BOAN BIOTECH (06955): BA1203 (masked PD-1/IL-2) Phase I clinical trial in China completes first subject enrollment

BOAN BIOTECH (06955) announces that the first subject has been enrolled in the Phase I clinical trial in China of the company's investigational PD-1/IL-2 antibody-cytokine prodrug BA1203. To the company's knowledge, this investigational drug is the world's only PD-1/IL-2 molecule that combines high IL-2 receptor activity, a masked design, and PD-1 blockade. The clinical trial being conducted is a multicenter, open-label Phase I study designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of BA1203 in patients with advanced solid tumors. Immunotherapy represented by PD-1/PD-L1 inhibitors has become a core treatment modality for malignant tumors, but benefits vary across cancer types and patient populations, and a considerable proportion of patients still face challenges such as primary non-response, relapse, or drug resistance, leaving unmet clinical needs. IL-2 is an important cytokine that promotes T-cell proliferation and functional restoration, but conventional IL-2 therapy is limited by a narrow therapeutic window, non-selective activation of peripheral immune cells, and the risk of systemic toxicity. Achieving precise delivery and selective activation of IL-2 in the tumor microenvironment has become an important exploration direction for next-generation cancer immunotherapy (IO) therapies. BA1203, a next-generation IO drug candidate independently developed by the company, integrates the dual mechanisms of action of a PD-1 antibody and an IL-2 cytokine, aiming to simultaneously achieve immune checkpoint blockade and local tumor immune activation. Its IL-2-masked prodrug design enables selective activation of IL-2 in the tumor microenvironment while maintaining low activity in peripheral tissues, thereby enhancing local antitumor immune responses and reducing the risk of systemic toxicity. Meanwhile, the molecule employs a high-affinity bivalent PD-1-targeting design, which helps enhance PD-1 pathway blockade and deliver IL-2 more precisely to PD-1-positive tumor-infiltrating T cells. In addition, BA1203 adopts a symmetric molecular structure design, which is conducive to improving molecular stability and manufacturing process controllability. Preclinical studies have shown that BA1203 demonstrated superior antitumor activity in multiple tumor models with low or no response to PD-1/PD-L1 inhibitors, significantly outperforming existing PD-1/PD-L1 inhibitors. In tumor-bearing mouse models, BA1203 showed better efficacy than similar competitor products and exhibited a safety advantage of tumor-dependent activation. In terms of safety, BA1203 enhances local tumor immune activation while causing low peripheral toxicity; in cynomolgus monkey studies, it showed a favorable safety profile and excellent tolerability. The company will accelerate the clinical development of BA1203 and comprehensively explore the potential of this investigational drug as monotherapy and in combination therapy across multiple solid tumors.