Inhaled Iloprost Relieves Symptoms of Severe Pulmonary Hypertension

Laurie Barclay, MD

July 31, 2002

Aug. 1, 2002 -- Inhaled iloprost was effective in improving symptoms and walking distance in people with severe pulmonary hypertension, according to the results of a randomized, placebo-controlled trial in the Aug. 1 issue of the New England Journal of Medicine. The benefit was similar to that of continuous infusion of epoprostenol.

"Uncontrolled studies suggested that aerosolized iloprost, a stable analogue of prostacyclin, causes selective pulmonary vasodilatation and improves hemodynamics and exercise therapy in patients with pulmonary hypertension," write Horst Olschewski, MD, and colleagues from the Aerosolized Iloprost Randomized Study Group.

The investigators compared the effects of repeated daily inhalations of iloprost with inhalations of placebo in 203 patients with selected forms of severe pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, New York Heart Association (NYHA) functional class III or IV. The iloprost regimen was 2.5 or 5.0 µg six or nine times daily; median inhaled dose was 30 µg per day.

"Targeted delivery of prostanoids to the pulmonary vasculature by means of inhalation may substantially reduce the drug requirements," the authors write.

After week 12, NYHA class and distance walked in six minutes were improved by at least one class and at least 10%, respectively, in 16.8% of patients receiving iloprost and in 4.9% of patients receiving placebo ( P=.007). Other benefits of iloprost treatment included improvements in hemodynamic values compared with baseline, NYHA class, dyspnea, and quality of life.

Study withdrawal, usually due to clinical deterioration, occurred in 4.0% of patients in the iloprost group, including one patient who died, and in 13.7% of patients in the placebo group, including four patients who died ( P=.024). Syncope was equally common in both groups but was more often rated as serious by patients in the iloprost group.

As in earlier studies, the investigators found that the benefit of iloprost was greatest in patients with primary pulmonary hypertension. The effect was similar to that of epopstenol and bosentan, an oral endothelin-1 antagonist shown to relieve symptoms of severe pulmonary hypertension, according to a report in the March 21 issue of the New England Journal of Medicine.

"The advantages of intermittent inhaled therapy over intravenous therapy, coupled with the improvement in a number of clinically meaningful variables, suggest that inhaled iloprost therapy is effective," the authors write. "It may be a suitable alternative to continuous intravenous prostacyclin, especially in patients who do not derive a clear survival benefit with intravenous therapy."

Schering supported this study and has financial arrangements with its authors.

N Engl J Med. 2002;347(5):322-329

Reviewed by Gary D. Vogin, MD


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