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FDA Grants Thelin Orphan Drug Designation
The U.S. Orphan Drug Act of 1983 provides incentives for companies that are developing and marketing therapies for diseases and disorders that affect fewer than 200,000 people in the United States. Following FDA approval, the Orphan Drug Act provides a drug market exclusivity for a particular indication for a period of seven years. Additionally, orphan drug designation provides protocol assistance, clinical trial support, tax credits, grant funding for research, and waiver of the Prescription Drug User Fee Act (PDUFA) filing fee.
About Thelin and PAH
Thelin is a small molecule that blocks the action of endothelin, a potent mediator of blood vessel constriction and growth of smooth muscle in vascular walls. Endothelin receptor antagonists may prove to be effective in the treatment of a variety of diseases where the regulation of vascular constriction is important. Thelin is 6,500 fold selective in the targeting of the endothelin A receptor.
Pulmonary arterial hypertension (PAH) is a condition that involves high blood pressure and structural changes in the walls of the pulmonary arteries, which are the blood vessels that connect the right side of the heart to the lungs. PAH causes shortness of breath, limits activity, and is eventually fatal unless treated successfully with heart and lung transplant. Primary and secondary PAH are estimated to afflict approximately 80,000 to 100,000 people worldwide, many of whom are children and young women.
Side effects of Thelin seen in the program to date, and which occurred more frequently than in placebo, include liver dysfunction (increased ALT and AST), headache, edema, constipation, nasal congestion and flushing. Because Thelin inhibits the metabolism of warfarin, the dose of warfarin should be adjusted downward when co-administered with Thelin.
Source: Encysive Pharmaceuticals