Encysive Pharmaceuticals Inc. said Wednesday Australian regulators approved the company's marketing application for its pulmonary arterial hypertension drug Thelin.

Pulmonary arterial hypertension is marked by abnormally high blood pressure and narrowing in the small arteries of the lungs, making blood flow more difficult and thereby causing the right side of the heart to become enlarged. The condition causes shortness of breath, limits activity and can develop into progressive heart failure, which is fatal unless treated successfully with a heart/lung or lung transplant.

The drug is currently under review by the Food and Drug Administration, but the approval process has been delayed. In July, the agency requested more data on the drug in order to consider it for approval.

Thelin was approved by the European Commission and is available in Britain.

Shares of Encysive rose 5 cents to $3.45 in morning trading on the Nasdaq Stock Market.