Discovery of (2S,4R)-1-(2-aminoacetyl)-4-benzamidopyrrolidine-2-carboxylic acid hydrochloride (GAP-134)13, an orally active small molecule gap-junction modifier for the treatment of atrial fibrillation.

Rotigaptide (3) is an antiarrhythmic peptide that improves cardiac conduction by modifying gap-junction communication. Small molecule gap-junction modifiers with improved physical properties were identified from a Zealand Pharma peptide library using pharmaceutical profiling, established SAR around 3, and a putative pharmacophore model for rotigaptide. Activity of the compounds was confirmed in a mouse cardiac conduction block model of arrhythmia. Dipeptide 9f (GAP-134) was identified as a potent, orally active gap-junction modifier for clinical development.