Double-blind, placebo-controlled clinical trial with a rho-kinase inhibitor in pulmonary arterial hypertension; a pilot efficacy trial

Background: We have previously demonstrated that long-term inhibition of Rho-kinase ameliorates pulmonary arterial hypertension (PAH) in animal models. In the present study, we examined the clinical effects of mid-term oral treatment with an extended release formulation of AT-877 (fasudil hydrochloride), a specific Rho-kinase inhibitor (AT-877ER) on PAH. Methods and Results: 23 PAH patients were treated with either placebo (10/2 females/males, 51±16 years, idio-pathic PAH (IPAH) in 6, PAH associated with connective tissue disease (CTD-PAH) in 3, PAH with congenital heart disease (CHD-PAH) in 2, and portal PAH in 1) or AT-877ER (6/5 females/males, 47±14 years, IPAH in 2, CTD-PAH in 5, and CHD-PAH in 4); 3 patients were excluded. We performed a 6-min walk test and right heart catheterization in the remaining 20 patients, before and 3 months after the treatment (placebo n=11, AT-877ER n=9). Although there were no significant differences between the 2 groups for the 6-min walk distance, pulmonary hemodynamics tended to be improved in the AT-877ER group, especially the prevalence of improved cardiac index from baseline, which was significantly higher in the AT-877ER than in the placebo group. In the AT-877ER group, serum levels of hy-droxyfasudil, an active metabolite of AT-877ER tended to correlate with improvements in the cardiac index and mean pulmonary artery pressure. Conclusions: Mid-term treatment with oral AT-877ER showed additional improvement in pulmonary hemodynam-ics in patients with PAH.