Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act.Yes☐No☒Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirementsfor the past 90 days.Yes☒No☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 ofRegulation S-T (§232.405 of this chapter) during the preceding 12 months (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, a smaller reporting company, or anemerging growth company. See definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule12b-2 of the Exchange Act. Large accelerated filer☐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 or revised financial accounting standards provided pursuant to Section 13(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 issued itsaudit 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 Rule 12b-2 of the Act).Yes☐No☒The aggregate market value of the registrant’s common stock held by non-affiliates of the registrant was approximately $62,397,025 based on the closing price of the registrant’s common stock on the Nasdaq Global Market of $1.31 per share on June 30, 2025. Shares of common stock held by each executive officerand director and each affiliated entity has been excluded from this calculation. This determination of affiliate status may not be conclusive for other purposes.The number of outstanding shares of the registrant’s common stock, par value $0.001 per share, as of March 5, 2026 was 49,221,246. DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Proxy Statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with theregistrant’s 2026 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. MEDICINOVA, INC.FORM 10-K—ANNUAL REPORTFor the Fiscal Year Ended December 31, 2025Table of Contents PART I Item 1BusinessItem 1ARisk FactorsItem 1BUnresolved Staff CommentsItem 1CCybersecurityItem 2PropertiesItem 3Legal ProceedingsItem 4Mine Safety Disclosures Item 5Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities59Item 6[Reserved]59Item 7Management’s Discussion and Analysis of Financial Condition and Results of Operations60Item 7AQuantitative and Qualitative Disclosures About Market Risk65Item 8Financial Statements and Supplementary Data65Item 9Changes in and Disagreements With Accountants on Accounting and Financial Disclosure88Item 9AControls and Procedures88Item 9BOther Information89Item 9CDisclosure Regarding Foreign Jurisdictions that Prevent Inspections89 PART III Item 10Directors, Executive Officers and Corporate Governance90Item 11Executive Compensation90Item 12Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters90Item 13Certain Relationships and Related Transactions, and Director Independence91Item 14Principal Accountant Fees and Services91 PART IVItem 15 Exhibits and Financial Statement Schedules Signatures95 The MediciNova logo is a registered trademark of MediciNova, Inc. All other product and company names are registeredtrademarks or trademarks of their respective companies. PART I CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS This Annual Report on Form 10-K includes forward-looking statements that involve a number of risks and uncertainties,many of which are beyond our contro