PDE4A and autosomal dominant polycystic kidney disease: A previous study showed that a novel therapeutic approach, which focuses on the specific activation of long isoforms of PDE4 by the small molecule MR‐L2 reduced cellular cAMP levels and, thereby, suppressed cAMP‐mediated cyst development in MDCK cells and in ADPKD patient‐derived kidney epithelial cells (Omar et al, 2019).