 Oncternal Therapeutics, Inc. Nasdaq: ONCT, a clinical-stage biopharmaceutical company focused on the development of novel oncology therapies, today announced that it has opened for enrollment a Phase 1b expansion cohort of its ongoing clinical trial evaluating TK216, a first-in-class, targeted, investigational small-molecule inhibitor of the E26 transformation-specific ETS family of oncoproteins, in patients with relapsed or refractory Ewing sarcoma. 