S44121

S44121 (also known as ARM036) is an investigational small molecule belonging to the 'Rycal' drug class, developed by Servier. It functions as a stabilizer of the cardiac ryanodine receptor (RyR2) by enhancing the binding of calstabin2 (FKBP12.6) to the receptor complex. This mechanism prevents abnormal diastolic calcium (Ca2+) leakage from the sarcoplasmic reticulum, which is a key driver of Ca2+-dependent arrhythmias. S44121 is primarily being investigated for the treatment of catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1), a rare inherited arrhythmogenic disorder. Preclinical studies have also explored its potential in post-myocardial infarction heart failure models to reduce ventricular arrhythmias and improve skeletal muscle function.