FORM10-K ANNUAL REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the FiscalYear Ended December 31, 2025 or (781) 652-4500(Registrant’s telephone number, including area code) Securities registered pursuant to Section12(b)of the Act:None. Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule405 of the Securities Act. Yes☐No☒ Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d)of the Act. Yes☐No☒ Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the Securities Exchange Act of 1934during the preceding 12months (or for such shorter period that the registrant was required to file such reports), and (2)has been subject to such filingrequirements for the past 90days.Yes☒No☐ Indicate by check mark whether the registrant has submitted every Interactive Data File required to be submitted pursuant to Rule405 of Regulation S-T(§232.405 of this chapter) during the preceding 12months (or for such shorter period that the registrant was required to submit such files).Yes☒No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or anemerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company”in Rule12b-2 of the Exchange Act: Largeacceleratedfiler☐Non-accelerated filer☒Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new orrevised financial accounting standards provided pursuant to Section13(a)of the Exchange Act.☐ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal controlover financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issuedits audit report.☐ If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filingreflect the correction of an error to previously issued financial statements.☐ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received byany of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Act).Yes☐No☒ The aggregate market value of the voting stock held by non-affiliates of the registrant the last business day of the registrant’s most recently completed secondfiscal quarter: $571,897. Indicate the number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date. AVENUE THERAPEUTICS, INC.ANNUAL REPORT ON FORM 10-KTABLE OF CONTENTS PagePART IItem 1.Business4Item 1A.Risk Factors26Item 1B.Unresolved Staff Comments54Item 1C.Cybersecurity54Item 2.Properties54Item 3.Legal Proceedings54Item 4.Mine Safety Disclosures54PART IIItem 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities55Item 6.ReservedItem 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations56Item 7A.Quantitative and Qualitative Disclosures About Market RiskItem 8.Consolidated Financial Statements and Supplementary Data66Item 9.Changes in and Disagreements with Accountants on Accounting and Financial Disclosure66Item9A.Controls and Procedures66Item 9B.Other Information66Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections67PART IIIItem 10.Directors, Executive Officers and Corporate Governance67Item 11.Executive Compensation71Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters74Item 13.Certain Relationships and Related Transactions, and Director Independence75Item14.Principal Accountant Fees and Services78PART IVItem15.Exhibits and Consolidated Financial Statement Schedules80Item16.Form 10-K Summary83 CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS Certain matters discussed in this report may constitute forward-looking statements for purposes of the Securities Act of 1933, as amended(the “Securities Act”), and the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements ofcurrent or historical fact contained in this report, including statements that express our intentions, plans, objectives, beliefs, expectations,strategies, predictions or any other statements relating to our future activities or other future events or conditions are forward-lo