Flares as dynamic predictive factor of response to adalimumab in hidradenitis suppurativa, real-life data.

BACKGROUND Hidradenitis suppurativa (HS) is characterized by periodic worsening of both clinical manifestations and symptoms. The aim was to investigate the role of flare outbreak as a possible predictive factor of response to Adalimumab. METHODS 115 HS patients in treatment with adalimumab, with moderate-severe HS, ≥3 abscesses and inflammatory-nodules (ANs) from 5 Italian centers were included in this retrospective analysis. The information about gender, ages at onset/baseline, therapeutic delay, family history, body mass index, smoking, comorbidities, phenotypes, body areas, severity indexes at baseline was collected. Baseline characteristics, total number and timeline of flares were analysed by regression and survival analysis with Hidradenitis Suppurativa Clinical Response (HiSCR). RESULTS During the observational period, 80.9% of patients developed flares, detecting 252 flares. Univariate model identified five factors associated with the absence of response: age (p-value=0.020), comorbidities (p-value=0.030), genital-perineal involvement (pvalue= 0.004), no response at week-12 (p-value=0.027), and flares outbreak (p-value=0.010). Joint analysis of recurrent and terminal events showed a positive correlation between flare recurrence and no-response (p-value<0.001). Among the identified variables associated with poor response to the therapy: occurrence of a flare before week-12 was the one with the highest risk of no response (p-value<0.001). The limitations are: study's retrospective design, limited number of patients, absence either of a consensus about flare definition, placebo control group or standard therapy of flares during adalimumab therapy. CONCLUSIONS The analysis of a "dynamic" variable, as flares evaluation together with an appropriate clinical baseline assessment can be a useful approach to predict the middle-long-term response to adalimumab.