Effects of Selexipag in Adults With Raynaud's Phenomenon Secondary to Systemic Sclerosis

Key inclusion criteria: * Signed informed consent prior to any study-mandated procedure. * Male and female subjects aged 18 years and above with a history of recurrent multiple weekly RP attacks secondary to SSc. * Women of childbearing potential must agree to use a reliable method of birth control. Key exclusion criteria: * Known moderate or severe hepatic impairment (i.e. Child-Pugh C). * Known hypersensitivity to selexipag or drugs of the same class, or any of their excipients. * Subjects who have received prostacyclin (epoprostenol) or prostacyclin analogs (i.e., treprostenol, iloprost, beraprost) within 3 months prior to the screening visit. * Subjects who have received a Phosphodiesterase type 5 (PDE-5) inhibitor within 1 week prior to the screening visit. * Any dose change or initiation of any of the following drugs within 1 month prior to the screening visit: Calcium channel blockers, Nitrates or nitric oxide donors, ERA's, Alpha-blockers, Antithrombotic agents, NSAIDs (occasional use allowed), Angiotensin Converting Enzyme (ACE) inhibitors, Beta-blockers, Clonidine, Systemic corticosteroids, Fluoxetine. * Severe renal insufficiency (at randomization). * Any circumstances or conditions, which, in the opinion of the investigator, may affect the subject's full participation in the study or compliance with the protocol