Oncternal Therapeutics, Inc. announced the receipt of a 'Study May Proceed' letter from the U.S. Food and Drug Administration (FDA), 30 days after submitting its Investigational New Drug (IND) application for a Phase 1/2 dose escalation study of ONCT-808, an autologous chimeric antigen receptor (CAR) T therapy targeting ROR1, in patients with aggressive B cell non-Hodgkin's lymphoma (B NHL), including those who have failed previous CD19 CAR T treatment.