Legend Biotech reports 100% ORR for in vivo CAR-T LB2501 in B-NHL
Legend Biotech has presented early clinical proof-of-concept for LB2501, its investigational in vivo CD19/CD20 dual-targeting CAR-T therapy, showing a 100% objective response rate and an 83.3% complete response rate at the higher of two dose levels tested in patients with relapsed or refractory B-cell non-Hodgkin lymphoma. The data were presented in a late-breaking session at the European Hematology Association Congress on 15 June 2026.
The Phase 1 open-label dose-escalation study enrolled 12 patients across two dose levels. All had received a median of three prior lines of therapy; 58.3% were refractory to their most recent treatment. At dose level 2, six of six patients responded, five achieving a complete response, with all responses still ongoing at the data cutoff. Across both dose levels, the overall response rate was 50.0% and the complete response rate was 41.7%, reflecting the expected dose-response gradient at this early stage.
Safety and pharmacokinetics
The safety profile from these 12 patients is notable in a field where ex vivo CAR-T toxicity has historically been a commercial and logistical hurdle. No dose-limiting toxicities, serious adverse events, immune effector cell-associated neurotoxicity syndrome, or deaths were reported. Cytokine release syndrome occurred in 66.7% of patients but was confined to Grade 1 or 2 severity, with a median onset of 11 days and a median duration of 4.5 days. No patient required glucocorticoids for CRS management, though four received tocilizumab. Infusion-related reactions, observed in 75.0% of patients, resolved within a median of 18.6 hours.
Pharmacokinetic data showed dose-dependent in vivo CAR-T expansion in all six patients at dose level 2, with CAR-T cells detectable in peripheral blood for up to 116 days. Viral vector copy number in blood peaked immediately after infusion and became undetectable within 24 hours. Translational analyses found no evidence of non-specific transduction in NK cells or other off-target lymphocyte populations, and vector integrations were described as highly polyclonal, which the company presents as a safety-relevant finding.
Lei Fan, Professor and Administrative Director of the Hematology Department at Jiangsu Province Hospital, who has advisory ties to Legend Biotech, said: "The absence of lymphodepletion, together with a favourable safety profile, supports further investigation of LB2501 as a novel in vivo CAR-T approach."
Market context and competitive positioning
The significance of LB2501 lies primarily in its delivery mechanism. Approved CAR-T therapies, including Legend Biotech's own CARVYKTI for multiple myeloma, require complex and costly ex vivo manufacturing: patient T cells are extracted, engineered outside the body, and reinfused, a process that can take several weeks and remains capacity-constrained. In vivo CAR-T aims to bypass that step entirely by delivering the viral vector directly to the patient and engineering T cells within the body. If the approach can be confirmed in larger cohorts, it could substantially reduce the manufacturing bottleneck that currently limits patient access to CAR-T therapies globally.
Several companies and academic groups are exploring in vivo CAR-T platforms, including programmes targeting haematological and solid tumour indications, making this a competitive frontier. However, at this stage most in vivo programmes remain at preclinical or very early clinical stages. Legend Biotech's ability to report clinical responses at all, with a manageable safety profile and without lymphodepletion, is an incremental but meaningful step.
The company has not yet identified a recommended Phase 2 dose, and the cohort of 12 patients is too small to draw conclusions about response durability. Investors will be looking for updated response data, including time-to-progression curves, as the dose-escalation study continues. A pivotal design and any partnering discussions around LB2501 are, as yet, unannounced.