UCB (UCB) Investor update summary

Study Overview and Rationale

• BE BOLD is a head-to-head, randomized, double-blind phase 3b trial comparing bimekizumab (IL-17AF inhibitor) and risankizumab (IL-23 inhibitor) in psoriatic arthritis, focusing on joint outcomes.

• The primary endpoint was ACR50 at week 16, a stringent and clinically meaningful joint response measure.

• The study included both biologic DMARD-naive patients and those intolerant to one prior TNF inhibitor, with balanced baseline characteristics.

• Licensed, approved doses were used for both drugs, with dosing adjusted for patients with moderate to severe skin disease.

• Hierarchical statistical testing prioritized non-inferiority, then superiority, followed by composite and skin outcomes.

Key Efficacy and Safety Results

• Bimekizumab achieved a 49.1% ACR50 response at week 16 versus 38.0% for risankizumab, an 11% statistically significant delta (p=0.0058).

• The ACR50 response was sustained over time, with over 50% of patients maintaining stringent joint control at three years, regardless of prior treatment history.

• Secondary outcomes showed numerically higher but not statistically significant differences in minimal disease activity and skin clearance for bimekizumab.

• Safety profiles were comparable; higher rates of mild or moderate candida infections were observed with bimekizumab, but no new safety signals emerged and no discontinuations occurred.

• One death occurred, unrelated to treatment, and no cases of suicidal ideation or anaphylaxis were reported.

Clinical and Prescribing Impact

• The 11% delta in ACR50 is considered clinically meaningful, especially given the challenge of improving joint outcomes in psoriatic arthritis.

• Early and sustained separation in efficacy is valued, as rapid symptom improvement is critical for patient outcomes.

• BE BOLD data reinforce clinical impressions and are expected to influence treatment guidelines and prescribing practices.

• Bimekizumab is viewed as a go-to, first-line agent for psoriatic arthritis by expert clinicians, though payer restrictions may limit access.

• The data are expected to inform upcoming updates to major treatment guidelines (GRAPPA, ACR, EULAR), with immediate impact on clinical decision-making and longer-term influence as guidelines are revised.