Evaluating clinically translatable conditioning for platelet gene therapy in murine hemophilia A with inhibitors.
J Thromb Haemost
; 2024 Aug 08.
Article
em En
| MEDLINE
| ID: mdl-39127324
ABSTRACT
BACKGROUND:
Platelet gene therapy is effective in hemophilia A (HA) mice even with inhibitors. Fludarabine (Flu), along with busulfan (Bu) or melphalan (Mel), preconditioning has been shown to be highly effective for hematopoietic stem cell transplantation in the clinic.OBJECTIVES:
To evaluate the efficacy of Bu-Flu and Mel-Flu preconditioning in platelet gene therapy of HA with inhibitors.METHODS:
Bu-Flu and Mel-Flu were used to condition HA mice preimmunized with recombinant human factor (F)VIII. An optimal 660 centigray total body irradiation was used as a control regimen in parallel. Platelet-FVIII expression was introduced by transplantation of 2bF8 lentivirus (LV)-transduced hematopoietic stem cells. Animals were analyzed by fluorescence-activated cell sorting, quantitative polymerase chain reaction, FVIII assays, and tail bleeding tests.RESULTS:
Bu-Flu, but not Mel-Flu, enabled successful 2bF8 gene therapy. All recipients achieved >55% chimerism post hematopoietic stem cell transplantation in both Bu-Flu and 660 centigray groups, with comparable copy numbers of 2bF8 cassette and the platelet-FVIII levels. The bleeding phenotype was rescued in 2bF8LV-transduced recipients. FVIII inhibitor titers declined with time, with comparable disappearance time of inhibitors between the 2 groups. When animals were rechallenged with recombinant human FVIII after the titers dropped to undetectable levels, no inhibitors were detected in 2bF8LV-transduced recipients. In contrast, all untransduced transplanted control mice produced inhibitors. These data demonstrate that immune tolerance was established in 2bF8LV-transduced primed HA mice under Bu-Flu conditioning.CONCLUSION:
Bu-Flu preconditioning allows for successfully introducing platelet-FVIII expression to restore hemostasis and induce immune tolerance in primed HA mice, suggesting that this approach is a promising clinically translatable strategy for gene therapy of HA with inhibitors.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Thromb Haemost
Assunto da revista:
HEMATOLOGIA
Ano de publicação:
2024
Tipo de documento:
Article
País de publicação:
Reino Unido