PSB205 (QL1706)

PSB205 is a bifunctional immunotherapy combining anti-PD-1 and anti-CTLA-4 monoclonal antibodies, co-produced from a single cell line using Sound Biologics' proprietary MabPair technology. The platform enables control of antibody ratios and independent engineering of each component. The anti-CTLA-4 antibody is designed with a shorter half-life to potentially reduce toxicity associated with CTLA-4 blockade.

In preclinical tumor models, PSB205 demonstrated greater antitumor activity than either checkpoint inhibitor alone. Clinical development began with Phase 1 studies in China and the United States (NCT03986606), followed by Phase 2 studies across multiple tumor types. A Phase 2 hepatocellular carcinoma study demonstrated improved efficacy without increased overall toxicity compared with PD-1 monotherapy (ASCO 2023).

PSB205 is also being evaluated in pivotal Phase 3 trials in China across several cancer indications, including non-small cell lung cancer, cervical cancer, hepatocellular carcinoma, and metastatic colorectal cancer.

Regulatory status: QL1706 received NMPA approval in 2024 (link->) for the treatment of metastatic cervical cancer in China.