X0508 4 2025-09-24 1 0001645469 Monopar Therapeutics MNPR 0001727357 Tactic Pharma LLC C/O 598 ROCKEFELLER RD LAKE FOREST IL 60045 1 0001727334 Robinson Chandler 1000 SKOKIE BLVD SUITE 350 WILMETTE IL 60091 1 1 Chief Executive Officer 0001035909 Brown Michael J C/O 598 ROCKEFELLER RD LAKE FOREST IL 60045 1 Member of 10% Owner Group 0001727481 O'Halloran Thomas V. C/O 598 ROCKEFELLER RD LAKE FOREST IL 60045 1 Member of 10% Owner Group 0001727393 Mazar Andrew Paul C/O 598 ROCKEFELLER RD LAKE FOREST IL 60045 1 Member of 10% Owner Group 0 Common Stock 2025-09-24 4 S 0 550229 63.6098 D 272026 D This Form 4 is being filed on behalf of Tactic Pharma LLC, an Illinois limited liability company ("Tactic"), and its managers, Andrew P. Mazar, Chandler D. Robinson, Michael J. Brown, and Thomas V. O'Halloran (collectively, the "Reporting Persons"). The managers collectively have voting control over the securities described herein. The managers each disclaim ownership of the shares of common stock owned by Tactic, except to the extent of their pecuniary interest therein. The Reporting Persons are no longer subject to Section 16, except for Chandler D. Robinson, who serves as Chief Executive Officer of Monopar Therapeutics Inc. /s/ Chandler Robinson, Attorney-in-fact 2025-09-26