MedicalResearch.com Interview with: Olivier Sitbon, MD, PhD Université Paris–Sud  MedicalResearch.com: What is the background for this study? How does this treatment competition differ from other treatments for PAH?  Response:  Pulmonary arterial hypertension (PAH) is a complex, progressive and potentially fatal disease with no cure. Over the past decades, advances in understanding the pathophysiology of PAH have led to major prognostic improvement and developments of new treatment guidelines and therapies. Current treatment guidelines recommend initial combination therapy for these patients to target multiple PAH-associated pathways in parallel. OPTIMA was a prospective, multicenter, single-arm, open-label, Phase IV trial designed to evaluate the efficacy, safety and tolerability of initial oral combination therapy with macitentan and tadalafil in patients with newly diagnosed PAH. Treatment with macitentan 10 mg once-daily and tadalafil 20 mg once-daily was initiated on the same day. After 8±3 days, tadalafil dose was increased to 40 mg once-daily. Safety and tolerability findings were consistent with previous clinical trials that supported the approval and use of macitentan 10 mg once-daily. Efficacy outcomes were assessed at Week 16 and safety continued to be monitored until study closure. The results from the OPTIMA analysis suggest that initial treatment with macitentan in combination with tadalafil is associated with hemodynamic improvement in newly diagnosed patients with pulmonary arterial hypertension (more…)