June 23, 2008

MediciNova Initiates Phase II Clinical Trial of MN-221 in Moderate to Severe Asthma Patients

SAN DIEGO, June 23, 2008 (PRIME NEWSWIRE) -- 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 initiated dosing in a Phase II clinical trial to determine the safety and efficacy of MN-221 in patients with moderate to severe, but stable asthma. This is the second Phase II trial currently underway to evaluate MN-221 in various populations of asthma patients.

This randomized, open-label, placebo-controlled Phase II clinical trial will involve approximately 15 to 25 patients in two dose cohorts at four clinical sites in the United States. Each patient will receive MN-221 at doses of up to 1,125 micrograms or placebo in a continuous intravenous infusion of up to two hours. Safety and preliminary efficacy data, including changes in forced expiratory volume in one second (FEV1), will be collected and summarized; however, the data will not be subjected to inferential statistical analysis. The data from this clinical trial, along with the other Phase II clinical trial in severe, acute exacerbations of asthma, will aid in the design of a larger Phase IIb Emergency Department (ED) clinical trial, which is anticipated to begin toward the end of 2008, as well as a future Phase III ED clinical trial.

"We continue to progress our clinical program for MN-221 with the initiation of this Phase II clinical trial," said Yuichi Iwaki, M.D., Ph.D., President and Chief Executive Officer of MediciNova, Inc. "This clinical trial will provide us with an initial observation into the potential safety and efficacy of MN-221 with more prolonged infusions and with different infusion rates in patients with stable, moderate to severe asthma. This clinical trial, being conducted in parallel with our other Phase II clinical trial which is evaluating MN-221 in the intended clinical population of patients with severe, acute exacerbations of asthma treated in the ED, will provide us with additional insight into the compound's activity, which will be beneficial as we plan for larger clinical trials with this product candidate."

About MN-221

MN-221 is highly-selective Beta2-adrenergic receptor agonist. Preclinical testing in vitro and in vivo shows MN-221 to be more selective for the Beta2-adrenergic receptor than other Beta2-adrenergic receptor agonists commonly used these asthma attacks. This improved selectivity, coupled with its partial agonist activity at Beta1-adrenergic receptors, may result in fewer cardiovascular side effects than are commonly observed with these other agents. Importantly, MediciNova has developed an intravenous formulation of MN-221 that may effectively bypass the constricted airways to deliver effective concentrations of the drug to the lungs. MN-221 has been shown recently to produce significant improvements in mean change in post-infusion (15 minute) FEV1 from baseline (objective measure of lung function) at doses of 3.5 micrograms/min (p=0.011), and at 10, 16, 30 and 60 micrograms/min (p less than or equal to 0.0001), compared to placebo in stable mild-to-moderate asthma patients.

MediciNova acquired an exclusive, worldwide (excluding Japan), sublicensable license to MN-221 from Kissei Pharmaceutical Co., Ltd. The intellectual property acquired from Kissei included extensive preclinical and clinical safety data.

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 status asthmaticus, 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 the development and commercialization of two prioritized assets in its development pipeline: MN-221 for the treatment of status asthmaticus, an acute, severe asthma attack, and MN-166 for the treatment of multiple sclerosis. 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.

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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,""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, 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, 2007 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           [email protected]            Rx Communications, LLC           Rhonda Chiger           (917) 322-2569           [email protected]