Exhibit 99.1

MediciNova Extends Conversion Deadline to January 11, 2010

SAN DIEGO, Calif., January 5, 2010 — MediciNova, Inc., a biopharmaceutical company that is publicly traded on the Nasdaq Global Market (Nasdaq:MNOV) and the Hercules Market of the Osaka Securities Exchange (Code Number:4875), today announced that it has extended the deadline for submission of conversion notices for the first conversion date for its floating rate secured convertible notes due 2011 from December 31, 2009 to January 11, 2010.

At the closing of the acquisition of Avigen, Inc. by a wholly-owned subsidiary of MediciNova, MediciNova issued $29,445,824.82 of Convertible Notes as part of the merger consideration. Under the terms of the indenture governing the Convertible Notes, holders may submit conversion notices, which are irrevocable, on a monthly basis instructing the trustee to convert such Convertible Notes into shares of MediciNova’s common stock at an initial conversion price of $6.80 per share. These conversion dates generally are the final business day of each calendar month. However, due to the ongoing crediting of the Convertible Notes to the accounts of individuals and entities holding such Convertible Notes in “street name” by banks, brokers or other nominees following the year-end Avigen merger, MediciNova has waived the requirement that conversion notices for the first conversion date be received by the close of business on December 31, 2009 and extended the deadline for submission of conversion notices for the first conversion date to the close of business on January 11, 2010. No subsequent conversion dates are affected by this waiver.

Individuals and entities holding their Convertible Notes through a bank, broker or other nominee should contact their bank, broker or other nominee for instructions on how to submit a conversion notice for the Convertible Notes.

About MediciNova

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, chronic obstructive pulmonary disease exacerbations, 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 chronic obstructive pulmonary disease exacerbations and MN-166 for the treatment of multiple sclerosis, and either pursue development independently in the United States, 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. These forward-looking statements include, without limitation, statements regarding MediciNova’s clinical trials supporting safety and efficacy of product candidates and the potential novelty of such product candidates as treatments for disease, plans and objectives for present and future clinical trials and product development, strategies, future performance, expectations, assumptions, financial condition, liquidity and capital resources. These forward-looking statements may be preceded by, followed by or otherwise include the words “believes,” “expects,” “anticipates,” “intends,” “estimates,” “projects,” “can,” “could,” “may,” “will,” “would,” or similar expressions. 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. Factors that may cause actual results or events to differ materially from those expressed or implied by these forward-looking statements, include, but are not limited to the risks and uncertainties inherent in clinical trials and product development and commercialization, such as the uncertainty in results of clinical trials for product candidates, the uncertainty of whether the results of clinical trials will be predictive of results in later stages of product development, the risk of delays or failure to obtain or maintain regulatory approval, the risk of failure of the third parties upon whom MediciNova relies to conduct its clinical trials and manufacture its product candidates to perform as expected, the risk of increased cost and delays due to delays in the commencement, enrollment, completion or analysis of clinical trials or significant issues regarding the adequacy of clinical trial designs or the execution of clinical trials and the timing, cost and design of future clinical trials and research activities, the timing of expected filings with the FDA, MediciNova’s failure to execute strategic plans or strategies successfully, MediciNova’s collaborations with third parties, MediciNova’s ability to realize the anticipated strategic and financial benefits from its acquisition of Avigen, Inc., to integrate the two ibudilast development programs and to pursue discussions with potential partners to secure a strategic collaboration to advance the clinical development of the combined development program, the availability of funds to complete product development plans and MediciNova’s ability to raise sufficient capital when needed, intellectual property or contract rights, and the other risks and uncertainties described in MediciNova’s filings with the Securities and Exchange Commission, including its annual report on Form 10-K for the year ended December 31, 2008 and its subsequent periodic reports on Forms 10-Q and 8-K. 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.

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CONTACT: MediciNova, Inc.

Shintaro Asako, Chief Financial Officer

(858) 373-1500

info@medicinova.com