Daiichi Sankyo Company, Limited has announced that it has initiated ESAX-DN, a phase 3 pivotal study of esaxerenone (INN) (Code name: CS-3150), a non-steroidal, selective novel mineralocorticoid receptor (MR) blocker, for patients in Japan with diabetic nephropathy.

In March 2006, Daiichi Sankyo and Exelixis entered into a research collaboration agreement to discover, develop and commercialize novel therapies targeted for MR. Under the terms of the agreement, Daiichi Sankyo has exclusive development, manufacturing and commercialization rights for the compounds worldwide.

Esaxerenone is one of the in-licensed compounds identified during the research collaboration with Exelixis, and has subsequently been developed by Daiichi Sankyo.

ESAX-DN is a phase 3 randomized, double-blind, 2-arm, parallel group comparison study with placebo in patients with type 2 diabetes with microalbuminuria who are taking an angiotensin II receptor blocker (ARB) or an angiotensin converting enzyme (ACE) inhibitor in Japan. The primary endpoint is rate of remission to normoalbuminuria after 52-week treatment, and the secondary endpoints are change rate in urinary albumin creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR).

Esaxerenone is an orally administered, non-steroidal, selective blocker of MR. As recently reported, aldosterone is regarded as a potent mediator of organ damage. Esaxerenone may have a role in preventing these organ damaging effects. In phase 2 multicenter, randomized, double-blind, placebo-controlled, study, esaxerenone 1.25, 2.5, and 5 mg/day on top of ARB or ACE inhibitor for 12 weeks significantly reduced UACR compared to placebo in type 2 diabetic patients with microalbuminuria.