On August 2, 2026 Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) reported that the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) has approved the investigational new drug (IND) application for an open-label, multicenter Phase Ib/II clinical trial of its proprietary PD-L1/4-1BB bispecific antibody, Opamtistomig (LBL-024), in combination therapy for metastatic colorectal cancer (mCRC). The study is designed to evaluate the safety and efficacy of Opamtistomig combination regimens in patients with mCRC and to explore potential predictive biomarkers. This marks an important step in expanding the indications for Opamtistomig in gastrointestinal cancers, extending the company’s immuno-oncology footprint from biliary tract cancer, gastric cancer and esophageal squamous cell carcinoma into colorectal cancer (CRC), an area of high unmet clinical need.
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mCRC is difficult to treat and carries a very poor prognosis, with a 5-year survival rate of less than 13%. While immunotherapy has achieved breakthroughs in the microsatellite instability-high (MSI-H)/deficient mismatch repair (dMMR) subtype, these patients account for only about 5% of mCRC cases. For the vast majority—up to 95%—of patients with microsatellite stable (MSS)/mismatch repair proficient (pMMR) tumors, conventional immune checkpoint inhibitors offer limited benefit. The current first- and second-line standard of care remains chemotherapy combined with targeted therapy, leaving an urgent need for more effective immunotherapy options.
Opamtistomig simultaneously blocks PD-1/PD-L1-mediated immunosuppression and conditionally activates 4-1BB co-stimulatory signaling. This dual mechanism restores T cell function while promoting T cell proliferation and long-term memory formation. The mechanistic advantages of Opamtistomig have been validated in multiple tumor types, including extrapulmonary neuroendocrine carcinoma (EP-NEC), non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and biliary tract cancer (BTC), and are expected to translate into meaningful clinical benefit in CRC as well, further reinforcing its position as an IO 2.0 pan-tumor cornerstone therapy.
Executive Commentary
Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, stated: "MSS/pMMR mCRC is widely recognized as an immunologically ‘cold’ tumor, and patients continue to face significant unmet medical needs with limited effective treatment options. Through the synergistic dual targeting of PD-L1 and 4-1BB, Opamtistomig has the potential to restore anti-tumor immune activity in cold tumors, a differentiated mechanism that has already shown encouraging preliminary signals in earlier clinical studies. We are excited to further explore this novel combination strategy in the ongoing Phase Ib/II study and hope to bring a more effective immunotherapy option to patients with metastatic colorectal cancer."
About Colorectal Cancer (CRC)
CRC is one of the most common gastrointestinal malignancies worldwide. According to 2022 data from the International Agency for Research on Cancer (IARC), there were approximately 1.926 million new cases and 904,000 deaths from CRC globally, making it the third most common cancer and the second leading cause of cancer-related death. Data from the China National Cancer Center show that in 2022, there were 517,100 new cases and 240,000 deaths from CRC in China, ranking second in incidence and fourth in mortality among all malignancies. Approximately 15%–30% of CRC patients have distant metastases at initial diagnosis, and 20%–50% of patients with initially localized CRC eventually develop mCRC. mCRC is difficult to treat and has a very poor prognosis, with a 5-year survival rate of less than 13%. Currently, immunotherapy is primarily approved for MSI-H/dMMR CRC patients, but these account for only about 5% of mCRC cases. The remaining 95% of patients with MSS/pMMR tumors are resistant to conventional immunotherapy, representing a significant unmet clinical need.
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. Developed using Leads Biolabs’ proprietary X-Body bispecific platform, Opamtistomig is designed to simultaneously block PD-1/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. To date, Opamtistomig has demonstrated first- or best-in-class potential in Phase II or registrational clinical trials across four indications: non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), biliary tract cancer (BTC), and extrapulmonary neuroendocrine carcinoma (EP-NEC).
As the first 4-1BB–targeting bispecific antibody globally to advance to a single-arm pivotal trial as monotherapy, Opamtistomig has been evaluated in 13 solid tumor indications in China, including 1 pivotal registration trial and 8 proof-of-concept studies. These cover EP-NEC, NSCLC, SCLC, BTC, ovarian cancer (OC), esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), gastric cancer (GC), triple-negative breast cancer (TNBC), malignant melanoma, and other areas with high unmet medical needs.
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. Recognizing its clinical potential, Opamtistomig received Breakthrough Therapy Designation (BTD) from China’s National Medical Products Administration (NMPA) in October 2024, and Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA) for the treatment of neuroendocrine carcinoma in November 2024. Additionally, in January 2026, Opamtistomig was granted Fast Track Designation (FTD) by the FDA and ODD by the European Commission for the treatment of EP-NEC, further underscoring its potential to address unmet medical needs in this patient population.
(Press release, Nanjing Leads Biolabs, AUG 2, 2026, View Source [SID1234669595])