Mydicar is a genetically targeted enzyme replacement therapy being studied for use in patients with severe heart failure. It is designed to increase the level of SERCA2a, a sarcoplasmic endoplasmic reticulum calcium (Ca) ATPase found in the membrane of the sarcoplasmic reticulum (SR). The SERCA2a gene is delivered to the heart via an adeno-associated viral vector. Using the α-myosin heavy chain gene promoter in the cardiac muscle cells, also called cardiomyocytes, Mydicar is able to direct the gene expression only to the heart muscle. Mydicar is being tested in a phase 2 study, in which has been compared to a placebo in 39 advanced heart failure patients. Thus far, patients treated with Mydicar have shown a 52% reduction in the risk of worsening heart failure compared to patients treated with the placebo.