LEADS BIOLABS-B(09887): Announces Updated Phase II Clinical Study Data for Vilxin (Opatilimab, PD-L1/4-1BB Bispecific Antibody) Combined with Chemotherapy as First-Line Treatment for NSCLC in an Oral Presentation at WCLC 2026

LEADS BIOLABS-B(09887) announces that it presented updated Phase II clinical study data for its self-developed investigational drug Vilxin (Opatilimab, PD-L1/4-1BB bispecific antibody) in combination with chemotherapy as first-line treatment for patients with non-small cell lung cancer (NSCLC) in an oral presentation at the 2026 World Conference on Lung Cancer (WCLC 2026). According to the updated data, unprecedented high response rates were demonstrated, with nearly identical clinical benefits observed in squamous NSCLC patients regardless of PD-L1 statusboth negative (PD-L1 tumor proportion score (TPS) <1%) and positive (PD-L1 TPS1%)while non-squamous NSCLC patients with PD-L1 TPS1% achieved deep and durable tumor responses. As of July 1, 2026, a total of 63 patients with previously untreated NSCLC were enrolled, including 31 with non-squamous NSCLC and 32 with squamous NSCLC, with over 90% having Stage IV disease. The proportion of patients with PD-L1 TPS1% was 35.5% and 43.8% in non-squamous and squamous NSCLC, respectively, far below the 60% to 70% PD-L1 positivity rate in the natural patient population. The median follow-up time was 7.1 months. Among 62 efficacy-evaluable patients, Vilxin combined with chemotherapy demonstrated encouraging antitumor activity in both squamous and non-squamous NSCLC first-line treatment. In the overall patient population, the ORR reached 71.0%, the disease control rate (DCR) reached 95.2%, and the 6-month PFS rate reached 70.6%. In the squamous NSCLC subgroup, the ORR reached 87.1%, the DCR reached 96.8%, and the 6-month PFS rate reached 86.7%. The benefit trend was consistent between PD-L1-positive and PD-L1-negative patients, with ORRs of 84.6% and 88.2%, respectively, 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 reached 100.0%, and the 6-month PFS rate reached 90.0%. Among patients with low PD-L1 expression (TPS 1% to 49%), very excellent responses were also observed. Vilxin combined with chemotherapy demonstrated a favorable overall safety profile, with safety characteristics similar to PD-L1 monoclonal antibody combined with chemotherapy, and no new safety signals were observed. In this study, the proportion of patients with PD-L1 TPS1% was only 35.5% and 43.8% in non-squamous and squamous NSCLC, respectively, far below the 60% to 70% positivity rate in the natural patient population. Meanwhile, the overall enrolled patient baseline was poor, with over 90% having Stage IV disease and a considerable proportion having multiple metastases including brain metastases and liver metastases, which to some extent diluted the ORR. Even so, Vilxin still demonstrated robust efficacy and differentiated advantages in first-line NSCLC, indicating that its dual-target synergistic mechanism has potential value in populations inadequately covered by prior immunotherapy, and is expected to provide a new effective 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, Vilxin leverages its differentiated dual mechanism of action to achieve deeper treatment responses and broader clinical benefits, and further extends this advantage on the basis of the long-tail survival benefit established by first-generation cancer immunotherapies. Currently, Vilxin is being investigated in clinical studies across 14 solid tumor indications, with growing evidence supporting it as a cornerstone therapy for pan-tumor immuno-oncology (IO) 2.0. Vilxin has demonstrated breakthrough efficacy data in 7 tumor types, covering major indications such as non-small cell lung cancer (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 especially in cold tumors that are difficult to tackle with immunotherapy; preliminary survival benefit trends have been observed in 3 tumor types, demonstrating long-tail effect potential; and a favorable safety profile has been shown in approximately 800 patients with solid tumors. With the continuous readout of clinical data across multiple indications, Vilxin is gradually validating its dual potential of broad-spectrum anti-cancer activity and durable benefit. The T cell priming and expansion brought by the 4-1BB co-stimulatory mechanism is expected to address the huge unmet clinical needs that PD-(L)1 monoclonal antibodies cannot cover. With extended follow-up time, tumor responses further deepened, leading to continuously rising ORR, which further corroborates that Vilxin's unique dual-target immune synergistic mechanism of "releasing the brake" and "stepping on the gas" can bring durable and deep tumor responses. Notably, Vilxin has efficacy in NSCLC patients with lower PD-L1 expression levels, and stable and reliable efficacy can be observed in patients with TPS greater than 1%. Currently, the Company is actively advancing the Phase III clinical study layout for Vilxin as first-line treatment for NSCLC, striving to bring this innovative therapy to more patients as soon as possible. Vilxin is a bispecific antibody targeting both PD-L1 and 4-1BB, with the potential to become a cornerstone therapy for pan-tumor IO 2.0 with survival benefits. Currently, Vilxin has initiated clinical studies across 14 indications, including 1 single-arm pivotal registration clinical study, 1 confirmatory Phase III clinical study, and 9 proof-of-concept studies, covering multiple major cancer types and "cold tumors." Among the 7 cancer types with existing clinical data support, Vilxin has demonstrated excellent clinical value and broad therapeutic prospects, including extrapulmonary neuroendocrine carcinoma (EP-NEC), non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), biliary tract cancer (BTC), hepatocellular carcinoma (HCC), esophageal squamous cell carcinoma (ESCC), and ovarian cancer (OC). Developed using the Group's self-developed platform X-body with fully independent intellectual property rights, Vilxin can achieve conditional activation of 4-1BB, strengthening 4-1BB-regulated T cell activation while relieving PD-1/PD-L1 immune suppression, thereby achieving synergistic tumor elimination. Vilxin has safety comparable to PD-1/PD-L1 inhibitors and stronger broad-spectrum cancer treatment potential. It is particularly worth noting that activating 4-1BB can reactivate exhausted T cells and induce massive expansion, making 4-1BB-targeting therapies potentially suitable for treating immunologically "cold tumors" that are resistant or unresponsive to PD-1/PD-L1 inhibitors, and can bring long-tail survival benefits. In October 2024, Vilxin received Breakthrough Therapy Designation from the NMPA, and in November 2024, it received Orphan Drug Designation from the U.S. Food and Drug Administration (FDA). In January 2026, Vilxin received Fast Track Designation from the FDA and Orphan Drug Designation from the European Union. In July 2026, the innovative biologic marketing application for Vilxin was included in the priority review and approval procedure by the NMPA, and was officially accepted in August, with the potential to become the world's first approved 4-1BB antibody drug, the world's first approved agonist-class antibody drug, and the world's first approved treatment for EP-NEC.