Watchlist Update: Arctic Bioscience (ABS.OL)

12-month data shows signs of efficacy – but is it enough?

Arctic Bioscience has just released top-line results from its pivotal HeROPA phase 2b trial, evaluating HRO350, an oral drug candidate for mild-to-moderate psoriasis. The company is trying to bring a well-tolerated, natural, marine-based treatment to a patient segment with limited good options – and today's update marks a critical inflection point.

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Key Efficacy Findings

The trial's primary endpoint (PASI50 at 26 weeks) was not met, as previously disclosed in October 2024. However, the focus has now shifted to a key secondary endpoint: PGA 0/1 (clear or almost clear skin) – a widely accepted clinical marker of meaningful treatment success.

Among patients who completed the full 52 weeks of treatment:

• In the moderate subgroup (PASI 6–10 at inclusion), 45% on HRO350 high-dose achieved PGA 0/1, vs 29% on placebo – a 16 percentage point difference.

• In the total population (PASI 3–10), 46% on HRO350 vs 36% on placebo – a 10-point gap.

• No new safety concerns or unexpected serious adverse events were reported across the year.

These numbers are especially relevant because PGA 0/1 is harder to achieve than PASI50 and is increasingly seen as a regulatory and clinical endpoint of choice.

Comparable Benchmarks

To put this in perspective:

• Approved oral treatments like apremilast (Otezla) achieved ~20 ppt differences over placebo on PASI75, a more aggressive endpoint, in phase 3 trials – supported by clear dose-response and strong statistical significance.

• For HRO350, a 10–16 ppt gap in PGA 0/1 – in a milder population – is clinically interesting, especially given the excellent safety profile, but it’s not clearly approvable yet without stronger data or better placebo control.

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⚠️ Challenges Remain

While the 12-month update is more encouraging than the interim data, there are reasons for caution: