Conference Coverage

Macitentan, tadalafil combo found effective for newly diagnosed PAH



– Treatment with macitentan and tadalafil can elicit improvements in patients with newly diagnosed pulmonary arterial hypertension (PAH), trial results suggest.

Dr. Olivier Sitbon, Université Paris–Sud in France Jennifer Smith/MDedge News

Dr. Olivier Sitbon

In the phase 4 OPTIMA trial, the combination significantly improved cardiopulmonary hemodynamics, functional class, 6-minute walk distance, and N-terminal pro B-type natriuretic peptide (NT-proBNP).

Olivier Sitbon, MD, PhD, of Université Paris–Sud in France, presented these results at the annual meeting of the American College of Chest Physicians.

The OPTIMA trial (NCT02968901) enrolled 46 adults who were newly diagnosed with PAH and had medium functional ability (WHO functional class II-III). The patients’ mean age was 57.4 ± 14.9 years, and 65% of them were female.

The mean time from PAH diagnosis was 29.6 ± 55.2 days. Patients had idiopathic PAH (63%), PAH associated with connective tissue disease (19.6%), heritable PAH (6.5%), drug- or toxin-induced PAH (4.4%), HIV-associated PAH (2.2%), and “other” PAH (4.4%).

Patients initially received macitentan at 10 mg once daily and tadalafil at 20 mg once daily. After 8 ± 3 days, the tadalafil dose was increased to 40 mg once daily. The median duration of treatment was 19.9 months.

The researchers assessed efficacy at week 16, but patients were monitored for safety until the study was closed by the sponsor. There were 44 patients who remained on study through week 16, and 39 patients completed the study.


The study’s primary endpoint was the change in pulmonary vascular resistance (PVR). The ratio of week 16 to baseline PVR was 0.53, which translates to a significant 47% reduction in PVR. In fact, 87% of patients had a 30% or greater decrease in PVR from baseline to week 16.

Patients had improvements in other endpoints as well. The mean cardiac index increased from 2.2 to 3.1 L/min/m2 (P less than .0001) from baseline to week 16. The mean pulmonary arterial pressure decreased from 50.0 to 42.2 mm Hg (P = .0002), and the mean right atrial pressure decreased from 8.1 to 7.8 mm Hg (P = .7321).

The mean mixed venous oxygen saturation increased from 63.0% to 68.2% (P = .0003). The mean total pulmonary resistance decreased from 1109.4 to 677.4 dynes/sec/cm-5 (P less than .0001).

NT-proBNP decreased 68% from baseline to week 16. The geometric mean ratio was 0.32 (P less than .0001). The 6-minute walk distance increased from 352.2 to 388.1 m (P = .0008).

None of the patients experienced a worsening of WHO functional class from baseline to week 16, and 63% of patients experienced an improvement.

Nearly 94% of patients (n = 43) had at least one adverse event, 28% (n = 13) had serious adverse events, and 6.5% (n = 3) stopped treatment because of adverse events. The most frequent events were peripheral edema (n = 13), headache (n = 11), diarrhea (n = 9), and dyspnea (n = 7).

Three patients died during follow-up, one due to multiorgan failure and two due to underlying disease.

Actelion Pharmaceuticals funded the trial. Dr. Sitbon disclosed relationships with Actelion, Bayer, GSK, Merck, Arena Pharmaceuticals, Gossamer Bio, and Ferrer.

SOURCE: Sitbon O et al. CHEST 2019. Abstract, doi: 10.1016/j.chest.2019.08.825.

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