 HOUSTON, May 25, 2021 PRNewswire -- Moleculin Biotech, Inc. , Nasdaq: MBRX Moleculin or the Company, a clinical stage pharmaceutical company with a broad portfolio of drug candidates targeting highly resistant tumors and viruses, today announced it has received clearance to initiate its Phase 1b2 clinical trial evaluating Annamycin for the treatment of soft tissue sarcoma STS lung metastases. The first of several planned clinical sites is now open and the Company expects to begin patient enrollment. 