TRANSTHERA-B - VOLUNTARY ANNOUNCEMENT

PHASE II CLINICAL TRIAL APPROVAL OF TINENGOTINIB IN COMBINATION WITH NOVEL HORMONE THERAPY FOR THE TREATMENT OF METASTATIC CASTRATION-RESISTANT PROSTATE CANCER PROGRESSING AFTER PRIOR TREATMENTS IN CHINA

TransThera Sciences (Nanjing), Inc.

藥捷安康（南京）科技股份有限公司 (A joint stock company incorporated in the People's Republic of China with limited liability) (Stock Code: 2617)

VOLUNTARY ANNOUNCEMENT

PHASE II CLINICAL TRIAL APPROVAL OF TINENGOTINIB IN COMBINATION WITH NOVEL HORMONE THERAPY FOR THE TREATMENT OF METASTATIC CASTRATION-RESISTANT PROSTATE CANCER PROGRESSING AFTER PRIOR TREATMENTS IN CHINA

This announcement is made by TransThera Sciences (Nanjing), Inc. (the "Company", together with its subsidiaries, the "Group") on a voluntary basis to inform the shareholders and potential investors of the Company about the latest business advancement of the Group.

The board of directors of the Company (the "Board") is pleased to announce that the Phase II clinical trial of the Company's core product Tinengotinib (TT-00420) in combination with novel hormone therapy (NHT) for the treatment of metastatic castration-resistant prostate cancer (mCRPC) progressing after prior treatments has obtained approval from the National Medical Products Administration (NMPA) on 25 May 2026.

This is an open-label, multicenter Phase II clinical study to evaluate the safety, efficacy, and pharmacokinetics of Tinengotinib in combination with NHT for the treatment of patients with mCRPC progressing after prior treatments.

Tinengotinib is the world's first and only investigational drug that simultaneously inhibits the FGFR/JAK pathway with clinical evidence in the treatment of mCRPC. Currently, NHT has

been established as the standard of care for mCRPC patients, but resistance will usually develop after a period of NHT treatment. Recent research has identified that activation of FGFR and JAK pathways will stimulate the transformation from androgen sensitive cancer cells to neuroendocrine cancer cells, thereby causing drug resistance. Simultaneous inhibition of FGFR and JAK pathways would be able to reverse this cell state transformation, or lineage reprogramming, making cancer cells restore sensitivity to androgen and re-sensitize to NHT therapy.

Tinengotinib monotherapy has shown encouraging antitumor efficacy in heavily pre-treated mCRPC patients. In addition, Tinengotinib monotherapy was granted the Fast Track Designation (FTD) by the U.S. FDA for the treatment of mCRPC in June 2025.

Warning under Rule 18A.08(3) of the Listing Rules: There is no assurance that the relevant products will ultimately be successfully developed and marketed by the Company.

By order of the Board TransThera Sciences (Nanjing), Inc. 藥捷安康(南京)科技股份有限公司 Dr. Frank Wu Chairman and Chief Executive Officer

Hong Kong, 26 May 2026