CXCL12 and ischemic cardiomyopathy: The observed beneficial effects could be biased by the limitation in the study design.440 Indeed, subsequent studies with double-blinded placebo-controlled designs failed to show positive results.448–450 Stromal cell-derived factor-1 (SDF-1) is a regulator of tissue repair that has multiple beneficial effects on ischemic cardiomyopathy.451,452 The phase 2 STOP-HF trial was designed to determine the therapeutic potential of a plasmid encoding stromal cell-derived factor-1 (pSDF-1) in chronic ischemic heart failure.