Tai Tsung Announces Continued Phase 3 Trial of U101 for Recurrent UTI Prevention in Taiwan Following Interim Safety Review

Release Date: July 24, 115 Statement Date: July 23, 115 Statement Time: 17:09:13 Company Code: 4169 Company Name: Tai Tsung Subject: Announcement of Press Release Regarding Material Information Applicable Clause: Clause 12 Factual Date: July 23, 115

Details: 1. Date of Financial/Business Information Release: July 23, 115 2. Location of Release: Taiwan Stock Exchange 3. Public Financial/Business-Related Information: Interim Analysis of U101 Phase 3 Clinical Trial 4. Content of Press Release:

Tai Tsung Biotechnology Co., Ltd. (hereinafter referred to as "Tai Tsung", stock code: 4169) today announced significant progress in the interim analysis (Interim Analysis) of its Phase 3 clinical trial in Taiwan for U101, a novel therapeutic agent designed to prevent recurrent Urinary Tract Infections (rUTI). After rigorous review by an External Independent Data Monitoring Committee (IDMC), overall trial safety was confirmed, and the committee recommended that the trial "continue as planned." The company will continue to fully advance enrollment toward its target of 348 participants.

The overall duration of U101’s Phase 3 clinical trial in Taiwan is 48 weeks, structured into two phases: the "Main Study" and the "Open-Label Extension (OLE)" period. The Main Study lasts 24 weeks and follows a randomized, double-blind, placebo-controlled design. In the subsequent OLE phase, eligible participants may continue receiving U101 treatment for another 24 weeks to further evaluate long-term efficacy and safety. According to the trial protocol, the interim analysis threshold is met when 60% (i.e., 208 participants) have completed 24 weeks of treatment or at least one UTI episode has occurred. Based on the interim analysis plan, the IDMC evaluates safety and efficacy data to make one of the following recommendations: (1) halt the trial due to safety concerns; (2) halt the trial if further enrollment is unlikely to achieve statistical significance for the primary efficacy endpoint; or (3) stop enrollment early if efficacy has already met pre-specified stringent statistical criteria. If none of these conditions are met, the trial is recommended to continue as planned.

Following completion of the interim analysis, the IDMC recommended that the Phase 3 clinical trial of U101 continue enrollment and execution as originally planned. This indicates no safety or other major issues requiring trial termination or design modification have been identified at this stage, supporting continued progression toward final analysis.

5. Other Matters to be Disclosed: None