Chin, Kelly M., Channick, Richard, Kim, Nick H., MacDonald, Gwen, Ong, Rose, Martin, Nicolas, Senatore, Assunta, and McLaughlin, Vallerie V.
Introduction: Historically, patients recently (≤ 6 months) diagnosed with pulmonary arterial hypertension (PAH; incident) have had poorer survival than those with a longer (> 6 months) time from PAH diagnosis (prevalent). Despite guideline recommendations for initial combination therapy for most patients with PAH, many are initiated and maintained on monotherapy. Real-world evidence to evaluate the benefit of early combination treatment in newly-diagnosed patients is lacking. Methods: Patients with PAH initiating combination therapy with the endothelin receptor antagonist macitentan and the phosphodiesterase-5 inhibitor tadalafil (M+T) were identified from the combined dataset of the US, multicenter OPUS (prospective, observational drug registry; NCT02126943) and OrPHeUS (retrospective, medical chart review; NCT03197688) studies (2013–2020). Descriptive analyses were performed for the incident and prevalent cohorts, as well as the subcohort of incident patients who received M+T as first-line combination therapy (incident initial combination). Results: In OPUS/OrPHeUS, 1336 patients with PAH received M+T during the observation period. For the incident [n = 453 (33.9%)], incident initial combination [n = 272 (20.4%)], and prevalent [n = 837 (62.6%)] cohorts: median (Q1, Q3) M+T exposure was 14.2 (4.2, 27.5), 12.2 (3.2, 25.5), and 14.7 (4.5, 28.0) months. 12-month Kaplan–Meier estimates (95% confidence limits) for survival were 91.2% (87.7, 93.7), 88.5% (83.2, 92.2), and 92.9% (90.6, 94.6), for patients free from hospitalization were 59.4% (54.1, 64.4), 56.3% (49.1, 62.9), and 62.3% (58.5, 65.9), and for patients persisting on combination therapy were 68.6% (63.9, 72.8), 65.0% (58.8, 70.6) and 66.9% (63.5, 70.0). Adverse events (OPUS only) were reported in 77.8%, 80.2%, and 80.3% of patients, respectively, with no unexpected adverse events observed. Conclusions: Despite a historically worse prognosis, incident patients receiving M+T, including as initial combination therapy, had similar survival and hospitalization as prevalent patients. Safety profiles were similar across cohorts. Together, these data support the use of early combination therapy with macitentan and tadalafil. Plain Language Summary: In earlier studies, patients diagnosed with pulmonary arterial hypertension (PAH) within the past 6 months (newly-diagnosed PAH, called 'incident patients' in this article) had worse health than patients diagnosed with PAH more than 6 months before (long-standing PAH, called 'prevalent patients' in this article). This is because some newly-diagnosed patients have very advanced disease and do poorly within the first 6 months. The OPUS (NCT02126943) and OrPHeUS (NCT03197688) studies collected information on patients with PAH treated in US clinics between 2013 and 2020. We identified patients that were treated with a combination of two PAH medications, macitentan and tadalafil. We then grouped them as newly-diagnosed (453 patients) or long-standing (837 patients). We also looked at the subgroup of newly-diagnosed patients who received the combination as their first treatment (272 patients, called 'incident initial combination patients' in this article). We then looked at how these patients did over time. Patients were treated with macitentan and tadalafil for an average of 12–14 months. We found that after 1 year of combination treatment, results were similar between the groups: patient survival was 91%, 89%, and 93% for those with newly-diagnosed, newly-diagnosed and previously untreated, and long-standing PAH; the proportion remaining hospitalization-free was 59%, 56%, and 62%; and the proportion remaining on combination treatment was 69%, 65%, and 67%, respectively. Side effects were in line with the known safety profiles of the medications. Despite historically having worse health outcomes, newly-diagnosed patients receiving the macitentan and tadalafil combination had similar survival and hospitalization as patients with long-standing PAH. These data suggest that there is a benefit to starting this combination of medicines early in the treatment of PAH. [ABSTRACT FROM AUTHOR]