Mesoblast Limited (MSB) announced that its United States-based associate company Angioblast Systems Inc. has initiated a Phase 2 clinical trial to evaluate the safety and effectiveness of the company's proprietary "off-the-shelf" adult stem cell product Revascor. The company said the purpose of the product is to improve heart muscle function in patients with the most severe, or class IV, end-stage form of heart failure. Mesoblast said if Revascor can improve heart muscle function in this patient population, it could result in a new therapy for large numbers of class IV heart failure patients without the need for a heart transplant. The company’s shares were up over 4% Wednesday morning.