On October 19, 2026 Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) reported that full abstracts from six studies of opamtistomig (LBL-024), its PD-L1/4-1BB bispecific antibody, and LBL-034, its GPRC5D/CD3 bispecific T-cell engager (TCE), have been published on the official website of the 2026 Annual Meeting of the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper). The abstracts span clinical trials, translational research and meta-analyses.
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The data show durable responses and long-tail survival signals with opamtistomig across multiple immunologically cold tumors, and deep, sustained responses with a low rate of severe cytokine release for LBL-034 in heavily pretreated multiple myeloma, supporting opamtistomig’s potential as a pan-tumor therapy, and highlight the differentiated capabilities of the Company’s X-body and TCE technology platforms. The Late-Breaking Abstract (LBA) relating to opamtistomig will be published on the date of its oral presentation.
Opamtistomig in First-Line EP-NEC (ABSTRACT NO. 5836)
As of April 3, 2026, the study had enrolled 69 patients with advanced extrapulmonary neuroendocrine carcinoma (EP-NEC) and no prior systemic therapy. Sixty-five patients were evaluable for efficacy, and median follow-up for the overall population was 16.9 months.
Across all dose levels, median duration of response (mDoR) was 10.2 months and median overall survival (mOS) had not matured. In the 6 mg/kg and 15 mg/kg cohorts, mDoR was 15.5 months and 10.2 months, and the 15-month overall survival (OS) rate was 63.6% and 58.4%, respectively.
Among patients with PD-L1-positive disease (combined positive score [CPS] ≥1），the 15-month OS rate was 66.7% in both dose cohorts; among PD-L1-negative patients (CPS <1), the rates were 57.1% and 53.6%.
No dose-limiting toxicities were observed. Treatment-related adverse events were primarily chemotherapy-induced myelosuppression, and no severe hepatotoxicity was reported.
EP-NEC is an aggressive malignancy associated with a poor prognosis. Historical data indicate an mOS of approximately 12 months with first-line platinum-based chemotherapy. In this study, mOS remained unreached after a median follow-up of nearly 17 months, with encouraging 15-month survival rates across dose cohorts. These findings suggest the potential for durable clinical benefit and warrant further follow-up to characterize long-term survival outcomes.
Opamtistomig in First-Line BTC (ABSTRACT NO. 5649)
As of April 1, 2026, 20 patients with advanced biliary tract cancer (BTC) had been enrolled in the safety lead-in phase. Median age was 61 years. The cohort included two patients with gallbladder cancer, 13 with intrahepatic cholangiocarcinoma and five with extrahepatic cholangiocarcinoma, and 85.0% had metastatic disease.
Overall objective response rate (ORR) was 55.0% and disease control rate (DCR) was 100.0%. Among patients with PD-L1-positive disease (CPS ≥1), ORR was 100.0%.
Treatment-emergent adverse events were mainly chemotherapy-related hematologic toxicities, including leukopenia, neutropenia and anemia. No new safety signals were observed.
Patients with PD-L1-negative disease (CPS <1) accounted for 60% of the study population, compared with generally less than 30% in comparable first-line BTC studies, while other baseline characteristics were broadly similar. Follow-up for the abstract data was limited, and updated data are expected at the 2026 ESMO (Free ESMO Whitepaper) Congress.
Translational Study of opamtistomig in MSS Colorectal Cancer (ABSTRACT NO. 5512)
In a preclinical translational study in microsatellite stable (MSS) colorectal cancer, opamtistomig produced dose-dependent tumor growth inhibition. Tumor growth inhibition by tumor volume was 69.27%, 94.53% and 99.84% in the 2 mg/kg, 8 mg/kg and 30 mg/kg groups, respectively. In the 30 mg/kg group, complete tumor regression occurred in two of five mice. At molar-equivalent doses, opamtistomig showed greater antitumor activity than pembrolizumab in this model.
The study further demonstrated that intratumoral soluble 4-1BB levels were several dozen times higher than peripheral levels, consistent with the intended local, conditional activation. Tumor-infiltrating T cells increased in a dose-dependent manner: the proportion of CD3+ cells rose from 30.84% in the control group to as high as 68.92%, and CD8+ cells from 56.05% to as high as 88.72%. The proportion of immunosuppressive regulatory T cells (Tregs) fell from 9.58% to as low as 1.71%, and intratumoral cytokines including TNF-α and IFN-γ increased dose-dependently.
The findings indicate that opamtistomig induces intratumoral immune activation and reshapes the tumor microenvironment by conditionally activating local CD8+ T cells and reducing immunosuppressive Tregs. The mechanism is consistent with the efficacy signals and safety profile observed in clinical studies and supports further clinical development in MSS colorectal cancer and other immunotherapy-resistant solid tumors.
LBL-034 in Relapsed or Refractory Multiple Myeloma (ABSTRACT NO. 4727)
As of March 31, 2026, 56 heavily pretreated patients with relapsed or refractory multiple myeloma (RRMM) had been enrolled. Median number of prior lines of therapy was five; 73.2% were triple-class exposed, 57.1% penta-drug exposed, 28.6% had undergone autologous stem cell transplantation, 16.1% had received prior BCMA CAR-T therapy and 23.2% had extramedullary disease (EMD).
Among 55 efficacy-evaluable patients, median follow-up was 16.0 months, median progression-free survival (mPFS) was 15.8 months and mDoR had not been reached.
At doses of 400–1,200 μg/kg, the 18-month PFS rate was 58.0%. Among 23 patients who achieved a complete response (CR) or better, the 18-month PFS rate was 87.7%, median time to CR or better was 3.94 months and the minimal residual disease (MRD)-negative rate at a sensitivity of 10⁻⁵ was 72.7%.
Among high-risk patients with EMD, ORR was 75.0%, median time to response was 3.07 months, mPFS was 11.5 months and the 18-month PFS rate was 46.9%.
LBL-034 showed a favorable safety profile, with only one grade 3 or higher cytokine release syndrome (CRS) event and no treatment-related deaths.
These findings demonstrate the potential of LBL-034 to achieve deep and durable responses in heavily pretreated patients, including those with high-risk EMD, while maintaining a low incidence of severe CRS. The results further support the clinical potential of the Company’s TCE platform and its approach to targeted T-cell engagement and activation.
Executive Commentary
Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, stated: "ESMO 2026 marks another important milestone for Leads Biolabs, with three studies selected for oral presentation, including a late-breaking abstract. Across multiple tumor types, the emerging clinical data reinforce opamtistomig’s potential to deliver durable responses and long-term survival benefit, including in immunologically cold tumors where existing immunotherapies have shown limited efficacy.
Our translational findings in MSS colorectal cancer further support the scientific rationale behind opamtistomig: combining PD-L1 blockade with tumor-localized, conditional 4-1BB activation to drive antitumor immunity where it is needed. This differentiated mechanism underpins our ambition to develop opamtistomig as a potential pan-tumor immunotherapy.
Meanwhile, the LBL-034 data demonstrate the potential of our TCE platform to deliver deep, sustained responses with a low incidence of severe CRS, even in heavily pretreated patients with multiple myeloma. These results reinforce our confidence in the platform’s potential to support a broader pipeline of differentiated TCE therapies.
We remain committed to advancing the global clinical development of opamtistomig and our TCE pipeline with urgency and scientific rigor, translating our differentiated technology platforms into meaningful clinical benefits for patients worldwide."
About Opamtistomig
Opamtistomig (LBL-024) is emerging as a next-generation pan-cancer backbone therapy with potential overall survival (OS) benefit that simultaneously targets PD-L1 and the co-stimulatory receptor 4-1BB. Currently, opamtistomig is being evaluated in 14 indications, including one pivotal single-arm registrational study, one confirmatory Phase III study, and nine proof-of-concept studies, covering major indications such as NSCLC and multiple cold tumors. To date, opamtistomig has demonstrated robust antitumor activity across seven tumor types—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)—highlighting its clinical value and broad therapeutic promise.
Developed using Leads Biolabs’ proprietary X-body bispecific platform, opamtistomig is designed to simultaneously block PD-1/PD-L1 immune suppression and conditionally activate 4-1BB, an agonist pathway, resulting in a potent and synergistic anti-tumor immune response. It has a safety profile comparable to PD-1/PD-L1 inhibitors and demonstrates broader-spectrum anti-cancer potential. Mechanistically, 4-1BB agonism can reactivate exhausted T cells and promote robust T-cell proliferation, offering significant promise for PD-1/PD-L1–resistant or immunologically "cold" tumors and potentially offering durable survival benefits.
Recognizing its clinical potential in EP-NEC, opamtistomig received Breakthrough Therapy Designation from China’s National Medical Products Administration (NMPA) in October 2024, Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA) in November 2024, Fast Track Designation from the FDA and ODD from the European Commission in January 2026, and ODD from Japan’s Ministry of Health, Labour and Welfare (MHLW) in September 2026. In October 2026, the FDA granted a second Fast Track Designation, this one for first-line advanced or metastatic biliary tract cancer.
In July 2026, its New Drug Application (NDA) was granted priority review designation by the NMPA, followed by NDA acceptance in August 2026, positioning opamtistomig as a potential world’s first approved 4-1BB-targeting antibody, the first approved agonist antibody, and the first approved treatment for EP-NEC.
About LBL-034
LBL-034 is a humanized bispecific T-cell engager targeting GPRC5D and CD3, developed using the Company’s proprietary LeadsBody platform. LBL-034 employs a 2:1 structural design comprising two high-affinity Fab domains targeting GPRC5D and one single-chain variable fragment targeting CD3. It is designed to selectively target GPRC5D-positive tumor cells and conditionally activate T cells, thereby reducing the risks of cytokine release, systemic toxicity and T-cell exhaustion while enabling potent, sustained antitumor activity.
LBL-034 has demonstrated encouraging efficacy signals in preclinical and clinical studies. Breakthrough clinical data for LBL-034 monotherapy in RRMM were presented in the opening oral presentation at the 2025 American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting, and further updated clinical data have been selected for a Proffered Paper presentation at the 2026 ESMO (Free ESMO Whitepaper) Congress. LBL-034 received Orphan Drug Designation from the FDA in October 2024 and Fast Track Designation from the FDA in January 2026. A Phase III clinical study of LBL-034 is currently in preparation.
(Press release, Nanjing Leads Biolabs, OCT 19, 2026, View Source [SID1234673596])