This article is part of MPR‘s coverage of the American Thoracic Society International Conference, taking place in Dallas, Texas. Our staff will report on medical research related to asthma and other respiratory conditions, conducted by experts in the field. Check back regularly for more news from ATS 2019.

DALLAS – Patients with pulmonary arterial hypertension (PAH) experienced a significant improvement in World Health Organization Functional Class when transitioned from a phosphodiesterase type 5 inhibitor to riociguat, according the results of a real-world study presented at the American Thoracic Society International Conference, held May 17-22, in Dallas, Texas.

Researchers conducted a retrospective chart review of patients with PH from July 2007 to August 2018. Patients with group 1 PAH receiving a phosphodiesterase type 5 inhibitor with treatment failure who were transitioned to riociguat were included. The primary outcome was change in 6-minute walk test (6MWT) distance after the transition, and secondary outcomes included functional class and hemodynamic data.

Data from a total of 11 patients (median age, 61 years) who were taking macitentan (n=5), bosentan (n=5), sildenafil (n=6), and/or taladafil (n=5) before the transition were analyzed. After the transition, 10 patients were taking 2.5 mg of riociguat. In addition to riociguat therapy, 5 patients continued to take macitentan, 4 continued to take bosentan, and 1 also took ambrisentan. The 6MWT distance increased from 369.0 m to 426.5 m posttransition, but the change was not statistically significant (P =.16). The researchers discovered that younger age was significantly associated with an increase in 6MWT distance (P =.02); specifically, 4 m per 1 year of age. In addition, World Health Organization Functional Class significantly improved (P <.01).

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The researchers noted that the small sample size may have had an effect on the lack of statistical significance of the 6MWT distance increase. Larger studies are also needed to determine the effect of age.

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Sun K, Kendzerska T, Mielniczuk L, et al. Effect of transitioning from phosphodiesterase type 5 inhibitors to riociguat. Presented at: the American Thoracic Society International Conference; May 21, 2019; Dallas, TX. Abstract A5072/P1148.

This article originally appeared on Pulmonology Advisor