Thelin was approved in 2006 for the treatment of pulmonary arterial hypertension. The safety reassessment was prompted by three cases of fatal liver injury, two of which were causally related to use of the endothelin A receptor antagonist. The cases were not associated with identifiable risk factors and were not detected by frequent monitoring, indicating that serious liver damage cannot be prevented in all patients.
The CHMP is initiating a cumulative review of all endothelin receptor antagonists to determine whether hepatic toxicity is a class effect.
Alternative treatments for patients currently receiving Thelin include the endothelin antagonists Tracleer (bosentan) and Volibris (ambrisentan). Thelin will be withdrawn using a phased approach to enable a safe switch to alternative treatment.