The main results of this project are as follows:
- WP1 showed long-term safety and efficacy (up to 10 years) of lentiviral GT for WAS (NCT02333760), with sustained immune correction and clinical benefit. New statistical methods for clonal tracking revealed HSC heterogeneity (Six Blood 2020). Platelet function analyses indicated partial recovery due to reduced WASP expression. Autoimmunity improved, with WASP+ B cells gaining a selective advantage over time (Magnani Nat Med 2022). Overall, lentiviral GT offers sustained treatment, though further improvements in transduction protocols and conditioning regimens could enhance platelet recovery.
- WP2 allowed us to perform all the pre-clinical studies for GT of SCID caused by an Artemis mutation. This included the assessment of efficacy and genotoxicity of this gene therapy strategy, based on the ex vivo transduction of HSPC with G2ARTE lentiviral vector, expressing the DCLRE1C cDNA. The efficacy of this approach was tested in vitro and in vivo. The Phase 1/2 Open Label non-randomized study was authorized in 2022, and the clinical trial started in 2023 (NCT05071222). Five patients were enrolled and treated between 2023 and 2025. We also performed a comprehensive characterization of HSPCs from P1 and observed that transduced HSPCs initiate early T-cell rearrangements in vitro and the T-cell differentiation in vivo, demonstrating success of the ARTEGENE gene GMP transfer protocol. A longer follow-up confirm that HSPCs gene-corrected cells provide a stable engraftment & immune reconstitution with a polyclonal T and B cell repertoire and early antigen-specific response. Altogether, our data demonstrate that the ARTEGENE GT clinical trial is an effective treatment for restoring a functional T- and B-cell compartment in patients with Artemis-deficient SCID phenotypes.
WP3 designed a bidirectional lentiviral vector for efficient FOXP3 and ΔLNGFR co-expression (Patents EP2020052731, EP2019081820), advancing GT for IPEX syndrome. Using scurfy mice, we established a novel assay of Treg functionality (EP2020052162). And we showed that FOXP3-transduced CD4 T cells rescued autoimmune disease on the long-term (Delville Blood 2021), achieving preclinical proof-of-concept and establishing the basis for clinical translation for IPEX.
- WP4 allowed the development of two innovative GT trials for Sickle Cell Disease (SCD)
First, a lentiviral vector expressing anti-sickling HBB transgene was designed. Transduced HSPCs from SCD patients showed up to 60% anti-sickling HBB expression, reducing RBC sickling by 50% under hypoxia. The vector demonstrated robust efficacy in preclinical studies and has been used in the DREPAGLOBE clinical trial (NCT03964792).
Second, we have developed a genome editing CRISPR-Cas9 technology targeted fetal hemoglobin (HbF) silencers to mimic hereditary persistence of fetal hemoglobin (HPFH) mutations, mitigating SCD severity. We showed reactivation of HbF synthesis, reducing sickling phenotypes in SCD patient-derived HSPCs. In vivo studies confirmed high editing efficiency in repopulating HSPCs. (Antoniani Blood 2018 and Weber Sci Adv 2020). These findings identify HbF repressor sites as potential therapeutic targets for genome editing approaches in beta-hemoglobinopathies.
Achievements were shared in top journals and at key conferences (EBMT, ESGCT, ASH), showcasing clinical breakthroughs and helping standardize GT protocols worldwide.
