 HOUSTON, April 14, 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, announced today that the U.S. Food and Drug Administration FDA has granted Rare Pediatric Disease Designation RPD to its p-STAT3 inhibitor, WP1066, for the treatment of ependymoma. Ependymoma is a rare type of tumor that can form in the brain or spinal cord. 