Report of Independent Registered Public Accounting Firm

Shareholders and Board of Directors

MediciNova, Inc.

La Jolla, California

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated balance sheets of MediciNova, Inc. (the“Company”) as of December 31, 2022 and 2021, the related consolidated statements of operations and comprehensive loss, stockholders' equity, and cash flows for each of the years then ended, and the related notes (collectively referred to as the“consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2022 and 2021, and the results of its operations and its cash flows for the years then ended, in conformity with accounting principles generally accepted in the United States of America.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the Company's internal control over financial reporting as of December 31, 2022, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) and our reported February 16, 2023 expressed an unqualified opinion thereon.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's consolidated financial statements based on our audits. We are a public accounting firm registered with PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that: (1)relates to accounts or disclosures that are material to the consolidated financial statements and (2)involved our especially challenging, subjective, or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Clinical Trial Accruals

As described in Note 1 to the consolidated financial statements, the Company recognizes costs it incurs for preclinical studies, clinical trials and manufacturing activities as research and development expenses based on its evaluation of its vendors' progress toward completion of specific tasks. Payment timing may differ significantly from the period in which the costs are recognized as expense. Costs for services incurred that have not yet been billed or paid are recognized as accrued expenses. In estimating the vendors' progress toward completion of specific tasks, the Company uses data such as patient enrollment, clinical site activations or vendor information of actual costs incurred. This data is obtained through reports from or discussions with Company personnel and outside service providers as to the progress or state of completion of trials, or the completion of services. As of December 31, 2022, the Company recorded $1.5 million in clinical trial accruals.

We identified the clinical trial accruals as a critical audit matter due to significant management judgment to estimate the progress toward completion of specific tasks that is dependent upon data and information from internal clinical personnel and outside service providers. Auditing these elements involved especially challenging auditor judgment due to the nature and extent of audit effort required to address these matters.

The primary procedures we performed to address this critical audit matter included:

・　Testing the appropriate measurement of clinical trial accruals by obtaining and inspecting significant agreements and agreement amendments, evaluating the Company's documentation of trial progress and status (including consideration of measures such as patient enrollment and milestones achieved), and testing a sample of transactions and comparing the costs against related invoices and contracts.

・　Testing the completeness of the Company's clinical trial accruals by evaluating publicly available information (such as press releases and public databases that track clinical trials) and board of directors' materials regarding the status of clinical trials and inquiring of clinical staff to gain an understanding of the status of significant on-going clinical trials.

・　Testing a sample of subsequent payments to evaluate the completeness of clinical trial accruals at the end of the year.

/s/ BDO USA, LLP

We have served as the Company's auditor since 2015.

San Diego, California

February 16, 2023

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