Eton Pharmaceuticals, Inc.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Stockholders and the Board of Directors of Eton Pharmaceuticals, Inc.

Opinion on the Financial Statements

We have audited the accompanying balance sheets of Eton Pharmaceuticals, Inc. (the "Company") as of December 31, 2024, the related statements of operations, stockholders’ equity, and cash flows for the year ended December 31, 2024, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024, and the results of its operations and its cash flows for the year ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audit. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) ("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 audit 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 financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audit we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audit included performing procedures to assess the risks of material misstatement of the 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 financial statements. Our audit also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

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

State Medicaid Rebates and Liability** **

Critical Audit Matter Description

As described in Note 3 of the Notes to Financial Statements, the Company recognizes revenue from product sales net of estimated sales deductions, including state Medicaid rebates. The state Medicaid rebate and related liability are estimated based on monthly sales, historical experience of claims submitted by the various states and jurisdictions, historical rebate rates and estimated lag time of the rebate invoices.

We determined that auditing management’s estimate of the state Medicaid rebates was a critical audit matter because it was especially challenging to evaluate management’s judgments related to the data and significant assumptions used to determine the rebates. These include the identification of product sales subject to state Medicaid rebates as well as the historical rebate percentage applied to eligible sales. Additionally, there can be timing differences between when product sales occur and when the Company receives the related state Medicaid rebate invoices, which can vary based on state Medicaid program requirements.

How the Critical Audit Matter was Addressed in the Audit

Our audit procedures over management’s estimated state Medicaid rebates and related liability included the following:

Valuation of Acquired Inventory and Intangible Asset for the Increlex Acquisition

Critical Audit Matter Description

As described in Note 4 of the financial statements, on October 2, 2024, the Company entered into an asset purchase agreement to acquire Increlex from Ipsen S.A., with the transaction closing on December 19, 2024. Management determined that the acquisition should be accounted for as a business combination under ASC 805.

We determined that auditing management’s valuation of the acquired inventory and intangible asset was a critical audit matter due to the significant judgment and estimation uncertainty involved in determining the fair value of the acquired inventory and intangible asset. Evaluating the valuation of acquired inventory and intangible asset was complex because it involved management’s estimates and assumptions regarding:

How the Critical Audit Matter was Addressed in the Audit

Our audit procedures over management’s valuation of the acquired inventory and intangible asset for the Increlex acquisition included:

/s/ Crowe LLP

We have served as the Company’s auditor since 2024.

Oakbrook Terrace, Illinois

March 18, 2025

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Stockholders of Eton Pharmaceuticals, Inc.

Opinion on the Financial Statements

We have audited the accompanying balance sheet of Eton Pharmaceuticals, Inc. (the “Company”) as of December 31, 2023, the related statements of operations, stockholders’ equity, and cash flows for each of the two years in the period ended December 31, 2023, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“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 financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the 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 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 financial statements. We believe that our audits provide a reasonable basis for our opinion.

/s/ KMJ Corbin & Company LLP

We served as the Company's auditor from 2018 through 2024.

Glendora, California

March 14, 2024