Biomarker analysis from the phase 2b randomized placebo-controlled trial of riociguat in early diffuse cutaneous systemic sclerosis

Rheumatology (Oxford). 2024 Nov 1;63(11):3124-3134. doi: 10.1093/rheumatology/keae150.

Abstract

Objective: To examine disease and target engagement biomarkers in the RISE-SSc trial of riociguat in early diffuse cutaneous systemic sclerosis and their potential to predict the response to treatment.

Methods: Patients were randomized to riociguat (n = 60) or placebo (n = 61) for 52 weeks. Skin biopsies and plasma/serum samples were obtained at baseline and week 14. Plasma cyclic guanosine monophosphate (cGMP) was assessed using radio-immunoassay. α-Smooth muscle actin (αSMA) and skin thickness were determined by immunohistochemistry, mRNA markers of fibrosis by qRT-PCR in skin biopsies, and serum CXC motif chemokine ligand 4 (CXCL-4) and soluble platelet endothelial cell adhesion molecule-1 (sPECAM-1) by enzyme-linked immunosorbent assay.

Results: By week 14, cGMP increased by 94 (78)% with riociguat and 10 (39)% with placebo (P < 0.001, riociguat vs placebo). Serum sPECAM-1 and CXCL-4 decreased with riociguat vs placebo (P = 0.004 and P = 0.008, respectively). There were no differences in skin collagen markers between the two groups. Higher baseline serum sPECAM-1 or the detection of αSMA-positive cells in baseline skin biopsies was associated with a larger reduction of modified Rodnan skin score from baseline at week 52 with riociguat vs placebo (interaction P-values 0.004 and 0.02, respectively).

Conclusion: Plasma cGMP increased with riociguat, suggesting engagement with the nitric oxide-soluble guanylate cyclase-cGMP pathway. Riociguat was associated with a significant reduction in sPECAM-1 (an angiogenic biomarker) vs placebo. Elevated sPECAM-1 and the presence of αSMA-positive skin cells may help to identify patients who could benefit from riociguat in terms of skin fibrosis.

Trial registration: Clinicaltrials.gov, NCT02283762.

Keywords: biomarkers; diffuse cutaneous systemic sclerosis; riociguat; soluble guanylate cyclase stimulators.

Publication types

  • Randomized Controlled Trial
  • Clinical Trial, Phase II

MeSH terms

  • Adult
  • Biomarkers* / blood
  • Biopsy
  • Cyclic GMP / blood
  • Cyclic GMP / metabolism
  • Double-Blind Method
  • Female
  • Fibrosis / drug therapy
  • Humans
  • Male
  • Middle Aged
  • Pyrazoles* / therapeutic use
  • Pyrimidines* / therapeutic use
  • Scleroderma, Diffuse* / drug therapy
  • Scleroderma, Diffuse* / pathology
  • Skin* / drug effects
  • Skin* / metabolism
  • Skin* / pathology
  • Treatment Outcome

Substances

  • riociguat
  • Pyrimidines
  • Pyrazoles
  • Biomarkers
  • Cyclic GMP

Associated data

  • ClinicalTrials.gov/NCT02283762