A DUE Is the First and Only Phase 3 Clinical Trial of a
Single-Tablet Combination Therapy vs ERA or PDE5 Inhibitor Monotherapy for PAH WHO FC II-III1

Multinational, multicenter, double-blind, randomized, and active-controlled phase 3 study of a once-daily, single-tablet dual combination of macitentan 10 mg and tadalafil 40 mg. The primary endpoint was change from baseline in pulmonary vascular resistance at Week 16.2

Patients were randomized into treatment arms depending on their treatment status at baseline


Select inclusion criteria1:

  • mPAP ≥25 mmHg
  • PAWP or left ventrical end-diastolic pressure ≤15 mmHg
  • PVR ≥3 Woods units (ie, ≥240 dyn·s/cm5)
  • PAH-specific treatment naive or on a stable dose of ERA or PDE5 inhibitor monotherapy for at least 3 months

Patient Demographics at Baseline

Treatment HistoryTreatment History graphic
EtiologyEtiology graphic
  • Among patients on a prior ERA—

    47% were previously treated with macitentan,
    31% with ambrisentan, and 22% with bosentan

  • Among patients on a prior PDE5 inhibitor—

    84% were previously treated with sildenafil and
    16% with tadalafil

Mean Age


years (range 18–80)






WHO Functional Class





Other etiologies include PAH associated with HIV infection, portal hypertension, or drug- or toxin-induced.1

Titration used in A DUE trial1

The double-blind treatment period began with a
2-week tadalafil titration phase followed by a maintenance phase:

Time LineTime Line
  • Patients received macitentan 10 mg once daily, tadalafil 20 mg once daily, or both as separate tablets, plus respective placebos
  • Patients who were receiving a stable dose of a PDE5 inhibitor at baseline did not require titration and tadalafil 40 mg was administered at Day 1
  • Tadalafil was up-titrated to
    40 mg once daily
  • Started on Day 15
  • Patients received either
    OPSYNVI® (macitentan/tadalafil) 10 mg/40 mg, macitentan 10 mg once daily, or tadalafil 40 mg once daily, along with respective placebos depending on treatment arm
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One treatment-naïve patient did not receive any treatment and was not included in the full analysis set.

Includes sildenafil and sildenafil citrate.

ERA=endothelin receptor antagonist; FC=Functional Class; HPAH=heritable PAH; IPAH=idiopathic PAH; mPAP=mean pulmonary arterial pressure; PAH=pulmonary arterial hypertension; PAH-CHD=PAH associated with congenital heart disease; PAH-CTD=PAH associated with connective tissue disease; PAWP=pulmonary arterial wedge pressure; PDE5i=phosphodiesterase type 5 inhibitor; PVR=pulmonary vascular resistance; WHO=World Health Organization.

References: 1. Grünig E, Jansa P, Fan F, et al. Randomized trial of macitentan/tadalafil single-tablet combination therapy for pulmonary arterial hypertension. J Am Coll Cardiol. 2024;83(4):473-484. 2. OPSYNVI® (macitentan/tadalafil) full Prescribing Information. Actelion Pharmaceuticals US, Inc.

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