UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. _1_) Medicinova, Inc. _____________________________________________ (Name of Issuer) Common Stock, .001 Par Value _______________________________________________ (Title of Class of Securities) 58468P206 _________________________________________________ (CUSIP Number) with a copy to: Austin W. Marxe Allen B. Levithan, Esq. 527 Madison Avenue, Suite 2600 Lowenstein Sandler PC New York, New York 10022 65 Livingston Avenue Roseland, New Jersey 07068 (973) 597-2406 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) July 31, 2009 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: ____ Rule 13d-1(b) _x__ Rule 13d-1(c) ____ Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be ?filed? for the purpose of Section 18 of the Securities Exchange Act of 1934 (?Act?) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Cusip No. 58468P206 13G Page 2 of 6 Pages 1.Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only): Austin W. Marxe and David M. Greenhouse 2. Check the Appropriate Box if a Member of a Group (See Instructions): (a) [ ] Not Applicable (b) [ ] 3. SEC Use Only 4. Source of Fund (See Instructions): 00 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e): Not Applicable 6. Citizenship or Place of Organization: United States Number of 7. Sole Voting Power: 0 Shares Beneficially 8. Shared Voting Power: 469,398* Owned by Each Reporting 9. Sole Dispositive Power: 0 Person With 10. Shared Dispositive Power: 469,398*____ 11. Aggregate Amount Beneficially Owned by Each Reporting Person: 469,398* 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): Not Applicable 13. Percent of Class Represented by Amount in Row (11): 3.9%* 14. Type of Reporting Person (See Instructions): IA, IN * This is a joint filing by Austin W. Marxe (?Marxe?) and David M. Greenhouse (?Greenhouse?). Marxe and Greenhouse share sole voting and investment power over 469,398 shares of Common Stock owned by Special Situations Life Sciences Fund, L.P. See Items 2 and 4 of this Schedule for additional information. Page 3 of 6 Pages Item 1. Security and Issuer: (a) Medicinova, Inc. (b) 4350 La Jolla Village Drive, Suite 950, San Diego, CA 92122 Item 2. (a) Name of Person Filing: The persons filing this report are Austin W. Marxe (?Marxe?) and David M. Greenhouse (?Greenhouse?), who are the controlling principals of AWM Investment Company, Inc. (?AWM?), the investment adviser to the Special Situations Life Sciences Fund, L.P. (?Life Sciences?). Marxe and Greenhouse are also members of LS Advisers L.L.C., (?LS?), the general partner of Life Sciences. (Life Sciences will hereafter be referred to as, the ?Fund?). The principal business of each Fund is to invest in equity and equity-related securities and other securities of any kind or nature. (b) Address of Principal Business Office or, if none, Residence: The principal business address for Marxe and Greenhouse is 527 Madison Avenue, Suite 2600, New York, NY 10022. (c) Citizenship: Austin W. Marxe and David M. Greenhouse are United States citizens. (d) Title of Class of Securities: Common Stock (e) CUSIP Number: 58468P206. Item 3. If this statement is filed pursuant to $240.13d-1(b) or 240.13d- 2(b), check whether the person filing is a: Not Applicable (a) ( ) Broker or Dealer registered under section 15 of the Act; (b) ( ) Bank as defined in section 3(a) (6) of the Act; (c) ( ) Insurance Company as defined in section 3(a) (19) of the Act; (d) ( ) Investment Company registered under section 8 of the Investment Company Act of 1940; (e) ( ) An Investment Adviser in accordance with $240.13d -1(b)(I)(ii)(E); (f) ( ) An employee benefit plan or endowment fund in accordance with $240.13d-1(b)(I)(ii)(F); Page 4 of 6 Pages (g) ( ) A parent holding company or control person in accordance with $240.13d- 1(b)(1)(ii)(G); (h) ( ) A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act; (i) ( ) A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940; (j) ( ) Group, in accordance with $240.13d-1(b)(1)(ii)(J). Item 4. Ownership: (a) Amount Beneficially Owned: Messrs. Marxe and Greenhouse beneficially own a total of 469,398 shares of Common Stock. This amount includes 469,398 shares of Common Stock owned by Life Sciences. (b) Percent of Class: Messrs. Marxe and Greenhouse beneficially own 3.9% of the shares outstanding. Life Sciences owns 3.9% of the outstanding shares. (c) Number of Shares as to which the person has: (i) Sole power to vote or to direct the vote: 0 (ii) Shared power to vote or to direct the vote: 469,398 (iii) Sole power to dispose or to direct the disposition of: 0 (iv) Shared power to dispose or to direct the disposition of: 469,398 Item 5. Ownership of Five Percent or Less of a Class: If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more that five percent of the class of securities, check the following _X_. Item 6.Ownership of More than Five Percent on Behalf of Another Person: Not Applicable. Item 7. Identification and Classification of the Subsidiary Which Acquired the Security being Reported on By the Parent Holding Company: Not Applicable. Item 8. Identification and Classification of Members of the Group: Not applicable Item 9. Notices of Dissolution of Group: Not applicable. Page 5 of 6 Pages Item 10.Certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated: August 7, 2009 /s/ Austin W. Marxe AUSTIN W. MARXE /s/David M Greenhouse DAVID M. GREENHOUSE Attention: Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001). Page 6 of 6 Pages JOINT FILING AGREEMENT Austin W. Marxe and David M. Greenhouse hereby agree that the Schedule 13G to which this agreement is attached is filed on behalf of each of them. /s/_Austin W. Marxe Austin W. Marxe /s/_David M. Greenhouse David M. Greenhouse - -6- S5313/1 1319328.02