mirabegron and Hypertension--Pulmonary

Pulmonary hypertension (PH) associated with left heart disease is an increasingly prevalent problem, orphan of targeted therapies, and related to a poor prognosis, particularly when pre- and post-capillary PH combine. The current study aimed to determine whether treatment with the selective β3 adrenoreceptor agonist mirabegron improves outcomes in patients with combined pre- and post-capillary PH (CpcPH).. The β3 Adrenergic Agonist Treatment in Chronic Pulmonary Hypertension Secondary to Heart Failure (SPHERE-HF) trial is a multicentre, randomized, parallel, placebo-controlled clinical trial that enrolled stable patients with CpcPH associated with symptomatic heart failure. A total of 80 patients were assigned to receive mirabegron (50 mg daily, titrated till 200 mg daily, n = 39) or placebo (n = 41) for 16 weeks. Of them, 66 patients successfully completed the study protocol and were valid for the main analysis. The primary endpoint was the change in pulmonary vascular resistance (PVR) on right heart catheterization. Secondary outcomes included the change in right ventricular (RV) ejection fraction by cardiac magnetic resonance or computed tomography, other haemodynamic variables, functional class, and quality of life. The trial was negative for the primary outcome (placebo-corrected mean difference of 0.62 Wood units, 95% confidence interval [CI] -0.38, 1.61, p = 0.218). Patients receiving mirabegron presented a significant improvement in RV ejection fraction as compared to placebo (placebo-corrected mean difference of 3.0%, 95% CI 0.4, 5.7%, p = 0.026), without significant differences in other pre-specified secondary outcomes.. SPHERE-HF is the first clinical trial to assess the potential benefit of β3 adrenergic agonists in PH. The trial was negative since mirabegron did not reduce PVR, the primary endpoint, in patients with CpcPH. On pre-specified secondary outcomes, a significant improvement in RV ejection fraction assessed by advanced cardiac imaging was found, without differences in functional class or quality of life.

Topics: Adrenergic Agonists; Double-Blind Method; Heart Failure; Humans; Hypertension, Pulmonary; Quality of Life; Stroke Volume; Treatment Outcome

Topics: Acetanilides; Adrenergic beta-3 Receptor Agonists; Heart Failure; Humans; Hypertension, Pulmonary

Beta-3 adrenergic receptor (β3AR) agonists have been shown to produce vasodilation and prevention of ventricular remodeling in different conditions. Given that these biological functions are critical in pulmonary hypertension (PH), we aimed to demonstrate a beneficial effect of β3AR agonists in PH. An experimental study in pigs (n = 34) with chronic PH created by pulmonary vein banding was designed to evaluate the acute hemodynamic effect and the long-term effect of β3AR agonists on hemodynamics, vascular remodeling and RV performance in chronic PH. Ex vivo human experiments were performed to explore the expression of β3AR mRNA and the vasodilator response of β3AR agonists in pulmonary arteries. Single intravenous administration of the β3AR agonist BRL37344 produced a significant acute reduction in PVR, and two-weeks treatment with two different β3AR selective agonists, intravenous BRL37344 or oral mirabegron, resulted in a significant reduction in PVR (median of -2.0 Wood units/m(2) for BRL37344 vs. +1.5 for vehicle, p = 0.04; and -1.8 Wood units/m(2) for mirabegron vs. +1.6 for vehicle, p = 0.002) associated with a significant improvement in magnetic resonance-measured RV performance. Histological markers of pulmonary vascular proliferation (p27 and Ki67) were significantly attenuated in β3AR agonists-treated pigs. β3AR was expressed in human pulmonary arteries and β3AR agonists produced vasodilatation. β3AR agonists produced a significant reduction in PVR and improved RV performance in experimental PH, emerging as a potential novel approach for treating patients with chronic PH.

Topics: Acetanilides; Adrenergic beta-3 Receptor Agonists; Animals; Blotting, Western; Disease Models, Animal; Female; Humans; Hypertension, Pulmonary; Immunohistochemistry; Male; Nebivolol; Pulmonary Artery; Random Allocation; Real-Time Polymerase Chain Reaction; Receptors, Adrenergic, beta-3; Swine; Thiazoles; Vascular Resistance; Ventricular Remodeling