NovaBridge presents mature givastomig Phase 1b data at ESMO 2026

NovaBridge Biosciences has presented updated Phase 1b results for givastomig, its CLDN18.2 x 4-1BB bispecific antibody, at the European Society for Medical Oncology Congress 2026 in Madrid. The data, drawn from 71 patients across two dose cohorts, provide close to 18 months of median follow-up at the 8 mg/kg dose the company has selected for registrational development in HER2-negative first-line metastatic gastroesophageal adenocarcinoma.

Among the 29 efficacy-evaluable patients treated at the 8 mg/kg dose, the reported objective response rate was 79%, with a disease control rate of 97%. Median duration of response reached 15.2 months and median progression-free survival came in at 16.9 months. Efficacy was also observed across a wide range of CLDN18.2 expression levels: an 82% response rate in patients with expression at or above 75%, and 75% in those with expression between 1% and 74%. The latter finding is notable because currently approved CLDN18.2-targeted agents, such as zolbetuximab, require high expression levels for eligibility, and broader activity could meaningfully expand the addressable patient population.

Dose selection and safety profile

NovaBridge said the safety data at the selected dose remained manageable and broadly consistent with earlier readouts. No Grade 4 or Grade 5 treatment-related adverse events were attributed to givastomig. Immune-related adverse events were uncommon, with the exception of gastritis, most of which were Grade 2. The company has concluded that 8 mg/kg offers the most appropriate benefit-risk profile ahead of a potential registrational trial.

Samuel J. Klempner, Associate Professor of Medicine at Massachusetts General Hospital and lead Phase 1b investigator, said: "What stands out in the updated analysis is not only the durability of benefit with longer follow-up, but also the strength and consistency of efficacy results across a broad range of CLDN18.2 expression, including very low expression."

Regulatory path and competitive context

NovaBridge holds both FDA Fast Track Designation and Orphan Drug Designation for givastomig, and says it has reached alignment with the FDA on key elements of a Phase 3 protocol, including patient population, dose, and primary endpoints. The company intends to discuss this further at an investor webcast on 2 November 2026, where Klempner will present alongside company management.

Gastroesophageal adenocarcinoma is an intensely competitive oncology segment. The approval of zolbetuximab (Astellas/Genmab) in CLDN18.2-positive, HER2-negative gastric cancer established proof of concept for the target, but its restriction to high-expression tumours leaves a substantial population underserved. Givastomig's conditional T-cell engaging mechanism, which activates 4-1BB signalling specifically in the tumour microenvironment, is positioned by NovaBridge as a differentiated approach that may overcome that expression threshold constraint. A number of other bispecific programmes are pursuing similar tumour microenvironment activation strategies, and the Phase 3 readout will be critical to determining whether givastomig's Phase 1b signal translates at scale.

The breadth of CLDN18.2 expression activity reported here, if confirmed in a randomised setting, could prove a meaningful differentiator. Investors and clinicians will be watching for Phase 3 trial design specifics, including whether the study will be stratified by expression level, and for clarity on the comparator arm given the rapidly evolving standard of care in this indication.