Although riociguat is indicated for treatment of pulmonary hypertension, Bayer HealthCare is looking to repurpose the drug to treat patients with diffuse cutaneous systemic sclerosis (dcSSc). Bayer initiated a randomized, double-blind, placebo-controlled phase 2 study using riociguat in patients with the most severe form of SSc.
If effective, riociguat would greatly benefit the SSc population, for which there are no drugs approved to halt or delay fibrotic damage. According to a Bayer news release, the study is designed to investigate the effects of riociguat on skin and lung fibrosis and digital ulcers.
“Riociguat Safety and Efficacy in patients with dcSSc” is designed for 130 patients enrolled at more than 60 international locations for one year of treatment. The small sample size reflects approval of the Food and Drug Administration and the European Commission for riociguat to be an orphan drug investigated in the context of SSc.
Riociguat may work in dcSSc because it is a soluble guanylate cyclase (sGC) stimulator. sGC is involved in pathways related to fibrosis and inflammation, which are features of dcSSc. Bayer discovered and developed riociguat for pulmonary hypertension treatment, but Merck has now joined the effort as of October 2014 to treat dcSSc with riociguat.
Scleroderma, which is more commonly known as “systemic sclerosis,” is an autoimmune disease that features thickening of the skin. While skin thickening is not life-threatening, when Scleroderma spreads to organs such as the lungs, the disease is fatal. Because the disease currently lacks FDA-approved treatments, the prospect of Riociguat being used to treat the disease comes as promising news to the Scleroderma patient population.