Efficacy of guselkumab in a subpopulation with pustulotic arthro‐osteitis through week 52: an exploratory analysis of a phase 3, randomized, double‐blind, placebo‐controlled study in Japanese patients with palmoplantar pustulosis

Background Previous studies of guselkumab have demonstrated clinical benefits in patients with plaque‐type psoriasis, generalized pustular psoriasis, erythrodermic psoriasis and palmoplantar pustulosis (PPP). Objective The aim of this exploratory analysis of a double‐blind, multicenter, placebo‐controlled, phase 3 study in Japanese patients with PPP was to evaluate the efficacy of guselkumab in the subset of patients with pustulotic arthro‐osteitis (PAO). Methods Patients were randomized to receive guselkumab 100 or 200 mg at weeks 0, 4, 12 and every 8 weeks, or placebo with cross‐over to guselkumab 100 or 200 mg at week 16 (placebo group). Efficacy endpoints were changes from baseline in magnetic resonance imaging (MRI) score, EuroQOL‐5 dimensions (EQ‐5D) index score, EQ‐5D pain/discomfort dimension score and C‐reactive protein (CRP, mg/L) level in all PAO patients through week 52. Data from both guselkumab groups were combined and presented as results for a single overall guselkumab group. Results Among 159 patients with PPP, 66 with PAO were randomized across treatment groups. For patients with MRI data for all regions assessed, the proportion of patients in the guselkumab group with PAO characterized as severe decreased from 23.8% (10/42) at baseline to 5.4% (2/42) at week 52. The mean (SD) change from baseline at week 52 in EQ‐5D index score was 0.20 (0.17) among PPP patients with PAO and 0.15 (0.17) among those without PAO in the guselkumab group. Among all PAO patients, the proportions with an EQ‐5D pain/discomfort dimension score of no or slight pain/discomfort in the guselkumab group increased from baseline to week 52 [33.3% (7/21) vs. 87.5% (35/40)]. The mean (SD) CRP levels decreased in all PAO patients in the guselkumab group at week 52 compared to baseline [−1.71 (8.16) mg/L]. Conclusion Guselkumab treatment showed beneficial outcomes for PAO signs and symptoms in Japanese patients with PPP.