CSPC PHARMA - VOLUNTARY ANNOUNCEMENT - SYS6090 (JMT108) GRANTED FAST TRACK DESIGNATION BY U.S. FDA FOR TREATMENT OF PATIENTS WITH MSS/pMMR mCRC

CSPC PHARMACEUTICAL GROUP LIMITED

石藥集團有限公司

(Incorporated in Hong Kong with limited liability)

(Stock Code: 1093)

VOLUNTARY ANNOUNCEMENT

SYS6090 (JMT108) GRANTED FAST TRACK DESIGNATION

BY U.S. FDA FOR TREATMENT OF PATIENTS WITH MSS/pMMR mCRC

The Board of Directors (the 'Board') of CSPC Pharmaceutical Group Limited (the 'Company', together with its subsidiaries, the 'Group') is pleased to announce that SYS6090 (JMT108) (the 'Product'), a first-in-class PD-1/IL-15 bispecific fusion protein developed by the Group, has been granted Fast Track designation by the U.S. Food and Drug Administration ('FDA') for the treatment of patients with microsatellite-stable ('MSS') or proficient mismatch repair ('pMMR') metastatic colorectal cancer ('mCRC') who have progressed on standard systemic therapies.

In the United States, colorectal cancer ('CRC') remains a major public health challenge. It is the third most commonly diagnosed cancer and the second leading cause of cancer-related death. The 5-year survival rate for patients with distant metastatic CRC is approximately 17% based on data from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute, and the median overall survival for patients with MSS/pMMR mCRC who have received third-line and subsequent therapies generally remains under 12 months, representing a significant unmet medical need.

MSS/pMMR mCRC is typically considered as a 'cold' tumor with limited responsiveness to standard immunotherapy. The Product is a bispecific fusion protein that simultaneously blocks PD-1 and activates the IL-15 signaling pathway. Its specifically designed asymmetric structure precisely directs IL-15 activity in a PD-1-dependent fashion, with the potential to selectively inflame the resistant or immunologically 'cold' tumor microenvironment and activate exhausted effector cells while minimizing immune-related toxicity.

The data supporting this Fast Track designation include preclinical study results, and data from Phase 1 clinical studies underway in both China and the United States. The granting of Fast Track designation by the FDA recognizes that the Product has demonstrated the potential to treat a serious or lifethreatening disease, and will facilitate and expedite its development and approval in the United States as well as globally.

By order of the Board

CSPC Pharmaceutical Group Limited CAI Dong Chen

Chairman

Hong Kong, 26 August 2026