【Tanvex-KY】Subsidiary Tanvex BioPharma USA, Inc. Receives Complete Response Letter (CRL) from U.S. FDA Regarding Biosimilar Drug TX05 (Herceptin Biosimilar) Due to Inspection Issues at Downstream Fill-Finish Facility

1. Date of Event: 115/06/24 2. Company Name: Tanvex BioPharma USA, Inc. 3. Relationship to Company (please indicate 'Company' or 'Subsidiary'): Subsidiary 4. Cross-shareholding Ratio: The Company holds 100% of this subsidiary. 5. Reason for Occurrence: Tanvex BioPharma USA, Inc. (the Company's subsidiary, hereinafter referred to as 'Tanvex US') received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) on June 23, 2026, U.S. time, regarding its Biologics License Application (BLA) for TX05 (a biosimilar to Herceptin). 6. Response Measures: None. 7. Other Matters to be Disclosed (If the entity responsible for the event or resolution is a publicly listed company or above, this material information also qualifies as a matter under Article 7, Paragraph 9 of the Enforcement Rules of the Securities and Exchange Act that significantly impacts shareholder rights or securities prices): (1) Name or Code of the New Drug under Development: Recombinant protein biosimilar TX05 (Herceptin Biosimilar). (2) Indications: Same as the reference drug Herceptin. Currently, the primary indication is breast cancer, with gastric cancer also included. (3) All Planned Development Stages: Not applicable. (4) Current Development Stage: A. Application Submission / Approval Status / Results of Human Trials (including interim analysis) / Other Major Events Impacting Drug Development: Except for items requiring improvement by the downstream manufacturer, the FDA did not raise any issues regarding the drug substance manufactured by Tanvex US in this CRL. B. Risks and Response Measures if Not Approved by the Competent Authority, Clinical Trial Results Not Statistically Significant, or Other Major Events Impacting Drug Development: Tanvex US is currently actively discussing relevant corrective measures with the downstream manufacturing partner and expects to submit a response to the FDA by the end of July. C. Future Business Direction if Approved by the Competent Authority, Clinical Trial Results Statistically Significant, or Other Major Events Impacting Drug Development: Not applicable. D. Cumulative R&D Expenses Incurred: Not disclosed, in order to protect the interests of the company and investors, considering the potential for future international collaboration on the TX05 product and confidentiality concerns. (5) Next Development Stage to be Undertaken: Tanvex US will continue collaborating with the downstream manufacturer to complete the BLA review process. A. Expected Completion Time: Subject to the review timeline of the regulatory authority. B. Expected Obligations: Not applicable. (6) Market Status: According to data from IQVIA, an international pharmaceutical statistics agency, as of March 2026, the U.S. market sales of Herceptin and other biosimilar products over the past year were approximately $1 billion. Currently, there are multiple treatment options for breast cancer, including biologic drugs such as Perjeta, Enhertu, and Kadcyla. (7) Drug development involves long development timelines, high investment costs, regulatory review by competent authorities, and does not guarantee success. These factors may pose investment risks, and investors should make careful judgments and invest prudently.