LEADS BIOLABS-B (09887) has disclosed via an official announcement that updated results from its Phase II clinical trial evaluating Vilixine® (Oritasomimab, a PD-L1/4-1BB bispecific antibody) in combination with chemotherapy as a first-line treatment for non-small cell lung cancer (NSCLC) were presented as an oral presentation at the 2026 World Conference on Lung Cancer (WCLC 2026).

The updated findings reveal unprecedented response rates, with nearly identical clinical benefits observed in both PD-L1-negative (tumor proportion score [TPS] <1%) and PD-L1-positive (TPS ≥1%) patients with squamous NSCLC, while those with non-squamous NSCLC and PD-L1 TPS ≥1% achieved deep and durable tumor responses.

As of July 1, 2026, a total of 63 previously untreated NSCLC patients were enrolled, comprising 31 with non-squamous NSCLC and 32 with squamous NSCLC; over 90% had Stage IV disease. The proportion of patients with PD-L1 TPS ≥1% was 35.5% in the non-squamous group and 43.8% in the squamous group, significantly lower than the 60% to 70% PD-L1 positivity rate observed in the general patient population. Median follow-up duration was 7.1 months.

Among the 62 efficacy-evaluable patients, the combination of Vilixine® and chemotherapy demonstrated encouraging antitumor activity as a first-line therapy in both squamous and non-squamous NSCLC. In the overall population, the objective response rate (ORR) reached 71.0%, the disease control rate (DCR) was 95.2%, and the 6-month progression-free survival (PFS) rate was 70.6%. In the squamous NSCLC subgroup, the ORR was 87.1%, the DCR was 96.8%, and the 6-month PFS rate was 86.7%. Consistent benefit trends were seen across PD-L1-positive and negative patients, with ORRs of 84.6% and 88.2%, and 6-month PFS rates of 84.6% and 87.4%, respectively. In the non-squamous NSCLC PD-L1-positive subgroup, the ORR reached 81.8%, the DCR was 100.0%, and the 6-month PFS rate was 90.0%. Remarkable responses were also noted in patients with low PD-L1 expression (TPS 1% to 49%).

The combination exhibited a favorable overall safety profile, consistent with that of PD-L1 antibodies combined with chemotherapy, with no new safety signals detected. Notably, in this study, the proportion of patients with PD-L1 TPS ≥1% was only 35.5% and 43.8% in non-squamous and squamous NSCLC, respectively, well below the 60% to 70% positivity rate in the natural patient population. Furthermore, the enrolled patients presented with poor baseline characteristics, including over 90% with Stage IV disease and a considerable proportion with multiple metastases such as brain and liver involvement, which to some extent diluted the ORR figures. Despite these challenges, Vilixine® still delivered robust efficacy and differentiated advantages in first-line NSCLC, underscoring the potential value of its dual-target synergistic mechanism in populations underserved by conventional immunotherapy, and positioning it as a promising new option for next-generation first-line treatment strategies.

As the world's first PD-L1/4-1BB bispecific antibody to have entered the marketing authorization review stage, Vilixine® leverages its differentiated dual mechanism of action to achieve deeper therapeutic responses and broader clinical benefits, further extending the long-tail survival advantage established by first-generation tumor immunotherapies. Currently, Vilixine® is being investigated across 14 solid tumor indications, with growing evidence supporting its role as a cornerstone therapy for pan-tumor immuno-oncology (IO) 2.0. It has demonstrated breakthrough efficacy data in 7 tumor types, covering major indications such as NSCLC and esophageal squamous cell carcinoma (ESCC), as well as multiple cold tumors including extrapulmonary neuroendocrine carcinoma (EP-NEC), biliary tract cancer (BTC), and platinum-resistant ovarian cancer (PROC), with clear clinical benefits observed particularly in cold tumors that are difficult to treat with immunotherapy. Preliminary survival benefit trends have been observed in 3 tumor types, exhibiting potential for a long-tail effect, and a favorable safety profile has been shown in approximately 800 solid tumor patients. As clinical data continues to mature across multiple indications, Vilixine® is progressively validating its dual potential for broad-spectrum antitumor activity and durable benefit.

The T-cell priming and expansion driven by the 4-1BB costimulatory mechanism holds the promise of addressing the substantial unmet clinical need not covered by PD-(L)1 antibodies alone. With extended follow-up, tumor responses deepen further, leading to rising ORR, which reinforces the ability of Vilixine®'s unique dual-target immune synergistic mechanism, described as simultaneously 'releasing the brake' and 'pressing the accelerator,' to produce durable and deep tumor responses. Importantly, Vilixine® demonstrates efficacy in NSCLC patients with lower PD-L1 expression levels, with stable and reliable responses observed in those with TPS greater than 1%.

The company is actively advancing the Phase III clinical trial layout for Vilixine® as a first-line NSCLC treatment, striving to bring this innovative therapy to a broader patient population as soon as possible.

Vilixine® is a bispecific antibody that simultaneously targets PD-L1 and 4-1BB, with the potential to become a cornerstone pan-tumor IO 2.0 therapy offering survival benefits. To date, clinical studies across 14 indications have been initiated, including 1 single-arm pivotal registration study, 1 confirmatory Phase III study, and 9 proof-of-concept studies, covering multiple major cancer types and cold tumors. In the 7 tumor types supported by existing clinical data, Vilixine® has showcased exceptional clinical value and broad therapeutic prospects, including EP-NEC, NSCLC, small cell lung cancer (SCLC), BTC, hepatocellular carcinoma (HCC), ESCC, and ovarian cancer (OC). Developed using the company's proprietary X-body™ platform with full intellectual property rights, Vilixine® enables conditional activation of 4-1BB, strengthening 4-1BB-mediated T-cell activation while relieving PD-1/PD-L1 immunosuppression, thereby achieving synergistic tumor eradication. Vilixine® exhibits safety comparable to PD-1/PD-L1 inhibitors alongside enhanced broad-spectrum anticancer potential.

Notably, activation of 4-1BB can reinvigorate exhausted T cells and drive their substantial expansion, making 4-1BB-targeted therapies potentially applicable to immunologically cold tumors that are resistant or unresponsive to PD-1/PD-L1 inhibitors, while also conferring long-tail survival advantages. In October 2024, Vilixine® was granted Breakthrough Therapy Designation by China's NMPA, followed by Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) in November 2024. In January 2026, it received FDA Fast Track designation and Orphan Drug Designation from the European Union. In July 2026, the Biologics License Application for Vilixine® was included in the priority review and approval procedure by the NMPA, with formal acceptance in August, positioning it to potentially become the world's first approved 4-1BB antibody drug, the first approved agonist antibody drug globally, and the first approved treatment for EP-NEC worldwide.