Background and Aims
The aim of the SCIENCE trial was to investigate whether a single treatment with direct intramyocardial injections of adipose tissue derived mesenchymal stromal cells (CSCC_ASCs) was safe and improved cardiac function in patients with chronic ischemic heart failure with reduced ejection fraction (HFrEF).

Methods
The study was a European multi-centre double-blinded placebo-controlled phase II trial using allogeneic CSCC_ASCs from healthy donors or placebo (2:1 randomization). Main inclusion criteria were NYHA II-III, left ventricular ejection fraction (LVEF) < 45%, and NT-ProBNP levels>300 pg/mL. CSCC_ASCs or placebo (isotonic saline) were injected directly into viable myocardium. Primary endpoint was change in left ventricular end-systolic volume (LVESV) at 6 months follow up measured by echocardiography.

Results
A total of 133 symptomatic HFrEF patients were included. The treatment was safe without any drug-related severe adverse events or difference in cardiac related adverse events during a 3-years follow-up period. There were no significant differences between the groups during follow up in LVESV (0.3 ± 5.0 ml, P = 0.945), nor in secondary endpoints left ventricular end-diastolic volume (−2.0 ± 6.0 ml, P = 0.736) and LVEF (−1.6 ± 1.0%, P = 0.119).

The NYHA classification improved slightly within the first year in both groups without any difference between groups. There were no changes in 6-Minute Walk Test, NT-ProBNP, CRP or quality-of-life the first year in any of the two groups.

Conclusion
The SCIENCE trial demonstrated safety of intramyocardial allogeneic CSCC_ASC therapy in patients with chronic HFrEF. However, it was not possible to improve the predefined endpoints and induce restoration of cardiac function or clinical symptoms