공시 • Mar 27
CStone Pharmaceuticals Updates Clinical Progress and Key Phase I/II Data for CS2009
CStone Pharmaceuticals announced encouraging clinical progress for CS2009, a novel PD-1/VEGF/CTLA-4 trispecific antibody. As of mid-March 2026, 113 heavily pretreated patients with solid tumors have been enrolled in the Phase I trial of CS2009, with a median follow-up of approximately 6 months. The more mature data continue to show a favorable safety profile, with 23% incidence of Grade =3 Treatment-Related Adverse Events (TRAEs). No excessive toxicities that typically occurred in combination therapies containing CTLA-4 and PD-(L)1 were observed, and the incidence of Grade =3 VEGF-related AEs was low. CS2009 monotherapy demonstrates potentially transformative Phase I/II efficacy in Non-Small Cell Lung Cancer (NSCLC). In first-line NSCLC (PD-L1 tumor proportion score [TPS]=50%), the overall response rate (ORR) reached 90%, with a disease control rate (DCR) of 100%. In AGA-negative, later-line NSCLC, ORR reached 25%. CS2009 monotherapy also demonstrates potent antitumor activity in later-line 'cold' tumors that are not sensitive to PD-(L)1 mAb. An ORR of 40% was observed in patients with non-clear cell renal cell carcinoma (nccRCC), and an ORR of 33.3% in soft tissue sarcoma (STS), demonstrating its broad-spectrum therapeutic potential across multiple tumor types. The company plans to initiate the first wave of Phase III global multi-regional clinical trials (MRCT) for CS2009 by the end of 2026, targeting indications including NSCLC, colorectal cancer (CRC), and small cell lung cancer (SCLC). Updated Phase I and Phase II clinical data for CS2009 are expected to be disclosed at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting and/or the European Society for Medical Oncology (ESMO) Congress. The global multi-center Phase I/II clinical trial for CS2009 is actively ongoing in Australia and China, and its Investigational New Drug (IND) application for Phase II has been approved by the U.S. Food and Drug Administration (FDA). As of mid-March 2026, a total of 113 patients with advanced solid tumors have been enrolled in Phase I, with a median follow-up of approximately six months. 85 patients have been enrolled in Phase II. CS2009 demonstrates a favorable safety and tolerability profile across all six dose levels evaluated, with no dose-limiting toxicities (DLTs) observed and the maximum tolerated dose (MTD) not reached. The incidence of Grade =3 TRAEs was 23%; Grade =3 immune-related adverse events (irAEs) was 12.4%; and Grade =3 VEGF-related TRAEs was 4.4%. No excessive toxicities that typically occurred in combination therapies containing CTLA-4 and PD-(L)1 were observed. Antitumor activity was observed across all dose levels, with robust efficacy signals in multiple tumor types. At the 30 mg/kg, Third Quarter, CS2009 monotherapy achieved an ORR of 25% (6/24) and a DCR of 58.3% (14/24) in AGA-negative, later-line NSCLC patients. Across dose levels, CS2009 monotherapy resulted in an ORR of 40% and a DCR of 100% in patients with nccRCC (n=5). Across dose levels, CS2009 monotherapy resulted in an ORR of 33.3% and a DCR of 66.7% in patients with STS (n=9). The global multi-center Phase II clinical trial employs a multi-cohort parallel expansion design to evaluate the efficacy and safety of CS2009 monotherapy and combination therapy across 15 cohorts in 9 solid tumor types, including NSCLC, CRC, extensive-stage small cell lung cancer (ES-SCLC), cervical cancer (CC), gastric or gastroesophageal junction cancer (GC/GEJC), esophageal squamous cell carcinoma (ESCC), platinum-resistant ovarian cancer (PROC), triple-negative breast cancer (TNBC), and hepatocellular carcinoma (HCC). CS2009 monotherapy (20 mg/30 mg, Third Quarter) achieved an ORR of 90% (9/10) and a DCR of 100% (10/10) in first-line NSCLC patients with PD-L1 TPS=50% (n=10). Safety data from multiple cohorts of CS2009 combined with standard chemotherapy showed that the combinations were well-tolerated across tumor types, with CS2009 without increasing the incidence or severity of chemotherapy-related adverse events. Initial potent antitumor activity was observed with combination treatment in first-line NSCLC and first-line CRC. CStone plans to initiate the first set of Phase III global MRCTs for CS2009 by the end of 2026, focusing on indications including NSCLC, CRC, and SCLC. Additional Phase I and Phase II clinical data for CS2009 are expected to be presented at the 2026 ASCO and/or ESMO Annual Meetings. CS2009, an innovative trispecific antibody designed and developed by CStone, with the potential to be first- or best-in-class. It combines three clinically validated targets—PD-1, VEGFA, and CTLA-4—and exerts multidimensional antitumor effects through synergistic actions. Specifically, anti-PD-1 activity reverses T cell exhaustion, anti-CTLA-4 activity promotes T cell activation and proliferation, while anti-VEGFA activity blocks tumor angiogenesis and improves the tumor micro-environment (TME). In the TME, anti-PD-1 and anti-CTLA-4 activities are significantly enhanced by crosslinking with VEGFA. Meanwhile, CS2009 preferentially blocks PD-1 and CTLA-4 on double-positive tumor-infiltrating T cells while minimizing interference with CTLA-4 regulation in peripheral T cells.