Pustular psoriasis: Molecular pathways and effects of spesolimab in generalized pustular psoriasis

BACKGROUND

The IL-36 pathway plays a key role in the pathogenesis of generalized pustular psoriasis (GPP). In a proof-of-concept clinical trial, treatment with spesolimab, an anti-IL-36 receptor antibody, resulted in rapid skin and pustular clearance in patients presenting with GPP flares.

OBJECTIVE

We sought to compare the molecular profiles of lesional and nonlesional skin from patients with GPP or palmoplantar pustulosis (PPP) with skin from healthy volunteers, and to investigate the molecular changes after spesolimab treatment in the skin and blood of patients with GPP flares.

METHODS

Pre- and post-treatment skin and blood samples were collected from patients with GPP who participated in a single-arm, phase I study (n = 7). Skin biopsies from patients with PPP (n = 8) and healthy volunteers (n = 16) were obtained for comparison at baseline. Biomarkers were assessed by RNA-sequencing, histopathology, and immunohistochemistry.

RESULTS

In GPP and PPP lesions, 1287 transcripts were commonly upregulated or downregulated. Selected transcripts from the IL-36 signaling pathway were upregulated in untreated GPP and PPP lesions. In patients with GPP, IL-36 pathway-related signatures, T_H1/T_H17 and innate inflammation signaling, neutrophilic mediators, and keratinocyte-driven inflammation pathways were downregulated by spesolimab as early as week 1. Spesolimab also decreased related serum biomarkers and cell populations in the skin lesions from patients with GPP, including CD3⁺ T, CD11c⁺, and IL-36γ⁺ cells and lipocalin-2-expressing cells.

CONCLUSIONS

In patients with GPP, spesolimab showed rapid modulation of commonly dysregulated molecular pathways in GPP and PPP, which may be associated with improved clinical outcomes.

Spesolimab, an Anti-Interleukin-36 Receptor Antibody, in Patients with Palmoplantar Pustulosis: Results of a Phase IIa, Multicenter, Double-Blind, Randomized, Placebo-Controlled Pilot Study

Introduction

Palmoplantar pustulosis (PPP) is a chronic, inflammatory skin disease, with high disease burden, that is often refractory to treatment. There is a high unmet clinical need for the treatment of patients with PPP. The objectives of this study were to evaluate the safety and efficacy of spesolimab, a novel anti-interleukin-36 receptor antibody, in patients with PPP.

Methods

This was a phase IIa, multicenter, double-blind, randomized, placebo-controlled pilot study comparing 900 mg spesolimab (n = 19), 300 mg spesolimab (n = 19), and placebo (n = 21) administered intravenously every 4 weeks until week 12 in patients with PPP. The primary efficacy endpoint was the achievement of Palmoplantar Pustulosis Area and Severity Index 50 (PPP ASI50) at week 16, defined as achieving an ≥ 50% decrease from baseline PPP ASI.

Results

At week 16, 31.6% of patients in both spesolimab dose groups achieved PPP ASI50 versus 23.8% receiving placebo (risk difference 0.078; 95% confidence interval –0.190, 0.338). Thus, the primary endpoint was not met. Spesolimab was well tolerated with no clinically relevant treatment-emergent safety signals observed.

Conclusions

PPP severity declined over time in all treatment groups after the start of treatment, with a faster decline in the spesolimab arms than in the placebo arm, indicating a potential treatment effect for spesolimab. Limitations to the study included a small sample size and lower overall disease severity than expected at baseline. It is possible that the primary efficacy endpoint may have coincided with natural disease resolution in some patients. Further effects of the efficacy of spesolimab in PPP are being explored in a phase IIb trial.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00504-0.