STARTS-2

Abstract

Background: The double-blind, placebo-controlled Sildenafil in Treatment-Naive Children, Aged 1 to 17 Years, With Pulmonary Arterial Hypertension (STARTS-1) study assessed sildenafil in pediatric patients with pulmonary arterial hypertension; improved hemodynamics and exercise capacity occurred in medium- and high-dose groups. STARTS-2 was the extension study. Methods and Results: In STARTS-1, 234 children ≥8 kg were randomly assigned to low-, medium-, or high-dose sildenafil or placebo orally thrice daily; within-group dose depended on weight. In STARTS-2, sildenafil-treated patients continued STARTS-1 dosing; placebo-treated patients were randomized to 1 of the 3 sildenafil dose groups. Patients requiring additional pulmonary arterial hypertension-specific therapy discontinued study treatment; survival follow-up was attempted. As of August 2011, all children received ≥3 years of treatment (unless discontinued) from STARTS-1 baseline; 37 deaths were reported (26 on study treatment), 1 of which occurred within the first year of treatment. Most patients who died (28/37) had idiopathic/heritable pulmonary arterial hypertension (76% versus 33% overall) and baseline functional class III/IV disease (38% versus 15% overall); patients who died had worse baseline hemodynamics. Kaplan-Meier estimated 3-year survival rates from start of sildenafil were 94%, 93%, and 88% for patients randomized to low-, medium-, and high-dose sildenafil, respectively; 87%, 89%, and 80% were known to be alive at 3 years. Hazard ratios for mortality were 3.95 (95% confidence interval, 1.46-10.65) for high versus low and 1.92 (95% confidence interval, 0.65-5.65) for medium versus low dose; however, multiple analyses raised uncertainty about the survival/dose relationship. Conclusions: Although children randomized to higher compared with lower sildenafil doses had an unexplained increased mortality, all sildenafil dose groups displayed favorable survival for children with pulmonary arterial hypertension. © 2014 American Heart Association, Inc.