensive French nationwide cohort study revealed that overall 3-year persistence rates remained low at 40.9% for psoriasis and 36.2% for psoriatic arthritis across all biologics. However, IL-17 inhibitors demonstrated superior persistence compared to TNF inhibitors for PsA (weighted HR 0.70) and IL-12/23 inhibitors (weighted HR 0.69). Long-term studies of established therapies have reinforced their durability, with ustekinumab showing sustained efficacy through 160 weeks in the SUSTAIN study, where 100% of patients rated tolerability as good or very good. Guselkumab demonstrated 3.0 times greater likelihood of on-label treatment persistence compared to subcutaneous TNF inhibitors at 12 months in real-world US data, with persistence rates of 71.5% versus 43.7% respectively.

Treatment approaches have become increasingly personalized based on disease phenotype and patient characteristics. Recent meta-analyses revealed significant sex-related differences in treatment response, with male patients showing higher ACR20, ACR50, and minimal disease activity response rates across most drug classes except JAK and TYK2 inhibitors. Expert consensus has shifted toward phenotype-driven treatment selection, recommending IL-17 inhibitors like secukinumab for extensive skin involvement and TNF inhibitors for predominant joint involvement. The emergence of dual IL-17A/IL-17F inhibitors such as bimekizumab has demonstrated sustained clinical efficacy for up to 2 years in both biologic-naïve and TNF inhibitor-experienced patients. Treatment patterns show increasing biologic utilization over time, with a corresponding decline in combination therapy after 2013, likely reflecting improved efficacy of newer biologics and reduced need for adjunctive oral small molecule therapy.

Bimzelx's PsA Victory: A New Chapter in Biologic Competition

The recent head-to-head Phase 3 results pitting UCB's bimekizumab (Bimzelx) against AbbVie's risankizumab (Skyrizi) in psoriatic arthritis (PsA) have sent a clear signal through the inflammatory disease market. Bimzelx demonstrated statistically significant superiority in achieving ACR50, a key measure of joint symptom improvement, at 16 weeks. This is a notable win for bimekizumab, which uniquely targets both IL-17A and IL-17F, a mechanism supported by literature suggesting its potential for robust efficacy in both psoriasis and PsA. Studies indicate bimekizumab's rapid onset and high rates of skin clearance, and its favorable ranking in network meta-analyses for PsA outcomes, including minimal disease activity.

However, the narrative is nuanced. While bimekizumab showed numerically better outcomes for minimal disease activity, this did not reach statistical significance. This suggests that while bimekizumab may offer a superior joint response for some patients, its overall disease control across all PsA domains might require further differentiation. Risankizumab, an IL-23 inhibitor, remains a highly effective treatment, with extensive evidence of superior skin clearance in psoriasis against multiple comparators and strong real-world efficacy in PsA. For patients with predominant skin manifestations or those prioritizing complete skin clearance, risankizumab continues to be a compelling option.

This direct comparison intensifies the competitive landscape for PsA biologics. Clinicians and patients will now have more specific data to consider when making treatment decisions, potentially leading to more individualized approaches based on primary disease manifestations (joint vs. skin) and patient preferences. Companies will need to refine their strategic messaging, emphasizing distinct efficacy profiles and long-term safety. Bimekizumab's known safety profile, including a higher frequency of oral candidiasis and diarrhea, will also be a factor in patient selection, underscoring the importance of a comprehensive risk-benefit assessment in this evolving therapeutic area.