 The company held its initial public offering in September 2013.At that time, the company had three protein therapeutic candidates being studied in 12 Phase 2 clinical trials, including sotatercept and luspatercept (ACE-536) which promoted red blood cell production and were being tested as potential treatments for anemia in people with thalassemia and myelodysplastic syndromes (MDS); its other candidate was dalantercept (ACE-041), an angiogenesis inhibitor as a potential cancer drug.In September 2016 Knopf retired and the company hired Habib Dable as CEO; at that time the company's lead product luspatercept was in Phase III testing for MDS and beta-thalassemia.