Stock code: 688266 Stock abbreviation: Zelgen Pharmaceutical Announcement No.: 2024-041

Suzhou Zelgen Biopharmaceutical Co., Ltd

Announcement on Voluntary Disclosure of Clinical Research Progress of ZG006 for Injection

The board of directors and all directors of the company guarantee that there are no false records, misleading statements or material omissions in the content of this announcement, and assume legal responsibility for the authenticity, accuracy and completeness of its content in accordance with the law.

Important Content Notes:

Suzhou Zelgen Biopharmaceutical Co., Ltd. (hereinafter referred to as the "Company") is conducting a Phase I/II clinical study of dose escalation and multi-cohort expansion of ZG006 in patients with advanced small cell lung cancer or neuroendocrine carcinoma (protocol number: ZG006-001). Preliminary data showed that ZG006 for injection (ZG006) demonstrated good tolerability, safety and excellent anti-tumor efficacy in the Phase I dose escalation and expansion study. Especially for patients with advanced small cell lung cancer

ZG006 has significant efficacy after treatment at doses of 10 mg and above, based on data as of August 8, 2024

The objective response rate (ORR) was 66.7% and the disease control rate (DCR) was 88.9%. Detailed study protocols and study data will be presented at the 2024 European Society for Medical Oncology (ESMO) and the 27th Chinese Congress of Clinical Oncology & CSCO Annual Meeting 2024.

The above matters will not have a material impact on the Company's near-term results. Due to the high-tech, high-risk, and high value-added characteristics of pharmaceutical products, the pre-research and development of drugs and the long cycle and many links of products from development, clinical trials, approval to production, are easily affected by some uncertain factors, and the company will fulfill its information disclosure obligations in a timely manner according to the follow-up progress. Investors are advised to make prudent decisions and pay attention to preventing investment risks.

In order to keep investors abreast of the company's relevant research results, the clinical data and latest progress of ZG006 for injection are hereby announced as follows:

First, the basic situation of drugs

ZG006 for injection is the result of the bispecific/multi-specific anti-drug developed by the Company and its subsidiary, Gensun Biopharma Inc

A trispecific antibody drug developed by the R&D platform has obtained clinical trial approval from both the United States FDA and the Chinese NMPA, and has been granted Orphan-drug Designation by the United States FDA. ZG006 is the world's first trispecific antibody (CD3×DLL3) against DLL3-expressing tumors

× DLL3), is a first-in-class molecule with the potential to be a best-in-class molecule.

ZG006 is a trispecific antibody against CD3 and two different DLL3 epitopes. ZG006

The anti-DLL3 terminal binds to different DLL3 epitopes on the surface of tumor cells, and the anti-CD3 terminal binds to T cells. ZG006

Bridging tumor cells and T cells, bringing T cells closer to tumor cells to take advantage of T cell-specific killing

Tumor cells. The results of preclinical studies have shown that ZG006 has a significant tumor suppressive effect in mouse tumor models, which can lead to complete regression of a significant proportion of mouse tumors, indicating that ZG006 has a potent tumor killing effect. ZG006 showed good safety profiles such as low toxicity and side effects in non-human primates.

2. Progress in clinical research of ZG006 for injection

As of August 8, 2024, ZG006 in patients with advanced small cell lung cancer or neuroendocrine carcinoma

A Phase I/II Clinical Study of Dose Escalation and Multi-Cohort Expansion of Tolerability, Safety, Efficacy, and Pharmacokinetics (Protocol Number: ZG006-001) in Patients With Advanced Small Cell Lung Cancer or Neuroendocrine Carcinoma Phase I Dose Escalation Phase has completed enrollment. The escalation dose groups that have been completed are 0.1, 0.3, 1, 3, 10, 30, and 60 mg, and can evaluate 24 subjects, most of whom (17/24) have received at least two prior lines of systemic antineoplastic therapy. Detailed study protocols and study data are coming soon within European Oncology 2024

The Society for Science (ESMO) and the 27th Chinese Congress of Clinical Oncology and the 2024 CSCO Annual Meeting were announced.

In terms of efficacy, 7 of the 21 subjects with efficacy evaluable small cell lung cancer (SCLC) were obtained

Partial response (PR) was obtained, and 5 patients had stable disease (SD) and 4 of them had reduced SD. In the acceptance of ZG006

Of the 9 subjects with SCLC at doses of 10 mg and higher (4 in the 10 mg group, 2 in the 30 mg group, 60 mg

3 cases in the group), there were 6 cases of PR, including 3 cases in the 10 mg group, 1 case in the 30 mg group, and 2 cases in the 60 mg group, ORR

66.7%; There were also 2 cases of SD with tumor shrinkage, with a DCR of 88.9%.

In terms of safety, the vast majority of treatment-related adverse events (TRAEs) were highly stringent in the 24 participants

Severity is grade 1 or 2. The most common TRAEs are fever, anemia, and cytokine release syndrome

(CRS, grade 3 CRS 1 case). No dose-limiting toxicities (DLTs) and immune effector cell-associated neurotoxicity syndromes (ICANS) were observed, nor were TRAEs occurring leading to treatment termination or death.

In summary, ZG006 showed good tolerability, safety and excellent anti-tumor efficacy, especially in patients with advanced small cell lung cancer who failed multiple lines of therapy after treatment with doses of 10 mg and above. Two Phase II clinical extension studies of ZG006 have been initiated and patients with small cell lung cancer and neuroendocrine carcinoma are being enrolled, respectively, to further evaluate the efficacy and safety of ZG006.

3. Risk Warning

This disclosure of the progress of clinical research of ZG006 for injection will not have a significant impact on the company's near-term results. Due to the high-tech, high-risk, and high value-added characteristics of pharmaceutical products, the pre-research and development of drugs and the long cycle and many links of products from development, clinical trials, approval to production, are easily affected by some uncertain factors, and the company will fulfill its information disclosure obligations in a timely manner according to the follow-up progress. Investors are advised to make prudent decisions and pay attention to preventing investment risks.

Board of Directors of Suzhou Zelgen Biopharmaceutical Co., Ltd

September 9, 2024