The Calcium Up-Regulation by Percutaneous Administration of Gene Therapy In Cardiac Disease (CUPID 1) study was a phase 1/phase 2 first-in-human clinical gene therapy trial using an adeno-associated virus serotype 1 (AAV1) vector carrying the sarcoplasmic reticulum calcium ATPase gene (AAV1/SERCA2a) in patients with advanced heart failure. The study explored potential benefits of the therapy at 12 months, and results were previously reported.