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September 29, 2006

Dear Stockholder of MediciNova, Inc.

You are receiving this letter because our Transfer Agent, American Stock Transfer & Trust Company (AST) has not received your completed proxy for the Special Meeting of Stockholders to be held on Friday, October 13, 2006.

At the Special Meeting, we wish to have as many stockholders represented as possible. In addition, your vote at this meeting is very important. Please find enclosed another form of proxy, along with a return envelope addressed to AST. Please mark and return your proxy as soon as possible.

In addition, do not hesitate to contact us if you have any questions or concerns.




Dr. Yuichi Iwaki

CEO, Chairman of the Board