Abstract Number: PB1106
Meeting: ISTH 2020 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia Gene Therapy
Background: Hemophilia A (HA) is a rare bleeding disorder caused by absence or dysfunction of FVIII protein. New regenerative medicine approaches to treat HA require insights into cell compartments capable of producing FVIII.
Aims: To develop a novel ex vivo cell-based therapy using a medical device (Cell Pouch, Sernova Corp.) leading to an improvement in patient quality of life.
Methods: Blood outgrowth endothelial cells (BOECs) were isolated from healthy and HA patients. HA BOECs were transduced with a lentiviral vector carrying the B-deleted form of FVIII under the control of an endothelial promoter (LV-VEC.FVIII). BOECs were characterized for endothelial phenotype, functionality, number of integrated LV copies/cell, FVIII expression and secretion. LV-VEC.FVIII-BOECs were transplanted in association with cytodex®3-microcarrier-beads in NOD/SCID g-null HA mice (n=6). Afterwards, cells were implanted in a prevascularized, scalable medical device (Cell Pouch), optimized for sustained secretion of therapeutic FVIII. Finally, chromosomal aberration, senescence markers, tumorigenic potential and integration analysis were performed at different procedure timepoints.
Results: BOECs expressed endothelial markers, maintained ECs functionality and, after transduction, the number of integrated LV copies/cell was ~3.
FVIII expression in LV-VEC.FVIII-BOECs was ~80% and was efficiently secreted in the supernatant (24 ng/ml LV-VEC.FVIII-BOECs vs 4.5 ng/ml HA BOECs). LV-VEC.FVIII-BOECs transplanted in HA mice with microcarrier beads, survived and secreted FVIII at therapeutic levels (12%) up to 18 weeks ameliorating the bleeding phenotype of HA mice. Subsequently safety tests were performed after large-scale expansion showing a safe profile and suggesting that BOECs can be expanded without negative consequences. Furthermore, LV-VEC.FVIII-BOECs were transplanted in the Cell Pouch, showing engraftment up to 12 weeks. Finally, genomic integration profile of LV-VEC.FVIII-BOECs showed the classic integration pattern of LVs, without enrichment for oncogenes.
Conclusions: Overall, these results pave the way for future human clinical testing in HA patients by transplantation of GMP produced autologous gene corrected BOECs within implanted device.
To cite this abstract in AMA style:
Olgasi C, Merlin S, Borsotti C, Cucci A, Bergmann T, Bittorf P, Patterson K, Mazzuca DM, Stolzing A, Zierau M, Toleikis PM, Benedicenti F, Calabria A, Montini E, Braspenning J, Follenzi A. Combined Gene and Cell Therapy for the Treatment of Hemophilia A within an Implantable Therapeutic Device [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/combined-gene-and-cell-therapy-for-the-treatment-of-hemophilia-a-within-an-implantable-therapeutic-device/. Accessed March 21, 2024.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/combined-gene-and-cell-therapy-for-the-treatment-of-hemophilia-a-within-an-implantable-therapeutic-device/