TRV120027, a Novel β-Arrestin Biased Ligand at the Angiotensin II Type I Receptor, Unloads the Heart and Maintains Renal Function When Added to Furosemide in Experimental Heart Failure

Background-TRV120027 is a novel beta-arrestin biased ligand of the angiotensin II type 1 receptor; it antagonizes canonical G-protein-mediated coupling while, in contrast to classical angiotensin II type 1 receptor antagonists, it engages beta-arrestin-mediated signaling. Consequently, TRV120027 inhibits angiotensin II-mediated vasoconstriction while, via beta-arrestin coupling, it increases cardiomyocyte contractility. We hypothesized that TRV120027 would elicit beneficial cardiorenal actions when added to furosemide in experimental heart failure. Methods and Results-Two groups of anesthetized dogs (n=6 each) with tachypacing-induced heart failure were studied. After a baseline clearance, 1 group (F+V) received furosemide (1 mg/kg per hour) plus saline for 90 minutes, whereas the other (F+T) received the same dose of furosemide plus TRV120027 (0.3 and 1.5 mu/kg per minute for 45 minutes each); 2 clearances were done during drug infusion. After a washout, a postinfusion clearance was done; *P<0.05 between groups. F+V and F+T increased diuresis and natriuresis to a similar extent during drug administration, but urine flow* and urinary sodium excretion* were higher in the postinfusion clearance with F+T. Glomerular filtration rate was preserved in both groups. Renal blood flow increased with F+T but this was not significant versus F+V. Compared with F+V, F+T decreased mean arterial pressure*, systemic* and pulmonary* vascular resistances, and atrial natriuretic peptide*. Pulmonary capillary wedge pressure* decreased to a larger extent with F+T than with F+V. Conclusions-When added to furosemide, TRV120027, a novel beta-arrestin biased angiotensin II type 1 receptor ligand, preserved furosemide-mediated natriuresis and diuresis, while reducing cardiac preload and afterload. These results provide support for TRV120027 as a promising novel therapeutic for the treatment of heart failure. (Circ Heart Fail. 2012;5:627-634.)