SBP GROUP - VOLUNTARY ANNOUNCEMENT - LANOVA MEDICINES PRESENTED LATEST RESEARCH DATA ON TWO ADC PROGRAMS AT AACR 2026

(Incorporated in the Cayman Islands with limited liability)

Website: www.sbpgroup.com

(Stock code: 1177)

VOLUNTARY ANNOUNCEMENT

LANOVA MEDICINES PRESENTED LATEST RESEARCH DATA ON

TWO ADC PROGRAMS AT AACR 2026

The board of directors (the "Board") of Sino Biopharmaceutical Limited (the "Company", together with its subsidiaries, the "Group") announces that the latest research data of LM-364 "Nectin-4TME ADC" and LM-338 "STn ADC", two antibody-drug conjugates (ADC) independently developed by LaNova Medicines Limited ("LaNova Medicines", a wholly-owned subsidiary of the Group), has been presented at the American Association for Cancer Research (AACR) Annual Meeting 2026.

LM-364 is a next-generation Nectin-4TME ADC developed by LaNova Medicines leveraging its proprietary tumor microenvironment (TME) platform. This molecule employs an adenine nucleotide (ANP)-dependent binding mechanism: since ANP concentration in the tumor microenvironment (micromolar level) is significantly higher than that in normal tissues (nanomolar level), LM-364 achieves conditionally activated high-affinity binding at tumor sites. This enhances internalization and payload release while significantly reducing off-target toxicity in normal tissues, offering a novel approach to addressing long-standing safety challenges in ADC development. Nectin-4 is a clinically validated target with high expression in various solid tumors, including urothelial carcinoma and triple-negative breast cancer. However, the key limitation in clinical development is its low-level expression in normal tissues, which can lead to dose-limiting toxicities such as rash and neurotoxicity.

Abstract No.: 4433

Title: Preclinical evaluation of LM-364TME: A next-generation anti-Nectin4 ADC with promising efficacy and reduced toxicity

Key Preclinical Data:

• Precise targeting and potent cytotoxicity: LM-364 demonstrated a broad ANP-dependent binding window, along with efficient internalization, potent targeted cytotoxicity against tumor cells and a

strong bystander effect.

• Broad-spectrum and potent in vivo antitumor activity: Significant tumor suppression was observed in multiple patient-derived xenograft (PDX) models, with tumor growth inhibition (TGI) rates of 119.1% in triple-negative breast cancer, 107.46% in urothelial carcinoma, 168.79% in cervical

cancer, and 86.73% in esophageal cancer.

• Favorable safety profile: A 7-week repeated-dose toxicity study in SD rats and rhesus monkeys demonstrated good tolerability; the highest non-severely toxic dose (HNSTD) in rhesus monkeys

reached 60 mg/kg.

Currently, an Investigational New Drug (IND) application for LM-364 has been submitted to the U.S. Food and Drug Administration (FDA), with a first-in-human (FIH) clinical study planned for 2026.

LM-338 is a potential global first-in-class ADC targeting the highly tumor-specific glycan antigen Sialyl-Thomsen-nouveau (STn). It consists of a humanized monoclonal antibody conjugated to a topoisomerase I inhibitor via a cleavable linker, with a drug-to-antibody ratio (DAR) of 4. STn is a truncated O-glycan antigen that is minimally expressed in most normal tissues but highly expressed in various solid tumors (such as ovarian cancer, breast cancer, bladder cancer, cervical cancer, colorectal cancer, pancreatic cancer, and non-small cell lung cancer), making it a highly promising ADC target.

Abstract No.: 5636

Title: Preclinical evaluation of LM-338: An innovative anti-STn antibody drug conjugate for solid tumors

Key Preclinical Data:

• High target specificity and internalization efficiency: Demonstrated high selectivity for the STn antigen with minimal cross-reactivity to its structural analog, sialyl-T-antigen, and exhibited

excellent internalization capacity.

• Potent in vitro and in vivo antitumor activity: Demonstrated potent cytotoxicity and a strong bystander effect in vitro; in cell line-derived xenograft (CDX) and PDX mouse models derived from STn-positive cells, including ovarian, colorectal, and non-small cell lung cancer, LM-338

monotherapy induced significant tumor growth inhibition and even complete tumor regression.

• Favorable safety profile: Toxicology studies in rhesus monkeys showed a HNSTD of 60 mg/kg,

with overall good tolerability.

These encouraging preclinical data provide a solid foundation for the clinical development of LM-338 in STn-positive solid tumors.

By order of the Board

Sino Biopharmaceutical Limited Tse, Theresa Y Y

Chairwoman

Hong Kong, 22 April 2026