Article
作者: Liberzon, Ella ; Morgan, Richard A ; Bainter, Wayne ; Couto, Ryan ; Keegan, Sean ; Yadav, Charuta ; Liu, Hanlan ; Mullen, Timothy J ; Thakur, Sakshisingh ; Shenker, Sol ; Ohsumi, Toshiro K ; Kshirsagar, Rashmi ; Patterson, Troy ; Dastagir, Shamael ; Lundberg, Amy ; Bullock, Caroline ; Li, Lily ; Arlauckas, Sean P ; Chilakala, Shalini ; Singh, Swati ; Lazzarotto, Cicera R ; Chen, Huei-Mei ; Scull, Chris ; Hohmann, Anja F ; Lazorchak, Adam ; Malloy, Connor R
Hemophilia B gene therapy treatments have not addressed the need for predictable, durable, active, and redosable factor IX (FIX). Unlike conventional gene therapy, engineered B cell medicines (BCMs) are durable, redosable, and titratable and thus have the potential to address significant unmet needs in the hemophilia B treatment paradigm. BE-101 is an autologous BCM comprising expanded and differentiated B lymphocyte lineage cells genetically engineered ex vivo to secrete factor IX (FIX)-Padua. CRISPR-Cas9-mediated gene editing at the C-C chemokine receptor type 5 (CCR5) locus was used to facilitate transgene insertion of an adeno-associated virus 6-encoded DNA template via homology-directed repair. Transgene insertion did not alter B cell biology, viability, or differentiation into plasma cells. Appreciable levels of BE-101-derived FIX-Padua were detected within 1 day after IV administration in mice, and steady state was reached within 2 weeks and persisted for over 184 days. Redosing produced an increase in FIX-Padua production close to linear dose proportionality. Comprehensive genotoxicity analysis found no off-target issues of concern. No safety signals were observed in animal tolerability and Good Laboratory Practice toxicology studies. In conclusion, BE-101 produces sustained levels of active FIX-Padua with the ability to engraft without host preconditioning and with the potential for redosing and titratability.