Phase 1 QUAIL-100 (LGNA-100) attenuated live bacterial γδ T-cell activator post-HSCT

This open-label, first-in-human, single ascending dose study tests QUAIL-100 (also described by Laguna Biotherapeutics as LGNA-100), an attenuated live bacterial immunotherapy intended to harness immune sensing pathways inspired by Listeria to expand and activate endogenous γδ T cells (innate-like T cells that can directly kill malignant cells and shape broader anti-tumor immunity). Pediatric and young adult participants with high-risk acute leukemias or high-risk myelodysplastic syndrome are eligible after a TCR αβ+ T cell/CD19+ B cell–depleted hematopoietic stem cell transplant, a setting where relapse remains a major cause of treatment failure despite intensive conditioning, transplant, and post-transplant monitoring/interventions. The design is single-dose, single-ascending-dose escalation (with doses described in CFU range), focusing on safety/tolerability and early biologic activity consistent with its proposed γδ T-cell–activating mechanism. The scientific angle is a live microbial vector approach positioned as a “precision microbial immunotherapy,” aiming for durable in vivo immune engagement rather than ex vivo cell manufacturing.