Udenafil as an oral tablet is in clinical development for congenital heart disease in adolescents after Fontan palliation. Functional single ventricle congenital heart disease is a condition in which babies are born with one of their lower heart chambers (ventricles) not working. As a result, the heart cannot pump blood properly to the lungs and the rest of the body. The Fontan operation is the final of three surgeries in the strategy of staged palliation for children born with congenital heart defects resulting in functional single-ventricle physiology. Fontan patients may have a shortened life span, often not surviving past the third or fourth decade of life, due to many factors including deteriorating ventricular performance and increasing pulmonary vascular resistance.
Udenafil works by blocking the enzyme phosphodiesterase type 5 which regulates the breakdown of ‘cyclic guanine monophosphate’ (cGMP) in the blood vessels of the lungs. Increased levels of cGMP leads to dilation (widening) of the vessels improving blood flow to the lungs, reducing the burden on the heart and improving oxygen supply to the blood. This is expected to improve the symptoms of the condition and may offer an additional treatment option for adolescents (12-18 years old) for the management of congenital heart disease after Fontan palliation who currently have few effective therapies available.