Study design: A double-blind randomised placebo-controlled trial

Intervention: Randomized placebo controlled treatment of 20 HS patients of which fifteen patients will be randomized to apremilast and five patients to placebo. The total duration of the treatment period per subject is 16 weeks.

Primary objectives: To evaluate the expression profile of inflammatory cytokines in HS lesional skin at week four (t=4) and week sixteen (t=16):

• of patients receiving apremilast compared to placebo;
• within both groups relative to baseline (t=0).

Secondary objectives:

• To prospectively evaluate the clinical efficacy of apremilast.
• To assess the effect of apremilast on patient reported outcomes measures.
• To assess the short-term safety and tolerability of apremilast in patients with hidradenitis suppurativa.

Rationale:

Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent, debilitating skin disease. It is characterized by painful, deep-seated, inflamed boils in the inverse areas of the body, most commonly the axillae, inguinal and anogenital regions.

Systemic therapy with immunosuppressive agents (systemic corticosteroids, dapsone, cyclosporin) has been investigated in the past decades and has shown limited efficacy. The use of the selective immunosuppressant apremilast has not yet been evaluated in HS. The investigators hypothesize a beneficial effect of apremilast in HS patients, similar to the efficacy of apremilast in psoriasis patients. Namely, it has been shown that the immune dysregulation in the pathogenesis of HS shows many similarities with that of psoriasis. Moreover, the TNF-α blocker adalimumab was registered for HS after approval for the treatment in patients with psoriasis.

Key inclusion criteria:

• Adult (≥ 18 years of age) male or female patients with moderate HS according to a PGA of 3 on the 5-point HS-Physician Global Assessment (HS-PGA);
• HS of more than 6 months duration; have lesions in at least two anatomical locations.

Key exclusion criteria:

• Contra-indication for apremilast; previous use of apremilast; have any current and/or recurrent clinically significant skin condition in the treatment area other than HS;
• Presence of other uncontrolled major disease;
• Pregnant or lactating women.