Treatment with riociguat, a soluble guanylate cyclase stimulator, was associated with improved clinical parameters and “an effective long-term treatment effect” in patients with technical inoperable and residual chronic thromboembolic pulmonary hypertension (CTEPH). Study findings were published in the International Journal of Cardiology Heart and Vasculature.
Data from consecutive patients with technical inoperable and residual CTEPH who initiated riociguat therapy from January 2014 onward were retrospectively reviewed (n=36) by Johannes J Mager, MD, PhD, and colleagues at St. Antonius Hospital in Nieuwegein, The Netherlands. Patients were followed annually until the end of the study, death, or until they were lost to follow up — whichever occurred first. End points assessed at each year included survival, clinical worsening, World Health Organization (WHO) functional class, N-terminal pro brain natriuretic peptide (NT-proBNP), and 6-minute walking distance (6MWD). The researchers also examined adverse events during treatment and sought to determine the maximum riociguat dose.
Patients in the study were mean age 64.9±12.1 years; 54% of patients had a WHO functional class III/IV and 6MWD of 337±138 meters. During mean follow-up of 2.3±1.2 years, the 3-year survival was 94%, whereas the 3-year clinical worsening-free survival was 78%. One significant predictor of clinical worsening was the 6MWD per 10 minutes at baseline (hazard ratio, 0.90; 95% CI, 0.83-0.97; P =.009). At 3 years, there were noticeable improvements in WHO functional class as well as in 6MWD (55±72 meters at year 1 [P =.0003], 60±65 meters at year 2 [P =.0002], and 89±61 meters at year 3 [P =.001]) compared with baseline. Reductions in NT-proBNP (-67 pg/mL; range, -1355 to 49 at 1 year; P =.04) were also observed during follow-up.
Study limitations included the small sample size, lack of a comparator control group, limited follow-up period, and the retrospective nature of the analysis.
“Although WHO [functional class] improvement was less profound, our results are largely consistent with other studies,” the researchers concluded. “More ‘real world’ research is necessary to establish more clinical long-term results.”
Disclosures: Drs van Thor and Mager report grant funding from Actelion Pharmaceuticals. Dr Snijder reports grant funding from Pfizer and Actelion Pharmaceuticals. Dr Post reports grant funding and speaking fees from Actelion Pharmaceuticals and grant funding from GlaxoSmithKline.
van Thor MCJ, ten Klooster L, Snijder RJ, Post MC, Mager JJ. Long-term clinical value and outcome of riociguat in chronic thromboembolic pulmonary hypertension. Int J Cardiol Heart Vasc. 2019;22:163-168.