X0609 4 2026-08-03 0001659617 Moleculin Biotech, Inc. MBRX 0000938419 KLEMP WALTER V false C/O MOLECULIN BIOTECH, INC. 5300 MEMORIAL DR., SUITE 950 HOUSTON TX 77007 1 1 CEO and President 0 Common Stock 2026-08-03 4 P 0 533333 A 564340 D Series I Warrants 2026-08-03 4 A 0 1599999 A 2026-08-03 2031-08-03 Common Stock 1599999 1926335 D On August 3, 2026, the reporting person acquired 533,333 shares of common stock and Series I warrants to purchase 1,599,999 shares of common stock at a combined purchase price of $0.75 per one share of common stock and three accompanying warrants in a public offering. /s/ Jonathan P. Foster by Power of Attorney 2026-08-05