Sirnaomics Ltd. — Share Issue/Capital Change 2025

Sep 17, 2025

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

This announcement is for information purposes only and does not constitute an invitation or offer to acquire, purchase or subscribe for any securities of the Company.

Sirnaomics Ltd.

(Incorporated in the Cayman Islands with limited liability)

(Stock Code: 2257)

SUPPLEMENTAL ANNOUNCEMENT

SUBSCRIPTION OF NEW SHARES UNDER GENERAL MANDATE

Financial adviser to the Company

RAINBOW

RAINBOW CAPITAL (HK) LIMITED

宏博资本有限公司

Reference is made to the announcement of Sirnaomics Ltd. (the "Company") dated September 7, 2025 (the "Announcement") in relation to the Subscriptions. Unless otherwise defined, capitalised terms used herein have the same meanings as defined in the Announcements.

This supplemental announcement is made to further provide supplemental information on the use of proceeds from the Subscriptions.

USE OF NET PROCEEDS FROM THE SUBSCRIPTIONS

As stated in the Announcement, the gross proceeds of the Subscriptions will be approximately HK$208.2 million and the net proceeds from the Subscriptions (after deducting all applicable costs and expenses of the Subscriptions) will be approximately HK$206.0 million.

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Set out below is the breakdown of the use of net proceeds from the Subscriptions and the expected timeline of utilization:

Use of Net Proceeds	Allocation of the Net Proceeds (HK$ million)	Percentage of the Net Proceeds	Expected timeline on utilization
To fund the development and commercialization of STP705	79.7	38.7%	By end of 2027
To fund the development of STP122G	40.0	19.4%	By end of 2027
To fund the development of other drug candidates, including STP707, STP125G and STP144G	45.1	21.9%	By end of 2027
For business development activities to enrich the Group’s pipeline	20.6	10.0%	By end of 2027
For general corporate and working capital purposes	20.6	10.0%	By end of 2027
Total	206.0	100.0%

The Company is pioneering the development of transformative RNA-based therapeutics to address critical unmet medical needs across global markets. As stated in the interim report of the Company for the six months ended June 30, 2025, our financial resources were strategically allocated to prioritize the clinical progression of STP705 and STP122G, while selectively advancing key preclinical assets. The Group expects to (i) complete the Phase II clinical trial of STP705 by end of 2027; (ii) complete the Phase I clinical trial of STP122G by mid of 2026 and start the Phase II clinical trial of STP122G by end of 2027; and (iii) complete the Phase I clinical trial of STP125G by end of 2027. The net proceeds from the Subscriptions will strengthen the Group’s financial position for its further development of its drug candidates. Accordingly, the Directors consider that the Subscriptions are in the interests of the Company and Shareholders as a whole.

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Given that completion of the Subscriptions is subject to conditions under the Subscription Agreements and the Subscriptions may or may not proceed, Shareholders and potential investors are advised to exercise caution when dealing in the Shares.

By order of the Board
Sirnaomics Ltd.
Monin Ung
Chairlady and Independent Non-Executive Director

Hong Kong, September 17, 2025

As at the date of this announcement, the Board comprises Dr. Poon Hung Fai as executive Director, Mr. Ouyang Yunlong and Dr. Yin Huijun as non-executive Directors, and Ms. Monin Ung, Dr. Cheung Hoi Yu, Mr. Wong Yu Shan Eugene, Dr. Zhang Peng and Ms. Lo Yee Hang as independent non-executive Directors.

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