Adenosine Receptor Agonists

Adenosine is a purine nucleoside that binds to adenosine cell surface receptors, which are widely expressed in heart and blood vessel cells as well as in the brain, kidney and adipose tissue.There are 4 subtypes of P1 (adenosine) G protein-coupled receptors (GPCR), named A1, A2A, A2B, and A3, which mediate a variety of cardioprotective and regenerative effects. In the heart, these effects are predominantly mediated through A1 receptors (A1R), which are expressed in atrial and ventricular cardiomyocytes and smooth muscle cells.  Pre-clinical studies have reported multiple potential benefits achievable by modulation of adenyl cyclase with beneficial effects in a variety of pre-clinical models of cardiovascular disease including chronic heart failure (HF). A1R blockade (e.g. rolofylline) was however not successful in the PROTECT trial, where 2033 patients with acute HF and renal dysfunction were randomized to rolofylline or placebo, showed no benefit on renal function, symptoms, rehospitalization, or mortality. Following this attention turned to partial adenosine agonists, capadenoson and neladenoson bialanate hydrochloride, which has two phase II studies underway, PANACHE (HFpEF) and PANTHEON (HFrEF).