Boan Biotech Announces First Subject Enrolled in Phase I Clinical Trial of BA1203 (A Masked Anti-PD-1/IL-2 Fusion Protein) in China

Yantai, October 22, 2026 – Boan Biotech announced today that the first subject has been enrolled in a Phase I clinical trial of BA1203 in China. BA1203 is an investigational anti-PD-1/IL-2 antibody-cytokine prodrug. To the company’s knowledge, it is the world’s only PD-1/IL-2 molecule that combines high activity at the IL-2α receptor with an IL-2 masking design and PD-1-blocking activity.

The Phase I clinical trial is a multicenter, open-label study designed to evaluate the safety, tolerability, pharmacokinetics and preliminary efficacy of BA1203 in patients with advanced solid tumors.

Immuno-oncology (IO) therapies, represented by PD-1/PD-L1 inhibitors, have become a cornerstone treatment for malignancies. However, clinical benefit varies across tumor types and patient populations. A significant proportion of patients still experience primary non-response, disease recurrence, or treatment resistance, underscoring the need for new treatment options.

IL-2 is a key cytokine that promotes T-cell proliferation and functional recovery. However, traditional IL-2 therapies are limited by a narrow therapeutic window, non-selective activation of peripheral immune cells and the risk of systemic toxicity. Achieving targeted delivery and selective activation of IL-2 within the tumor microenvironment (TME) has become a key focus of next-generation IO therapies.

As a next-generation IO drug candidate developed by Boan Biotech, BA1203 combines the mechanisms of action of a PD-1 antibody and an IL-2 cytokine, aiming to achieve immune checkpoint blockade and localized immune activation within the TME simultaneously. Through its IL-2 masking prodrug design, BA1203 is intended to selectively activate IL-2 within the TME while maintaining lower IL-2 activity in peripheral tissues, thereby enhancing local antitumor immunity and reducing the risk of systemic toxicity. The molecule also incorporates a high-affinity, bivalent PD-1-targeting design that strengthens checkpoint blockade and facilitates the precise delivery of IL-2 to PD-1-positive tumor-infiltrating T cells. In addition, BA1203 features a symmetric molecular structure, which helps improve molecular stability and the controllability of the manufacturing process.

Preclinical studies have shown that BA1203 demonstrates excellent anti-tumor activity, significantly outperforming existing PD-1/PD-L1 inhibitors across multiple tumor models that showed limited or no response to these agents. In tumor-bearing mouse models, BA1203 demonstrated superior efficacy compared to competitors in the same class and exhibited a favorable safety profile characterized by tumor-dependent activation, with low peripheral toxicity and enhanced local immune activation within tumors. BA1203 also demonstrated a favorable safety and tolerability profile in cynomolgus monkey studies.

Jiang Hua, Chairlady and Chief Executive Officer of Boan Biotech, said: “PD-1/IL-2 has become a key focus of next-generation IO drug development worldwide. BA1203’s differentiated design incorporates high-affinity, bivalent PD-1 targeting, a masked IL-2 prodrug and a symmetric molecular structure. These features are intended to enhance local immune responses within tumors while reducing the risk of peripheral toxicity, potentially offering a new approach to improving the efficacy of cancer immunotherapy. We will accelerate BA1203’s clinical development and explore its potential as a monotherapy and in combination regimens across multiple types of solid tumors.”

About Boan Biotech

Boan Biotech (6955.HK) is a fully-integrated biopharmaceutical company developing, manufacturing, and marketing biologics, with a focus on oncology, autoimmune diseases, ophthalmology, and metabolic diseases. The company’s drug discovery activities revolve around multiple platforms: Human Antibody Transgenic Mouse Technology Platform, Bispecific/Multi-specific/Probody Technology Platform, ADC Technology Platform and Artificial Intelligence/Big Data Application Platform.

Boan Biotech operates across the entire value chain of the industry covering antibody discovery, cell line development, upstream and downstream process development, analytical and bio-analytical method development, technology transfer, non-clinical research, clinical research, regulatory affairs and registration, and commercial production.

Boan Biotech currently has five products that have been approved for marketing, along with a robust pipeline of proprietary investigational biologics and biosimilars. In addition to China, the company is also developing biopharmaceutical products in overseas markets, including the U.S., Europe, and Japan. With a differentiated portfolio and well-established commercial capabilities, Boan Biotech operates across the industry’s value chain from research and development to manufacturing and commercialization, laying a solid foundation for long-term, high-quality growth in the future.