423 Baseline C-reactive protein correlates with adalimumab and placebo 3non-response in patients with hidradenitis suppurativa

Hidradenitis Suppurativa (HS) is a chronic inflammatory disorder that causes skin nodules, sinus tracts, and fistulas to develop in the intertriginous areas. Moderate-to-severe disease is often treated with adalimumab, a tumor necrosis factor alpha inhibitor that demonstrated clinical efficacy in two double-blinded, randomized controlled trials (RCTs): PIONEER I and PIONEER II. Despite its success, adalimumab treatment failure is common. Identifying biomarkers that predict adalimumab non-response in patients with HS remains an unmet need. In this post-hoc analysis of the PIONEER I and PIONEER II RCTs (access to data provided by Vivli.org), patients with moderate-to-severe HS and an elevated C-reactive protein (CRP) (> 3 mg/L) at baseline (n= 466) in comparison to those with a normal CRP at baseline (n= 128) had a greater body mass index (p < .001), Hurley score (p < .001), and International Hidradenitis Suppurativa Severity Score System score (p < .001) at baseline. These patients also had a greater number of abscesses and inflammatory nodules (p < .001) and draining fistulas (p < .001) at baseline. Among patients who responded to treatment (i.e., achieved Hidradenitis Suppurativa Clinical Response at week 12), there was no significant difference between the baseline CRP of patients who received adalimumab or placebo (p = .88). Two separate univariate logistic regressions found a significant positive relationship between CRP at baseline and non-response to either placebo (p = .01) or adalimumab (p < .001) at week 12. Our findings suggest that baseline CRP in patients with moderate-to-severe HS correlates with higher disease severity and lower likelihood of improvement on either placebo or adalimumab therapy. Multivariate analyses may help further clarify interactions between confounders.