Riociguat in children with pulmonary arterial hypertension: The PATENT–CHILD study

Riociguat, a soluble guanylate cyclase stimulator, is approved for treatment of adults with pulmonary arterial hypertension (PAH). The safety, tolerability, and pharmacokinetics (PK) of oral riociguat in a pediatric population with PAH was assessed in PATENT–CHILD (NCT02562235), a multicenter, single‐arm, 24‐week, open‐label, Phase 3 study. Patients aged 6–17 years in World Health Organization functional class (WHO‐FC) I–III treated with stable endothelin receptor antagonists and/or prostacyclin analogs received riociguat equivalent to 0.5–2.5 mg three times daily in adults, as either oral pediatric suspension or tablets, based on bodyweight. Primary outcomes were safety, tolerability, and PK of riociguat. Twenty‐four patients (mean age 12.8 years), 18 of whom were in WHO‐FC II, were enrolled. Adverse events (AEs), mostly mild or moderate, were reported in 20 patients (83%). Four patients (17%) experienced a serious AE; all resolved by study end and two (8%) were considered study‐drug related. Hypotension was reported in three patients and hemoptysis in one (all mild/moderate intensity). Riociguat plasma concentrations in pediatric patients were consistent with those published in adult patients. From baseline to Week 24, mean ± standard deviation increase in 6‐minute walking distance was 23 ± 69 m (n = 19), and mean decrease in NT‐proBNP was –66 ± 585 pg/ml (n = 14). There was no change in WHO‐FC. Two patients experienced clinical worsening events of hospitalization for right heart failure. PK results confirmed a suitable riociguat dosing strategy for pediatric patients with PAH. The data suggest an acceptable safety profile with potential efficacy signals.