Leads Biolabs LBL-034 posts 21.8-month PFS in RRMM at ESMO 2026
Leads Biolabs has presented updated first-in-human data for LBL-034, its GPRC5D/CD3 bispecific T-cell engager, at the 2026 ESMO Annual Meeting in an oral session. In patients with relapsed/refractory multiple myeloma (RRMM) treated at the effective dose range of 400–1,200 μg/kg, median progression-free survival reached 21.8 months across 41 evaluable patients, with a median follow-up of 17.8 months. The PFS data remained immature at the July 2026 cutoff, and median duration of response had not yet been reached.
The 56-patient cohort was heavily pretreated, with a median of 4.5 prior lines of therapy. More than half the patients were penta-drug exposed, and 60.7% were triple-class refractory. Notably, 16.1% had previously received BCMA-directed CAR-T therapy, a group historically difficult to treat with subsequent lines.
Efficacy across high-risk subgroups
LBL-034 showed strong response rates in several subgroups with substantial unmet need. Patients who had failed prior BCMA-targeted therapy achieved an overall response rate of 85.7%, with a stringent complete response rate of 57.1%. In the extramedullary disease subgroup, ORR was 75.0% overall and reached 100% in the 1,200 μg/kg cohort. Penta-drug-exposed patients recorded an ORR of 73.9%. The 18-month PFS rate across the effective dose range was 54.8%, and the 18-month duration-of-response rate was 68.4%.
The company also reported a dose-dependent trend toward faster complete responses: median time to CR or better fell from 5.60 months at the 400 μg/kg dose to 3.06 months at 1,200 μg/kg, which Leads Biolabs says supports its recommended Phase 2 dose selection.
On safety, no dose-limiting toxicities were observed up to the maximum dose tested, and the maximum tolerated dose was not reached. Cytokine release syndrome events were predominantly low-grade, with only one Grade 3 or higher event reported. Two cases of immune effector cell-associated neurotoxicity syndrome were recorded, both resolving fully. Median treatment exposure was 11.3 months.
Charles Cai, Chief Medical Officer of Leads Biolabs, said the findings "underscore the potential of LBL-034 to become a differentiated treatment option for patients with substantial unmet medical needs," adding that the safety profile was consistent and concentrated in the early treatment period.
Market context and competitive landscape
GPRC5D has emerged as one of the most closely watched targets in multiple myeloma following the success of Johnson and Johnson's talquetamab (Talvey), which received FDA approval in 2023. Several biotechs and larger pharmaceutical groups are now running GPRC5D-directed programmes, making clinical differentiation on PFS and tolerability the key battleground. A median PFS of 21.8 months in a population this heavily pretreated would, if confirmed in a larger registrational dataset, represent a competitive data point, though cross-trial comparisons are complicated by patient selection and dosing differences.
Leads Biolabs has already secured FDA Orphan Drug Designation and Fast Track Designation for LBL-034, and the company says Phase III preparation is under way. The bispecific antibody also sits within a broader platform ambition: the LeadsBody TCE technology is being explored for autoimmune indications and solid tumours, a diversification strategy increasingly common among Chinese biotechs seeking global regulatory and commercial reach. Whether the ESMO data is sufficient to attract a Western licensing partner will be a near-term question for the company's business development team.