Efficacy results using a novel hidradenitis suppurativa endpoint, HiSCR (hidradenitis suppurativa clinical response), from the placebo-controlled phase of a phase 2 adalimumab study

Introduction: Hidradenitis suppurativa (HS) is a chronic inflammatory skin follicular disease with symptoms such as recurrent inflamed nodules, abscesses, and fistulas. We report efficacy results using the novel endpoint Hidradenitis Suppurativa Clinical Response (HiSCR; = 50% reduction from baseline in total abscess and inflammatory nodule [AN] count, with no observed increase in either abscess or draining fistula counts) from the 16-week, double-blind, placebo (pbo)-controlled phase of a 52-week adalimumab (ADA) study. Methods: Moderate to severe HS patients (pts) were randomized 1:1:1 (intent to treat population [ITT]) to pbo (n=51), ADA 40mg every other week, 80 mg atWeek 0 (W0) (eow, n = 52), or ADA 40 mg every week, 160 mg at W0, 80 mg at W2 (ew, n = 51). For pts with baseline AN count = 3 and draining fistula count = 20 (mITT population), the following retrospective evaluations are reported for W12 and W16: percentage of pts achieving HS-Physician Global Assessment (HS-PGA)-based Clinical Response (non-responder imputation [NRI]); percentage of pts achieving HiSCR; percentage of pts achieving 50%, 75%, 100% reduction in total AN count (AN50, AN75, AN100) relative to baseline (NRI), and percent change from baseline in AN count (last observation carried forward). Results: mITT population W12 and W16, HS-PGA-based Clinical Response rates (%) for pbo/eow/ew groups were, 4.7/6.7/25.0 (P<.05 pbo vs ew) and 2.3/6.7/20.5 (P < .05 pbo vs ew), respectively. HiSCR response rates (%) at W12 and W16, respectively, for pbo/eow/ew groups were 16.3/35.6/59.1 (P<.05 pbo vs ew and pbo vs ewo) and 25.6/33.3/54.5 (P<.05 pbo vs ew). For pbo/eow/ew groups, pts (%) achieving specified percent reduction in AN counts at W12 were 32.6/42.2/63.6 (AN50); 20.9/28.9/43.2 (AN75); 4.7/6.7/22.7 (AN100); at W16, 34.9/48.9/56.8 (AN50); 27.9/24.4/40.9 (AN75); 2.3/8.9/20.5 (AN100). For pbo/eow/ew groups, mean percent (%) reduction from baseline in AN count at W12 was 12.2/32.3/60.3, and at wk16, 19.8/38.8/59.7. Conclusion: ADA efficacy was demonstrated in moderate to severe HS pts. Differences for ADA ew versus pbo in HS-PGA-based Clinical Response and HiSCR at W12 and W16 were statistically significant. Percent improvement in AN counts was greater after ADA ew treatment. HiSCR appeared more responsive to change and better able to discriminate improvement in eow-treated pts than HS-PGA-based Clinical Response and may be a useful new tool to assess HS therapy efficacy.