1、 Table of ContentsAs filed with the U.S.Securities and Exchange Commission on July 29,2026.Registration No.333-_ UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington,D.C.20549 FORM S-1REGISTRATION STATEMENTUNDERTHE SECURITIES ACT OF 1933 Moleculin Biotech,Inc.(Exact name of registrant as specif
2、ied in its charter)Delaware283447-4671997(State or other jurisdiction of(Primary Standard Industrial(I.R.S.Employerincorporation or organization)Classification Code Number)Identification Number)5300 Memorial Drive,Suite 950Houston,Texas 77007(713)300-5160(Address,including zip code,and telephone num
3、ber,including area code,of registrants principal executive offices)Walter V.Klemp,Chief Executive Officer and Chairman5300 Memorial Drive,Suite 950Houston,Texas 77007(713)300-5160(Name,address,including zip code,and telephone number,including area code,of agent for service)Copies to:Cavas S.PavriJoh
4、nathan C.DuncanArentFox Schiff LLP1717 K Street NWWashington,DC 20006Telephone:(202)857-6000Fax:(202)857-6395Charles Phillips,Esq.Ellenoff Grossman&Schole LLP1345 Avenue of the Americas,11th FloorNew York,New York 10105Phone:(212)370-1300 Fax:(212)370-7889 2026/7/30 08:54mbrx20260716_s1.htmhttps:/ww
5、w.sec.gov/Archives/edgar/data/1659617/000143774926024774/mbrx20260716_s1.htm1/41Table of Contents Approximate date of commencement of proposed sale to the public:As soon as practicable after the effective dateof this Registration Statement.If any of the securities being registered on this Form are t
6、o be offered on a delayed or continuous basis pursuant toRule 415 under the Securities Act of 1933,check the following box.If this Form is filed to register additional securities for an offering pursuant to Rule 462(b)under the Securities Act,please check the following box and list the Securities Ac