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Mail Stop 4720          November 9, 2009   Shintaro Asako Chief Financial Officer MediciNova, Inc. 4350 La Jolla Village Drive, Suite 950 San Diego, CA 92122  Andrew A. Sauter Chief Executive Officer, President and Chief Financial Officer Avigen, Inc.  1301 Harbor Bay Parkway Alameda, CA 94502
 Re: MediciNova, Inc.
  Registration Statement on Form S-4/A
  Filed October 23, 2009
  File No. 333-161969

Dear Messrs. Asako and Sauter:
  We have conducted a limited review of  your filing.  Our review was limited to
legal issues and did not incl ude a review of the financia l statements and disclosures
related to accounting issues.  Where indica ted, we think you should revise your document
in response to these comments.  If you disagr ee, we will consider your explanation as to
why our comment is inapplicable or a revisi on is unnecessary.  Please be as detailed as
necessary in your explanation.  In some of our comments, we may ask you to provide us with information so we may better understand your disclosure.  Af ter reviewing this
information, we may raise additional comments.
Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our comments or any other aspect of our review.  Feel free to call us at the telephone numbers listed at the end of this letter.

MediciNova, Inc.
Avigen, Inc.  November 9, 2009 Page 2   FORM S-4

Risk Factors, page 22
Risks Related to MediciNova’s Business and Industry, page 32
“MediciNova is dependent on its management team…” page 46

1. We note your response to our prior comment 23 and your statement that
MediciNova has revised the risk factor to  the effect that it has not experienced
difficulties attracting and retaining ke y personnel.  However, it does not
appear that you have added this disclo sure.  Please revise accordingly.

Background of the Merger, page 69
2. Please refer to our prior comment 32.  We note that you have disclosed that
RBC conducted a liquidation analysis and stock trading analysis.   Please
summarize the results of these analyses.  Specially, please state the
approximate liquidation value you refe rence throughout this section.

3. Please refer to prior comment 34.  We not e that you have added a description
of the four parties the board instructed  management to continue discussions
with.  Please revise this de scription to include the re lative size of each of the
four entities (i.e. large or  mid-size public company, small private company).
 Opinion of RBC Capital Markets Corporation. -  Financial Advisor to Avigen, page 89

4. Please refer to prior comment 48.  Please re vise your disclosure to discuss the
basis for your belief, as se t forth in your response, th at stockholders of Avigen
are not entitled to rely on RBC’s fair ness opinion.  Please disclose that the
availability of such a defense will be resolved by a court of competent jurisdiction and include your assessment of recent court decisions.  Please also disclose that resolution of the question of availability of such a defense will have no effect on the rights and responsib ilities of the board  of directors under
applicable state law.  Finally, please disclose that the availability of such a state-law defense to RBC would ha ve no effect on the rights and
responsibilities of either  RBC or the board under the federal securities laws.

Avigen’s Business, page 148

5. Please break out the total payments Avigen may receive pursuant to
assignment agreement with Genzyme by aggregate milestone payments,
sublicensing fees and royalty payments.

MediciNova, Inc.
Avigen, Inc.  November 9, 2009 Page 3  Compensation Discussion and Analysis, page 194

Use of Compensation Consultants, page 195
6. We note that there are fourteen biot echnology companies listed in the peer
group on page 195, but your narrative desc ription states there were only 12.
Please correct this apparent discrepancy as appropriate.
 Material U.S. Federal Income Tax C onsequences of the Merger, page 213

7. We note the following statements in your disclosure of material tax
consequences:
• “Avigen stockholders receiving Conv ertible Notes in the Merger should
have an adjusted basis in the Convertib le Notes … equal to…” (page 214);
• “While not free from doubt , shares received generally have a holding
period that includes …” (page 214);
• “Amounts received on account of th e Second Payment Consideration
rights … should have  an amount of unstated interest equal to …”
(page 215); and
• “While not free from doubt , we intend to take th e position that the Non-
U.S. Holders receiving Second Paym ent Consideration rights in the
Merger are …” (page 217)
(emphasis added)
 If doubt exists because of a lack of authority directly addressing the tax
consequences or conflicting authority , counsel may use the words “should”
or “while not free from doubt” to make it clear that its opinion is subject to a
degree of uncertainty.  However, in such cases, you must provide disclosure explaining why counsel cannot give a “w ill” opinion, describe the degree of
uncertainty in the opinion and set forth th e risks to investors in a risk factor
and/or other appropriate disclosure.
8. Your discussion must also identify counsel and clearly state that the discussion in the prospectus as to ea ch identified tax item is counsel’s
opinion.  Please revise accordingly.
 Exhibit 8.1 – Form of Dechert Opinion

9. Item 601(b)(8) of Regulation S-K requires an opinion of counsel as to tax matters for registered offerings where th e tax consequences are material to an
investor and a representation as to tax c onsequences is set forth in the filing.

MediciNova, Inc.
Avigen, Inc.  November 9, 2009 Page 4
The tax opinion must address and express a firm conclusion for each material federal income tax consequence.  Acco rdingly, please revise your tax opinion
to affirmatively state that the legal conclusions containe d in the material
federal income tax consequences section of the prospectus constitute your opinion rather than “summaries of Un ited States federal income tax law.”
The opinion will need to be executed a nd delivered to the company prior to
effectiveness and filed as  an exhibit to the S-4.

Exhibit 8.2 – Form of Cooley Opinion

10. Item 601(b)(8) of Regulation S-K requires an opinion of counsel as to tax
matters for registered offerings where th e tax consequences are material to an
investor and a representation as to tax c onsequences is set forth in the filing.
The tax opinion must address and express a firm conclusion for each material
federal income tax consequence.  Acco rdingly, please revise your tax opinion
to affirmatively state that the legal conclusions containe d in the material
federal income tax consequences section of the prospectus constitute your
opinion. The opinion will need to be ex ecuted and delivered to the company
prior to effectiveness and file d as an exhibit to the S-4.

* * *

As appropriate, please amend your regist ration statement in response to these
comments.  You may wish to provide us with marked copies of the amendment to expedite our review.  Please furnish a cove r letter with your amendment that keys your
responses to our comments and provides any requested information.  Detailed cover
letters greatly facilitate our review.  Please understand that we may have additional comments after reviewing your amendmen t and responses to our comments.
  We urge all persons who are responsible for the accuracy and adequacy of the disclosure in the filing to be certain that the filing includes all in formation required under
the Securities Act of 1933 and that they have  provided all information investors require
for an informed investment decision.  Since the company and its management are in possession of all facts relating to a company’ s disclosure, they are responsible for the
accuracy and adequacy of the disclosures they have made.   In addition, please be advi sed that the Division of En forcement has access to all
information you provide to the staff of the Di vision of Corporation Finance in connection
with our review of your filing or in response to our comments on your filing.   We will consider a written request for acceleration of the effective date of the registration statement as conf irmation of the fact that t hose requesting acceleration are
aware of their respective re sponsibilities under the S ecurities Act of 1933 and the
Securities Exchange Act of 1934 as they rela te to the proposed public offering of the

MediciNova, Inc.
Avigen, Inc.  November 9, 2009 Page 5  securities specified in the above registration statement.  We will act  on the request and,
pursuant to delegated authority, grant acceleration of the effective date.
  We direct your attention to Rules 460 and 461 regarding requesting acceleration
of a registration statement.  Please allow ad equate time after the filing of any amendment
for further review before submitting a request for acceleration.  Please provide this request at least two business days in a dvance of the requested effective date.
  Please contact Nandini Ac harya at (202) 551-3495, Dani el Greenspan at (202)
551- 3623 or me at (202) 551-3715 with any questions.          S i n c e r e l y ,             J e f f r e y  R i e d l e r          A s s i s t a n t  D i r e c t o r     cc: David E. Shulman, Esq.
Dechert LLP 1775 I Street, N.W. Washington, DC 20006
 cc: Brett D. White, Esq.  Cooley Godward Kronish LLP  Five Palo Alto Square  3000 El Camino Real  Palo Alto, CA 94306