Arctic Bioscience — Regulatory Filings 2025

Nov 4, 2025

HRO350 in mild-to-moderate psoriasis The HeROPA phase 2b clinical trial

Attachment to stock exchange release November 4th 2025

Psoriasis severity assessments and inflammation measured in blood

PASI is a measure of skin symptoms, SII reflects systemic inflammation and immune status of the patient¹

Comments

PASI: The Psoriasis Area and Severity Index

• 0–72-point scale where < 10 is mild-moderate disease¹⁴

All patients in HeROPA had a PASI 3-10 at start

SII: Systemic Immune-inflammation Index – a biomarker which correlates with psoriasis severity and disease activation^2-8

SII < 500 may reflect mild-to-moderate inflammation

Half of the patients in the HeROPA trial had SII > 506, associated higher systemic inflammation

Systemic Immune-inflammation Index (SIII) reflects systemic inflammation and immune activation. SII = (Neutrophils × Platelets) / Lymphocytes

^1. Guo H huan, Chen R xi. Association of systemic inflammation index with psoriasis risk and psoriasis severity; A retrospective cohort study of NHANES 2009 to 2014. Medicine, 2024 Feb 23;103(8);e37235, 2. Dincer Rota D., Tanacan E. The utility orkers yestemic inflammation index with psoriasis risk and psoriasis severity; A retrospective cohort study of NHANES 2009 to 2014. Medicine, 2024 Feb 23;103(8);e37235, 2. Dincer Rota D., Tanacan E. The utility orkers as potential biomarkers or systemic inflammation index spatial properties. The Relationship Between Neutrophil-to-Lymphocyte Ratio, and Systemic immune-Inflammation index spatial properties. A group of the inflammation per very systemic inflammation index spatial properties. The Relationship Between Neutrophil-to-Lymphocyte Ratio, and Systemic immune-Inflammation index spatial properties. A group of the inflammation index spatial properties of the disease severity in psoriasis patients. A chang Y, Gian H, Kuang Y, Chen WQ, Zhu W, Evaluation of the inflammation index as potential biomarkers or systemic inflammation index as potential biomarkers or systemic inflammation index as patients with psoriasis: A retrospective study. Tropical Medicine & International Health. 2024;29(11):971–8. The Systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a measure of systemic inflammation index as a mea

HRO350 reduced systemic inflammation in the HeROPA trial

SII post-hoc analyses on all patients in per-protocol population

Comments

PGA is a measure of psoriasis skin symptoms:

• PGA 0/1 "clear-or-almost clear skin"

Systemic inflammation is measured in blood:

• 25% reduction in SII

Reducing inflammation is beneficial for patients with inflammatory conditions

Dermatology Life Quality Index (DLQI). DLQI 0/1 means skin symptoms have "no effect at all on patient's life"

Systemic Immune-inflammation Index (SII) reflects systemic inflammation and immune activation. SII = (Neutrophils × Platelets) / Lymphocytes

Preliminary analyses, data on fileHeROPA preliminary analyses, Data-on-file. Efficacy and Safety Study of HRO350 in Patients with Mild-to-moderate Psoriasis (the 'HeROPA' Study) ClinicalTrials.gov ID NCT06125808 1. Kimak-Pielas A, Robak E, Zajdel R, Żebrowska A. The Relationship Between Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, and Systemic Immune-Inflammation Index Markers and Response to Biological Therapy in Patients with Psoriasis. International Journal of Molecular Sciences. 2025 Jan;26(8):3868

PP: Per Protocol population who completed 52 weeks: n = 272. Data as observed.

^*: Statistically significant difference to placebo with p < 0.005. **: Statistically significant difference to placebo with p < 0.01

Static PGA (sPGA) measures physician's impression at a single time point. Static form is standard due to reliability. PGA 0/1 means the physician assesses the patient as "clear-or-almost clear skin.

Systemic inflammatory state impacted response in the HeROPA trial

Patients with mild-to-moderate inflammation (SII ≦ 506) at baseline showed significant improvements in skin symptoms (PGA), and clinically relevant improvement in inflammation

Half the patients in the HeROPA trial had a SII under 506, where the two lower quartiles align with lower systemic inflammation, associated with mild-moderate psoriasis

Reduction in SII appear before changes in skin symptoms

SII may be useful to evaluate in patients in future clinical trials

PP: Per Protocol population who completed 52 weeks: n = 272. Patients with SII ≦ 506 at baseline (lower two quartiles: n = 261, Data as observed. *: Statistically significant difference to placebo with p < 0.005. ***: Statistically significant difference to placebo with p < 0.001

Static PGA (sPGA) measures physician's impression at a single time point. Static form is standard due to reliability PGA 0/1means the physician assesses the patient as "clear-or-almost clear skin. Dermatology Life Quality Index (DLQI). DLQI 0/1 means skin symptoms have "no effect at all on patient's life"

Age and weight impacted response in the HeROPA trial

Response rates higher in patients with weight $\leq$ 98 kg Placebo rates lower in patients age $\geq$ 50 years

Comments

PGA 0/1 means "clear-or-almost clear skin"

All patients had PGA scores $\geq 2$ and $\leq 4$ at inclusion

Placebo rates lower in patients age ≥ 50 years (median age)

Effect rate higher in patients with weight ≤ 98 kg (lower three weight quartiles)

PP: Per Protocol population who completed 52 weeks: n = 272. Data as observed.
*: Statistically significant difference to placebo with p < 0.005