SSc-PAH Risk Category Improves With Ambrisentan and Tadalafil Combo Therapy

This article is part of MPR‘s coverage of the American Thoracic Society International Conference, taking place in Dallas, Texas. Our staff will report on medical research related to asthma and other respiratory conditions, conducted by experts in the field. Check back regularly for more news from ATS 2019.

DALLAS — Combination treatment with ambrisentan and tadalafil is associated with a reduced mortality risk profile in patients with scleroderma-associated pulmonary arterial hypertension (SSc-PAH), according to study findings presented at the American Thoracic Society International Conference held May 17 to 22 in Dallas, Texas.

“SSc-PAH is characterized by a worse prognosis in comparison to other PAH etiologies, and a decreased response to PAH therapies,” the researchers wrote. “Improvements in risk category are associated with better survival, although a minority of SSc-PAH patients improved their risk category at first follow-up.”

The ATPAHSS trial (ClinicalTrials.gov Identifier: NCT01042158) was conducted by obtaining data from treatment-naive patients with SSc-PAH who received initial upfront therapy with once-daily 40 mg tadalafil and 10 mg ambrisentan. Patients with follow-up data at 36 weeks (n=23) were included in the trial. An abbreviated risk assessment tool was also applied that used World Health Organization functional class, 6-minute walking distance, right atrial pressure, cardiac index, mixed venous oxygen saturation, N-terminal prohormone of brain natriuretic peptide, right atrial area, and pericardial effusion. The instrument resulted in varying scores that categorized patients as low risk or score 1 (n=7), intermediate risk or score 2 (n=15), or high risk or score 3 (n=1). Results from the abbreviated model were compared with the SSc-PAH group.

At the 36-week follow-up, no patient was in the high-risk category and a greater number of patients achieved a low-risk profile (n=12). During the same period, 11 patients were categorized as intermediate risk. These results suggest that treatment was possibly effective in improving the risk profile of these patients. A higher percentage of patients in the ATPAHSS cohort remained in or improved to the low-risk category compared with the SSc-PAH historical cohort (52.8% vs 21.7%, respectively; P =.004).

Study limitations include the relatively short follow-up, lack of a randomized control, and the small sample size.

“In this recent prospective clinical trial initial upfront combination treatment resulted in a relevant improvement in risk category that was more significant in comparison to previously reported results in the literature,” the researchers wrote, “thus further confirming the usefulness of the risk score stratification and the beneficial effects of this therapeutic approach which is likely to lead to improved survival in SSc-PAH.”

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Reference

Mercurio V, Mathai SC, Damico RL, et al. Changes in risk category among patients with systemic sclerosis- associated PAH treated with initial combination therapy in the ATPAHSS trial. Presented at: the American Thoracic Society International Conference; May 21, 2019; Dallas, TX. Abstract A5078/P1154.

This article originally appeared on Pulmonology Advisor