Phase II/III Trial of Sildenafil for Sickle Cell Disease Associated Pulmonary Hypertension

  • Principal Investigator: Victor R. Gordeuk, MD

The proposed multi-center phase II/III clinical trial will have three major objectives:

  1. Screening: 1000 subjects with SCD will be screened with historical and laboratory data and Doppler echocardiography to determine tricuspid regurgitant velocity (TRV). Plasma and DNA will be obtained.
  2. Main study: 180 SCD patients with PAH will be enrolled in a randomized, double-blinded, placebo-controlled phase II/III trial, to determine the safety and efficacy of 16 weeks of sildenafil therapy on exercise capacity (six-minute walk distance), symptoms, and hemodynamic parameters including pulmonary artery pressure in patients with SCD and PAH. In patients undergoing right heart catheterization, determine the acute hemodynamic effects of three escalating doses of intravenous sildenafil at rest and during exercise.
  3. Extension study: after completion of the main 16 week trial, all participants in the main study will be invited to continue in a one-year, double-blinded extension study that will compare two different doses of sildenafil.