NHLBI stops study of pulmonary hypertension treatment in sickle cel...(rs also evaluated the safety of the drug...),Health

Sildenafil is approved by the Food and Drug Administration for use in patients with pulmonary hypertension. In general, the drug treats pulmonary hypertension by relaxing the blood vessels in the lungs to allow blood to flow more easily. Since sildenafil is not FDA-approved to treat pulmonary hypertension in patients with sickle cell disease, the walk-PHaSST study was conducted under an investigational new drug application. The FDA was notified of the termination of the study on July 14.

Walk-PHaSST began recruiting participants in July 2007 and enrolled 74 patients over the age of 19 (average age 45). Participants had sickle cell disease and mild to severe pulmonary hypertension. They were randomly assigned to receive sildenafil or placebo for 16 weeks. Participants could also receive other therapies as needed to manage sickle cell and related complications. After completing the study treatment (or placebo), participants could choose to be part of the open-label follow-up phase of the study and continue to be assessed for up to one year. In the open-label study, participants and clinicians knew that sildenafil was being taken. When the study was stopped, 33 participants had completed the clinical trial.

Researchers found that 38 percent of participants taking sildenafil had serious adverse effects -- primarily sickle cell pain crises -- compared to 8 percent of participants in the placebo group.

"Although these preliminary results are disappointing, we expect that the study's results, once fully analyzed, will provide important insights into the role of pulmonary hypertension in sickle cell disease," said Mark Gladwin, M.D., lead investigator of walk-PHaSST and director of the Vascular Medicine Institute at the University of Pittsburgh. Gladwin is also a special volunteer for the NHLBI and was fo
'/>"/>