Riociguat for the Treatment of Chronic Thromboembolic Pulmonary Hypertension

TLDR: Riociguat significantly improved exercise capacity and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension.

Abstract: BACKGROUND Riociguat, a member of a new class of compounds (soluble guanylate cyclase stim ulators), has been shown in previous clinical studies to be beneficial in the treat ment of chronic thromboembolic pulmonary hypertension. METHODS In this phase 3, multicenter, randomized, double-blind, placebo-controlled study, we randomly assigned 261 patients with inoperable chronic thromboembolic pul monary hypertension or persistent or recurrent pulmonary hypertension after pul monary endarterectomy to receive placebo or riociguat. The primary end point was the change from baseline to the end of week 16 in the distance walked in 6 minutes. Secondary end points included changes from baseline in pulmonary vascular resis tance, N-terminal pro–brain natriuretic peptide (NT-proBNP) level, World Health Organization (WHO) functional class, time to clinical worsening, Borg dyspnea score, quality-of-life variables, and safety. RESULTS By week 16, the 6-minute walk distance had increased by a mean of 39 m in the riociguat group, as compared with a mean decrease of 6 m in the placebo group (least-squares mean difference, 46 m; 95% confidence interval [CI], 25 to 67; P<0.001). Pulmonary vascular resistance decreased by 226 dyn · sec · cm –5 in the riociguat group and increased by 23 dyn · sec · cm –5 in the placebo group (least-squares mean difference, –246 dyn · sec · cm –5 ; 95% CI, –303 to –190; P<0.001). Riociguat was also associated with significant improvements in the NT-proBNP level (P<0.001) and WHO functional class (P = 0.003). The most common serious adverse events were right ventricular failure (in 3% of patients in each group) and syncope (in 2% of the riociguat group and in 3% of the placebo group). CONCLUSIONS Riociguat significantly improved exercise capacity and pulmonary vascular re sistance in patients with chronic thromboembolic pulmonary hypertension. (Funded by Bayer HealthCare; CHEST-1 and CHEST-2 ClinicalTrials.gov numbers, NCT00855465 and NCT00910429, respectively.)