Shintaro Asako Chief Financial Officer Phone: 858-373-1500 E-mail: info@medicinova.com FOR IMMEDIATE RELEASE MediciNova Sends Letter to Avigen Board of Directors

MediciNova Sends Letter to Avigen Board of Directors

SAN DIEGO, Calif. March 19, 2009

MediciNova, Inc., a biopharmaceutical company that is publicly traded on the Nasdaq Global Market (Trading Symbol: MNOV) and the Hercules Market of the Osaka Securities Exchange (Code Number: 4875), today sent the following letter to the Board of

Directors of Avigen, Inc.:

4350 La Jolla Village Drive, Suite 950

1301 Harbor Bay Parkway

Dear Members of the Board:

We feel compelled to publicly

express our extreme disappointment with the process by which Avigen, to date, has reviewed our offer to pursue a proposed merger with Avigen. Yesterday, members of senior management of MediciNova, Inc. met with your management team and financial

advisor in San Francisco to formally present the case for our proposal. As you are aware, this was our first face-to-face meeting despite our repeated requests for such a meeting since we first made public our proposal back in December 2008.

Unfortunately, as has been the case throughout this process, your management team has so far refused to grant us access to the due

diligence materials and management guidance that we believe Avigen has made available to the other three bidders. In our meeting yesterday, your management team repeatedly stated that Avigen, as a small company, does not have the

capacity to continue to evaluate multiple offers. Frankly, we now believe that your management team had no bona fide interest in evaluating our proposal from the outset, and your management team s statements and actions so far confirm for us

From time to time, management teams of public companies run sales processes that, in retrospect, are

ill-conceived and incapable of obtaining the best value for shareholders. In our opinion, the Avigen sales process is just such a situation. In case your management team has not apprised you of their actions through March 18, we wish to make

you and the Avigen shareholders aware of the following matters that we believe you, on behalf of the Avigen shareholders, should independently verify and, where appropriate, rectify.

1. Lack of a Fair Evaluation of the MediciNova Offer in an Honest and Open Process

Over the past three months, we have repeatedly attempted to initiate a dialogue with your management team about our merger proposal. We have continually

been met, in our opinion, with delays and misrepresentations. For example:

2. Public Misstatements with No Means of Rebuttal

Instead of an honest and open evaluation process, you and your management team have chosen to criticize our proposal in your public filings. Beyond the

fact that we believe that your statements contain material misrepresentations and misleading inaccuracies, it is disappointing that your management team and financial advisor have actively resisted any discussions regarding these inaccuracies. For

3. Failure to Provide Us Due Diligence Materials in Order to Improve Our Offer:

At the meeting yesterday, we were

told that we must improve our offer. In response, we indicated the following:

Unfortunately, as noted above, your

management team and financial advisor advised us that they were unwilling to abide by our previous agreement regarding any staged due diligence. In fact, we were told by your management team that certain other interested parties had improved their

offers without access to such materials. When we asked if any other bidder had been given access to Avigen due diligence materials, we were specifically told by your financial advisor that your team was not at liberty to say the

clear implication being that some bidders in fact had been given meaningful access to Avigen due diligence materials as we would have expected in a public company auction and that your management team was, at this late stage in the auction

process, too busy evaluating the other proposals to cooperate in a meaningful exchange of information at this time.

this exclusionary behavior unsustainable. Put simply, we believe that it is manifestly unreasonable for your management team and financial advisor to refuse to provide us with the requested due diligence materials in accordance with our

previously-agreed staged due diligence process. How can it be appropriate for Avigen, consistent with Delaware law, to arbitrarily and prematurely terminate an auction process that would in several weeks time generate a superior offer from

properly? Furthermore, we are very interested in learning how difficult it would be for Avigen: (1) to allow us access to the Avigen electronic data

room that we believe must already exist for other bidders or (2) to access our electronic data to which we provided access several weeks ago but which has not yet been accessed by any member of the Avigen team.

4. MediciNova s Improved Offer:

At the meeting yesterday, and in our previous letters and communications, we stressed that we were prepared to meaningfully increase the value of our offer upon receipt of the requested due diligence materials. However, in advance of

receipt of any such materials, we did outline three immediate improvements to our offer:

Notwithstanding the disappointing absence of progress to date, we believe it is time to move forward on a more positive note. Given that your largest

shareholder, Biotechnology Value Fund, continues to support our initial proposal even before today s improvements, we ask that you direct your management team to provide us with the requested due diligence materials and that you avoid ending

this sales process prematurely. In particular, we are committed to completing our due diligence review within 10 days following receipt of these materials, and we asked your management team to refrain from entering into any third party merger

agreement during this period of our diligence review while we developed an improved bid. As you are aware, your fiduciary duties require you to run a sales process that is designed to solicit the highest price reasonably attainable, and we

continue to believe that we can offer a superior offer for your shareholders given the appropriate opportunity. We strongly believe that requiring your management team to allow us 10 days of due diligence as described above is eminently reasonable.

We hope that you agree.

MediciNova, Inc. is a publicly-traded biopharmaceutical company focused on acquiring and developing novel, small-molecule

therapeutics for the treatment of diseases with unmet need with a specific focus on the U.S. market. Through strategic alliances primarily with Japanese pharmaceutical companies, MediciNova holds rights to a diversified portfolio of clinical and

preclinical product candidates, each of which MediciNova believes has a well-characterized and differentiated therapeutic profile, attractive commercial potential and patent assets having claims of commercially adequate scope. MediciNova s

pipeline includes six clinical-stage compounds for the treatment of acute exacerbations of asthma, multiple sclerosis, asthma, interstitial cystitis, solid tumor cancers, Generalized Anxiety Disorder, preterm labor and urinary incontinence and two

preclinical-stage compounds for the treatment of thrombotic disorders. MediciNova s current strategy is to focus its resources on its two prioritized product candidates, MN-221 for the treatment of acute exacerbations of asthma and MN-166 for

the treatment of multiple sclerosis, and either pursue development independently, in the case of MN-221, or establish a strategic collaboration to support further development, in the case of MN-166. MediciNova will seek to monetize its other product

candidates at key value inflection points. For more information on MediciNova, Inc., please visit www.medicinova.com.

Statements in this press release

that are not historical in nature constitute forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Actual results could differ materially because of risks and

uncertainties associated with MediciNova s business and the proposed transaction, the timing to consummate the proposed transaction and any necessary actions to obtain required regulatory approvals, and the diversion of management time on

transaction-related issues. For further information regarding risks and uncertainties associated with MediciNova s business, please

refer to the Management s Discussion and Analysis of Financial Condition and Results of Operations and Risk Factors sections

of MediciNova s SEC filings, including, but not limited to, its annual report on Form 10-K for the year ended December 31, 2007 and its subsequent periodic reports on Forms 10-Q and 8-K, copies of which may be obtained by contacting

MediciNova s Investor Relations department at (858) 373-1500 or at MediciNova s website at http://www.medicinova.com. These forward-looking statements involve a number of risks and uncertainties that may cause actual results or events

to differ materially from those expressed or implied by such forward-looking statements. Undue reliance should not be placed on these forward-looking statements, which speak only as of the date hereof.

MediciNova disclaims any intent or obligation to revise or update these forward-looking statements.

This communication does not constitute an offer to sell or the solicitation of an offer

to buy any securities or a solicitation of any vote or approval. This material is not a substitute for the prospectus/proxy statement MediciNova, Inc. would file with the SEC if an agreement between MediciNova, Inc. and Avigen, Inc. is reached or

any other documents which MediciNova, Inc. may file with the SEC and send to Avigen, Inc. shareholders in connection with the proposed transaction. INVESTORS AND SECURITY HOLDERS OF AVIGEN, INC. ARE URGED TO READ ANY SUCH DOCUMENTS FILED WITH THE

SEC CAREFULLY IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

security holders will be able to obtain free copies of any documents filed with the SEC by MediciNova, Inc. through the website maintained by the SEC at http://www.sec.gov. Free copies of any such documents can also be obtained by directing a

request to Investor Relations Department, MediciNova, Inc., 4350 La Jolla Village Drive, Suite 950, San Diego, CA 92122, USA.

MediciNova, Inc. and its

directors and executive officers and other persons may be deemed to be participants in any solicitation of proxies in respect of the proposed transaction. Information regarding MediciNova, Inc. s directors and executive officers is available in

its Annual Report on Form 10-K for the year ended December 31, 2007, which was filed with the SEC on March 17, 2008, and its proxy statement for its 2008 annual meeting of stockholders, which was filed with the SEC on April 29, 2008.

Other information regarding the participants in any proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in any proxy statement filed in connection with the proposed