Aslan fails to roar with atopic dermatitis data

Dupixent has set such a high bar in atopic dermatitis anyone coming for its crown had better come prepared. This could be why questions around Aslan Pharmaceuticals' trial design and results contributed to a 31% fall in the group’s share price. In the phase 1 trial a 600mg dose of ASLAN004 showed a statistically significant 65% change in skin clearance from baseline at week 8. However, there were concerns about the removal of nine patients from the original intent-to-treat population and the study using a one-sided p value. Perhaps more worrying was that the number of patients achieving a IGA score of 0/1, ie clear or almost clear skin, was not significant at 48.3% versus 15.4% for placebo (p=0.107); this is important as the IGA 0/1 score is used for US approval. Arguably the sample size of 29 – reduced from 38 – was not powered to show a definitive result, but the result also appeared to show reduced efficacy; in March 22% of patients achieved IGA or 0/1, compared with 0% on placebo. Aslan is looking to begin a phase 2 trial before the end of the year and one concern is that what looks like waning efficacy could be exacerbated with larger numbers.

ASLAN004 phase 1 trial
Endpoint (8 weeks) RITT (n=29) ITT (n=38)
  600mg Placebo p-value1 600mg Placebo p-value1
  (n=16) (n=13)   (n=22) (n=16)  
Mean % change from baseline in EASI -64.9 -27.2 0.021 -61.3 -31.9 0.023
EASI-50 (%) 81.3 30.8 0.008 77.3 37.5 0.016
EASI-75 (%) 68.8 15.4 0.005 50 12.5 0.018
EASI-90 (%) 37.5 15.4 0.183 27.3 12.5 0.245
IGA 0/1 (%) 43.8 15.4 0.107 31.8 18.8 0.301
Mean % change from baseline in peak pruritus -38.6 -15.3 0.051 -37.1 -15.7 0.032
RITT = revised intent to treat; p-value1 (one-sided p-value). Source: Company announcement.

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