New Clinical Trial Tests Ambrisentan in Preventing SSc-PAH

Treating patients with systemic sclerosis (SSc) who have borderline pulmonary arterial hypertension (PAH) is vital to patient health, as life expectancy after a diagnosis of SSc-PAH is only one year. Accordingly, Heidelberg University, along with GlaxoSmithKline, initiated a clinical trial to investigate “Early Treatment of Borderline Pulmonary Arterial Hypertension Associated with Systemic Sclerosis (SSc-APAH) (EDITA).”

The trial focuses on treating SSc patients 18 years and older with ambrisentan in a phase 2 proof-of-concept, efficacy and safety clinical trial. Patients randomized to the ambrisentan group will be given a dose between 5 and 10 mg daily, based on consultation with an investigator concerning patient tolerability. Alternatively, another group of patients will be given a placebo. Subjects, caregivers, investigators, and outcomes assessors will be blinded to which patients are in which treatment group.

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At the beginning of the trial, patients will undergo a physical examination that includes an electrocardiogram, laboratory tests, and right heart catheterization. Afterward, 19 enrolled patients will be randomized into the ambrisentan group, and 19 will be randomized into the placebo group. Treatment will last for 180 days, plus or minus two weeks, followed by a follow-up phase of approximately 30 days. The study is expected to be complete in December 2016.

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In previous studies, ambrisentan improved mean pulmonary arterial pressure (mPAP) by 15% in patients with PAH, and improvements were also shown in SSc-IPAH patients. In the current study, a reduction in mPAP of 3 mmHg is the primary outcome measure. Blood pressure during exercise, lung function tests, and six minute walk distance are secondary outcome measures.

Throughout the study, patients will interact with investigators to correctly tune the dose of ambrisentan required for an effect without causing tolerance issues. No more than 10 mg per day will be allowed for any patient. The goal is to prevent PAH in SSc patients using this or a lower dose of ambrisentan to improve the quality of life and life expectancy of enrolled patients.