Christmas came early for Actelion Ltd., as the FDA approved its pulmonary arterial hypertension (PAH) treatment Uptravi (selexipag), putting the company on track to launch the oral prostacyclin receptor agonist early next month for use in delaying PAH progression and patients' risk of hospitalization for symptoms related to the condition. The therapy will be marketed by San Francisco-based Actelion Pharmaceuticals US Inc.