Arctic Bioscience — Investor Presentation 2025

Nov 4, 2025

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

Attachment to stock exchange release November 4th 2025

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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 activation2-8

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 (SII) reflects systemic inflammation and immune activation, SII = (Neutrophils × Platelets) / Lymphocytes

1. Guo H huan, Chen R xi. Association of systemic inflammation index with psoriasis severity: A retrospective cohort study of NHANES 2009 to 2014, Medicine. 2024 Feb 23;103(8);e387236. 2. Dincer Rota D, Tanacan E. The utility of systemic inflammation index with psoriasis is severity: A retrospective cohort study of NHANES 2009 to 2014. Medicine. 2024 Feb 23;103(8);e386.4. 2 Dincer Rota D, Tanacan E. The utility of systemic inflammation index Marker in psoriasis is severity: A protect part of the Relationship Between Neutrophil-to-Lymphocyte Ratio, and Systemic Immune-Inflammation index Marker and Response in Biological Therapy 1, 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1), 2014 (1)

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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

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.

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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

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

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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