LEADS BIOLABS-B - VOLUNTARY ANNOUNCEMENT

LBL-024 (OPAMTISTOMIG, PD-L1/4-1BB BISPECIFIC ANTIBODY) RECEIVED IND APPROVAL FROM NMPA FOR THE TREATMENT OF METASTATIC COLORECTAL CANCER

Nanjing Leads Biolabs Co., Ltd.

南京維立志博生物科技股份有限公司

(A joint stock company established in the People's Republic of China with limited liability)

(Stock Code: 9887)

VOLUNTARY ANNOUNCEMENT

LBL-024 (OPAMTISTOMIG, PD-L1/4-1BB BISPECIFIC ANTIBODY) RECEIVED IND APPROVAL FROM NMPA FOR THE TREATMENT OF

METASTATIC COLORECTAL CANCER

This announcement is made by Nanjing Leads Biolabs Co., Ltd. (the "Company", together with its subsidiaries, the "Group") on a voluntary basis to inform shareholders and potential investors of the Company about the latest business development of the Company.

The Company is pleased to announce that the Center for Drug Evaluation (the "CDE") of the National Medical Products Administration of the People's Republic of China (the "NMPA") has approved the Investigational New Drug (the "IND") application of its self-developed drug candidate LBL-024 (Opamtistomig, a PD-L1/4-1BB bispecific antibody) for the treatment of metastatic colorectal cancer ("mCRC"). The approved clinical trial is an open-label, multicenter Phase Ib/II study designed to evaluate the safety and efficacy of LBL-024 in combination therapy for the treatment of mCRC. This milestone marks an important step in expanding the indications of LBL-024 into gastrointestinal cancers. It further extends the Company's immuno-oncology portfolio from biliary tract cancer (BTC), gastric cancer (GC) and esophageal squamous cell carcinoma (ESCC) to colorectal cancer (CRC), a malignancy with significant unmet medical needs.

mCRC remains difficult to treat and is associated with poor prognosis, with a five-year survival rate of less than 13%. Although immunotherapy has achieved significant advances in patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) tumors, these patients account for only approximately 5% of mCRC cases. For the remaining approximately 95% of patients with microsatellite-stable (MSS) or mismatch repair-proficient (pMMR) tumors, conventional immune checkpoint inhibitors provide limited clinical benefit, and chemotherapy in combination with targeted therapy remains the standard first- and second-line treatment, creating an urgent clinical need for more effective treatment options. LBL-024 is designed to simultaneously block the PD-1/PD-L1 immunosuppressive pathway and conditionally activate the 4-1BB co-stimulatory pathway. Through this dual mechanism of action, LBL-024 is intended to restore T-cell function while promoting T-cell proliferation and the formation of long-term immune memory. Clinical activity of LBL-024-based therapies has been observed in multiple tumor types, including extrapulmonary neuroendocrine carcinoma (EP-NEC), non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC) and biliary tract cancer (BTC). The Company believes that these mechanistic advantages may similarly translate into meaningful therapeutic benefits in colorectal cancer ("CRC") and further reinforce the positioning of LBL-024 as an immuno-oncology (IO) 2.0 cornerstone therapy.

ABOUT CRC

CRC is one of the most common gastrointestinal malignancies worldwide. According to the International Agency for Research on Cancer ("IARC"), there were approximately 1.93 million new CRC cases and 904 thousand deaths globally in 2022, making CRC the third most commonly diagnosed cancer and the second leading cause of cancer-related death worldwide. According to the National Cancer Center of China, there were approximately 517 thousand new CRC cases and 240 thousand deaths in China in 2022, ranking second and fourth among all malignancies in terms of incidence and mortality, respectively. Approximately 15% to 30% of patients with CRC present with metastatic disease at initial diagnosis, while 20% to 50% of patients with initially localized CRC eventually develop mCRC. Despite advances in treatment, mCRC remains associated with poor prognosis, with a five-year survival rate of less than 13%. Currently, immunotherapies are primarily approved for patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) CRC. However, these patients account for only approximately 5% of mCRC cases, whereas approximately 95% of patients have microsatellite-stable (MSS) or mismatch repair-proficient (pMMR) disease, which generally exhibits limited responsiveness to conventional immunotherapy, highlighting a significant unmet medical need.

ABOUT LBL-024 (OPAMTISTOMIG)

LBL-024 is a bispecific antibody simultaneously targeting PD-L1 and 4-1BB, and is a pantumor IO 2.0 cornerstone therapy with potential survival benefit. Leveraging our selfdeveloped X-body™ platform with full intellectual property rights, LBL-024 achieves conditional activation of 4-1BB, relieving PD-1/PD-L1 immunosuppression while enhancing 4-1BB regulated T-cell activation, achieving a synergistic effect in eliminating tumors. LBL024 demonstrates a safety profile comparable to PD-1/PD-L1 inhibitors and greater potential for broad-spectrum cancer treatment, and has demonstrated first-in-class (FIC) or best-inclass (BIC) potential in non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), extrapulmonary neuroendocrine carcinoma (EP-NEC) and biliary tract cancer (BTC).

As the first molecule targeting the co-stimulatory receptor 4-1BB to have reached the pivotal single-arm registrational clinical stage globally, LBL-024 has the potential to become the first drug approved for treating EP-NEC. LBL-024 has initiated clinical studies across 13 solid tumor indications in China, including one pivotal registrational clinical study and eight proofof-concept studies, covering EP-NEC, NSCLC, SCLC, BTC, ovarian cancer (OC), esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), gastric cancer (GC), triple-negative breast cancer (TNBC) and melanoma, among other areas with high unmet medical needs.

4-1BB, as an agonist, can reactivate apoptotic T cells and induce substantial proliferation, making it suitable for treating "cold tumors" that are resistant or unresponsive to PD-1/PD-L1 therapies. LBL-024 received the Breakthrough Therapy Designation (BTD) from CDE of the NMPA in October 2024, as well as the Orphan Drug Designation in treating neuroendocrine carcinoma (NEC) from the FDA in November 2024. In January 2026, LBL-024 received Fast Track Designation (FTD) from the FDA for the treatment of EP-NEC and Orphan Drug Designation from the European Union.

Cautionary Statement required by Rule 18A.05 of the Rules Governing the Listing of

Securities on The Stock Exchange of Hong Kong Limited: The Company cannot guarantee that it will be able to develop, or ultimately market, LBL-024, successfully. Shareholders and potential investors of the Company are advised to exercise due care when dealing in the shares of the Company.

By order of the Board

Nanjing Leads Biolabs Co., Ltd.

南京維立志博生物科技股份有限公司

Dr. KANG XIAOQIANG

Chairman, Executive Director and Chief Executive Officer

Nanjing, PRC, August 3, 2026