CSTONE PHARMA-B (02616) announced that multiple critical clinical developments for its internally developed PD-1/VEGF/CTLA-4 trispecific antibody, CS2009, will be formally presented at this year's American Society of Clinical Oncology (ASCO) Annual Meeting through two poster presentations. The disclosed information will include Phase I/II clinical trial data for CS2009 in non-small cell lung cancer (NSCLC) cohorts (both first-line and later-line settings), along with extended follow-up results from the Phase I trial in patients with advanced solid tumors.

Key highlights include the rapid progression of clinical trials, steadily advancing towards global registration. The global multicenter Phase I/II clinical trial for CS2009 is progressing swiftly in both Australia and China. An Investigational New Drug (IND) application has also been approved in the United States, and the company is actively preparing to initiate the first Phase III international multicenter clinical trial (MRCT) before the end of the year, focusing on indications such as NSCLC and colorectal cancer (CRC). To date, over 200 subjects have been enrolled. CS2009 has demonstrated excellent safety and tolerability across all evaluated dose groups, with no occurrence of the severe toxicities commonly associated with combination therapies containing CTLA-4 and PD-(L)1 inhibitors, establishing a solid clinical safety foundation for use in combination with chemotherapy or antibody-drug conjugates (ADCs).

In first-line NSCLC, the efficacy data continues to be encouraging, covering PD-L1 negative and low-expression subgroups. CSTONE PHARMA-B will disclose the latest data from the first-line NSCLC cohort (including monotherapy and combination with chemotherapy) in its ASCO poster presentation. To date, clear anti-tumor activity has been observed in patients who have completed efficacy evaluations, with CS2009's objective response rate (ORR) and disease control rate (DCR) remaining impressive. Notably, within the subgroup of patients with PD-L1 negative and low expression—a population traditionally with limited benefit from immunotherapy—CS2009 has shown significant efficacy signals. Coupled with its excellent safety profile, it holds the potential to offer a more differentiated option for the first-line treatment landscape of lung cancer.

For later-line NSCLC, responses have been deep and durable, showing potential to overcome the challenge of immunotherapy resistance. In patients with driver gene-negative, heavily pre-treated advanced NSCLC, most of whom had previously received immunotherapy (IO), CS2009 monotherapy has demonstrated clinically meaningful signals of deep response and sustained disease control, along with an excellent safety profile. The company will present updated data from the later-line NSCLC cohort (including 20 mg/kg and 30 mg/kg dose groups) at ASCO, further validating the drug's mechanistic advantages in overcoming both primary and acquired immune resistance.

Driven by its mechanism of action, CS2009 shows broad-spectrum activity, with promising performance in "cold" tumors like CRC. Based on the deep remodeling of the immune microenvironment facilitated by its triple-target synergistic mechanism, positive clinical response signals have been observed for CS2009 in typical immunologically "cold" tumors such as CRC. This includes cohorts for later-line CRC monotherapy and first-line CRC in combination with chemotherapy, providing strong proof-of-concept for its expansion into a wider range of solid tumor indications.

More mature safety and PK/PD data will also be shared. CSTONE PHARMA-B will present extended follow-up data from a larger patient population in the Phase I clinical study at ASCO, providing a comprehensive overview of CS2009's safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) characteristics.