SAN DIEGO, June 20, 2016 /PRNewswire/ — Oncternal Therapeutics, Inc., a clinical-stage oncology company developing first-in-class therapies for rare and common malignancies, today announced that its ets-family inhibitor TK216 has received Fast Track Designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with Ewing sarcoma …