INSILICO - VOLUNTARY ANNOUNCEMENT

INSILICO MEDICINE RECEIVES FDA FAST TRACK DESIGNATION FOR ISM6331 IN ADVANCED MESOTHELIOMA

INSILICO MEDICINE InSilico Medicine Cayman TopCo

英矽智能 (Incorporated in the Cayman Islands with limited liability) (Stock code: 3696)

VOLUNTARY ANNOUNCEMENT INSILICO MEDICINE RECEIVES FDA FAST TRACK DESIGNATION

FOR ISM6331 IN ADVANCED MESOTHELIOMA

This announcement is made by InSilico Medicine Cayman TopCo (the "Company", together with its subsidiaries, the "Group" or "Insilico Medicine") on a voluntary basis to inform the shareholders and potential investors of the Company about the latest business updates of the Group.

The board of directors of the Company (the "Board") is pleased to announce that, ISM6331, a novel, potential best-in-class pan-TEAD inhibitor driven by Insilico's proprietary AI, has received Fast Track Designation (FTD) from the U.S. Food and Drug Administration (FDA), for

the treatment of adult patients with unresectable malignant pleural mesothelioma whose disease has progressed on or after prior treatment with anti-PD-1 antibody therapy, with or without anti-CTLA-4 antibody therapy, and platinum-based chemotherapy.

According to the FDA's relevant policy, "Fast Track" is a process designed to facilitate the expedited development and the review of new drugs to treat serious or life-threatening conditions and fill an unmet medical need. With the Fast Track Designation, ISM6331 gains access to regulatory benefits designed to streamline its clinical development path, including enhanced FDA engagement represented by more frequent meetings and written feedback regarding clinical trial design, biomarker strategies, and overall development plans.

Additionally, subject to meeting the relevant criteria, the program may qualify for Accelerated Approval, Priority Review and Rolling Review process. Under the Rolling Review process,

completed sections of a Biologic License Application (BLA) or New Drug Application (NDA) may be submitted to FDA for review as they become available, rather than waiting for the entire application to be completed.

About ISM6331

ISM6331 is a potent pan-TEAD inhibitor, which not only effectively targets tumors with abnormalities in the hippo pathway but also shows synergistic anti-tumor effects and overcomes drug resistance in combination therapy. The novel, non-covalent structure of ISM6331 was guided by Chemistry42's structure-based drug design strategy.

In preclinical studies, ISM6331 demonstrated broad anti-tumor efficacy, potent activity at low doses, and a favorable safety profile with favorable ADMET characteristics. In 2024, ISM6331 was granted orphan drug designation (ODD) by the FDA for the treatment of mesothelioma. In January 2025, the first patient was dosed in the global multicenter Phase I trial of ISM6331. In July 2026, ISM6331 received FDA Fast Track Designation.

Forward Looking Statement

There is no assurance that any forward-looking statements regarding the business development of the Group in this announcement or any of the matters set out herein are attainable, will actually occur or will be realized or are complete or accurate. The financial and other data relating to the Group as disclosed in this announcement has also not been audited or reviewed by its auditors. Shareholders and/or potential investors of the Company are advised to exercise caution when dealing in the shares of the Company and not to place any excessive reliance on the information disclosed herein. Any shareholder or potential investor who is in doubt is advised to seek advice from professional advisors.

By order of the Board InSilico Medicine Cayman TopCo Mr. Aleksandrs Zavoronkovs, Ph.D. Chairman, Executive Director, CEO and CBO

Hong Kong, July 29, 2026