Serelaxin (brand name Reasanz; developmental code name RLX-030) is a medication which is marketed in Russia for the treatment of acute heart failure (AHF), targeting the relaxin receptor.

[1] It was also under development in other places in the world, including in the United States, Europe, and Asia, but ultimately was not marketed in these areas.

Serelaxin has undergone clinical trials in patients with acute heart failure,[12] conducted by Novartis.

[12][15] The FDA granted serelaxin "breakthrough therapy" designation, meant to expedite the development and review of drugs for life-threatening conditions.

[16] On 22 March 2017, Novartis announced that the global Phase III study of serelaxin in patients with acute heart failure did not meet its primary endpoints.