Concomitant antibiotic use in patients with moderate-to-severe hidradenitis suppurativa who were treated with adalimumab or placebo in a phase 3 study (PIONEER II)

Introduction: Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease characterized by nodules, abscesses, and fistulas; the pathogenesis is not well understood. Despite limited efficacy and high recurrence rates, antibiotics are recommended as first-line treatment. Adalimumab (Humira) is a fully human anti- TNF-α monoclonal antibody that targets noninfectious, inflammatory causes of HS. Objective: This subgroup analysis evaluated the effect of stable concomitant antibiotic use on the proportion of patients who achieved HS clinical response (HiSCR) while being treated with ADA or placebo in a phase 3, double-blind study (PIONEER II). Methods: The study enrolled adults with at least a 1-year history of moderate-to severe HS who had an inadequate response to a 90-day trial of oral antibiotics. Patients were randomized 1:1 to receive ADA (160 mg at week 0, 80 mg at week 2, and 40 mg weekly starting at week 4) or placebo for 12 weeks, with randomization stratified by baseline Hurley stage and antibiotic use. Concomitant use of a stable dose of oral doxycycline or minocycline was permitted. The primary outcome was the proportion of patients who achieved HiSCR, defined as ≥50% reduction in total abscess and inflammatory nodule count with no increase in abscess or draining fistula counts relative to baseline. The P values for treatment effect were calculated using the Cochran-Mantel-Haenszel test and stratified patients by baseline Hurley stage and antibiotic use. Results: Of the 326 patients who were randomized, 63 (19%) were taking stable concomitant antibiotics at baseline, and 53 (16%) patients were on stable antibiotics throughout the trial. Among patients who were taking concomitant antibiotics throughout the trial, the proportion who achieved HiSCR was 68% (19/28) for those who received ADA and 20% (5/25) for those who received placebo (P <.001). Among patients who were not taking antibiotics, HiSCR was achieved by 57% (77/135) and 29% (40/138) of patients who received ADA and placebo, respectively (P<.001). Conclusions: Irrespective of concomitant, stable antibiotic use, more patients who received ADA achieved HiSCR at week 12 than did those who received placebo.