Arctic Bioscience (ABS) Study result summary

Study design and objectives

• Phase IIb HeROPA study evaluated HRO350 in 521 patients with mild-to-moderate psoriasis across multiple European countries, using a randomized, placebo-controlled design with primary and secondary endpoints at 26 and 52 weeks.

• The primary endpoint was PASI50 at 26 weeks; secondary endpoints included change in PASI and Physician's Global Assessment (PGA 0/1) at 52 weeks.

• Study protocol was based on scientific advice from the EMA, with dosing arms of 2100 mg and 1050 mg HRO350 versus placebo.

• The study included a follow-up period post-treatment to assess durability and safety.

Efficacy and safety results

• The primary endpoint (PASI50 at 26 weeks) was not met due to high placebo response and disease fluctuation in mild cases.

• Key secondary endpoint PGA 0/1 approached statistical significance (p=0.07) in the per protocol population, with nearly half of high-dose patients achieving clear or almost clear skin at 52 weeks compared to 34% on placebo (p=0.073).

• Statistically significant improvements were observed in relevant subgroups by age (≥50 years, p=0.043) and weight (≤98 kg, p=0.041), with lower placebo rates in these groups.

• Efficacy was consistent in patients who completed one year of treatment, with higher response rates in certain subgroups.

• HRO350 demonstrated a robust safety profile with no serious safety concerns, drug-related SAEs, or SUSARs reported, and was well tolerated over 12 months.

Study context and challenges

• High placebo response complicated data analysis and interpretation of efficacy, especially in younger patients and those with lower baseline severity.

• Patients with higher baseline disease severity (PASI ≥6) had lower placebo response and similar active arm response.

• The study included skilled clinical staff and provided good patient care throughout.