| Abstract | BACKGROUND: Bosentan, an oral ET(A)/ET(B) receptor antagonist, is approved for the treatment of pulmonary arterial hypertension (PAH). However, some patients discontinue bosentan because of hepatotoxicity or inadequate efficacy. Sitaxsentan, an oral, ET(A)-selective endothelin antagonist currently under investigation, may be an alternative treatment option. In this study we evaluate the safety and efficacy of sitaxsentan in patients discontinuing bosentan. METHODS: Forty-eight patients with idiopathic PAH or PAH associated with connective-tissue disease or congenital heart disease were randomized (double-blind) to a single daily dose of either 50 mg or 100 mg sitaxsentan. Thirty-five of the 48 patients discontinued bosentan because of inadequate efficacy, as judged by the investigator, and 13 discontinued bosentan for safety concerns. Study end-points included change in 6-minute walk distance (6MWD), change in World Health Organization (WHO) functional class, time to clinical worsening, and change in Borg dyspnea score (Borg) from baseline to Week 12. RESULTS: With 100 mg sitaxsentan, 5 of 15 patients (33%) who discontinued bosentan because inadequate efficacy improved, demonstrating a >15% increase in 6MWD, vs 2 of 20 patients (10%) treated with 50 mg sitaxsentan. Fifteen percent and 20% of these patients had a >15% decrease in 6MWD in the 50- and 100-mg groups, respectively. Similar results were seen for the Borg and WHO functional class. Of the 12 patients discontinuing bosentan because of hepatotoxicity, 1 developed elevated liver enzymes at 13 weeks of sitaxsentan therapy. Overall, sitaxsentan was well tolerated. CONCLUSIONS: Sitaxsentan may represent a safe and efficacious alternative endothelin receptor antagonist for patients discontinuing bosentan. |
| Authors | Raymond L Benza, Sanjay Mehta, Anne Keogh, E Clinton Lawrence, Ronald J Oudiz, Robyn J Barst
(Affiliation: Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006, USA. rbenza at uab.edu)
|
| Journal | The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation
(J Heart Lung Transplant)
Vol. 26
Issue 1
Pg. 63-9
(Jan 2007)
ISSN: 1557-3117 United States |
| PMID | 17234519
(Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- Antihypertensive Agents
- Isoxazoles
- Receptors, Endothelin
- Sulfonamides
- Thiophenes
- sitaxsentan
- bosentan
|
| Topics |
- Adolescent
- Adult
- Aged
- Antihypertensive Agents
(therapeutic use)
- Child
- Double-Blind Method
- Female
- Follow-Up Studies
- Humans
- Hypertension, Pulmonary
(drug therapy)
- Isoxazoles
(therapeutic use)
- Male
- Middle Aged
- Receptors, Endothelin
(antagonists & inhibitors)
- Sulfonamides
(therapeutic use)
- Thiophenes
(therapeutic use)
- Treatment Outcome
|
