Trial of sildenafil for PAH in patients with sickle cell disease terminated because of safety concerns

The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) has prematurely terminated a trial of sildenafil for the treatment of pulmonary arterial hypertension (PAH) in adult patients with sickle cell disease because of safety concerns. The trial was stopped nearly 1 year early.

An interim review of data from 33 patients who completed 16 weeks of treatment demonstrated that 38% of sildenafil-treated patients had serious adverse effects compared with 8% of placebo-treated patients. The most common adverse effects were sickle cell pain crises that resulted in hospitalization.

The study was stopped based on the recommendation of an independent data and safety monitoring board.

Sildenafil is approved for the treatment of PAH (World Health Organization [WHO] Group 1) to improve exercise ability and delay clinical worsening. NHLBI investigators stated that patients without sickle cell disease who are currently taking sildenafil for this indication should not base a decision to stop treatment on the results of this study, as these findings are specific to patients with sickle cell disease. Patients with sickle cell disease who are currently taking sildenafil for the treatment of PAH should discuss the potential risks and benefits of this therapy with healthcare professionals.