Ixekizumab Restores Clinical Response in Patients With Hidradenitis Suppurativa After Secondary Loss of Effectiveness From Adalimumab: Results From a Retrospective Analysis of a Case Series

Background: Hidradenitis suppurativa (HS) is a severe chronic inflammatory skin disease with a high burden of those affected. The tumor necrosis factor alpha (TNF-α)-inhibitor adalimumab was the first approved biologic in 2015, followed by secukinumab in 2023 and just recently, as of July 2024, the so far only selective dual IL-17A/F-inhibitor bimekizumab (Kimball et al. 2023). Analog to psoriasis treatment, there is still a strong need for further drug therapy options in case of primary nonresponse or secondary loss of effectiveness.

Objectives: The study aim was to observe the effectiveness of ixekizumab in routine care for HS.

Methods: We performed a retrospective analysis of structured data from ten patients with HS, treated with ixekizumab in 2019, after a secondary loss of effectiveness under adalimumab, at a time when adalimumab was still the only approved biologic for HS in Germany. Clinical response was measured using the International Hidradenitis Suppurativa Severity Score System (IHS4) and quality of life was assessed using the Dermatology Life Quality Index (DLQI) at baseline (week 0) and 16 weeks after the initiation of treatment.

Results: Nine out of ten patients were female, mean age: 39.7 ± 11.0 years. The average IHS4 score decreased from 13.6 in week 0 to 9.6 in week 16. Three patients did not respond to treatment. DLQI resulted in an average decline of almost four points from 11.7 (week 0) to 7.8 (week 16).

Conclusions: This case series indicates that a major proportion of patients with HS being treatment failures to adalimumab still respond to ixekizumab. Further studies with a larger study population are necessary to assess the long-term effectiveness and safety of ixekizumab in HS patients.