Leads Biolabs opamtistomig hits 87% ORR in squamous NSCLC at WCLC
Nanjing Leads Biolabs presented updated Phase II data for opamtistomig (LBL-024), its PD-L1/4-1BB bispecific antibody, at the 2026 World Conference on Lung Cancer, reporting what the company described as durable antitumour activity across both major NSCLC histologies when the drug is combined with chemotherapy in first-line patients.
The dataset covered 63 treatment-naive patients enrolled as of 1 July 2026, of whom 32 had squamous and 31 non-squamous disease. More than 90% had stage IV disease and a substantial proportion presented with brain or liver metastases, making the enrolled population notably high-risk. Median follow-up was 7.1 months.
The data
Across the 62 efficacy-evaluable patients, overall response rate (ORR) was 71.0%, disease control rate (DCR) was 95.2%, and the six-month progression-free survival (PFS) rate was 70.6%.
The squamous subgroup produced the headline numbers: ORR 87.1%, DCR 96.8%, and a six-month PFS rate of 86.7%. Critically, responses were essentially flat across PD-L1 expression categories, with ORRs of 84.6% in PD-L1-positive patients and 88.2% in PD-L1-negative patients. That PD-L1-agnostic profile is commercially significant: PD-L1 TPS of 1% or above was observed in only 43.8% of squamous patients enrolled, well below the 60-70% typically seen in broader NSCLC populations, suggesting the trial captured a population that current checkpoint inhibitors serve less well.
In PD-L1-positive non-squamous patients, ORR reached 81.8%, DCR was 100%, and the six-month PFS rate was 90.0%. Responses were also reported in patients with low PD-L1 expression (TPS 1-49%).
Safety was characterised as manageable and broadly consistent with existing PD-(L)1 plus chemotherapy combinations, with no new signals identified.
Charles Cai, Chief Medical Officer of Leads Biolabs, said: "With longer follow-up, tumour shrinkage continued to deepen and ORR continued to increase, providing further evidence of the durability of opamtistomig's antitumour activity."
Regulatory path and competitive context
Opamtistomig's NDA was granted priority review designation by China's National Medical Products Administration (NMPA) in July 2026 and accepted in August 2026, positioning it as potentially the first approved 4-1BB-targeting antibody globally. The company also holds FDA Fast Track Designation (granted January 2026) and FDA Orphan Drug Designation for a separate indication. Phase III development in NSCLC is described as ongoing.
The competitive landscape in first-line NSCLC immunotherapy is formidable. Pembrolizumab, atezolizumab, and nivolumab-based regimens are entrenched, and a wave of bispecific and next-generation IO candidates are progressing in parallel. The 4-1BB co-stimulatory agonist approach has attracted significant industry interest, though earlier-generation 4-1BB agonists were limited by hepatotoxicity. Leads Biolabs' thesis is that conditional activation via the bispecific format mitigates that risk by restricting 4-1BB agonism to the tumour microenvironment, a mechanism-of-action argument it will need to defend with longer-term safety data across its broader 14-indication programme.
For squamous NSCLC specifically, the unmet need is real: median PFS with current standard-of-care chemo-immunotherapy regimens is reported at five to eight months, against the 86.7% six-month PFS rate opamtistomig reported here. Investors will watch for a Phase III PFS readout and overall survival data before drawing firm conclusions, and for any NMPA approval timeline following the priority review acceptance.