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Leads Biolabs' PD-L1/4-1BB opamtistomig posts 77.4% ORR in 1st-line sqNSCLC

Edited by Robert McTiernan··3 min read
Leads Biolabs' PD-L1/4-1BB opamtistomig posts 77.4% ORR in 1st-line sqNSCLC

Phase II data for opamtistomig, Nanjing Leads Biolabs' (HKEX: 9887) PD-L1/4-1BB bispecific antibody, in first-line non-small cell lung cancer (NSCLC) have been published on the World Conference on Lung Cancer (WCLC) website ahead of an oral presentation scheduled for September 14, 2026, according to a voluntary announcement filed with the Hong Kong Stock Exchange. The abstract data, cut off at March 6, 2026, represent only 3.6 months of median follow-up; updated results with more than seven months of follow-up will be presented at the conference.

Among 60 efficacy-evaluable patients with locally advanced or metastatic NSCLC receiving opamtistomig in combination with chemotherapy as first-line treatment, the objective response rate (ORR) was 65.0% and the disease control rate (DCR) was 95.0%. The squamous subgroup reported an ORR of 77.4% and DCR of 96.8%, while the non-squamous subgroup reported ORR of 51.7% and DCR of 93.1%. The safety profile was described as manageable with no new safety signals. Leads Biolabs said that with longer follow-up, responses have continued to deepen and the trend toward progression-free survival (PFS) benefit has strengthened, though no PFS figures were disclosed in the abstract.

Opamtistomig (LBL-024) simultaneously blocks PD-L1-mediated immunosuppression and conditionally agonizes the 4-1BB (CD137) co-stimulatory receptor in the tumor microenvironment, an approach designed to both release immune braking and actively amplify T-cell responses. Prior 4-1BB agonists such as urelumab caused severe hepatotoxicity at efficacious doses; Leads Biolabs reports that opamtistomig's conditional activation design, enabled by its proprietary X-Body platform, has maintained liver enzyme profiles comparable to PD-1/PD-L1 monoclonal antibodies across nearly 800 treated patients.

The NSCLC data add to an accumulating body of evidence across indications. At the 2025 ASCO Annual Meeting, Phase Ib/II data in extrapulmonary neuroendocrine carcinoma (EP-NEC) showed a 75.0% ORR with combination chemotherapy. A biologics license application (BLA) for opamtistomig as monotherapy in late-line EP-NEC was accepted for priority review by China's National Medical Products Administration (NMPA) in July 2026, shortening the review timeline to 130 working days. The NSCLC program remains at Phase II with no regulatory filing in any jurisdiction for that indication.

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The squamous NSCLC signal carries particular weight. Approved PD-1/PD-L1 plus chemotherapy regimens — including Merck's Keytruda (pembrolizumab) plus carboplatin and paclitaxel or nab-paclitaxel — achieve ORRs typically in the range of 55–60% in squamous first-line populations in registrational trials, with median PFS of 5 to 8 months according to Leads Biolabs' own disclosure. The 77.4% squamous ORR from opamtistomig's Phase II data exceeds that range, though cross-trial comparisons from a non-randomized, 3.6-month follow-up dataset cannot support efficacy claims. No approved therapy combines PD-L1 blockade with 4-1BB co-stimulation.

The WCLC oral presentation will include updated ORR, a six-month PFS rate, and subgroup analyses by PD-L1 expression level in both histological subtypes — data that will be needed to assess whether the early response signal holds with extended follow-up and a larger evaluable population. Leads Biolabs has also disclosed that six studies, including EP-NEC and biliary tract cancer data, have been selected for presentation at the 2026 European Society for Medical Oncology (ESMO) Annual Meeting in October, with a late-breaking abstract submission planned for September.

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