TYK Medicines, Inc. has issued a circular convening its second Extraordinary General Meeting (EGM) of 2026 for 16 October 2026 at 2:00 p.m. (local time) in Shanghai. Shareholders will vote on two principal matters:

1. Re-election of Directors • Executive Director: Dr Wu Yusheng (also Chairman & CEO). • Non-executive Directors: Dr Li Jun, Dr Gu Eric Hong, and Mr He Chao. • Independent Non-executive Directors: Dr Leng Yuting, Dr Xu Wenqing, and Dr Shen Xiuhua. Independent candidates have confirmed compliance with Hong Kong Listing Rules’ independence criteria. Service terms will be three years, subject to shareholder approval. Proposed remuneration for each independent non-executive director is RMB12,000 per month; the other directors will not receive remuneration for board service.

2. Amendments to the Articles of Association Key revisions align the company’s constitution with China’s Company Law effective 1 July 2024 and refine governance structures. Highlights include: • Clarification of the election process for the director who serves as legal representative. • Reduction of the shareholder threshold for nominating directors from 3% to 1% voting rights. • Confirmation that the board will consist of ten members, including at least one-third independent non-executive directors. • Enhanced mandates for the board’s special committees, notably expanded responsibilities for the Scientific Committee. • Procedural updates on Audit Committee meeting notices and other technical adjustments.

Shareholder logistics • H-share register closure: 13–16 October 2026 (both dates inclusive); transfers must be lodged by 4:30 p.m. on 12 October 2026. • Record date: 16 October 2026. • Voting method: poll in accordance with Listing Rule 13.39(4). • Proxy forms must reach Computershare Hong Kong Investor Services by 2:00 p.m. on 15 October 2026. • The trustee of the company’s share incentive scheme will abstain from voting on 2.06 million treasury shares, as required by Listing Rule 17.05A.

If approved, the board will be authorised to handle post-meeting filings and make minor editorial adjustments to the amended Articles as requested by regulators.