 HOUSTON, June 21, 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 commenced enrollment and dosed the first subject in its U.S. Phase 1b2 clinical trial evaluating Annamycin for the treatment of soft tissue sarcoma STS lung metastases. Soft tissue sarcomas are the most common form of sarcoma, accounting for an estimated 130,000 incident cases per year worldwide. 