Bimekizumab beats risankizumab on joint outcomes in first psoriatic arthritis head-to-head

Overview

Updated 1 hour ago

Bimekizumab produced higher joint-response rates than risankizumab in psoriatic arthritis, and the gap held at every measured timepoint through Week 24. At Week 24, 54.9% of patients on bimekizumab reached ACR50 against 43.8% on risankizumab.

The statistically validated win is the Week 16 primary endpoint: 49.1% versus 38.0%, an 11.1 percentage-point gap with a p-value of 0.0058. The trial then missed its first ranked secondary endpoint, minimal disease activity, which halted the formal testing sequence and makes every later comparison, including the Week 24 numbers, descriptive rather than confirmed.

Why it matters

Psoriatic arthritis treatment choices between two major biologic classes now rest on direct trial evidence rather than indirect comparisons.

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Key Indicators

54.9%

ACR50 response at Week 24, bimekizumab

Share of patients achieving a 50% improvement in American College of Rheumatology response criteria.

43.8%

ACR50 response at Week 24, risankizumab

The comparator arm in the same 553-patient trial.

11.1 pts

ACR50 gap at the Week 16 primary endpoint

49.1% versus 38.0%, the only comparison that cleared the trial's pre-specified superiority test.

553

Patients randomized in BE BOLD

277 received bimekizumab and 276 received risankizumab; 93.1% and 90.2% respectively completed Week 24.

2.9%

Candida infections on bimekizumab

Versus 0.7% on risankizumab; all cases were mild or moderate and none led to discontinuation.

Voices

Curated perspectives — historical figures and your fellow readers.

Organizations Involved

US Children's Bureau

Federal Agency

Sponsor of BE BOLD and maker of bimekizumab (BIMZELX)

Belgian drugmaker that ran the first head-to-head trial of an IL-17A/F inhibitor against an IL-23 inhibitor in psoriatic arthritis.

AbbVie (Allergan)

Pharmaceutical company

Makes risankizumab (SKYRIZI), the comparator drug in BE BOLD

Manufacturer of the IL-23 inhibitor that bimekizumab was tested against.

Timeline

June 2026 November 2026

4 events Latest: Today

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November 2026
BE BOLD abstract presented in ACR plenary session
Upcoming Conference

Full 24-week efficacy and safety results presented at ACR Convergence in Orlando.
Tomorrow • 10:15 AM
UCB reports Week 24 data
Today Readout

ACR50 reaches 54.9% on bimekizumab versus 43.8% on risankizumab, with no new safety signals.
Today
June 2026
UCB briefs investors on the Week 16 readout
Readout

Company presents BE BOLD's primary endpoint result to investors ahead of full disclosure.
June 8th, 2026
Week 16 results presented at EULAR 2026
Conference

Bimekizumab shows 49.1% versus 38.0% ACR50, clearing superiority with p=0.0058.
June 2026

Scenarios

EULAR and GRAPPA guidelines cite the head-to-head data

Possible Resolves by End of 2027

Discussed by: Rheumatology commentators covering the ACR presentation, including RheumNow

Guideline panels weigh direct comparative evidence differently from network meta-analysis. If BE BOLD is cited in the next round of psoriatic arthritis recommendations, it would give IL-17A/F inhibition an explicit place in treatment sequencing rather than leaving the choice to clinician preference.

US payers keep IL-23 inhibitors as preferred psoriatic arthritis biologics

Likely Resolves by Q2 2027

Discussed by: No specific analyst commentary found in cited sources; scenario reflects standard formulary behavior

Formulary placement turns on price and negotiated rebates as much as on efficacy. A single trial showing an 11-point joint-response advantage may not move a pharmacy benefit manager that already has a discounted IL-23 contract in place.

UCB seeks expanded labeling based on the comparator data

Uncertain Resolves by Q2 2028

Discussed by: UCB, in its own framing of the trial as a treatment-decision tool

Comparative trial results sometimes appear in a drug's prescribing information as clinical study sections, which gives sales representatives something more concrete than cross-trial comparison. Whether regulators accept the descriptive Week 24 data, given the halt in the testing sequence, is the open question.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2019-2020

SPIRIT-H2H (2020)

Ixekizumab, an interleukin-17A inhibitor, was tested head-to-head against adalimumab, then the most widely used TNF inhibitor in psoriatic arthritis. The design used a combined joint-and-skin primary endpoint rather than a joint measure alone.

Then

The trial reported superior combined responses for ixekizumab, giving the IL-17 class a comparative claim in psoriatic arthritis.

Now

Head-to-head trials became an accepted way to differentiate biologics in this disease, though the primary endpoints tended to blend joint and skin outcomes.

Why this matters now

BE BOLD follows that template but puts a joint-focused measure, ACR50, at the primary endpoint, which is why its result carries more weight for musculoskeletal outcomes.

2019-2025

The IL-17 versus IL-23 choice (2019-2025)

Both IL-17 inhibitors and IL-23 inhibitors accumulated approvals for psoriatic arthritis. No trial had directly compared the two classes, so clinicians chose between them using network meta-analyses and separate placebo-controlled studies. The BE BOLD investigators state that no head-to-head study of biologic disease-modifying drugs had shown superiority in joint-focused outcomes in psoriatic arthritis before this one.

Then

Prescribing split by skin severity, infection risk tolerance and payer coverage rather than by direct comparative evidence.

Now

The IL-23 class gained ground on a reputation for durable skin clearance and a lower Candida infection rate than IL-17 inhibitors.

Why this matters now

BE BOLD replaces an indirect comparison with a randomized one, and its Candida finding (2.9% versus 0.7%) shows the trade-off that made the IL-23 class attractive has not disappeared.