Bimekizumab, a selective interleukin (IL)-17A/IL-17F inhibitor, and risankizumab, an IL-23 inhibitor, are approved treatments for psoriatic arthritis (PsA).¹ The phase 3b BE-BOLD study is the first head-to-head PsA trial to evaluate superiority of bimekizumab vs. risankizumab for a joint-focused primary endpoint.¹ At the EULAR 2026 Congress, Dr. Joseph Merola from the University of Texas Southwestern Medical Center, United States, presented the updated 24-week efficacy and safety data from the ongoing study.¹

BE-BOLD enrolled adults with active PsA, with a tender joint count (TJC) of ≥3/68 and swollen joint count (SJC) of ≥3/66, who were biologic-naïve or had an inadequate response or intolerance to ≤1 prior tumor necrosis factor (TNF) inhibitor.¹ Patients were randomized to receive bimekizumab 160mg every 4 weeks (Q4W) in those with no to moderate psoriasis (n=248), bimekizumab 320mg Q4W to week 16 followed by Q8W in those with moderate to severe psoriasis (n=29), or risankizumab 150mg at baseline, week 4, and every 12 weeks (Q12W) thereafter.¹ The primary endpoint was superiority of bimekizumab vs. risankizumab in the proportion of patients achieving at least 50% improvement in the American College of Rheumatology response criteria (ACR50) at week 16.¹

A total of 553 patients were randomized, with >90% completing week 24.¹ Baseline characteristics were generally balanced, with ~20% having had prior TNF inhibitor exposure and ~10% having moderate-to-severe psoriasis at baseline.¹ BE-BOLD met its primary endpoint, with significantly more bimekizumab-treated patients achieving ACR50 at week 16 than risankizumab-treated patients (49.1% vs. 38.0%; D11.1 percentage points; p=0.0058).¹ Treatment differences emerged as early as week 4 and were maintained through week 24, with higher ACR50 response with bimekizumab at all assessed time points (nominal p<0.0001 at week 8; p=0.0055 at week 12; p=0.0179 at week 20; p=0.0059 at week 24).¹

Numerically higher response rates with bimekizumab were observed across multiple secondary efficacy outcomes through week 24.¹ Although statistical significance was not achieved for minimal disease activity (MDA), responses consistently favored bimekizumab over risankizumab.¹ Among patients with ≥3% baseline body surface area (BSA) involvement, most had mild-to-moderate psoriasis, and 83.5% received the PsA dosing regimen of bimekizumab 160mg every 4 weeks.¹ In this subgroup, numerically higher proportions of bimekizumab-treated patients achieved the composite ACR50 + Psoriasis Area and Severity Index 100 (PASI100) response across all assessed time points through week 24, while PASI100 responses were higher with bimekizumab through week 12 and comparable at weeks 20 and 24.¹ Similarly, Disease Activity Index for Psoriatic Arthritis (DAPSA) low disease activity/remission responses numerically favored bimekizumab throughout the 24-week evaluation period.¹

Safety findings to week 24 were consistent with the established safety profile of bimekizumab, with a comparable safety profile between treatment groups and no new safety signals identified.¹ Serious adverse events were infrequent across both treatment arms.¹ Candida infections occurred more frequently in bimekizumab-treated patients, but all cases were mild or moderate, with no serious systemic infections or discontinuation.¹ No cases of suicidal ideation or behavior, anaphylaxis, or active tuberculosis were reported.¹

In conclusion, BE-BOLD demonstrated superiority of dual IL-17A/IL-17F inhibition with bimekizumab over IL-23 inhibition with risankizumab for the joint-focused primary endpoint of ACR50 at week 16 in patients with active PsA.¹ Numerically higher response rates across joint, skin, and overall disease activity outcomes were maintained through week 24, with comparable overall safety profiles between treatments.¹ As the first head-to-head PsA study to demonstrate superiority for a joint-focused primary endpoint, these findings may inform treatment decisions and future clinical recommendations for PsA management.¹