United Therapeutics has signed an agreement for the worldwide licence to develop, manufacture and commercialise Arena’s ralinepag for the treatment of pulmonary arterial hypertension (PAH). For US$800 M upfront, ralinepag joins United’s arsenal of PAH drugs - some of which are facing generic competition - and allows Arena to focus on its other pipeline assets including etrasimod and olorinab. The deal follows United’s acquisition of SteadyMed for its drug-device combination Trevyent (treprostinil sodium) and its collaboration with MannKind for a dry powder formulation of treprostinil.