United Therapeutics Corporation has withdrawn its Marketing Authorization Application (MAA) for Tyvaso (treprostinil sodium) 0.6 mg/ml nebuliser solution for the treatment of pulmonary arterial hypertension (PAH) in the European Union.

United Therapeutics submitted its MAA for Tyvaso to the European Medicines Agency (EMA) in December 2008. The data included in the MAA is based upon clinical work performed from 2005 to 2007 by United Therapeutics' wholly-owned subsidiary Lung Rx, LLC. The MAA was withdrawn following communication from the Committee for Medicinal Products for Human Use (CHMP) of the EMA citing a major objection. The major objection noted that findings of non-compliance with good clinical practices (GCP) at two clinical sites would preclude a recommendation by the EMA for approval of the MAA for Tyvaso.

"Notwithstanding the fact that the EMA's major objection noted findings of non-compliance with good clinical practices, it is important to note that there were no major objections related to the safety or efficacy of Tyvaso," said Roger Jeffs, United Therapeutics' President and Chief Operating Officer.

"Our revenue growth targets are unaffected by the withdrawal," said Martine Rothblatt, United Therapeutics' chairman and chief executive officer. "We have long based our growth targets on the estimated 30,000 diagnosed PAH patients in the US, including approximately 12,000 New York Heart Association Class III patients."

Tyvaso is an inhaled medicine used to treat PAH, a life-threatening disease that constricts the flow of blood through the pulmonary vasculature.

United Therapeutics Corporation is a biotechnology company focused on the development and commercialization of unique products to address the unmet medical needs of patients with chronic and life-threatening conditions.