Riociguat Fails in Systemic Sclerosis-Associated Digital Ulcers Save

Riociguat is an oral, selective soluble guanylate cyclase stimulator that has been studied in patients with digital ulcers (DU) due to systemic sclerosis (SSc) but study results show that short term (16 weeks) riociquat therapy does not sufficiently reduce the DU burden in SSc patients.

SSc patients wwith active or painful indeterminate DUs were enrolled in a -blind, randomized, placebo-controlled, proof-of-concept trial. Patient were treated with placebo or riociguat in individualized doses (maximum of 2.5 mg three times daily) during an 8-week titration period, followed by an 8-week stable dosing period. The primary endpoint was the week 16 change in net ulcer burden (NUB), analyzed using ANCOVA. 

Seventeen participants were enroleld an 8 received placebo and 9 riociguat. Baseline characteristics were comparable between the treatment groups.

At baseline ulcers (NUB) wwere the same in the placebo (2.5) and riociguat (2.4) groups. But there was no significant treatment difference in NUB after 16 weeks of therapy. (adjusted mean treatment difference − 0.24, 95% CI (− 1.46, 0.99), p = 0.70).

Four participants experienced five serious AE (four in riociguat and one in placebo); none was considered related to study medication.

Six participants in each group transitioned to the open-label extension and thos in the riociguat-riociguat arm had complete healing of their DUs.

THese data suggest that long term (not short term) riociguat therapy is necessry to reduce the number of DU net burden in SSc  patients.